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Tesla Energy

teslamotors.com

1,162 pointstga_d566 comments

What I'd love to see is a ROI calculator that:

* uses my zip code to figure out what my non-peak costs might be.

* allows me to optionally calculate solar energy capture (so I can see what impact having solar would be, given the average sunny days in my area)

* takes into account the wear and tear average cold weather would have on the lifetime of the batter and the payback period.

For example, I live in Michigan, and I don't know what my off peak cost is off the top of my head. I also have no idea how much sunshine I get, or how 10 degree lows for two months would impact the battery's ability to keep a charge.

Anybody know if something like this exists?

I would guess for most people it would show an ROI number that is not conducive to sales.

Also, what is the environmental impact of the manufacture of LI batteries at this scale? Lithium mining, processing, assembly, delivery... we can't just ignore that.

The environmental impact shouldn't be significantly more than any other hunk of metal of the same mass. And that has to be weighed against the fact that cost-efficient battery technology can make solar/wind viable and cost-effective relative to fossil fuel plants.

There's about $10,000 worth of work in a battery. It's not just a hunk of metal, it goes through a very complicated and energy intensive creation process.

The cost of the raw lithium is about 1% of the cost of the battery. It's engineering it in a very precise way that's expensive.

The battery costs $3000 - that is likely a cap on the cost of the work involved in producing it.

You'd think, but that depends on how many times you can sell the same battery. As others have said, it's plausible that this is a way for Tesla to make use of used car batteries.

I really doubt that's true, just because it's too early for it. There are approximately zero used Tesla batteries available right now. The fleet is just too new. Maybe in another ten years.

When the used batteries start piling up, it's best for tesla if this system is already in place. Entirely possible that this will be new and subsidized batteries initially. They will need to find a use for the old car batteries.

Could be, but they're jumping the gun a lot if that's the main idea. Tesla sales didn't really ramp up until 2014, and the batteries will probably last at least 10 years in the cars themselves.

In any case, they wouldn't need to subsidize these batteries. $350/kWh is a pretty decent price, and consistent with estimates of what they cost in Tesla's cars.

The large packs are priced at $250/kWh which I think is the real news. That means their cost is very likely under $200. Don't think the other car manuf are close to that.

Is the precision itself so energy-intensive, though?

Just as a thought experiment, compare the environmental impact of producing a hunk of steel, nickel, lead, gold, plutonium of the same mass. These are vastly different.

I agree.

Strangely, all of these issues were conveniently left out of the article.

Not sure everybody knows this, but its not economically feasible to recycle these batteries:

"Recycled lithium is as much as five times the cost of lithium produced from the least costly brine based process. It is not competitive for recycling companies to extract lithium from slag, or competitive for the OEMs to buy at higher price points from recycling companies. "

Add in the fact there are currently very few dedicated LI recycling companies in the world, let alone in the US:

"With lithium recycling in its infancy, there is currently no main recycling infrastructure in the world that treats only automotive Li-ion batteries. A few pilot plants, such as Umicore's Hoboken plant in Belgium that are at a demonstration stage exist. Lack of standardisation in battery chemistries and changing landscape with respect to different elements under research for battery production other than lithium have made evaluation of the recycled value of the components uncertain for the recyclers."

source: http://www.waste-management-world.com/articles/print/volume-...

Call me skeptical, but I'm not sure Tesla has really given consideration to these issues. Their approach to these obvious issues are not addressed at all in their press release.

So I recently needed a special cable to make some old gear work. It was only available from a single source and they charged me an arm and a half for it.

Why am I telling you all of this? Because the price of something has very, very, very, very, very little to do with how feasible something is, how much work is required on a fundamental level.

So what? Recycling lithium isn't profitable right now this very instant? Because the price is too high? Apart from the circular logic here, this means nothing.

(This kind of thinking is disappointingly common here. We will never get anywhere when we do some adhoc "price" analysis on every new technology and obviously deduce it's infeasible and should not be explored. Cars were economically infeasible back when you bought petrol from the pharmacy.)

Yes. Thank you. I wish I could upvote your comment more than once.

Musk has addressed this a few times. If I recall correctly Cobalt production will be more of a constraint than lithium... for example, from the Q1 2014 earnings call:

the lithium, although lithium is sometimes thought of as a bigger thing than it really is for lithium ion cell.

It’s like using maybe a couple percent of the cell mass, but the biggest cost constituent is nickel

There's a great analysis of material constraints here [1].

1. http://seekingalpha.com/article/654441-ev-myths-and-realitie...

This is the recycling system. Ex-car batteries into house batteries.

I posted the same link in this thread already, in another context, but it's relevant enough: http://www.teslamotors.com/blog/mythbusters-part-3-recycling... "The result from this process is that we are able to recycle about 60% of the ESS materials and reuse a further 10% (by weight). We currently plan to landfill only the benign fluff, which comprises about 25% of the ESS, but we expect to nearly eliminate this in the future when our volumes get higher and we can justify the effort required to separate and reuse the plastic."

Lithium mining has relatively little environmental impact: it's mostly evaporation of lithium-rich brines.

But lithium is still not cheap. I suppose that a different battery technology, with lower energy density per unit of weight, could be much cheaper with comparable efficiency. But Tesla only has expertise in lithium batteries, so some other manufacturer could use the momentum with a lower-cost offer.

> But lithium is still not cheap.

Lithium is extremely cheap. The cost of the Lithium has practically no impact on the cost of the batteries. Most of the cost of batteries is work.

This venture makes sense because as lithium batteries are used, they lose capacity, and thus their specific energy gets worse. At this point, they are no longer very useful for cars, yet still can be used for other things. As Tesla recovers the used batteries from their cars, they can resell them as home batteries.

Recycling this way batteries that are not good for cars but fine for less demanding applications would be really smart. Is there any indication that they actually do this?

I think they've been doing it in one-off situations with Solar City now for a while. If they are not doing exactly this with this venture, I'd be surprised.

Seems they alluded to exactly that some years ago (2008!): http://www.teslamotors.com/blog/mythbusters-part-3-recycling... "... at some unfortunate point, the ESS will come to the end of its useful life in the application :(. However, it might be possible to use the ESS in other applications. For example, the ESS could be used as a power source for off-grid backup or load leveling. "

do you have a cost breakdown for a Li ion battery?

Would you not install the battery in a heated place in your house (garage, basement, furnace room)?

What if it's in the garage and someone hits it with the car and pierces the cells?

I didn't see "insurance" anywhere on that Tesla page. Ideally my insurance company won't pitch a fit about about me installing this in my house, but will Tesla guarantee that?

Does your insurance company allow you to keep one liter of gasoline in your garage? It has the same energy content as the Powerwall, is insanely flammable, is frequently implicated is home fires, and regularly causes human deaths.

(Ok, a burning lithium battery will release more energy than its storage capacity, but I'm not finding a nice reference, Tesla knows all about containing cells to prevent chain reactions, and one liter of gasoline is still enough to burn down your whole house.)

Gas fumes are very flammable, but the gasoline itself will flow down and out of my garage, and the fire would be very easy to contain with a simple garden hose.

A gas can also will not light on fire just because it gets hit with a car. It would take malicious use of a gas can -- splashing it on a wall and then lighting it on fire -- to match the default configuration of a Powerwall.

Or a vapor reaching an open flame. Common source of human immolation.

You ever try to put out a gasoline fire with a garden hose?

While you are correct, you can at least snuff out a gasoline fire.

Lithium fires do not require oxygen, so your typical Class ABC fire extinguishers won't actually work on it. You need a class D (dry powder) extinguisher, which is very rare and expensive.

> Lithium fires do not require oxygen

I thought fire is by definition a combustion reaction, meaning some kind of material reacting with oxygen. What's fire, then? (I feel like a little kid, having to ask that...)

Generally, a fast exothermic reaction. Oxygen may be the most popular oxidant, but not the only one. Lots of stuff burns in pure chlorine gas, for instance.

Some substances bundle together their oxygen source (think of rocket fuel, or napalm), so they don't need to consume it from air.

It's possible for something to burn hot enough to split water molecules apart. I don't know if lithium metal qualifies, but that could be what the MSDS is referring to.

While true for lithium fires, a venting lithium-ion battery is not a typical lithium fire.

According to the MSDS for lithium ion batteries, fires involving them can be extinguished with a typical ABC fire extinguisher.

Lithium batteries (not the rechargeable kind) are the ones that need a class D extinguisher.

Edit:

> CO extinguishers, halon or copious quantities of water or water-based foam can be used to cool down burning Li- ion cells and batteries. Do not use for this purpose sand, dry powder or soda ash, graphite powder or fire blankets.

> Extinguishing media Use water or CO2 on burning Li-ion cells or batteries

http://www.uscg.mil/hq/cg4/cg432/docs/msds/MSDS_LiIon.pdf

Using water on an electric fire sounds like a dumb idea to me. But yeah, the MSDS does seem to say that...

A venting lithium ion battery isn't usually an electrical fire.

And what of all the molten wires that _were_ charging said battery?

Overcharging a battery isn't the only way to cause it to vent :)

Obviously there should be a physically separate circuit for cutting off power in the event of catastrophe. That's pretty much rule-of-thumb for large li-ion battery banks.

I don't think you use the same gasoline as the rest of the planet if that's your experience.

It's common advice not to leave rags that have gasoline on them sitting in your garage because in enough heat the fumes from the evaporating gasoline will combust. Gasoline is very volatile, we've just gotten fairly good at managing it.

edit: my karma https://news.ycombinator.com/reply?id=9471929&goto=threads%3...

edit: my karma http://i.imgur.com/rjNrXTc.gifv

Moderation is pretty weird in this thread. I got voted down for pointing out that the US power grid is likely to experience problems when entire residential neighborhoods full of Tesla owners try to charge their Model S at once.

I don't think many people around here understand (a) just how efficient gasoline really is at storing energy, and (b) just how much energy is used by a typical passenger car.

Talk to your insurance people. Usually when you have expensive items, you can get a specific rider for it.

For example, a friend had a rack with about $80k of servers in his basement a few years ago. I believe he paid an additional $400 for coverage.

I have the opposite problem: Living in Texas, my garage easily gets above 110F many days during the summer (it would be crazy to pay for A/C in it). But, I'm also not going to put the battery pack(s) "inside" my house (e.g. utility/laundry room).

But, I'm also not going to put the battery pack(s) "inside" my house (e.g. utility/laundry room).

Why not? The whole point to making it wall-mounted is that it won't take up any substantial amount of space. A utility/laundry room seems like exactly the logical place that you would want to put it.

Fire hazard

I doubt many homes would have adequate fire separation between a garage and main home to make a difference between laundry vs garage.

It may not make much of a difference from the overall perspective of damage, but it certainly makes a difference in warning and escape time. Also, the chance of dangerous fumes while trying to escape is lower.

Depends on design. Garage could share a wall with a bedroom and the laundry could be on other side of the house or vice versa. I would say that garage may be the most obvious choice, but not always.

The big technological thing Tesla batteries have going for them is, short of complete mechanical destruction, they don't catch fire. There's a thermal shutoff on every cell. So not the big issue it might have been.

My electrical panel is in the garage. Knowing my existing plans to add solar panels, a generator and transfer switch that's the only place battery pack(s) could go. Except it will be above the max temperature for a good period of time, and even below the minimum other times.

Sure, there could be some trade off where it makes sense to add heat and A/C to my garage (and appropriate insulation) based on the economics. But, that's even more I need to spend.

I live in Iowa. It gets to -20F some days in winter. This thing stops working at -4F. So inside is My only option.

The wear and tear on lithium-ion batteries can be significant. It's a big capital cost and every time you cycle it you take a little of its life away. Eventually you have to replace it.

And you really need to be using it, because a lithium-ion will still degrade even if its sitting unused on a shelf in a perfect climate-controlled room.

Demand shifting seems a much bigger payoff: using your AC to superchill parts of your building overnight (or build up ice packs) when electricity is cheap.

What I'd like to see is an ability for me to provide a list of appliances that I tend to use in my house (makes/models) along with a "typical" use pattern like "washer, dryer, dishwasher, fridge, freezer, stove, 50" TV, 200W sound system and blu-ray player or cable box frequently get used at the same time" With a usage pattern like that, which of the two batteries would be most useful? would I need multiples wired in series or parallel? is that possible? how long would it last under a load like that? My target is for off-grid use, so ROI isn't as big a concern to me as longevity of power and charging requirements from off-grid power generation.

There are easy to use meters such as the Kill-A-Watt for 120V appliances to measure usage directly.

This is good for monitoring single appliances, but it's a pain in the neck to keep moving it from appliance to appliance. Do you know of one that I can attach to my power meter and it'll give me realtime usage, tracking, reports so that I can see my peak, minimum and average draw for the whole house?

There's a product called the Efergy True Power meter that does exactly that. It measures mains electricity, wirelessly reports to a central server and shows you real time and historical graphs of energy usage at sub-minute resolution. http://efergy.com/us/elite-true-power-meter

I also live in Michigan, and can tell you it will be a money loser for one major reason: the full cost of the system you install will be added to your local property tax valuation, as the state tax exemption on renewable energy equipment was nullified several years ago and never replaced. In my case I had $500 in taxes added to my annual bill, which outpaces the value of the energy I produce and creates an infinite payback period.

Wait until this tax issue is resolved, then it will actually make good sense here. (It's sunnier than most people think!)

> the full cost of the system you install will be added to your local property tax valuation

Why is that? And are you absolutely certain it's true?

I also live in Michigan, and I've never heard of this. I've replaced major appliances before without it impacting my property tax assessment -- including appliances that have cost more than the Tesla Battery pack and been inspected+verified by the city (such as a new 96% efficient furnace).

I don't see why adding a Tesla Battery would change property tax assessment any, when adding a $6,000 furnace, $5,000 air conditioner, or a $2,000 refrigerator doesn't.

Yes, I am unfortunately. I am in the midst of protesting an assessment now for a system I installed last year. See this pdf (sorry), page 17: http://www.michigan.gov/documents/mpsc/marketbarrierssolarin...

Solar systems are considered "real" property, i.e. property that is permanently attached to the house, and thus subject to taxation.

A property would be assessed at a lower value if it didn't have any HVAC appliances installed in it. Since most properties start with such appliances, replacing them or upgrading them to similar, or even more efficient models, is likely considered a nominal effect on property value, i.e. an act of sustaining the properties existing value. A real battery backup system, assuming one didn't already exist on the property, would be considered a significant addition to property value.

This is also standard with other parts of a house. For example if you upgrade your kitchen to high-end finishings (granite countertops, etc.) that it didn't have before, that increases the value of the house. Not necessarily by the amount of the purchase/installation price, though.

You don't need to obtain a permit to upgrade your countertops.

I believe the only time that an upgrade could possibly increase the taxable value of your house is if the township/county knows about it (I.e., you got a permit to install it).

I also live in Michigan, but haven't researched renewable energy sources vs taxable value. I'm surprised to hear the gp say they had an increase.

It varies by state, but in Texas at least, major (>$5,000) improvements to a property are supposed to be reported. You could just not report it, but that's technically illegal. Also, one thing that makes reporting compliance relatively high is that there's a separate registration requirement (for different reasons) on the construction contractor's side: contractors undertaking home-improvement projects of >$5,000 are required to use a specific type of escrow account to hold the money temporarily, in order to resolve any disputes that might arise. There are contractors who will take your payment in cash and not register an escrow account, but reputable contractors won't risk that. And if you go that route, you aren't protected against what the escrow account is designed to protect against, that the contractor does shoddy (or no) work and just walks away with your cash. So people tend to do that only if they're having the work done by friends/family.

It's really tricky. Replace the counter top--fine. Move the sink a few inches you're suppose to get a permit. A new electrical outlet--a permit. Solar system--permit. I can only think of a few things that don't require a permit--a fence maybe?

Always claim you just replaced the switch. Just replaced the plumbing. Even then they can make your life miserable if they want. (I can go into most people homes and find multiple code violations--some homes just a few years old.)

These towns are trying to make money. In my town, if you take a few pictures and sell them on eBay, or elsewhere the town wants a fee from you--guess what, you're a Professional Photographer.

My point is these counties/towns are drunk with power, and preventing homeowners from upgrading their homes. They are looking for every dime they can extract from you. A simple electrical switch in you house will require an Inspector in you home at least two times.

If you feel an inspector is picking on you; pull your video camera out and tape every move they make.(Keep the evidence if needed in a lawsuit.)

A building inspector can walk into your home without a warrant at any time. That needs to change, along with enacting all these petty laws most people don't even know they are breaking. Stop passing their bonds, bonds, bonds, bonds, until they stop harassing us.

(It's up to an inspector if they feel the improvements added to the value of your home in the counties I have worked in. Try arguing with some guy who just just looks up codes, and given way too much authority.)

Pretty short-sighted. You know its all about keeping con men from cheating you by installing substandard or dangerous plumbing/electric etc? Those inspectors are not just out to make your life miserable. They're trying to keep your house, and the neighbors house, from burning down.

Does that mean when you sell your house, you will recoup the cost of the system?

If that's the case, the system itself wouldn't be a non-refundable investment, and calculating ROI on it would be as silly as calculating ROI on your house.

Good point. It's unclear to me though. In some places (Hawaii, California, Germany) where there's huge acceptance of renewables and much shorter payback periods I believe a PV system would add value to a sale. Here in Michigan it's much less clear - plenty of my neighbors think it's ugly and an eyesore, or are somehow opposed to the whole concept. So I am pretty sure in the end it's a net zero here (no pun intended!)

I wish it did; we are very far from harmonizing all the different utility rates. Once that data is clean up and available, an interactive website should not be too difficult to build. If anyone is interested in doing a paid internship to help us build it, send me a note with a portfolio at dfong@lightsail.com -- I run a compressed air energy storage company.

Was going to ask if you are ever planning on doing a home system, as although compressed air tanks can be risky, presumably they are slightly less risky than normal gas supplies.

Compressed air tanks are tested very rigorously; including the gunfire test, bonfire test, impact test, sulfuric acid test, over test, over pressurization test...

It is definitely safer than gas supplies, which strike me as an insane idea, especially in San Francisco where it previous burned down the city.

We will eventually do a home system. It is in the planning stages

Thanks for the reply. I have been keeping a close eye on Lightsail and am hugely looking forward to the day when I can install one of your systems. My power bill this winter has been atrocious.

Funny that something called Tesla Energy brings back direct current to the home. I wonder how many people will catch that.

Or Tesla laughing from beyond the grave at the fact that a company named after him is getting the credit for bringing DC to the home?

That's the joke.

Less funny when you consider that the Tesla press release submitted here for discussion says, "The Powerwall consists of Tesla’s lithium-ion battery pack, liquid thermal control system and software that receives dispatch commands from a solar inverter." The inverter, of course, converts battery DC current to household AC current so that people can continue to enjoy AC power in their homes.

http://electronics.howstuffworks.com/gadgets/automotive/dc-a...

That raises a question: if one were to build a new house with solar and battery integration present from the start, would it make sense to run DC appliances?

Well obviously. Everything runs off AC, no one would buy this battery pack if it didn't have an inverter.

That didn't look at all obvious when I replied above, because I was replying to a comment that said, in so many words, "Funny that something called Tesla Energy brings back direct current to the home." No, Tesla Energy is not bringing back direct current to the home. It is providing battery backup for continuing provision of alternating current to the home, which is strictly necessary in a world of appliances that run on AC current. I took the trouble to read the fine article before replying the first time, after first reading the previously posted comments.

(My late dad was an industrial engineer for a company that manufactured electric generators, so this issue immediately jumped into my mind when I saw the comment I replied to. The difference between AC power and DC power was dinner-table conversation in my home when I was growing up.) Does anyone think that my comment above was in any way harmful to the community or to the discussion here?

I wonder if technology becomes prevalent if we will see appliances change to run on DC.

At the very least it might make some sense to have a 5V and a 12V rail to charge stuff. USB(C) and car lighter socket.

I would take a wall plug standard for low current DC. If I have a giant battery pack in my garage full of DC, why do I need to convert it back to AC to run 15 feet into my house where it then gets turned back into DC to charge my phone & laptop?

I had a boat with both AC & DC sockets, but we had the normal socket for both and the label plates showed you which was which. I don't think that solution is acceptable for the wider marketplace, the plugs should probably be physically distinct. Maybe USB-C is the solution, though I don't know how long the cables can be.

From an efficiency standpoint, the only thing that matters is how you handle the high drain equipment. It doesn't make sense to worry about inefficiencies in your 5V phone charger because its power draw is trivial anyways.

oh but think how much nicer the cable looks without the bulky box of the transformer.

I definitely got a chuckle out of it.

I'd consider it less of a joke and more of a tribute! They carried on his dream and his name.

Perhaps even better; the one of the most prominent inventors of the Lithium Ion batteries is a man named Goodenough.

Nice, that came in lower than I was expecting. I was thinking $5K for the 7kWh unit. Of course that is the "installers" price so who knows what those folks will consider the 'retail' price. My wife still has her solar installer certification so we could presumably get one that way.

It also makes for a really interesting opportunity for grid tied solar inverters. Now you want the inverter to power the house first, then push power to the batteries and only if they are full push it back to the grid. Software update for sure :-) of course it might make more sense to leave it DC for the push into the battery and only have the AC conversion happen post battery, so charge controller between the battery and the DC disconnect.

On a safety note I'd also really like to mount this outside, preferably against firebrick rather than my house. I realize the batteries are much safer than they have ever been, but still a cascading lithium battery failure inside my garage is not my idea of a party

On the grid tied solar inverter front - the spec sheet says the battery voltage is 350~450 V, so we're looking at 108 lithium ion cells (25 x 18650 cells?) at 400 VDC nominal. This is quite different from typical lead acid battery pack voltage of 12, 24, or 48VDC that's used for battery backup storage, so a lot of existing solar battery storage infrastructure may not even work... this means that people may need to buy a whole new set of supporting hardware to integrate this into the existing solar systems instead of being able to update the software on existing hardware.

Lithium Ion also has quite a different (and much less forgiving!) charging cycle that requires much more monitoring of things like temperature, though I'd imagine a lot of that would be built-in as a safety mechanism directly into the Powerwall.

What I've heard is that National Electrical Code becomes much more stringent on battery systems greater than 48V, with the line drawn at 48V due to it being used widely in the phone landline system. I'm not sure how true that story is, but I'd imagine extra care is probably warranted. 10kWh is about 9kg of TNT. :-)

48V is under the threshold at which electrical shocks become dangerous. 48V or less is "low voltage" class. And, 48V is a multiple of both 12V and 1.5V (most individual battery cells are 1.5V), making it much easier to hook up by using a combo of parallel and series connections.

Yes talk to telco Engineers from the power side of the biz and they will have war stories about accidents and close misses with the Central Offices (Exchanges) DC power.

High Voltage/Amperage DC is quiet different to AC power and i suspect that building/wiring codes are going to need to be updated if this local storage takes off.

dropped a wrench across the terminals on the deep cycle backup batteries inside a telco switching center. Had to disconnect the whole bank of batteries to fix it because the wrench welded itself to the terminals. it wasn't a tack weld either.

That makes for a very exciting day.

The one I remember is decorators placing a paint tin across the bus bars - which explosively painted the walls

Yes, it would be interesting to know if there's an advantage of connecting so many cells in series

Most systems limit themselves to something like 48v as you said (I think 48v is the threshold of "being dangerous")

Higher voltage means lower current and thus lower voltage loss, and lower percentage losses for the same voltage loss, so you don’t need lots of copper.

Yes, but you're throwing it into an inverter, and it's not like you're carrying it too far. High voltages also present problems in itself (isolation, etc)

Now, on a second thought, maybe it's more efficient to do 400VDC to 120VAC/240VAC (don't know the exact values)

DC-DC buck converters may be a little simpler and more efficient than boost converters, I don't really know.

Solar systems are generally HVDC off the panel. I think in practice you'd tie the three sources (grid, panels, battery) together in the AC domain with a computer monitoring consumption and generation then signalling the battery system to charge or discharge.

But you might not want someone to vandalize or steal the battery either which can happen if it's outdoors. Maybe it would be best to put it in a separate shed with lock or something.

Outdoors you're going to need to heat and cool it more - you want those cells kept within a fairly narrow range to keep the lifespan up.

How about stuck to the side of your house?

From further down the comments, this is a rebranding of a battery already offered to SolarCity customers.

http://www.solarcity.com/residential/backup-power-supply

The image on SolarCity has been updated to show Tesla branding.

Apropos of nothing but that product page has a lovely clean design.

That was my thought took until I remembered people already steal copper wiring whether or not it's carrying load. That would be a tempting target for theft. I think I'd stick it in my garage instead, but that's just me being paranoid.

Good point, hopefully the controller is DRM'ed to keep it from being used by a thief.

This is a three-pronged stroke of genius:

1) Immediate benefits to just about anyone. If you have your own solar panels, you need this (or something like it). Even if you don't, you can benefit by drawing more power during cheaper off-peak times.

2) If lots of people get in on this, we'll have the storage capacity we need on the grid to be more dependent on renewable energy. Lack of storage capacity is one of the biggest obstacles to increasing renewable generation.

3) If lots of people buy this, the price per unit goes down, and it's the most expensive component of Tesla's main product, their cars - which are effectively batteries on wheels.

I don't see how it's immediately beneficial for just about everyone. I currently have a flat rate for kWh and no solar panel... and moving soon. It's not worth the $. In 6 months I'll be renting for a year, still not beneficial. Perhaps in a couple years I can purchase solar, a battery, and an energy system that can automate some demand shedding but we're talking about 1%ers here.

In fact, I'd say it's only immediately beneficial to a minority.

A better way of looking at it is that it's immediately beneficial to anyone who owns real estate.

Or anyone who lives on Earth with a vested interest in limiting carbon emissions.

I think I'd want to see an environment impact assessment of manufacturing the batteries.

OK; here's a well cited study from 2010 on electric cars: http://pubs.acs.org/doi/abs/10.1021/es903729a

"The share of the total environmental impact of E-mobility caused by the battery (measured in Ecoindicator 99 points) is 15%. The impact caused by the extraction of lithium for the components of the Li-ion battery is less than 2.3% (Ecoindicator 99 points). The major contributor to the environmental burden caused by the battery is the supply of copper and aluminum for the production of the anode and the cathode, plus the required cables or the battery management system."

The copper and aluminium foils that make up the electrodes of the battery dominate. Both these metals are highly recyclable. Not much Li-ion recycling goes on currently as there's lots of different battery shapes + sizes, and there haven't been the economies of scale. I would imagine that whatever technology Tesla have standardised on, there will be (possibly closed loop) recycling plants.

15% and 2.3% didn't really mean much to me without seeing the total composition (chart on page 3). Turns out operation is dominant source of electric vehicles' environmental impact. I guess the operational impact is primarily from electricity generation, which is always going to be cleaner than refining crude oil unless every power plant switches to coal. Compared to internal combustion engine vehicles, the battery impact is much less than the total improvement in operational impact in all 4 impact assessments.

But if the ease of installing these batteries makes home solar panels more attractive, that may offset their impact outside of EV use.

Thank you for that, much appreciated.

As someone who rents an apartment with no garage and has a traditional gas-powered car, I can echo your sentiment and claim that Tesla has had zero impact on my life and that this announcement doesn't change that. I sincerely hope that Tesla's many innovative business efforts improve society in some major way, but right now they're still just a high-end automative company that's exploring the renewable energy space.

I'm not trying to discount anything they've done, because it's forward-thinking and technologically impressive, but it's not like Elon Musk has saved the world just yet.

Agreed. I'd love to have a living situation where a tesla or electric vehicle was realistic for me. They're just better pieces of engineering. But sadly due to renting an apartment, parking underground, and so forth, it's not a life style I can change to.

Not trying to sound snarky, but how does parking underground preclude you from owning an electric vehicle? Is there a physical reason for this? There are apartments that have electric vehicle chargers. You might even be able to convince your complex to install a few as an amenity that will make it more attractive to new tenants.

>" but it's not like Elon Musk has saved the world just yet."

"I choose to rent, I choose to have no property rights over the building I live in, I choose to be legally incapable of installing solar panels and batteries on a structure I don't own: Elon Musk has failed me"

Come on now. You made your choice to not be a part of the greater community and culture of property owners.

These options, they're available to owners, not renters.

Did you realize Google Fiber was the same way? As a renter, you have 0 ability to install Google Fiber without your owners permission. (https://support.google.com/fiber/answer/2847916?hl=en)

This is the same.

If you care, you'll petition your landlord to invest in these technologies. Or you'll buy property and change your status to enable yourself materially and legally to be able to do it yourself.

But you can't blame Elon because of your choice to make yourself willingly devoid of the legal authority to make these decisions for yourself.

Elon can never overcome your landlords property rights. Not now, not in 100 years. That's not his failure, it's your choice in a free society. Next time, rent in a location that has these options already installed, or make it known that these are your priorities. I personally have sat down with my landlord and discussed Fiber and the costs and the benefits, and I'm confident he will make that investment on behalf his property. It's not hard to take the initiative and make a case.

Oh, give me a break.

Asking your landlord to switch ISPs is not the same as instantly acquiring 100 grand to buy yourself a Tesla automobile. Nor is it the same as instantly having the financial and personal freedom to say "I'm going to go buy some property!" Have you ever considered that some people can't buy certain things because they don't have the means to do so? (Save me the tirade of libertarian talking points, please...)

I'm not blaming Elon for anything and I don't really have any interest in owning property at the moment. I'm simply pointing out that his company isn't really changing the lives of most people.

If he manages to significantly reduce greenhouse gas production by selling these to homeowners and utilities at a massive scale, then he'll definitely be changing the life of most people.

"I'm not blaming Elon for anything and I don't really have any interest in owning property at the moment. I'm simply pointing out that his company isn't really changing the lives of most people.

Please, sir, it's ME who needs to be given a break.

* I'm not a libertarian as you have insultingly labeled me, I'm a social democrat

* Just because you cannot afford a $3500 battery doesn't mean anything except you cannot afford a $3500 battery

* Had you watched even 10 minutes of Elon's presentation, you'd understand that your utility could install a large scale version of these for your benefit. It doesn't have to be a personal installation, a 'smarter' grid means you can send your solar during the day to a central storage run by a utility or government, and then spend that credit when you draw from grid at night.

* Considering that utilities can do this, that means socially speaking, a government could invest in these. In fact, you'll find California providing deep incentives for exactly this kind of work.

Your "100k on a Tesla" remark, when in reality we're discussing $3500 batteries and similarly priced solar setups, goes a long way towards showing that you have an IRRATIONAL reaction here, not a rational once. You clearly have not investigated even the basics of this, and are using hyperbole to make an emotional statement. $100k would power several homes independently of the grid, or power a multi-family structure like an apartment building.

You could ask your landlord to install a $3500 battery, that's a conversation you could have with your landlord.

It's one you choose not to have, and even though you choose that, you still blame Elon.

This world will change without you. Your attitude is no different that that "one guy" we all know who has a clam-shell dumbphone and is good with it. The world changed around him, although that one guy we know is still bemoaning that Steve Jobs did nothing for him.

For all we know, apartment complexes will install 50kwh setups with solar panels on their facility as a way to attract people: "NO POWER BILLS! POWER INCLUDED IN RENT! NO BROWNOUTS! NO BLACKOUTS!" It'd be a powerfully interesting marketing tactic. Just because you don't own a house doesn't mean Elon's ideas can't change the world.

>> "I choose to rent, I choose to have no property rights over the building I live in, I choose to be legally incapable of installing solar panels and batteries on a structure I don't own: Elon Musk has failed me"

> Come on now. You made your choice to not be a part of the greater community and culture of property owners.

More and more young people are moving to urban areas and making property ownership a low priority.

But given that this is HN, there's a high chance he lives in SF/SV/NYC, where most tech workers could not afford to own property if they wanted to. Property ownership would entail relocating, which isn't always an immediate option for everyone.

> Elon can never overcome your landlords property rights. Not now, not in 100 years.

With sufficient lobbying juice he could. I mean, the government has intervened in property rights in favor of renters and against property owners when it comes to antennae for certain kinds of data, there's no fundamental reason they couldn't for residential backup power systems. [0]

[0] https://www.fcc.gov/guides/installing-consumer-owned-antenna...

As someone who just started walking to work, I can't wait for the day that the smelly fumes of gasoline exhaust disappear from our streets. And Tesla, among others, is bringing us closer to that day.

Renters may not have direct benefits, but if the product works, they could have indirect benefits. For instance:

Assuming someone rents, and has to pay the monthly energy bill, wouldn't they prefer living in an apartment that had tools like this that lowered the monthly energy bill?

Assuming you rented an apartment, and either paid for the monthly energy bill, or wanted to make your property more appealing, wouldn't you want to install a product that lowered your costs?

> Tesla has had zero impact on my life

Replacing pouluting cars has had and impact, if infinitesimal at this moment. Point is you don't have to physically own/use any of their products to benefit from the better world their products create.

Tesla may not have the direct impact to you that the Model S driver or Powerwall customer will have, but there's another element to the announcement: Industrial-scale storage for energy companies.

If that works, if they get update on that, then it will have a much larger impact at once that homeowner uptake will. Being able to take a natural gas plant offline entirely is a phenomenal win.

There's benefits for you as well. They just won't be as directly felt being that they're a few degrees removed. But I'd argue that those wins at the large-scale will have an enormous impact.

You missed an additional subset of users. I live in an old neighborhood that experiences power outages and fluctuations once or twice a year. This is fantastic and something I will be installing as soon as I can. So older neighborhoods, rural areas with inconsistent power supply. All of these potentially benefit from this.

Living in a region with cold weather, this is the kind of situation I would like to solve too. The problem is that a generator still has benefits over a battery, it can be refilled (i.e. when you lose electricity for a longer period).

And is a fraction of the cost, best case, or about the same if you want one capable of powering your entire household load indefinitely. And if you have natural gas service, you don't need to refuel either.

I agree, but I guess that the generator have a no zero starting time. (Do you have o turn it on manually?) So the battery keeps the electricity for the meanwhile.

Also, the generators are noisier. Perhaps you can turn them off during the night and use only the battery while you are sleeping and the electricity consumption is smaller.

Having lived through Hurricane Sandy in NYC: don't assume you can get gas to fill your generator in a disaster situation. Solar panels paired with a battery aren't dependent on a supply chain (that itself needs energy).

Yes, getting energy from a sustainable source of energy is the best way, but assuming you only use it for power outages once or twice a year, I am not sure it is worth the investment. Especially if you expect it to last a day/few days (if you are self sufficient for a few days you'd better do it all year long).

How is a power outage once or twice a year problematic? Did you mean once or twice a month?

(Just curious :)

When the power outages lasts more than a couple hours.

I actually didn't miss it, I was simply pointing out types of users who don't benefit from it to counter the "beneficial to almost everyone" argument. I realize there are many types of people who will use this product and benefit immensely.

> power during cheaper off-peak times

Pretty sure my rate is the same all the time. I wonder what percentage of electricity customers have variable rate pricing.

Yea my rate is the same too. I've lived in many places, and only in Canada I had variable rate.

I'm just excited about maybe having a relatively cheap way to do whole house backup. Living in Florida we experience many power outages a year.

NYC has it now, but I think as generation/fuel prices rise (in the long-term) and utilities get slightly more sophisticated, we're going to see more on-demand pricing as utilities seek to apply the same price changes they pay generators for peak-demand supply to consumers.

In a situation where many people were doing load shifting, I think this could even benefit those who aren't doing load shifting themselves (by reducing peak demand across the network).

For each person that load-shifts, it slightly reduces the payoff for the next person to load-shift.

In the UK, the peak demand is already in the evening[1], because solar has eaten the cheap lunch during the day (which it was supposed to do, but it means that each additional solar panel is going to have a harder job paying for itself). And the demand difference between low and high is about 30GW to 40GW.

[1] http://www.gridwatch.templar.co.uk/

Great point about marginal benefits of load shifting. I do think we're so far from that reduction being significant at this point that it's worth attempting.

I believe peak demand in most non-industrial areas is already evening, because residential areas tend to have less efficient energy use than commercial spaces due to density, and everyone is home at the same time, often doing energy intensive tasks such as cooking, using the A/C, opening the fridge. I heard from someone at a power company that advertisements during the Super Bowl are a major issue, because everyone opens their fridge and flushes the toilet at the same time, and power supply has to spike for 3 minutes and then return to normal.

I think we're instead going to see more direct load-shifting agreements with end-users, not on-demand pricing. For example in Texas it's now common for utilities to give you a discount on your electric rates if you sign up for a program where you install a smart thermostat, and agree to let them slightly reduce your A/C power usage when the grid is nearing peak capacity. This lets them do exactly the peak load-shedding they want, controlled directly by the system operators, rather than having to design a system of price incentives, educate users about them, and hope the incentives produce the desired outcome.

In my experience, at least in the midwest USA, electric companies give you a choice between a flat rate or "time of use" pricing. You can pick whichever you prefer, and switch between them if you want to try a different one.

"Time of use" charges more for kWh use during peak hours and less during off-peak. Depending on your usage patterns it can be cheaper to do time of use pricing.

One point is that if batteries in houses (or electric cars) become more common, there's more incentive for a utility to offer variable pricing, because more people can actually make use of it, letting the utility company get by with less peak capacity.

I agree in the long term (50 years) that is true, but in the medium term (15 years) solar + storage might be moving faster than utility companies want. If you built a power plant with a 40 year lifespan in the year 2000, you would not be happy if peak demand is lower than expected in 2025.

I would not expect the utility companies to be allies in this transition period to clean energy. It requires major capital outlays from them, it invalidates previous investments that have not fully depreciated, and in the end they will probably make less money.

This is not to throw a wet blanket on solar and storage, I just think we need to be cognizant of the idea that in all likelihood utility companies are both required to change for this whole thing to work and will be very resistant to that change. There might need to be changes to incentives or regulation to get the utility companies moving in the right direction faster.

That doesn't really make sense.

Electric utilities require capital investment proportional to peak usage, but only earn returns on average usage. This will only increase the ROIC of an electric utility by reducing the peak:average ratio.

Additionally, electric utilities are in a constant cycle of capacity upgrades to keep up with increasing demand. Customers adding distributed storage allows utilities to delay capital investment (which makes the company look better in the near-term).

I think they're saying that the investment in peak capacity may be already made, whereas the returns on use are ongoing, so creating incentives to save electricity may not be valuable to the companies.

Don't know if that's their actual cost-structure, but it's plausible in the abstract.

> but only earn returns on average usage

Not if the price they sell at is different at different hours.

re 1: part of the benefit of solar locally is that the rate you get for pushing power back into the grid is way in excess of what you have to pay to pull it out.

Whilst storing it for your own use later makes sense in theory, it doesn't work with the current economics

lucky you. Here (in one of the sunniest cities of the world) you can only earn parity - if you're lucky. The power company are disallowing new grid-feed connections in some suburbs because their aged infrastructure can't handle too much 'unconventional' input. (!!)

It's a good idea; I would place it more in the "obvious" category than "stroke of genius" but it's clearly got a market.

I think that the technology to do (2) at grid scale is far from ready. The grid was built to distribute power from generating stations out to users. It was not designed to have power flowing into it from thousands of dispersed battery packs at the tips of the network (i.e. residential service points). Significant reengineering and investement will be needed to make this really workable.

Your point is valid, but it's still beneficial to the grid even now to have a bunch of batteries on it: you won't get power flowing into the grid from them, but it does mean output power can be varied a lot more with batteries soaking up some of the difference.

1) You don't need this if you have solar. Most states and utilities have pretty favorable subsidies for "selling back" energy to the grid. The utility is credit the feeding back to the grid at 100%. This device will introduce efficiency losses and it is expensive.

Unless you have extreme peak v. non-peak fees, I doubt this will save you money. Even at 20 cent difference, 7kW hours is a 1.40 a day. But that assumes that you could use all 7kW hours at peak times (you probably aren't). Also, you'll lose 10% going form AC-DC, you'll lose 8% on the battery, and you lose 10% going from DC-AC. That is about 25% loss.

2) If lots of people get them, the peak v. non-peak difference will collapse.

I see this product targeted at current tesla owners. A PowerWall driven supercharger in-house could reduce charge times by 80%. Today's 10 hour charge time is a huge inconvenience compared to a 10 minute gas station run.

Doesn't Telsa already sell a product like that?

The home charger cable is capable of 240V/80A (20 kWh) connections.

Superchargers are around 363V/225A (90 kWh) but supposedly capable of 120 kWh.

http://www.autoblog.com/2013/02/01/hands-on-with-the-tesla-s...

So you're looking at 3 hours at home vs 45 minutes at a supercharger for a full charge. With the 10 kWh wall charger you might be able to cut 45 min off a home charge.

Not possible. The specs on their site say 2.0kW continuous and 3.3 peak power per power wall.

I tend to disagree that the subsidies make sense. In New Zealand, the sell back price recently was reduced in half. The problem is that the price is effectively set by the electricity supplier, which means it's not exactly competitive to sell back. It's gotten to the point where the ROI calculations from this reduction has affected the feasibility of installing solar panels in NZ.

In our area (the bay area), you can't have battery storage and have a grid connection. So in the setup you describe when the power goes out we couldn't run our house on solar energy. We would have to wait for the grid to come back up. It's crazy. That means batteries would be necessary. But we don't have a battery room or room for one. So this is the perfect solution. Will it save money? Tier 4 pricing with PG&E is 34 cents per kwh and the rates are going up. In the summer it's quite easy to hit tier 4.

Smoothing out peak/non-peak demand has an enormous economic and ecological benefit. Power plants don't turn on a dime. We often overproduce to handle the peaks.

I am not so sure. On paper, I would be an ideal candidate, I have a 4.8kW PV system (20 panels), with an inverter the Tesla could likely use. But in practice I generate enough extra power during the sunny months to have credit for the winters, and that's in Portland OR. $3K for a whole-house UPS seems like a lot, somehow...

You have credit because you're selling power back to the electric company (PGE?), is that not right? The ideal candidate for one of these systems doesn't have the option of selling power back into the grid, either because their utility company doesn't want to buy electricity from consumers, or because they're off the grid completely.

One thing that might go overlooked: Load shifting could, in theory, lower electric bills such that there's ROI without solar panels.

---

Edit for why: On-demand power is expensive. "Spinning up" additional power during the day is more expensive than having certain types of power generation running all the time. In theory, pumping power into a battery at night during non-peak hours will cost less than consuming directly off the grid during the day.

I'm forgetting all the details of energy economics, but IIRC there would also be far less emissions by having consistent load on the grid all day long. Something about the ones we "spin up" also being the worst for the environment.

If what you say is true, then with better economies of scale and longer investment horizons, utilities would quickly erase any peak-vs-non-peak arbitrage opportunities.

Different entities have different risk profiles, and utilities are extremely conservative. It will probably be profitable to load shift for several years before utilities start to do it on their own. And even then, it may take quite some time before there's enough battery capacity for all the fluctuations to even out.

Utilities with electricity production are more conservative because they have technical limitation due to the infrastructure they run.

However, there is a bunch of companies that buy and sell electricity on the open market, so they have a direct financial interest to play with this arbitrage.

In the UK, another reader has calculated the best case scenario was profitability in about 10 years. (his numbers ring true to me, I calculated recently that there was no reason to take an economy 7 contract for my electricity usage using similar data) That's a lot of time even in the utility market. So if batteries not attached to solar panel are going to be profitable (in the UK), that would be a future generation.

> utilities would quickly erase any peak-vs-non-peak arbitrage opportunities.

Probably right around the same time they're no longer necessary, as the cost of distribute solar continues to plummet. Its actually truly amazing how quickly the price continues to drop for panels each year.

Depends on country. I doubt you could ever run, say, Germany or Britain on locally produced solar power.

Relevant: http://en.wikipedia.org/wiki/Renewable_energy_in_Germany

There also wind... But solar already provides quite a substantial contribution in Germany. See this live chart: https://www.energy-charts.de/power.htm.

Considering the rate at which solar power is getting cheaper, I'd say a solar power based economy is within reach.

Great link. It's also amazing how Solar power generation falls significantly in the winter months. For instance, December output is less than 10% of June!

Chart here: Check out monthly/weekly energy production for 2014 https://www.energy-charts.de/energy.htm

Sure, wind, geothermal, nuclear etc.

But you could run it on a combination of onshore wind, offshore wind, distributed solar, utility solar, and energy storage (ie Tesla's Utility Storage solution).

It's hard to wrap your head around all the challenges in energy. If you're REALLY good at it you can find some incredible arbitrage opportunities...see Enron.

Consider the power output characteristics of some common energy sources:

Gas, Nuclear, Hydro, Wind, Solar

Our "sustainable" sources of power - hydro, wind, and solar - are also the ones with the most irregular and unpredictable power output. This creates a problem, because even if there was enough cumulative power output from sustainable sources today, it most likely wouldn't align with our usage schedule.

So there are two solutions: 1) find a way to map the sustainable power output to our usage 2) find a way to store energy

Today, our most readily available form of energy storage is gas. We just put it in a container and burn it when we need to. "Spin it up," if you will.

An alternative to gas is a crazy network of Powerwalls. The hope is that, eventually, instead of spinning up gas turbines during peak demand, we can just draw from our Powerwall.

There was another alternative on HN recently. Basically a super-deep hole in the ground with super heavy object falling into it, but suspended by a rope. You run a motor to lift the object during off-peak hours, then let it fall and spin a generator during peak hours. I can't find it right now but I remember thinking they had a great name.

---

That said, power output is only part of the problem. If you're looking to factor the potential disappearance of arbitrage opportunities into your buying decision, you also need to consider the time until regulatory changes allow for perfect pricing, and the time until these Powerwalls have precise enough information to decide exactly when to draw from the grid versus the battery.

tl;dr: "quickly" is probably optimistic. We're a long ways away from economies of scale.

Actually, hydro with reservoirs is not just very predictable, it's the least expensive source to turn on-off-half on demand, or even to run in reverse as a storage mechanism with some upgrades.

was it a gravity battery?

> There was another alternative on HN recently. Basically a super-deep hole in the ground with super heavy object falling into it, but suspended by a rope.

Or a train going up and down a hill...

http://www.aresnorthamerica.com/

Both are basically the same concept as pumped hydro which has been in use for a long time... pump water up a hill when energy is cheap, let it fall down and turn a turbine when energy is expensive. And hey, if it rains, free energy!

The rail/hole in the ground approach have the advantage of taking up less land I suppose, but I suspect are less efficient.

Gravity batteries have really low power densities, in general.

Now, vanadium-redox flow batteries... That's always been my pet large-scale energy storage. That or hydro.

I could do this today. With my current time-of-use electric rate, I pay an average of $0.25/kWh more for peak power than I do for off-peak [the differential is larger in the summer, smaller in the winter]. If I shift 8kWh per day, then I would generate positive ROI in less than five years.

Your edit is spot-on. Utilities typically use natural gas "peaker" plants to meet mid-day spikes in demand, while nuclear plants are better suited to running at a steady state.

And you'd get a free backup power system too. That's worth something.

Is 8kWh/day realistic? I'm curious, honestly wouldn't know.

Seems like that would be charging and discharging 80% of the 10kWh battery's capacity every day. Would that affect lifespan? Also, it would seem to render the device less useful as a battery backup system during most of the day, since it would be mostly depleted.

My home uses about 1000 kWh per month, so shifting 8kWh per day of my in-house demand is feasible. However, there's really no correlation with my usage, since I can just push and pull that power from the grid, as if I had a solar or wind generator.

Lithium batteries are fairly tolerant of deep discharge, but yes, I would expect that the pack would be worn out after max 7-10 years if used like this.

Yes, using the pack like this would make it much less useful for battery back-up, but where I live (SF Bay Area), I haven't had an outage that lasted longer than 2 hours since we moved into our house, and this would cover the basics (probably everything but A/C) for that time. You could always split the difference, for example using 4 kWh per day -- this would pay still give you 6kWh+ of backup power and let you get the battery at half off or better.

Economy 7 power is significantly cheaper in the UK than peak power. Charging overnight in the E7 period could save money long term depending on the lifetime of the battery.

I did a quick bit of calculation on this. Assuming you use 10KWh per day and a perfect battery:

Economy 7 KWh cost : 8.4p (Best deal I saw was 9.4 for me, but this was a figure on MSE)

Standard tariff KWh cost : 14.5p (Best deal I saw was ~12 for me, but this was a figure on MSE)

That'd be a £306/year cost on economy 7 and £530 on a standard, taking some more extreme figures.

A $3500 (~£2300) battery would then have a payoff time of about 10 years.

Using the other figures (9.4 and 12) gives a £95/year saving or a ~25 year payoff.

That's also assuming the batter is perfect, no extra costs in installation and you use exactly 10KWh per day. Economy 7 tariffs are about 22p/unit during the day so any overrun would quickly eat into savings.

I do think this is all very interesting, but with current offers in the UK it doesn't look too beneficial. However, if someone were to offer cheaper rates on a more granular level (rather than always midnight-7am) then this could work out better. Perhaps an energy company owned battery would be a good idea, they offer a flat rate back to you knowing they can smooth things out.

Oh interesting, I hadn't considered the aspect of charging overnight while it's cheaper. Of course, the moment it starts to get popular the energy companies will be eating that particular cake too, I'm sure. Sounds like right now there's not a huge margin anyway.

I guess the energy companies have a financial incentive to run a more consistent supply if it could reduce the peak load.

Just reminded me of a brilliant BBC documentary from a while back - The Secret Life of the National Grid. I think you probably have to piece it together from clips on youtube these days.

If you get 90% charge/discharge efficiency, you're multiplying the economy 7 tariff by 1/0.81 = 1.23456790 (so close) so it's more like 12.5 years, and a bit less compelling.

That is of course ignoring the other aspects, like battery backup for the house, better for the environment (?), the ability to do solar tie in, and any possible government incentives.

In the UK power cuts are very rare in most places (and generators are cheap), so it's not a huge advantage. The enviroment factor is at best tenuous due to 20% of energy stored lost as heat and high energy requirements for producing the batteries; and in any case unilateral green action makes no difference.

The solar tie in is quite nice, but current feed-in tariffs are huge in the UK (30p per kWh perhaps), so you're getting more out of paying it back than you would for storing.

Government incentives obviously change the calculations, but there aren't any at the moment.

You are planning to charge the thing overnight and use it exclusively during the day, nearly exhausting it each time?

The battery is going to wear out well before 10 years. If you oversize your battery so you are only pulling out half the charge in the battery[1], you can probably get 1500 cycles out of it[2]. That's still less than 5 years.

(This is a common pattern if you are trying to price-compare an electric car to a gas car. For the electric car, the electricity cost is a rounding error compared to the capital cost of the battery, so you can just about assume electricity is free, and worry instead about how long the battery will last.)

You will get a much bigger bang-for-the-buck by demand-shifting: if the biggest load is cooling your building in the heat of the day, run the A/C overnight to superchill a heat sink that can be accessed during the day. No battery installation needed.

[1] Toyota did this with the Prius. They purposefully did not use the full range of the battery because they wanted the battery to last 7+ years.

[2] http://batteryuniversity.com/learn/article/how_to_prolong_li...

It comes standard with a 10 year warranty, with an optional 10 year extension. If they don't have different numbers than you, I don't see why they would even attempt that.

Warrantied to what, though. That you can still get 20% capacity levels in year 10, or that it will still turn on? This might be considered "normal wear and tear."

3000 deep cycles is really pushing what the industry knows to be state of the art.

Maybe they are just taking the economic chance that most people won't be deeply cycling these batteries, and planning to do replacements for those who actually put it through its paces.

> Warrantied to what, though.

That's a good question, and it makes a big difference.

> That you can still get 20% capacity levels in year 10, or that it will still turn on? This might be considered "normal wear and tear."

Given that you can optionally warranty it for an additional 10 years, I doubt it's nearly that bad. If people are confused as to how they how they hope achieve 10 years reliability, and they are willing to warranty 20 years, they must have something up their sleeves.

> 3000 deep cycles is really pushing what the industry knows to be state of the art

I suspect that the powerwall's true capacity is higher than it's rating, and it uses that reserve so it's not doing deep cycles, similar to another commenter's assertion to how the Prius gets it's 7+ year rating,

> Maybe they are just taking the economic chance that most people won't be deeply cycling these batteries, and planning to do replacements for those who actually put it through its paces.

I think a combination of most users not fully cycling every day, extra reserve capacity to keep it from deep cycling, and some subset of people not using failing warranty conditions may all contribute.

Yep. This is targeted at ERCOT as much as it is targeted at the home consumer.

http://www.greentechmedia.com/articles/read/Bring-on-the-ene...

Doesn't this ignore completely the efficiency of the batteries? These batteries aren't ideal, you won't get out 100% of the energy that is put in. I don't know the efficiency rating, and I haven't done the math, but I suspect that the losses will cut into the savings significantly.

The page says >92% round trip efficiency. Since they also claim that they're selling them to utilities for exactly this purpose I'd guess it's theoretically possible and probably comes down to the pricing structure offered to consumers in your local area to buy and sell to the grid.

Can grid arbitrage and time-shifting solar co-exist? Some clever software might be able to predict your energy demand (e.g. based on seasons and past usage patterns) and your likely solar output (this time based on seasons and weather forecasts) and make the maximum use out of the battery.

I'm also wondering if the same software is going to be rolled out to Tesla's cars so that they act like Tesla Energy when plugged in overnight.

Big cities are prone to brown outs on hot days in the summer due to air conditioners. The 2003 European heat wave killed thousands1. I could imagine mayors mandating use of this kind of technology in apartment buildings. Let them charge overnight to offset peak usage. You'd cover 100 or more people at a time.

[1] https://en.wikipedia.org/wiki/2003_European_heat_wave

Normal homes in Europe simply do not have air conditioners, not even in southern Europe. So the electricity is irrelevant.

That's no longer really true. A/C units are in the past 10 years getting quite common in the hot parts of Europe now. In the '90s fewer than 10% of households had them in Italy or Spain, but that has jumped to nearly 50% now. People do use it a lot less, though: they are typically individual units, not central A/C, and only used for short periods on very hot days, not run continuously with a thermostat setting.

(Posting from my phone after the event). If you are excited about this and want to work on it then please email me at tcasebolt@teslamotors.com. We are very excited about the technology and future!

$3,500. That's crazy good for your average household, on par with natural gas backup generators with half the logistics. I might just be ordering sooner rather than later given some of the grid instabilities in my area over the past year, and through the mid-term in preparation for a solar switch here in Chicago.

While Elon might not be the best orator, you can easily derive his authenticity and belief in the product by virtue of his delivery. You can't do that with accuracy in the canned and carefully rehearsed.

$3500 doesn't include the inverter or transfer switch. Transfer switch is maybe $200, and it's not clear what the inverter might cost. It's a nontrivial part, since it would be responsible for daily cycle estimation and cost optimization.

For $3300 you can get a 17 kW generator with inverter and transfer switch [0], which will run for days on a house-sized propane tank. At my house in the woods, we do sometimes get multi-day power outages after storms. Though, to be fair, you need a concrete pad and 30 square feet to install the generator.

It doesn't seem like a competitive backup system, but load shifting is still appealing.

[0] http://www.costco.com/Honeywell-17-kW-Automatic-Standby-Gene...

Some people (like me) are simply unwilling to keep using carbon-based sources of energy. At some point it just feels awful to be contributing to such a terrible problem. I'm counting the days till I can sell my worn out petrol car and get an electric car. If I had a home and dollars, I'd want one of these batteries.

Batteries are not clean; lithium mines are one ugly slight and recycling is difficult: http://whenonearth.net/awe-inspiring-aerial-images-worlds-me...

In my clueless opinion these batteries should be used strategically in places where solar, wind, and hydro power are unavailable.

Yes the real breakthrough tech needed is a new battery! Which hopefully Tesla is on track to develop,because as is, electric cars are just not scalable.

People say that, but from what I've heard there is plenty of lithium in the world to increase use 20% every year for 30 years before we need to get more creative in how we mine it. That's a huge total increase and means that electric cars totally are scalable.

Do you have information supporting the idea that electric cars aren't scalable? My understanding is that they definitely are scalable.

Charging is where the scaling problems come in. If everybody in your neighborhood plugs in their Tesla at their home at night and/or at their office during the day, it will likely cause brownouts and blackouts in areas with grid service that's already marginal for current demand. Hence Musks's interest in load-shifting technology.

Utilities have existing techniques for distributing that load. They already work with smelters and other large power users to coordinate their power demands.

In some places utilities are offering discounted electricity prices if the car charging infrastructure is hooked up to their smart metering/control system. This allows the company to signal when cars should start/stop charging.

There's no reason they can't work with car makers to introduce two way signalling between the charging infrastructure and the grid - the car can tell the grid that it needs to use X kW by Y time, and the grid can communicate the current permitted load.

Potentially with some option for the customer to pay a premium to charge immediately at a higher rate.

You're assuming a world where 80% of the people already have an EV. You don't think most of those people will also have solar panels and battery backups at home (from which to charge the car at night).

it isn't so much how many people charging, its the ability of people to charge where they live and the lack of ability to truly quick charge the battery.

As in, damn the kids left the car unplugged and I have to work. even thirty minutes at a super charger is not a good solution.

So it comes down to a compromise, a good range extender technology and batteries for the majority of driving. That until truly faster charging can be achieved with house hold wiring.

> As in, damn the kids left the car unplugged and I have to work. even thirty minutes at a super charger is not a good solution.

I don't see this as something to worry about - it's just a household habit problem. Pretty much every new device introduces some, and people quickly adapt to use the device properly.

The argument is silly. The kids could also forget (or just not bother) to put gas in the car and leave it on empty. Yet strangely we manage to make do with gas-powered cars.

Solar power, local wind turbines, , etc. We need to get off the grid and start working on isolated energy systems.

There is definitely enough lithium in the world to increase the production of lithium-ion EVs. From how I understand it it though, it is unlikely that lithium-ion EV could replace every car currently running in the world. http://large.stanford.edu/courses/2010/ph240/eason2/

Whether or not batteries are "clean" seems to be a matter of opinion. My understanding is that lithium mines aren't inherently unclean, but many current lithium mines are unclean. The idea is that it is good to support bad tech, since public pressure could ensure it is clean. That's unlike fossil fuels, which can never be clean. All that is just hearsay though, I can't confirm its accuracy.

Still, some might say that carbon pollution and groundwater pollution are different problems. One may decide the trade off between one and the other is worthwhile.

> Batteries are not clean; lithium mines are one ugly slight and recycling is difficult:

You are conflating two senses of "clean" that are radically different in meaning and importance.

-- Fossil fuels are !clean in that they may destroy all life on earth via catastrophic climate change.

-- Lithium mines are !clean in that they present waste disposal challenges and some people find them "ugly".

It's like saying "your non–blood diamond is still a blood diamond because the jeweler got a papercut while handling the documentation".

I feel like a backup generator is the last place where I would make my decisions based on the environment. I mean how long is it actually going to be active? Also batteries aren't exactly environment friendly either.

That may well be how you feel, but lately I feel like any burning of petrol is just disgusting (though I still do it as I cannot afford alternatives at the moment). I want to completely divest from fossil fuels, even for intermittent use. That's as much for the social value of saying "yeah I don't use fossil fuels and it's great" as it is for the environmental impact. I want to try all this tech to be an early adopter and help people prove it out to the rest of the world.

Your comments vex me. I don't mean for this to be an attack, but clearly you ARE willing, so why would you say you aren't? We all want to do more.

Isn't that a bit of an overreaction?

You might want to reevaluate any moral position you have where a significant basis of your values is the ability to brag about them. I would be fairly disgusted if someone said a significant amount of the reason they're so devout in their religion was so they could boast about it with their peers.

I didn't read the GP comment as "bragging" so much as wanting to be an existence proof that it's possible to live a modern life without (directly) burning any dinosaurs.

This. I want to be an early tester so I can relate to others the value of the tech.

That's ridiculous.... the only way to actually achieve that is to abstain from all plastic consumption, and abstain from all electricity consumption.

> that may well be how you feel, but lately I feel like any burning of petrol is just disgusting (though I still do it as I cannot afford alternatives at the moment).

LOL. that's some serious self-delusion. some of the best i've ever seen in the wild.

the alternative to fossil fuels is free -- just don't use them. your feet are free. bikes are almost free and subsidized in many cities.

the reason you use it is not because you "can't afford the alternative" but because you find the convenience and utility quite high, i.e. WORTH THE COST, compared to walking your ass around town and going cold in the winter, just like everyone else.

fundamentally this is a problem of economics, not of really really really wanting to do the right thing.

How do you think every data center in the world is backed up for power? Diesel generators. You'd have to quit using the internet until a different power backup method is adopted.

> Also batteries aren't exactly environment friendly either.

Kind of a straw man argument. They are still far more environmentally friendly than gas or coal.

If you're talking about cost/benefit that's a reasonable calculation to make.

If you're talking about being "disgusted" and wanting to completely avoid polluting at any cost, not so much. Sacred values and all that.

Fumes from backup generators are problematic without the environmental considerations: they're seldom-run and often minimally maintained, and there are exhaust-gas fatalities most winters.

That's crazy cheap. The closest competitor which comes into my mind is probably SMA Sunny Boy Smart inverter with lithium battery, costing more than double while offering only 2 kWh of energy (but includes a solar inverter).

It's not crazy cheap at all. The incumbent technology here is flooded lead-acid, a proven solution used everywhere from telco COs to forklifts to off-grid cabins for over a century. Industrial FLA batteries (the top grade, longest-lasting, etc.) retail for somewhere around $250 per kWh, and typically have warranties ranging from 7 to 10 years. We don't know exactly what the differences are between Tesla's two offerings, but even if we assume that the 10 kWh model is rated for continuous deep cycling for 10 years (their language suggests it may not be), we would still have to justify the $350 per kWh price tag. The other model comes in at $428. So this is somewhere around 50% more costly than existing solutions with a similar expected life span. The limitation of 2 kW continuous power is also a major drawback relative to FLA solutions, which can typically provide at least 200 A (around 10 kW at 48V, much more at the higher voltages the Tesla unit operates at). Since the Li-ion battery is maintenance-free, a better comparison might be AGM or other VRLA technologies, which are slightly more expensive than FLA, but still less expensive than the Tesla units.

Since no inverter, grid-tie transfer relay, or charge controllers are included in this unit, those will all be additional costs just as they would with any other batteries. And it appears you will be limited to a few inverters and probably a micro-inverter PV design; this is purely a grid-tie-only design. Existing battery technologies can do all of that, but they also give you much broader flexibility for other applications and system designs.

I'm not sure why I would want this. I'd be paying above the odds for some serious design constraints and limitations I wouldn't otherwise have. Tesla seem to be taking a very different approach from their launch of the Roadster, which was a super-premium offering at a super-premium price. This is a modest offering at a premium price in relative terms, but low enough in absolute terms to appeal to people who aren't well-versed in the field. Their success will probably depend on installers deciding it's easier to just take people's money and sell them the Tesla than to educate their customers and give them the best value available. Not a bad gamble, for Tesla.

I meant "crazy cheap" as lithium-based product, i.e. compared to other lithium chemistry storages. Sure, lead-acid technology still offers better capacity/price ratio, but lithium chemistry has many advantages especially when used as domestic energy buffer for sun: longer lifespan (more cycles) in daily use, more peak power, wall mountable / lighter, etc.

I don't think most households (in the US at least) could run off a single unit. You would need three units, and they would only give you 1 days capacity, compared to a natural gas generator which could keep running indefinitely.

http://www.eia.gov/tools/faqs/faq.cfm?id=97&t=3

The competition doesn't sleep: http://www.greentechmedia.com/articles/read/sungevity-and-so...

In fact they seem to be ahead. Sonnenbattery offers http://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery since 2011 in Germany.

For technical details see http://www.sonnenbattery.com/strom-energie-speicher/sonnenba...

The article has been updated as the price is $3,000 and not the predicted $13,000.

Questions:

1. How is this different from a UPS? (Similar capacities can be obtained for less money.)

2. How many cycles can we expect to get out of these? (One assumes these are designed to be cycled more often than a UPS)

3. What are the risks when temperature is outside the operating range? (If non-negligable, the stated operating range of -20C to +43C limits use in some applications, such as field stations without heating (or AC, depending on locale).

4. Is this technology viable on the scale of an entire powergrid? If it's advantageous for individual users, one would think economy of scale would make this more efficient to implement grid-wide.

5. Do these present an additional hazard in the case of fires, floods, etc.?

A notable beta user:

AWS will be running a 4.8 megawatt hour pilot program with Tesla's batteries in the us-west-1 AZ (Northern California).

Hopefully this allows AWS and other hosting providers to use intermittent, renewable sources of energy more often.

EDIT: I'm guessing AWS will be using a cluster of 48 power packs (100 kilowatt hours each).

This might be a reason to move your production environment out of us-west-1 for a few years.

I wouldn't want any experiments going on around my main servers.

While that' one way you can look at it, another is that hopefully this region should now be less prone to power outage related downtimes. I wonder if they are an issue currently though.

I imagine that these are on the grid side of their existing UPS/Generator systems, rather than part of it.

If you don't want experiments going on around your servers you better host them in your own data center. Amazon is guaranteed to be running many experiments in all of their data centers (and not just with power, with the actual server hardware!).

AWS is one giant set of experiments.

This was offered to SolarCity customers in late 2014, I see that the image here http://www.solarcity.com/residential/backup-power-supply now reflects Tesla branding.

Thing looks like a giant Apple Magic Mouse[1] bolted to your wall.

[1]: http://store.storeimages.cdn-apple.com/4572/as-images.apple....

Iinteresting how they are branding it as a backup solution, while Tesla is branding it as a complete replacement.

"What if we could move the electricity grid off of fossil fuels" (Tesla)

"Be prepared the next time the power goes out."(Solar City)

"Models

10 kWh $3,500 For backup applications

7 kWh $3,000 For daily cycle applications"

From http://www.teslamotors.com/powerwall

Maybe Solar City has been using the ones meant for daily cycle - that would make sense.

Doesn't include inverter or installer markup and can only provide 2kW output.

It will get expensive by the time you actually have all the bits you need inside your house.

How is this better than deep-cycle batteries (with 20+ year lives) again? Why does it need to be slimline?

> Why does it need to be slimline?

"so you don't need a battery room" - Elon Musk

10kWh of deep-cycle batteries aren't that large. It's not like people in apartments are going to be using this product.

But they could now, and most deep cycle lead acid batteries are flooded, not sealed, which means they have to be ventilated to prevent hydrogen explosions hazards. Not so with Tesla's offering.

Fine. 4.8kW Li-Ion battery for USD$3,278

1.9kW for USD$1,678.

My point is that Tesla isn't really doing anything really unique here. Sure, they're giving it more press than anyone really has before, but the products aren't especially cheap, innovative or special.

http://ironedison.com/12-volt-lithium-battery-for-solar

> Sure, they're giving it more press than anyone really has before

Ahh! But that's the most important part! Elon's portfolio companies are a pieces of an incredible future machine, all working together. Solar City is able to draw on Tesla's batteries, Tesla was able to draw on SpaceX for some of its engineering capabilities.

Tesla made electric cars sexy. Now, its making energy storage sexy. Clearly, marketing is important, and will be necessary for convincing the world a clean energy future is the right direction.

Less storage than a Nomad.

Lame

No wireless! (Nikola would be so disappointed...)

Wow, I have a deja vu - it's like reading comments about Apple announcing a new product :)

What about the power wall for utilities. I haven't heard of any other similar offerings. That seems even more important than the home based ones. Plus open sourcing designs to the gigafactory. Hey Branson want to step up and build one on your side of the pond?

This is pretty much the "why the iPod isn't interesting" argument. It's been done before, and the new one is more expensive.

What this product has is much better luxury marketing, and as part of that much better user experience.

Tesla is selling over double the capacity of your quoted 4.8kWh system for about the same price, and you say it's not especially cheap?

"and can only provide 2kW output."

only 2kW? 2kW is enough to power any residential, single-family house for 95-98% of the time; you only need (a little bit) more than that at very short (few minutes) peak intervals - when heating up an oven, or some cycles of doing laundry. A second unit would provide that headroom, and otherwise (when the extra $5k for a second unit is prohibitive) you could still draw from the grid for peak loads and just not run an oven and washing machine at the same time during grid blackouts.

It does require a 21st century house - led lighting (but it's 2015 - who still uses incandescent except for those places where you don't turn on the lights more than 4 times a year anyway?), energy-conscious appliances, moderate need for A/C (sane insulation and ventilation, localized and intelligently controlled A/C needs - i.e. no 'bring all room in my 3000 square feet sheet rock and tin roof house down to 75 degrees when it's 110 degrees outside'). But whoever doesn't have that, has options to start reducing their bills that are much better than buying energy packs.

I use incandescent lights. They produce a much more pleasant spectrum than “white” CFLs or LEDs.

LED's are available in various color temperatures, including 2700K (commonly referred to as 'warm white' which is basically the temperature of incandescent). It's true that the dollar-bin Chinese LED's have all sorts of bad characteristics that used to be associated with all things LED - pale color, bad spread, bad (or no) dimming capabilities, etc.

It's 2015 though - take a 20$ Philips Master LED for example (I decided upon those for myself so I looked into them more heavily; I have about 20 in use now, with another few boxes in my basement awaiting installation). The GU10 socket halogen-replacement version is available in 3 temperatures and 3 spread bundles, has a 20k burn hour rating (vs 1-2k for incandescent!) and can be dimmed very well using a 50$ leading edge electronic dimmer.

I'm no tree hugger - even purely economical (apart from the convenience of not having to replace lamps every year), in 2015 it doesn't make any economic sense to buy incandescent (in those places where it's possible to buy them at all...) for all purposes where the light is used on a 'regular' basis (more than an hour a day or so).

Of course it does require an initial 'investment'. But one that would be spread over 1 or 2 years - the normal replacement cycle of incandescent bulbs. Throwing out working incandescent bulbs to replace them with LED is not rational either, of course.

Color temperature is nowhere near everything. Or rather, it would be, were LEDs actually anywhere near a blackbody in terms of radiation output over the visible spectrum. But they aren't. Nowhere near.

There is no every-day use case where the difference in light perception from an incandescent bulb is different, or even distinguishable without measurement, from an LED bulb. Feel free to try it yourself in a light studio, or otherwise, please cite any studies with modern lamps that conclude that the 'light quality' (by whatever metric) of an incandescent bulb is higher (that is, 'higher' as in 'makes a material difference for normal use cases', not 'in the lab using our spectrometer we measured a difference').

As always, there are people (analogous to 'vinyl produce a richer sound' idiots) who have 'opinions' on light quality, but well, we all know what they say about 'opinions'. In 2015, it's plain nonsense to take 'light quality' as a reason not to use LED light for domestic purposes, full stop.

The subjective experience of a home lit with incandescents is very different than one lit with LEDs. I don't care if the color temperature is the same. Things just look different. The bulbs cast their light differently.

There may not be a difference in "light quality", photons are photons, but if you convert a home from one to the other things will look different, and you may prefer one way or the other.

And don't forget about fixtures that were designed to work with clear incandescent bulbs for aesthetic reasons. LED bulbs will look downright hideous in those even when the lights are off.

There are people who like how vinyl sounds better because they like the hiss and the pops, not because they fall for audiophile silliness. The same holds for lighting.

Yes, but being unwilling to spend 1 day adjusting to a different look is a pretty silly reason to continue to run a bunch of spaceheaters in your house that, as a byproduct, happen to produce some light.

Particularly if you ever use air conditioning.

In my experience, while it's true its hard to find the right LEDs, it's certainly not impossible. Try some out - you might be surprised. The biggest challenge is that most of what's sold as "warm white" is nothing of the sort, and you might not be able to pick the cheapest LEDs if you're picky about the colour.

There are LED bulbs with very high CRI scores now. Before those existed it did indeed make sense not to switch to CFL or LED. (Though halogen/xenon make more sense than pure incandescent.)

I thought so too until I discovered the Philips Corepro bulbs. I replaced every single bulb in my house with them last year. They're a massive improvement on the CFLs we had before. The only thing that took some getting used to was the lack of light shining upwards - ie illuminating the ceilings.

(I know this reads like a sales pitch but I am genuinely just a fan)

I don't like the "warm" light from LEDs, either, which is 2700-3000K. However, now I use 4500K "natural/neutral light" LEDs. I can't describe how much nicer it is than incandescent light.

It's "sunny middle of the day" light. It's brilliant and I love it. I could never use anything else now. Just make sure it's 4500k.

It says 3KW peak output which would handle things starting up.

> only 2kW? 2kW is enough to power any residential, single-family house for 95-98% of the time

You obviously don't live where it's hot. I live in Houston, TX and while I rarely run the A/C right now, in another month it's going to run on average 15 minutes per hour, every hour, for 3-4 months straight. Highs in the low 90s to high 100s and lows in the 80s (F).

I have 2.5 tons of A/C which is pretty moderate. The condenser draws something like 3kW with an 8kW surge and the furnace fan is another 500 watts. I live in a fairly modest house compared to a lot of people, I'm sure there are places that 5 tons is more common.

In California where humidity isn't really a problem and it tends to cool off more at night and there's nearly always great solar, this seems like a great solution. But don't forget that not everywhere in the world is the target market. There are some places that are very different in terms of electrical consumption.

I guess that my phrasing of "any residential house" is a bit unfortunate, and that 'the majority of all residential houses' would have been better, but that doesn't take away from the fact that with one extra of these units + 10k Wp of solar panels, you could power your AC's with power to spare to be stored in the battery pack, which you can then use to power the AC at night. Many people use AC's as a counterpoint to 2kW battery packs, whereas actually it's one of the more appropriate cases to use solar panels combined with (relatively) cheap local storage for nighttime consumption!

How much is your power bill in summer? Must be $300+, going on 500 during the hottest months? At that rate, you'll make back the $20k + $10k that 10k Wp + 2 of these batteries would cost you in what, 5 to 7 years? Add financing costs and you'll be at breakeven in 10 years, not counting possible government grants.

> How much is your power bill in summer? Must be $300+, going on 500 during the hottest months? At that rate, you'll make back the $20k + $10k that 10k Wp + 2 of these batteries would cost you in what, 5 to 7 years?

No, here in Houston we've got "deregulated" power in a completely reasonable way. One company owns the lines and handles recording the meters. They charge about $0.015/kWh for this. Then there are about 100 companies that offer electricity in a multitude of different ways. I'm paying $0.08/kWh delivered to my "door" so my worst months are only $150 or so.

Your idea is a nice one, except that I would need more panels and at least 2x the batteries/inverters. If I need 3kW CONSTANT to run the AC then 3kW PEAK doesn't do me any good.

> but that doesn't take away from the fact that with one extra of these units + 10k Wp of solar panels, you could power your AC's with power to spare to be stored in the battery pack

Not really. Look I know Tesla is awesome, and solar is awesome. I'm interested in both. But the economics really aren't here yet in Houston because of how cheap power is, because there's not a state owned utility screwing us bigtime. Houston has a lot of problems to be sure but power prices aren't one of them.

tl;dr Houston isn't California.

> You obviously don't live where it's hot.

It's a really strange paradox that, in places where it gets very hot during the day, we're drawing tons and tons of energy from the grid to cool the house precisely at the time of the day when even more energy is pouring down on us freely from the skies.

Seriously, A/C is basically Universe's most heavy-handed hint that we should use more solar.

Yep. Just on principle, I'd have a hard time living somewhere that was insufferable without A/C. It's a clear sign you're doing something wrong.

Of course, you could make a similar argument about needing artificial heat, but that's at least far more efficient!

> Yep. Just on principle, I'd have a hard time living somewhere that was insufferable without A/C. It's a clear sign you're doing something wrong.

Welp, I'll get right on telling 40% of the world that they're wrong, then.

https://tropicaldatahub.org/research-in-focus/people-and-soc...

Live Stream:

0. Tesla will open source its patents for the Gigafactory.

1. Elon thinks all the world's energy needs can be served with 2 billion Tesla GW powepacks.

2. Elon: "This is something we can do, need to do and should do."

It's over.

but unlike Elon, you don't think fuel cells are complete crap?

Tesla doesn't own most of the patents related to the Gigafactory. They're licensing the battery technology and manufacturing techniques from Panasonic.

I have four rack-mount uninterruptible power supplies that provide battery backup to my workstations and servers in my house. My curiosity here is whether this Tesla battery pack will obviate those UPSs, providing automatic and immediate in-line switching to battery whenever there is an interruption.

That alone would be compelling at this price.

Edit: Incidentally, when I submit the reservation form, there is no confirmation.

That would be determined by the inverter, not the batteries. And yes, almost all grid-tie inverters will serve your load with a switching time fast enough that computer equipment would continue running.

The wall mount surprised me, but 10KWh at the same density as the Model S battery should be only 155lb. That's not too bad, although you need a solid connection to the building structure. Having it above floor level is a good thing, since it won't be shorted out by minor flooding.

If you get a new solar installation, installing one of these seems an obvious win. The solar installation already includes the inverters and control gear. Without solar, it's probably not worth the trouble for residential.

The average American house uses 30 KWh per day. If you have daily sun and a low nighttime air conditioning load, 10KWh should get you through the night. Hawaii - perfect. Southern California - looks good. Texas - get two to get you through the night with A/C.

As I've learned more about heat pumps I've been wondering why we all use air-source cooling for central A/C. We are cooling our condensers with hot summer time air when the temperature is much lower just four feet under the yard.

The energy requirements would drop way down by cooling the condenser with a water ground loop.

Ground loops are seen as expensive for installation, but I don't understand why. It's just plastic tubing buried in the yard. I've been wondering if a hole digging robot could lower the price. The carbon and money savings would be huge if we could bring down the cost of ground loop installation.

I'm just spitballing here, but one has to be concerned about how much heat soaking the ground loop can take before its effectiveness goes down significantly. Dirt is a pretty good insulator. How much will the "ambient dirt temp" increase after X hours of running AC? How long does it take for the heat to dissipate?

That is why its critical to properly size the system. With the right size loop it works well. Also if you figure an ambient air temperature of 80-100 you can raise the dirt temp a lot before its as warm as the air.

I very briefly looked into this. It seems to be the same reason that simple and obvious things like solar water heating systems are so expensive in the US, but not elsewhere: Lack of awareness & low demand but few installers who target the eco/luxury niche product at a high price. These systems usually get installed only in high-end homes.

Climatemaster has about a million US ground-heatsink heat pump installations. In their system, the ground loop is water with antifreeze, not Freon, so there's an additional heat exchanger.

Rheem, the big water heater manufacturer, sells solar water heating systems. That's progress; previous solar-only sellers were kind of flaky. (See "hot2o.com", which disappeared.) Solar water heating systems have a reputation for leaking. Buying something that is supposed to last 10-20 years from a small company is a problem.

One of the things I've been working on are open source designs that transform sunlight into heat. I used cardboard, black aluminum foil and tacks for much of the heat for my home this past winter.

I'm also working on a simple open source design for an outdoor solar thermal panel that heats air to 130F. It can be built using diy vacuum forming and foam insulation.

I have a vision of open source diy solar thermal fixing the market failure you are talking about.

I wish the thing was built in such a way as to allow it to sit on a raised pedestal of sorts, with only lightweight bolts into the wall. That would address the flooding concern just fine.

I am just going to cut and paste my previous comment on Musk.

The Musk M.O: 1. Identify industry with big inefficiencies that depends on huge government subsidies. That's cars, commercial space vehicles, mass transit and now: colonizing another planet with the 0.1%. 2. Convince the media and envious government officials you are Tom Swift, boy inventor. Have these governments fight over how many billions to give you to build your space car factory. 2. Use these taxpayer dollars and gigantic tax breaks to create iconic products and services for the elite class, effectively transferring huge dollars from the poor to the rich. 3. Rinse and repeat.

I see no evidence at all that Musk cares any more about technologies to enable several billion of us to live together without slaughtering each other than he does about money.

Add the utility business to the growing list of government supported industries Musk wants to "disrupt" by which I mean establish a publicly funded, government subsidized mechanism to siphon off dollars for himself, just like Tony Stark in fact. The electricity generating and distribution system is one of the most provably useful "common goods" in the history of the human race-- why not convince people to spend more than 10 grand to power their house for 24 hours?

His reasons:

Load Shifting - residences generally have NO economic incentive to ride the demand curve, only businesses do in some cases. It is one of the most important things about the electrical system--these huge monopolies manage that curve collectively for us. Sure, transmission is inefficient, but so is decentralizing that task, while adding the risks of keeping your battery from breaking/catching fire.

Increasing self consumption- a battery does not stimulate this at all - the grid needs your power most when the sun is shining. Solar power and an inverter provides that incentive today.

Backup - One day of power in the event of a true natural disaster for $10,000 is expensive and not sufficient.

I am not a Luddite and I am a libertarian, and certainly our society needs technology visionaries right now, but I find Musk's increasingly cynical ploys and the adulation they receive pretty annoying. They seem designed to distract from the overall failure of his businesses, even if he continues to generate ideas and hype.

Your comments on his reasons are clearly counter-factual:

Load shifting on a consumer scale has been happening for decades in various places around the world (e.g. cheap nuclear energy at night powering storage heaters)

Self-consumption: in a grid increasingly fed by solar power all those peaks hit at the same time and there's been multiple recent news stories about power prices going negative at those peaks.

Backup - no-one said anything about "true" natural disasters. Backup from short power outages is already an established market in many outlying areas and a fringe benefit for almost anyone. And no-one said that you had to buy it and use it for this single purpose.

This whole area has been predicted as a growing market for years, there's others in this thread complaining that it's nothing new compared with less famous competitors, so complaints that it's a product dreamt up to soak up subsidies is a bit odd.

Having said that, if I was in charge of a government, I'd be subsidising these kinds of decentralised grid backup right now as they are already useful when viewed at a national scale. It seems likely that in a few short years they'll make economic sense for more and more people without any subsidy though.

Not at all trying to pick a fight. But:

>Load shifting on a consumer scale has been happening for decades in various places around the world (e.g. cheap nuclear energy at night powering storage heaters)

Sorry, but as a consumer I pay the same rate day and night, and I think most in the US are like me. I personally have no incentive for load-shifting. Why do I need PowerWall?

>Self-consumption: in a grid increasingly fed by solar power all those peaks hit at the same time and there's been multiple recent news stories about power prices going negative at those peaks.

Solar, including concentrated solar which is outside this discussion, is currently 0.48% of all US electricity generation. Not a big effect for many years, unless one of the other Musk businesses (Solar City) gets a big boost.

>Backup - no-one said anything about "true" natural disasters. Backup from short power outages is already an established market in many outlying areas and a fringe benefit for almost anyone. And no-one said that you had to buy it and use it for this single purpose.

Okay, but it seems like a pretty expensive way to ride out a few hours of blackout.

> This whole area has been predicted as a growing market for years, there's others in this thread complaining that it's nothing new compared with less famous competitors, so complaints that it's a product dreamt up to soak up subsidies is a bit odd.

I've been called worse, but my point here is that these predicted schemes haven't taken off because they would depend on MASSIVE subsidies, and Mr. Musk does dream big.

The main point is that everyone should probably have a battery in their garage, but that battery should be in a car, and since business is not working out so well for Musk he is trying to access another source of regulated government support. The economics/policy of electric cars seem much better than home electricity storage, and all the benefits of PowerWall, if they materialize, can and hopefully will be delivered by lithium under your hood. Battery-powered cars will take over America, I just doubt most of those batteries will be made by Tesla.

> Sorry, but as a consumer I pay the same rate day and night, and I think most in the US are like me.

Where do you live? I pay the same rate 24 hours/day as well, but I could switch to a plan with different rates if it provided value to me. I suspect most power companies provide the option at this point.

> Okay, but it seems like a pretty expensive way to ride out a few hours of blackout.

Is there actually a cheaper option, aside from sitting in the dark with flashlights and making sure that no one opens the fridge or freezer? If you want to ride out a blackout without basically sitting in the dark, you need either a big battery backup or a generator. My in-laws put in a whole-house generator and I think the total cost was nearer to 30K than 3K. (Edit: Actually, just looked at generators and they seem closer to 3K, so I have no idea why their setup would have cost nearly 30K. Edit2: They probably installed something closer to a 25kW generator, which would explain much of the cost.)

> The economics/policy of electric cars seem much better than home electricity storage, and all the benefits of PowerWall

A battery in my car will spend a large chunk of its time somewhere else. It's in intriguing idea to use the car battery this way, but it means when I take my car out, my backup power is gone. If I have solar panels, it also means my daylight charging is also gone (assuming I'm gone, with my car, during the day). So I think this would be great, but would not obviate most of the value of a home battery.

With respect to blackouts, I guess it depends on what's the typical pattern where you live. If it's a short outage (<= few hours), my personal reaction is "who cares?" The main one I worry about, living in the Northeast, is an extended outage in winter that could result in frozen pipes. Spoiled food due to an extended outage in the summer would be annoying but that's a much more bounded cost associated with a rare event. And a battery probably wouldn't last long enough to help in a > 24 hour outage situation--which is when protection would be needed.

I agree that $30K sounds like a lot for a generator. I periodically think about looking into it; I've never seriously priced the whole thing out--generator, connection to house, installation, enclosure--but my expectation us that it would be less than $10K. In such an event I certainly have no problem minimizing my electricity use so long as there's enough juice for the furnace in the winter and the refrigerators.

I'm not aware of an option for non-fixed rate electricity where I live.

his reasons: load shifting, self consumption, backup, (saving the planet from global warming)

This is much more groundbreaking than it may appear. The innovation is entirely in the price.

At $3500, you can put in two and be entirely off grid. Solar panels are cheap enough you only need batteries to last one night, as you can size the array to operate your loads even on cloudy days.

2 is not enough. 4kW seems to be the maximum potential drain from the battery. That wouldn't power an oven… let alone anything else at the same time.

4kW inverters seem to be around the $1000 mark… but they don't seem to increase linearly (10kW inverter $4000 for example).

Of course you could go totally off-grid, but the cost isn't going to be just $7k… it's likely to be at least $15-20k by the time you get everything you need and installed. At that price, you could've bought a larger capacity deep-cycle storage solution already readily available on the market with batteries that will last 20+ years.

Obviously there is a lot more than just the batteries. In solar systems, $7k is not a big amount compared to all the other expenses.

I'm assuming you'd minimize your loads, it is silly to size your solar system for a business-as-usual set of loads.

You definitely could, but that will increase costs even further. You're potentially replacing all your lighting, climate-control, water heating, cleaning (dishes/clothes), cooking & fridge/s to be more energy efficient also.

Actual power storage is a reasonably small cost (probably < 20%) in even the solar, power equipment (inverter, switches, controllers, etc), power-storage equation anyway if you want to go completely off-grid. So why does this product make anyone more likely to switch than the existing options?

Going off grid isn't something one does lightly.

Which was my point :).

You seemed to be suggesting you could just buy 2x $3500 batteries and go completely off the grid.

Obviously you can't go off grid without a solar system, what would charge the batteries?

To quote from the original post:

"Solar panels are cheap enough you only need batteries to last one night, as you can size the array to operate your loads even on cloudy days."

> At that price, you could've bought a larger capacity deep-cycle storage solution already readily available on the market with batteries that will last 20+ years.

Citation? Deep cycle lead acid batteries have a maximum life expectancy of 5-8 years, even if aggressively managed.

Iron Edison talks about their Ni-Fe batteries lasting 25+ years.

http://ironedison.com/iron-edison-usa-series-nickel-iron-nif...

But do they actually warranty them for that long? I could find no mention of a warranty on their site.

They provide a 10 year warranty on their Ni-Fe batteries… but their spec sheets allow for a much longer lifespan: https://ironedison.com/renewable-energy-batteries

Price reference? Looks like they are 2x Tesla's price.

My 2200ah Lead Acid bank is still healthy after almost 20 years.

Just did some load tests yesterday.

Are they flooded? Do you have to maintain them? I assume you keep them in a battery box that's ventilated?

Tesla's product requires none of that to be done.

The key to successful Solar Living is an understanding of energy efficiency.

Suggesting running an electric oven on solar is crazy talk.

So if your main priority is carbon what do you do, use a wood oven?

Use the heat directly, like in a concave mirror?

Maybe a solar oven? Unlike Li-ion batteries and solar cells, you can make a solar oven without mass production and using materials fabrication technologies available 2000 years ago. (You can make it cheaper if you use modern mirrors instead of polished bronze.) Typical solar cells are 16% efficient; your pre-medieval-materials solar oven will be about 50% efficient.

Have you ever tried to bake in a solar oven? In anything less than ideal solar conditions baking either fails completely or takes a long time.

I admit that I haven’t! However, I think you’re talking about baking in a crappy solar oven, not baking in a solar oven in general. For example, http://www.solare-bruecke.org/infoartikel/Papers_%20from_SCI... describes a 3.4m² kilowatt prototype solar oven successfully used to cremate chunks of goat meat at temperatures of 800° to 900° in under an hour.

Larger solar ovens (usually known as “solar furnaces”) can reach 4000°, adequate not just for cooking or even cremation but also for firing terra-cotta, blowing glass, calcining lime, firing earthenware, making glass, firing porcelain, calcining portland cement, making borosilicate glass, casting aluminum, melting porcelain, purifying metals by zone melting, casting iron, smelting iron, casting steel, melting lime refractory, making quartz glass, casting basalt, boiling aluminum, vaporizing steel, vaporizing quartz, vaporizing lime refractory, melting tungsten, and sublimating graphite. Although people have been doing most of these with solar ovens for a while, especially the famous solar furnace at Odeillo, you can’t do all of these with Iron Age materials; apparently if you want to do anything useful with melted tungsten, you have to use Ta₄HfC₅ or similar.

Of course none of this works when it’s cloudy or dark, although molten-salt heat storage might be a usable solution to that even at a household scale.

I could use an exotic molten-salt-backed oven, or I could pop in a third battery pack for $3500.

Are you really saying that a metal bucket full of saltpeter (tree stump remover) is “exotic” compared to a giant electrical battery based on lithium, a metal which doesn’t exist in nature, violently explodes on contact with water, and needs a solid-state electronic charge controller to keep the battery from exploding when you charge it? Why would you say something like that?

By itself it's not exotic. Using it in molten state to cook things is exotic, yes.

Lithium clearly exists in nature. Elemental lithium might not, but they don't make the batteries from that either.

Molten salt also explodes on contact with water.

A charge controller is unnecessary. It's just a cheap way to improve efficiency. The bucket of salt would have a similar controller.

Also since price isn't a part of the equation for whether it's exotic, feel free to mentally replace the lithium ion battery with a lead acid one, made out of utterly boring materials and full of water.

You have some good points. I didn't realize that lithium-ion batteries didn't actually contain metallic lithium! I thought they did, just like nonrechargeable lithium batteries, but you're right. Thank you!

However, I don't think it's true that the charge controller is just a cheap way to improve efficiency; it's actually necessary to keep the battery from exploding like a firebomb when you try to charge it.

The bucket of molten salt has a much higher energy density for cooking purposes, although you're right that this only becomes an overwhelming factor if you consider joules per dollar instead of joules per kilogram. Lead-acid batteries are 0.17 MJ/kg; the particular molten saltpeter mix commonly used for energy storage is 0.16 MJ/kg just from the melting, plus another 0.3 or 0.4 MJ/kg from melting, depending on the temperature range. The practicality difference is that saltpeter costs US$1/kg, while lead-acid batteries cost about US$6/kg.

>However, I don't think it's true that the charge controller is just a cheap way to improve efficiency; it's actually necessary to keep the battery from exploding like a firebomb when you try to charge it.

You only need to worry about it when you're riding near the edge of what the batteries can handle. If your solar array outputs 4 volts and needs a minimum of 6 hours to mostly-charge the batteries, and your batteries are in a nice cool basement, I'm pretty sure you can just hook them all together. It wouldn't be ideal but I don't think you'd have any real fire hazard.

Well, you clearly know more about Li-ion batteries than I do, so you’re more likely to be right about that.

Just make sure you prepare your evening meal at noon in the Winter... Solar ovens are not a practical means of cooking unless you've dedicated your life to being off-grid and have few other obligations.

Is it that crazy? The amount of energy you'll spend on an electric oven isn't that large, relative to your overall consumption, unless you run a bakery or have somebody in your house who does nothing but make cookies and bread all day.

Most people don't cook/bake every day anymore, but I do. My wife is a baker and a foodie; we are always making something.

However, I replaced my electric with gas last year.

" 4kW seems to be the maximum potential drain from the battery. That wouldn't power an oven… let alone anything else at the same time."

4kW is enough to power an entire home continuously, without thinking about energy use, even a large one with a home office with several people working in it + washing machine + oven + electrical stove at the same time. I have the data to prove it, too - 10 second interval power consumption logs for the last 4 months for my house/office, and I never had a load of more than 3.5kW. To be fair, this is all with modern, top of the line appliances, so yes that 199$ no-brand Chinese oven will probably draw a lot more power, but still.

Worst case, you'd need a second 'peak power' supply, which could provide e.g. 6 or 8 kw for 10 mins max, maybe using some sort of XXL capacitor. I don't know about the EE side of this, or whether such a thing exists already, just saying - 4kW is perfectly feasible and even heavy users would maybe need just a little bit more.

(of course this also assumes you have a better quality house than the standard American cardboard 'house' in which you need A/C running 24/7 just to not die in summer).

> I never had a load of more than 3.5kW

Different issues over the pond, my kettle can draw 3kW :)

Since so many of my countryfolk have something similar, this actually causes our energy production quite severe issues when popular TV shows finish. Often a 200-400 MW spike but at the end of the 1990 world cup semi final penalty shootout against Germany, there was a spike of 2.8GW.

An interesting example of some of the problems that could be solved at least to a large degree by local batteries.

http://en.wikipedia.org/wiki/TV_pickup

I wonder if this will move more from ones in the home to ones placed by the national grid. While every house on my road might have one, and it's not enough to cover the load from a kettle, one for the whole street could cover it just fine as long as we don't boil them at an identical time (the worst case there is basically equivalent to the normal case for individual batteries).

"Different issues over the pond"

Well depending on which pond you're talking about, we're actually on the same side :)

" my kettle can draw 3kW :)"

True, you have some special circumstances in your country. You'd still be better off with a boiling water tap, the cost of which (even when amortized over only a few years) is the same as using a kettle (when accounting for all costs - lost energy, water, installation costs etc). So for somebody implementing this in the UK, they'd have to budget for an additional 1500 pound up front cost - which has the potential to turn into a cost saver after 5-10 years (probably closer to 5, depending on how fast energy costs will rise - which I think is fair to expect will be at a higher-than-linear rate).

> my kettle can draw 3kW

Pretty awesome for when you want that coffee ready in like 30 seconds flat, huh?

A 2 or 3 kW kettle is pretty common in the UK. We enjoy a good queue, but not to have to wait for a cuppa.

My air conditioner is 12 kW. No chance.

If your air conditioner actually draws 52 amps at 230 volts (or 110 @ 110 if you're in the US), you must be air conditioning a gym hall with a black, tin roof somewhere in a desert.

But you're probably not, and that was my whole point - my stove top is rated at 10kW, too, yet even when using alongside all other appliances in my house I have never gone above 4kW actual use. Actual need != summing all the nominal maximum rated loads of all appliances. In other words, it's not because your AC is rated 12kW, that you'd need 3 of these battery packs just for the AC. You might need 2, or maybe 3, I'm not saying that 2 (or 4) kW is enough always, everywhere for everybody - but there is no 'normal' (middle to upper middle class) home anywhere that would need 5 or 10 of these units, as is suggested at various places in this thread.

To be honest, I don't know. It has 12kw on the outside. It's a DC inverter ducted system. I had to get the wiring to the house upgraded with 3 phase when it was put in. It doesn't use 3 phase but one of the phases is dedicated to the aircon. My electricity bill in summer is 20% higher.

Is that the output or the input? If it's the output (i.e. the amount of heat coming out of the condenser outside your house), the input might be only 5kW or even less.

(Probably some jackass is going to downvote me because they think this violates conservation of energy, but no — those 12kW coming out of the heat exchanger include the 5kW of electrical energy that went in, plus another 7kW of heat that’s being extracted from the air being conditioned; and if you were to try to run a heat engine off that 7kW of heat difference, you wouldn't be able to recover the original 5kW. All perfectly thermodynamically copacetic.)

Not a chance without an investment in energy use optimisation and/or a change of habits. 12kW is a _lot_ of power.

Thank you for mentioning this. Too many people in this thread forget that not everyone lives in a temperate coastal area.

Wow

This thing could sell like crazy in places like India. 10 kwH is enough to power an Indian home for more than a day and at 3500 dollars most middle class people would consider buying it seeing how frequent power cuts here are.

10 kWh is good spec. But $3500 is around Rs. 2.1 lakhs. That's a way too costly UPS(inverters) considering a 1kWh one costs within Rs. 25k and bumping it two more car batteries.

Really? According to wiki, India's middle-class makes anywhere from $10 to $50 per day. When you factor in that this will cost a lot more than $3500, would these really sell like crazy?

For a small percentage (just enough to match inflation), I'd gladly loan an Indian middle-class family the money.

Great idea. I can't afford to loan this amount, but I do make micro-loans regularly on kiva.org. Would love to see some loans appear there for these kinds of power systems.

They can afford scooters, which cost one quarter that much. On $50 a day, it could be saved for in less than a year even if it costs $5000. Relative to their income, Indians have a lot of savings, due to their high savings rate (30%+). India's accumulated household wealth per adult is $5500. If you have two pairs of parents and one pair of grand-parents in one house, that is 6 * $5500 = $33000. Could be worth it, IMO it depends what is the lifetime of one such installation.

EDIT: Thanks for the correction on scooter pricing.

You get a good new scooter in India for less than $1000.

You'll find about 50 million people in middle class in India, who'll earn about $1k a month. Once you buy it, ship it, install it etc, I think $5k is a pretty typical cost figure.

That's quite steep. It's nearly 50% of your income. Also consider that as a rule, generally, the less affluent you are, the smaller percentage of income will be 'disposable' income. i.e. if you make $100k, you might have $60k in essential expenses, the remaining 40% of your income can be spent on savings or non-essential consumption like holidays. But if you make $5k like an average person in India might, you'll be hard pressed to not spend the vast majority on essential spending. So an investment that's 50% of a 1-year income may sound reasonable, but not when 95% of your income normally goes to essential expenses. That'd mean that you'd have to forgo 10 years of your entire disposable income to finance this.

Now how essential is it? I've traveled both in Africa and Asia and am familiar with powercuts (hell, I'd get em monthly in Montreal, too!) Generally though, it's not something I'd spend a lot of money on to fix. Cooking and heating is still gas powered. Essential lighting tops out at 100W, no need for a $3.5k battery that can deliver 20x that power. My smartphone/laptop are battery powered.

I mean, don't get me wrong, power cuts suck and nobody likes them. And for businesses (different story) they can be a disaster. (e.g. check out the World Bank 'Doing Business' reports [0], they look at power cuts affecting industry. It's a big factor)

But for homes? Most people cope just fine. You lose your TV and maybe your wifi if you don't have mobile internet, the rest can be managed.

Anyway India is obviously going to become a huge market, but that's a pretty long-term thing. You have hundreds of millions of middle class consumers in OECD countries who have the purchasing power and different motivations (environmental), backed by governments that are shifting to pro-solar, and huge profits-first industries that are seeing solar drop to super competitive prices within the next 10-20 years. India probably won't be a huge market in comparison. China perhaps, they're bigger, have more solar capacity and more purchasing power.

As for the scooter, you can buy 5-6 of them for the price of installing one of these, new, let alone second hand. And they're an essential part of transportation for which having nothing, or public transport is often not a viable alternative.

[0] http://www.doingbusiness.org/reports

True, and also it would have to compete with a typical generator using petrol.

$3500 is 217000 Rs and $5000 is 310000 Rs. That's simple too expensive for a Battery pack. The prices need to be far lower with a good ROI for this to work in India.

I'm going to install a 9kW solar grid on my roof in the next couple of months - capital cost is ~$40K USD. Without the Power Wall, I'd be selling power back to the utility at around $0.10 / kWh, and buying it back at $0.09 / kWh in the evenings. The Power Wall will also let me endure grid outages as well (you can't run your house on your solar panels directly).

I'm really curious about what the end-user cost is going to be for one of these batteries, after distributor markup and utility company rebates. Would be interesting to see if it pays for itself over the 10 year lifespan of the batteries.

I just reserved one.

Is it really worth it if it really takes 10 years to break even (and that's the lifespan as you mentioned)? That's like giving someone a 10 year 0% interest loan.

Maybe you're better off buying a bunch of Tesla stock with that money if you think they'll stick around that long.

If you're only looking at it from a financial perspective, it may not be "worth it" (I haven't done the math).

But if you want to pay a little to be able to have reliable power from unreliable sources, then it could be "worth it". It may save you zero dollars over ten years, but during that time you're provided the service from this system.

But even if the life time cost for the energy is the same, if you can afford the initial payment, why wouldn't you do it? Especially if there are other advantages to the newer technology?

> But even if the life time cost for the energy is the same, if you can afford the initial payment, why wouldn't you do it? Especially if there are other advantages to the newer technology?

There's an opportunity cost. You'd have to weigh the lost gains you could make elsewhere to the advantages.

$40K for 9kW solar sounds really expensive, I advice you to shop a bit or consider Solar lease. I have a 10 kW plant from SolarCity installed in late 2013. It is a prepaid 20 year lease, meaning I own the electricity and they own the panels, and the total cost (including installation, pv, inverters) to me is about 10K.

You seem to be getting a 1 cent more for the electricity, so your only motivation for this must be to have a back-up. But the 7kW powerwall is daily cycle, it may be a OK backup but not beyond a day or two.

Where I live (WA state USA), there are some crazy tax incentives here for solar. Rough math:

1. 30% rebate on federal income tax, so that's $12K back in the first year. 2. $0.54 / kWh WA state energy production credit which is capped at $5K / year. The estimated power production of a 9kW array over 1 year should get me pretty close to $5K back. The production credit expires in June 2020, which means that best case I get $25000 back from the state.

Without factoring in energy cost savings, I nearly break even in 5 years. Energy cost savings are somewhere in the neighborhood of $1200 / year with solar.

If the only rationale was energy savings, it's not a good investment. However, the tax incentives make it very attractive indeed.

More details on WA state incentives here: http://www.solarpowerrocks.com/washington/

That is some killer state energy production credits. Now your plan makes complete sense.

> 9kW solar grid on my roof in the next couple of months - capital cost is ~$40K USD

That's crazy expensive. My parents just installed 5kW last month in Australia for $10k AUD (and the government rebated them $5k AUD) so their out-of-pocket was $5k, or $1k / kW, fully installed, including the inverter.

As someone from a country that gets less sunlight, how do you know the difference between good solar cells and less efficient ones?

Get quotes from a few different places, and read the specs on the panels they're offering.

How many decades is the ROI on that?

Today is a big deal.

Open sourcing the patents to build fully solar-powered electrical grids around the will be a paradigm shift in the power structures of the world. I expect from today onward there will be a full-scale attack from those who stand to lose because of the reduced dependency on oil.

First they ignore you.

Then they laugh at you.

Then they fight you. <--- WE ARE HERE

Then you win.

As someone who avoided the startuposphere so that I could focus on climate change activism and pricing carbon, seeing Elon Musk implore the world to avoid winning a Darwin Award was so incredibly rewarding and validating.

He will most certainly be fought tooth and nail, but he has allies.

> I expect from today onward there will be a full-scale attack from those who stand to lose because of the reduced dependency on oil.

Maybe. But remember we don't have the technology yet to completely move away from fossil fuels. The biggest issue I know of is making Airplanes electric which so far has not proven really feasible (as far as I can find anyway). This solves a huge chunk of issues but there are still plenty more before we can claim we have the technology to completely transition.

I'm excited for the possibility however.

Well, not jets, but propeller craft might be within reach:

http://www.electronicsweekly.com/news/design/power/siemens-e...

While it's a long way off that's pretty neat! Thanks!

Elon has been working on an VTOL electric jet. He references his desire to fully develop it often. Obviously, he is extremely busy, but he says he will try and work on it at some point.

Zepplins can be run with very minimal environmental cost. They are slower, though.

Airplanes are extremely energy-hungry and carbon-intensive. Just one intercontinental round trip can put as much carbon per person into the air as a half a year of driving, assuming you have a new-ish car. And yes, this is after dividing the total emissions by the number of passengers.

An intercontinental round trip is in the range of 10-15k miles, right? That's a plausible mileage for 6 months of driving, sure. Would match up with my understanding that fuel use for planes per passenger-mile is about the same as for cars with just a driver.

The big difference, of course, it that it takes a lot less time to travel that many miles in a plane. But on a per-passenger-mile basis they're no worse than non-carpooling cars. Admittedly a low bar.

It's an issue for sure, but at ~5% of global CO2 there are other easier sources to target first.

https://en.wikipedia.org/wiki/Environmental_impact_of_aviati...

As I recall, Musk says that if you can double current energy densities, electric airliners become feasible. That could happen in some decades.

If that doesn't happen (or if he's underestimating what it takes), then I figure the solution for air travel will be synthetic fuels. Synthetic fuels are not very good right now simply because it takes a lot of energy to make them, but if energy is cheap and abundant because, say, the world is covered in solar panels, it's less of a problem.

Most of the power in the US comes from coal. Solar is 0.4%: http://www.eia.gov/tools/faqs/faq.cfm?id=427&t=3

What do you do with the batteries and the toxic materials inside when you're done with them (and how long do they last)?

What do you do with all the toxic materials produced during mining, refining, and production of batteries and materials?

How do you deal with these same issues as they affect solar panels, which are made of silicon?

> Most of the power in the US comes from coal

No, that's not true. Most power comes from sources other than coal. Yes, coal is the largest single source but it is < 50% and decreasing every year.

Decreasing perhaps, but it's being offset by natural gas, which is yet another hydrocarbon and comes with its own slew of hazards and problems.

Methane is less harmful than coal by far.

That's good, because the next century will likely be fueled by Methane Hydrates from the ocean floor.

Are you satirizing some hypothetical ignorant anti-solar activism movement I've never heard of?

1. As already posted, no, coal does not produce most of the electric power. It does dominate other sources though. The problem with your rejoinder is it assumes the past, not the future generation fleet. Musk's goal is to enable renewable generation, eliminating coal.

2. There are no particularly toxic materials in the batteries. Landfills accept discarded lithium batteries as regular waste. While lithium is not currently economical to recycle, by the time the industry is as large as the lead-acid battery market (a very toxic product chain) it will be just as easy to recycle lithium.

3. What toxic materials are you referring to? I'm not aware of anything that stands out, especially compared to coal mining, or tar sands production, etc. Lithium mining in particular is a very similar process to the one that produces table salt from salt flats. The biggest problem is the use of water in areas that are very water-poor, ie the Atacama desert.

4. Silicon is non-toxic and inert. There are some hazards associated with dust particles during production, but those are easily handled by proper manufacturing processes. Perhaps you were thinking of thin-film solar panels, which may use e.g. Cadmium? They're less common and seem unlikely to displace silicon PV in the near future.

>*"What toxic materials are you referring to? I'm not aware of anything that stands out, especially compared to coal mining, or tar sands production"

Water usage, along with the carbon emissions from the large diesel vehicles that are actually digging the stuff up.

Emissions from vehicles are eminently fixable in the long term, with the very batteries they're being used to produce.

A quick analysis of our local (St Louis) rates for an average (1700 sq ft) suburban house indicate that time shifting to get peak rate savings isn't worth it:

Payback time on the 10kWh battery would be around 26 years, and on the 7kWh battery would be 33 years.

So, at least in the midwest, I think you'd have to be either using a ton of peak energy or coupling the battery pack with solar to make the investment worth it.

And as long as utilities are forced to buy back electricity at market-or-higher rates, there's zero incentive to every use a battery system with solar.

It's perfect for data centers that need UPS and generators for outages.

Isn't that the idea though? Solar + battery + electric car = no gasoline, electricity, or natural gas bill.

If the average car gasoline bill is $3000/year, electricity is $1000/year, and we demand a 5-year payback, we can spend at most $20,000 on a solar+battery+car system over what we would spend on a conventional gasoline-car and grid-house.

Yeah, that's the primary use, but there has been speculation here and elsewhere that a battery could be worthwhile just for exploiting the difference between peak and off-peak rates. This indicates that, at least for my area and usage, the answer is no, it's not worth it.

Unless we actually started taxing carbon emissions, in which case you could see those numbers change very quickly. I'm not saying it's likely, but you can't assume your future payments for specific items will stay consistent years in the future.

The maximum temperature will be an issue here in Australia. In a typical place where it will be mounted, i.e. the garage, the temperatures will readily get over 40, close to 50 during summer.

I could see this also being a problem in places like Nevada and Arizona in the USA.

I think the minimum temperature will actually be a larger problem for the U.S. There's a lot of states where it easily gets colder than -4 F throughout winter, but the max will be a problem too.

110°F is going to be a problem even in SoCal potentially.

Though, I guess you could somewhat justify using solar power for cooling the battery when the temperature gets excessive. Presumably you'd be getting peak power at the same time you get peak temps.

-4F is definitely not that low, but at the same time when the house is heated, garage is going to get some of that heat as well.

If your garage is getting to 50°C you've got a major insulation problem! Where are you located?

In both cases if min and max operating temperature are an issue it may be best to install in an FIP enclosure and use ducting to keep the enclosure and an optimal temperature.

In many houses, the garage is outside of the insulation; the garage itself has very little insulation between itself and the outdoors, and there's lots of insulation between the garage and the "habitable" parts of the house.

My garage door faces the southwest meaning it gets hit by the sun for a good chunk of the day. It easily gets to 120F during a Houston summer in there.

Store it underground.

In Canada, the temperatures dip well below -20C regularly, but not 10 feet underground they don't.

It takes months of sub-zero above-ground temperatures to even break the freezing mark and crack pipes that are 6 feet underground.

Proof, if anyone still needs it, that Tesla is a battery company that builds cars, not a car company that builds batteries.

How big is their battery business compared to their car business?

Check back in 24 months.

effectively zero until their battery factory is built, but their money is being put where their mouth is.

Very shortly, its going to be as big as the entire world's lithium cell consumption currently.

1/2 or more (by price) of their car business is battery business.

So why not solar power (1kW), storage (3.6kWh) with 25+ year life, inverter (2.8kW) and other electrical systems for just USD$8,702.

The batteries are only USD$2,910 of that.

http://ironedison.com/edison-power-plus-system

You are probably right, and from a quick technical comparison it looks like a much better deal. Definitely not an expert in this field.

At the end of the day Tesla is generating mounds of press, and as a result will probably sell (or in this case reserve) more units.

What if one has already dozens of photovoltaic solar panels, and just need a good energy storage solution that lasts many years? I trust Tesla more than some others companies that they can deliver it.

You shouldn't. Tesla have a much shorter track record than someone like Iron Edison.

Also… if you read my comment, you'll see the batteries are cheaper than Tesla's… and if you look online, you can see they come in various configurations… rather than predefined 10kWh bricks with 2kW output.

History repeats itself :) Prepare for the 2nd round of Edison vs. Tesla!

Am I missing something or are Iron Edison's batteries almost twice as expensive as Tesla's? I'm not adjusting for Tesla's reseller markup.

I must say Elon is a brilliant engineer but not the best of orators.

As an investor, I'll take this anyday.

Indeed, it seems much more authentic than any crisp marketing mumbo jumbo.

I would agree. He's not very compelling.

I find it endearing. Makes me trust him more and not make him seem like a shyster selling snake oil.

I was thinking the same as I watched it. I was wondering if there were some technical issues to explain the slow start of his speaking part and if he might have been frazzled from whatever happened behind the scenes.

He was the same at the Dragon 2 launch. I get the impression that he doesn't rehearse for these events much, probably because he's probably got much more important things to work on.

Who cares, he will be remembered in history. Tony Robbins will not.

One of the best orators I've ever heard was a CFO / COO of a company I've worked for. I was in awe of how great his delivery was, how he had great comedic timing, and how empathic he seemed to be with his audience.

Turns out, from people who worked with him, he was a complete imbecile, and completely incapable of getting anything done.

I'll take the substance over the sizzle any day of the week.

How do you define "best"?

He's not the smoothest or most polished by any means. But he grabbed my attention and kept it from the first moment, because it's sincere and informative. I didn't feel like I was an anonymous member of an audience in front of a multi-billionaire. I felt like I was at a small gathering of nerds where one of them was enthusiastically telling me about his latest cool project.

Apple is often considered to set the standard for these sorts of events. I've been watching Apple's announcements since long before they were cool again, and I enjoy them a great deal. But I'll take Musk's halting sincerity over Steve Jobs or Tim Cook's empty polish any day of the week.

This is very clever! They're trying to increase demand for batteries independent of sales of vehicles, thus driving the economics of battery cost down and driving their vehicle prices down as a result. Get more batteries out there in different forms and use that demand to make the rest of their portfolio more affordable. Very rational strategy! Let's see what demand is like for their battery products.

Also given they just built the world's largest battery factories, it makes sense to sell some more batteries.

This is also Amazon's strategy with AWS (in terms of servers, not batteries)

> 7kWh or 10kWh

Can anyone speak to what that could power? Could I run a load of laundry with it? How about dry it afterwards? Here in Italy people mostly take advantage of "solar power" by hanging clothes to dry, but just to get an idea of what the battery could run.

that would be an interesting comparison.

could you (eventually) save time and money by using an electric dryer + solar power + battery as opposed to hanging out clothes?

Not as long as you're connected to the grid, and the energy you're wasting could have otherwise been sold.

To put it in perspective: in Florida, in the summer, using a 4ton very old/inefficient AC in a 2000sqft house in 100 degree summer weather, electric oven, refrigerator, washer/dryer and all other household stuff. I would burn about 3kw / hr in the middle of the day. So in theory the 10kwh would power a extreme case like this for ~3hours, and 9 of them could do it for ~27hrs. So yes you could do everything you would normally do with household electricity with this.

Moving to geothermal heat pump for the AC would drastically drop your peak power consumption.

As a fellow (part-time) Florida resident, I'd encourage you to send a comment in to the Florida Public Service Commission:

"The Florida Public Service Commission (FPSC) staff is gathering information regarding enhancing development of solar technologies in Florida. To this end, we encourage individuals, businesses, and utilities to provide input on demand-side and supply-side policies and programs, and any other information that would be useful to the FPSC. Comments should be limited to 20 pages, excluding attachments.

The comments are due to Lee Eng Tan via e-mail at LTan@psc.state.fl.us on June 23, 2015 by 5:00 pm. Please note that comments provided to the FPSC will be public record and will be posted to the FPSC’s website."

http://www.floridapsc.com/utilities/electricgas/solarenergy/...

Interesting numbers if you contrast them to another comment on this article saying his A/C was 12kWH.

I'm not aware of any consumer level ACs that draw that kind of juice. Given 10¢/kwhr (for easy math) that would still cost $1.20/hr or ~$8xx in electricity per month just for the AC.

I hope they have taken the safety technology from their Tesla vehicles and put it into their Tesla Energy batteries, because the thought of a 10Kwh lithium-ion battery exploding in my garage does not sound like the kind of mess I would want to be cleaning up. I couldn't see it mentioned anywhere, but presumably these batteries will be available in Australia for the same price? We always get charged more. If I can get one for $3500 AUD, count me in!

They certainly won't be $3,500 AUD.

3,500.00 USD = 4,447.86 AUD according to xe.com right now...

That, and the factory is in the USA. I would assume shipping something that large and heavy would add to the cost in Australia.

> That, and the factory is in the USA. I would assume shipping something that large and heavy would add to the cost in Australia.

Put it on a boat. Shouldn't cost more than shipping inside the US.

You still need to ship it inside the US to the boat dock, and then pay to put it on a boat, and then pay to ship it from the australian dock to the homeowner.

Freight costs are so cheap they're essentially negligible. There's a reason why it's cost-effective to make stuff in China, and ship it all the way across the Pacific to the US, instead of just making them in the US.

It's still $1,000 AUD above what OP was hoping for even at free shipping costs.

Yes, so the only extra part is the boat in the middle. Boats are cheap. (OK, Australian unloading costs are crazy from what I've heard, because of the unions here..)

Dont count on it, we also get the product release lag for things like this too. Buying a Tesla Car here is at least double what it is in the US too.

Double? Try 10%,

Telsa Model S 70D:

USA: USD$75,000 cash price = AUD$95,153

AUS: AUD$102,400, the other AUD$13,893 you pay (in NSW) is to the state and federal governments in various taxes.

Admirably, tesla is the only premium car company that is not gouging Autralians on price.

The gouging done by BMW and Mercedes is shocking. I expect Tesla to really start to cut into their sales.

hahaha less than zero chance these would be in oz for that price.

Comparably the USD3500 price is pre US state sales tax. Its really $3850 (assuming 10% sales tax) after costs and converted today is AUD4891.50. Given historical price discrepancies in Australia of +40%, you are prob looking at AUD6800.

Elon mentioned during his talk that the batteries contain all the same active thermal management and safety systems that are in the car batteries.

The main advantage of Lithium Ion is the high energy density which is good for reducing the weight of laptops and electric cars but doesn't seem that useful in a house, especially when you compare it with cheaper and longer lasting battery technologies.

This feels more like them trying to find a new business line for their existing technology than coming up with the perfect technology for the home market.

There's been some talk about end-of-life electric car batteries getting recycled into these kind of devices, they may be priming that market too.

I'm sure it is about finding more uses for their existing technology than coming up with the perfect technology. If you could sum up both SpaceX and Tesla in one phrase, it would probably be "perfect is the enemy of the good." You're much better off taking something that's good enough that you can get right now than you are trying to invent the perfect technology.

You should be able to put this thing on the top of your Tesla (it even looks like a roof box) to double your range!

Tesla car batteries are between 60kwh and 85kwh. These packs are 7kwh or 10kwh. Not going to get you that much farther with only a 10-15% increase in capacity...

To those who say that this battery doesn't do anything new and lead acid is cheaper, I would like to refer you to this article.

http://www.thebestpageintheuniverse.net/c.cgi?u=iphone

How hacker friendly is this?

I'm not crazy enough to do anything fancy. But I would like to build some metric system to see the data and usages. If I can some how hack it so that it keep track of which devices uses the Tesla battery the most.

I highly doubt that will be possible. Actually I think it is entirely impossible, but I'm trying to future-proof my statement :-)

The battery system will just know how much power is currently being used. It will have no way to identify which devices are currently drawing power. For that, you'd need something like this on each outlet: http://www.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/...

Maybe future smart homes will have the Kill A Watt built-in to electrical outlets for monitoring purposes.

I imagine you will be able to get metrics on current usage, peak usage periods et cetera.

It may be possible to use non-intrusive load monitoring to determine the devices. However, I'm not aware of any products on the market using this tech.

http://en.m.wikipedia.org/wiki/Nonintrusive_load_monitoring

I live in a condo in Toronto, and peak hour electricity is more than double non-peak. How do I install this and have it charge during off hours and use the battery during peak?

Germany has implemented so much solar they can overload the EU grid.

Batteries are the next thing for them. Many of the comments here aimed at the States make sense. Use cases aren't as broad here for many reasons.

But, who says these have to be sold here?

Great move, IMHO. Storage is a growing concern. Most all of the renewables suffer from variances in production.

Elon is likely thinking globally. Just get storage production moving and boot strapped into self-sufficiency. Doesn't matter who buys it, just that they do.

Costs drop, scale improves on things, and he's positioned to take advantage of materials science as it yields better / more diverse options. Think of those aluminum batteries just announced at Stanford. The energy density is lower, but they charge very quickly.

If those prove viable, they can be added to the Tesla catalog, and if their life time is high enough, might just be perfect for augmenting things like solar and wind.

Any news on international orders? I live in Australia, and would love to integrate this as a full off-grid solution.

I wonder how many years this battery will last before requiring replacing?

Storing power over the course of the day is an intriguing idea, because the house is generally empty then. Instead of selling back to the power companies, I would rather have it power this battery so that my night time use is "free".

See an analysis of whether this makes sense for home, business, and utilities: http://www.purewatercraft.com/thinking-about-energy-storage-...

For those interested in investing and finance, I have a question.

Why would this news not cause Tesla's share price to go up?

It seems generally well-received (well, as much of an indicator as 812 points on HN is). Surely that's a good sign? Or did the announcement not live up to the hype, causing people to dump stock?

Tesla stock price has been gradually increasing the last week or so in anticipation of the event, so the event has already been "priced in." Further, the FOMC (fed) recently scared the market, because interest rates may be rising some time in the future (September? December? who knows), causing people to switch from investing in equities (stocks) into treasury bills. In short, this information was already anticipated but it also had to fight the FOMC announcement.

Thanks. Makes sense.

Buy on the rumour, sell on the announce. Sharetrading 101.

buy on the rumour, sell on the news.

I know they pitched this for solar, but I bet that won't be the most common use, at least initially.

My power company (XCel, if it matters) keeps trying to install a "Saver Switch" in everyone's house to shut down their A/C when demand is high. Basically they want to load shed your air conditioner, and they're willing to pay you for the privilege.

This is a lot more expensive, but it's also a hell of a lot more versatile. How much would it be worth for them to subsidize installing these with a switch that would let the utility remotely toggle you off the grid at their discretion? Plus it would actually save consumers money in any market with tiered electric rates. Plus it would help them deal with the intermittency of solar power.

Massive news for doomsday preppers everywhere...

Great, except that all these nice batteries are produced with extremely toxic processes, involve heavy metals, and consume a whole bunch of fossil fuel during their production. Hardly a good case for the environment when you factor everything together.

Lithium-Ion batteries aren't all sweetness and light, but it's not a particularly dirty process compared to Ni-Cd, and certainly you have to factor in benefits of reduced generation.

> have to factor in benefits of reduced generation

Well the outcome really depends on how long they last before you need to replace them. Plus you have the take in account the recycling cost (for the environment as well).

Ni-Cd batteries are so bad for the environment that the EU is forcing companies to phase out their use. Saying that Lithium Ion batteries are better than something that's been banned for most purposes because it's so toxic is not exactly high praise.

I would like to buy one. Can we use it in Western Europe? Will it be certified for the EU power grid network? How long will the battery last (expected battery life)? About 7-8 years would be the minimum, but is that the lifespan of lithium batteries?

I might spend $480 on electricity per year. I can't see this thing having an ROI within its lifespan. I also don't have solar panels, and have a very reliable power grid. Any reason I should consider buying one?

I know people who spend $480 per month.

Yep. I had electric water heater (60A @ 120v) and still use a small electric AC unit (12A). And I still can't find anything that matches incandescent or halogen lights (I'd pay a lot for real, bright, warm lights, not the ugly yellowish fluorescent, or the weird off-white LED stuff - some LEDs are getting close, but not good enough for residential). Electricity costs were over $480 some months.

This is Guatemala, where I don't trust the grid much. I ended up buying ~$1000 worth of portable battery backups (UPS) and plug them in wherever I need it, but they need replacing every couple of years.

It'd be much simpler to have a simple battery pack, although I'm not sure this would handle the load.

Yeah, anyone in the northeast US with electric heat.

Electric bills in Hawaii can top $1000/month.

IIRC, that's because of the silly way (given Hawaii's abundant solar and geothermal resources) in which most electricity is generated in Hawaii: burning imported fossil fuels. If the local renewables were fully exploited, I can't think of a reason for costs to be so high.

You're right! Hawaii's utility is fighting against solar installations, and I see Tesla's energy solution coming in to push the uptake of solar installs in Hawaii.

You don't have to wait on the utility for their approval if you're not connected to them.

The island layout doesn't help either. The geothermal resources are all on the Big Island, and that's also where it would be easier to install large-scale solar facilities. But the main energy usage is on Oahu, and there isn't an inter-island power grid.

We spend over $2,000 per year and it's just me and my girlfriend. From the sounds of it you have either very good rates or perhaps a frugal lifestyle? Either way it's impressive.

I think it depends on local weather. We spend about $600 on electricity and $600 is gas per year for 4 people in the Bay Area. And this is with an older water heater and furnace in an old house with moderate insulation. We would replace the heater, furnace and improve the insulation before even considering solar ourselves.

+1 to first upgrading your home. I live in the Bay Area but in a tightly sealed late 90's 1600 sqft house. No A/C. Recently upgraded our furnace and water heater to high efficiency models, and now spend about $400/year electricity, $400/yr for gas. Even accounting for the warmer winter this year, the gas savings was about 14%. There are pretty good incentives in the Bay Area for home energy upgrades if you do multiple at once: https://www.bayareaenergyupgrade.org/program-overview

We spend less than that for a family of 5.

But that's not impressive at all; all these numbers really depend on what that electricity is being used for. Our heat and hot water are not electric. AC doesn't get used much, since we're far enough north (Massachusetts) that it's not a big deal. So that leaves lights, electronics, and the stove/microwave/vacuum...

My parents, on the other hand, are in the DC area, electric AC, heat, hot water. They're spending probably triple what you are on electricity.

Anyway, point is counting just electricity spending is typically comparing apples and oranges. You want to include the natural gas or oil or whatever else people are using for heat if you want to get numbers that are even remotely comparable.

I think it depends on your house size and whether you have a pool, etc. When we lived in an apartment, we spent $40-50/mo on utilities total.

I have a family of 5 in a small home and we spend $1200/yr in pricey CA (rates start at 16c/kWh going up to 35c). We don't run AC (whole house fans/attic fans), and use room heaters in winter.

While I think this announcement is great news, there are at least two caveats to keep in mind that can mine the long term value proposition:

- If there are many users, the peak/non-peak price differences (arbitrage) will disappear. This is because of supply/demand law.

- If solar energy/battery storage takes off, it will be heavily taxed. There is an impending "Sun tax" being implemented in Spain, that aims to make more expensive running a home solar source than taking power from the grid. If necessary, they will tax Lithium.

So the Tesla value proposition is in all cases short term.

If Peak / Non-peak is smoothed out, one could argue prices may fall.

Your analysis of the arbitrage is faulty - if there's a cost associated with time-shifting energy, then the gap will only narrow to the extent that it's still economically justifiable for people to invest the money in time-shifting energy. What you're describing (no peak/non-peak difference plus people still buying batteries to time-shift energy) isn't a steady state - why would people continue to buy the batteries when they're going to lose money on the deal? You'd actually expect the gap to be the price difference per watt plus some additional amount for the capital and inconvenience.

Also, if there's significant arbitrage, it will also reduce peak prices - because of reduced demand, and also because of reduced costs of expensive additional capacity. I.e. it can reduce energy costs for people who don't use it.

Yes, what I meant is that each Tesla battery sold will contribute to reduce the peak price and to increase the non-peak price, effectively reducing the gap that is the basis for the value proposition.

Because of this effect, the value proposition for existing Tesla battery owners will lower over time. Ironically, the ones that benefit at long term are the non-owners because their peak time price will be lower.

I wonder if Elon and the owner of SolarCity will get in touch. Oh wait... ;)

I actually really wanted him to put his "blue square" in context. Would have been interesting compared to land area dedicated to rooftops, parking lots or something.

How well do you think these would work in RVs when paired with the number of solar panels that fit on top of an RV? Would this work well at burning man vs running a generator?

You'd have to calculate it and your expected power usage. You probably wouldn't be able to run AC on full all day without a massive solar array. Check out how big a 100w solar array is, how many of those can fit on your RV roof, and how much power your AC uses. You'd also need a big (and not 100% efficient) inverter. Also take heat and dust inefficiencies into account.

TL;DR you're better off going in on that industrial diesel 3-phase generator rental which comes on its own trailer.

I felt the 'area needed in the US' to be a bit disingenuous. I very much recommend David Mackay's Without the Hot Air, a great talk he did at Harvard on area required can be found here:

https://www.youtube.com/watch?v=GFosQtEqzSE

Beyond that, very glad to see this happen. It's one of the factors necessary to push a sustainable electrified future forward.

I suppose this must be better than storage heaters. Not sure how big these are outside the UK, but basically they use off-peak electricity to heat bricks that then slowly release the heat the next day. We had them when we were a kid and they were rubbish.

http://en.wikipedia.org/wiki/Storage_heater

Is there anyway to model the energy saving costs of these in like a small town?

I mean if power stations only had to produce N/kW/h at a constant rate to power every home in the region then would there be any energy savings? Instead of the typical, scale back at night, boost up during the day system?

If we could calculate the energy usage of every home down to the Watt then surely there wouldn't be any waste?

I'm curious if local governments will give subsidies to aid in distribution of such devices - many places have issues with the power grid.

If everyone had these and they were all attempting to "charge during nonpeak hours" wouldn't those hours become the peak hours?

If enough people had these in their homes then there would no longer be "peak hours" or "non-peak hours", I would think that this would normalize the grid so that pricing is always fairly consistent.

Which is more or less the point, of course. If you can even out the peaks and troughs then you can make all this stuff much more efficient.

Of course, that assumes that generation can be consistent. Right now, that is the case. If we took the existing grid and just gave everybody batteries, we could make power consumption flat throughout the day, which would greatly reduce costs. That would be cool!

The idea is that in the future, solar dominates. There you inherently have peak and non-peak hours, because you generate more electricity at noon than at midnight. This is completely impractical if you go straight from generation to use, because the times don't match up. But throw in storage to flatten it all out, and it works.

Implementation of such technologies is exactly what I worked on in grad school, and now I'm happy that a company like Tesla is actually gonna bring it to the masses. Batteries are essentially the "killer app" for the power-grid, and will accelerate the adoption of renewables with stochastic power outputs such as solar and wind. Thank you Tesla!

The max temperature basically makes it a no-go in much of the so-called "sun belt" where solar power conditions are optimal.

In those areas I guess you just install it inside the home somewhere, which is the whole point of making it look decent.

This would all make more sense if they made solar panels to go with the powerpack. Otherwise, it's just a huge battery.

SolarCity is another startup that Elon chairs... The idea is that the batteries and the energy generation process/supplier don't have to be the same.

I think this is a move that will break the focus rule for a startup. Batteries _and_ cars. There is room for only one.

Wright brothers: focus on wings or controls or engines! you only have room for one!

Apple: focus on hardware or software! Macs or iPods. You only have room for one.

Edison: focus on lights or electricity! You only have room for one.

Uber: focus on the driver network or the app! You only have room for one.

It's not a hard and fast rule. The point of focus is to get you to prioritize what important, but something you need to do multiple things.

The problem with all of your examples is they still only sell one thing. Tesla now sells 2 things. That means sales, marketing team, strategy, support, for 2 things. Like, having 2 companies.

Another example, Standard Oil: don't just sell the oil. Refine it, and sell the kerosene, and the lamps, and also sell the gasoline, and when you're left with paraffins invent paraffin candles and sell those too...

Ha! The aboriginal Americans have nothing on Standard Oil. They just used every part of the buffalo. Standard Oil invented uses for every part of the oil.

GM sells more financial instruments than cars.

With the hoped roll out of more electric cars charging them will place an undue load on the grid, if it isn't orchestrated. Tesla plan to be able to control when they discharge to the grid, so this could go some way to reduce stresses on the electric grid when more people want to recharge it. Just a thought.

$3500. Nice!!!

That's the price to the installer. They'll mark it up, and then you have the necessary accessories and installation.

This looks more like a $6,000-$8,000 item once it's all up and running. Gonna have to run some math here to figure out the ROI.

Yeah this doesn't factor in Solar Panel Costs and the cost to install this power pack.

I'm intrigued at the backup possibilities, because we live in a forested area of the northeast where outages are common during storms. But at 3Kw a single unit isn't large enough to power our entire home, and I didn't see a figure for how long it can operate at peak load. If I need two then we're getting closer to the cost of a natural gas fired generator. This analysis, of course, is completely ignoring the environmental benefits.

10kWh and the details will be forthcoming I am sure.

3kW is the power, 10kWh is the energy. Your 10kWh battery would discharge in 3h20min at peak power.

Or, you could listen to music on your 250W sound system for 40h.

I thought he said the wall unit was 10 kwh?

EDIT: Unless you mean it's limited to a 3 kw power draw - looks like it's 3.3 peak and 2 continuous.

can we just try living without electricity for 2 days? millions of humans did it for hundreds of years prior to us and they managed just fine

During hurricane Sandy our family was without power for 12 days. What's the longest you've gone?

My power bill is rarely more than $60/mo. ROI just isn't going to happen. Am I missing the point of this product?

The AWS roll-out also seems like big news. Last I checked, data centers accounted for 2-3% of domestic energy spend, and they typically feature backup batteries and generators. Tesla may have entered the (enormous) data center market the moment it broke ground in Nevada.

Tesla vs Edison, Round 2.

Interesting twist that this time around, Tesla is pushing for DC, while Edison is behind AC.

I believe the Chinese innovator BYD has a portfolio of similar products already. BYD got some press play in the West when Warren Buffet invested in them. They are making a slow patient push in the U.S with electric buses after flopping with electric cars.

A German company is doing this too. Nice to know it's more like an industrial movement not just one company doing it. There is hope.

http://www.asd-sunstorage.com/

Here's the link to live stream: http://www.teslamotors.com/livestream

One interesting thing to note is the collaboration with Amazon...

> The world currently consumes 20 trillion kWh of energy annually.

> Enough energy to power a single family home for 1.8 billion years or supply energy to a nuclear power plant for 2,300 years.

That's, ..., not the way I would have written it.

The map graphic at the beginning was pretty powerful (please excuse pun)

You can buy a used Mitsubishi i-MIEV (early electric car with very short range) for less than $8,000.

So, do that. Then strap one of these Tesla home batteries on it.

Bam!

(NB some experience with heavy-duty DC electricity required.)

I can't wait to see the first users proudly cutting their connection to the power grid, claiming they are now energy independent and free from oppressive utility companies...

It would be cool if Tesla could also come up with something to improve batteries used in portable devices, so we can use phones or laptops more than 1-2 days without recharging.

How sustainable is putting a large lithium battery in every home?

I doubt they would install one in an RV... but I can dream.

Likewise for boats. It's high time we stop using lead batteries in vehicles where weight matters, and the pricing on this looks great.

I thought about boats as well.

Do you know the weight and dimensions of this?

It looks like it is equivalent to 835 Ah @ 12V. That is 10 lead batteries. You probably can buy more than 3 lead batteries for 300 dollars, but the weight and 10 year warranty does look attractive.

Those would be crap lead acid batteries at $100.

I have 500 Ah in 4 AGM batteries that cost me $1200. If all that 835 is usable I'd have to spend $3600 to come close with the same AGM's I'm using now.

Enough energy to power a single family home for 1.8 billion years or supply energy to a nuclear power plant for 2,300 years

I think I see the problem...

Do these green numbers take into consideration the energy expended on producing the Li-ion batteries? Surely that must be a messy mining operation.

Can someone please share what a single family home can do with 10kWh?

If I pay for this do I have to plug this thing into my own electrical grid to keep charging it?

According to http://www.eia.gov/tools/faqs/faq.cfm?id=97&t=3 the average U.S. home uses 10,908 kWh/year, so this would be enough to keep the home running at full load for about 8.4 hours. Not bad.

If you took steps to reduce consumption (avoiding using heavy demand appliances like electric ovens, etc.) it would last a lot longer. With a little care, you could probably run for a couple of days on one of these, particularly if you had LED lights, etc.

Due to the fairly low peak power draw the battery supports (3 kW) you would have to avoid using those heavy appliances anyway, especially simultaneously.

For Australia - 19.5kWh in winter and 16.4kWh in summer.

http://energymadeeasy.gov.au/bill-benchmark/results/3660/4

It would be interesting to see what is the daylight vs. nighttime usage. And if you can daisy chain these batteries. Seems like a few would be needed to ensure for high usage days if you wanted to be largely self-sufficient.

I predict Venezuela will be the biggest importer of powerwalls to cope with daily outages.

Who knew oil-rich but impoverished countries would help fuel innovation.

Venezuela has almost no dollars. They don't have the money to import toilet paper much less multi-thousand-dollar battery installations.

Venezuela has plenty of money from oil which goes to the hands of the power elites and their cronies and families.

So yes, while 29 million people lives in total poverty, there is one million families that would benefit a lot from that invention, and they will get it, believe me.

Do we know the prices they're charging for the utility versions? Does it make it a viable option for a lot of utilities?

I'm amazed at the price. This actually makes it competitive with whole house generators at least for backup electricity.

As the picture shows, can this evolve into a battery station residing within the garage? Experts please share your opinion.

Pretty decent pricing, good enough for developing nations with power cuts where people currently use diesel generators.

Well done Tesla. Next project? I have an idea. How about standardizing battery packs for robots.

Forget the USA.

Imagine what these decreased battery prices are going to do for solar power in LEDCs.

How is lithium mined and disposed of? Is that much of an issue?

Feels like we're finally living in the future.

I thought Panasonic made batteries for Tesla?

With

it sounds so awesome, are there any reasons why I shouldn't get this?

2 billion battery packs, and how many solar panels to feed them ? Did I miss the number ?

The solar panel count was not mentioned. Though he did show the blue square and the red dot for the USA.

Right, that one pixel was 2B powerpack. Solar Panels are quite larger than powerpacks, but that still looks like a large number to me.

A lot of the stuff Tesla is saying about this is quite weird. (In the press kit and in Musk's live stream.) For example, the first sentence of the press kit:
> The world currently consumes 20 trillion kWh of energy annually. Enough energy to [...] supply energy to a nuclear power plant for 2,300 years.
Am I missing something, or is that an entirely bizarre comparison to make? What does this even mean?

> Batteries are not a source of energy. They store energy. (You'd be surprised at how many people don't grasp that.) Talking about how many batteries we need to power the world without talking about where that energy is coming from is silly.
I'm not sure why you got such a weird impression. In his talk he clearly states that the power would be coming from solar energy. He even explained how much space you'd need for solar arrays and batteries if you want to provide the entire United States with power day and night (the biggest need for batteries).
He also mentioned there is utility for the battery to be used with your powergrid but the big win is using it with solar energy.

Not a direct reply, but to put some scale around the numbers:
20,000,000,000,000 kWh = 20,000,000,000 MWh = 20,000,000 GWh / 8,760 hours/year ~= 2,283 GW average steady-state generation, globally.
A typical utility-scale nuclear reactor produces around 0.5 GW.

My tweet from a few days ago:
It would be poignant if Tesla (the company) decentralized power generation & storage considering free energy was Tesla's (the man) dream

Everyone has known what this announcement was going to be for a month.

I wasn't implying that I predicted the future. I'm commenting on how this brings their product mission more in line with their company name.

Hey, for fun let's use this to do a rough math check on Tesla's future plans.
The battery is $3500 for 10kWh.
Model S with a 270kWh battery is advertised with a range of 240mi.
Model 3 aims for a minimum range of 200mi, or 5/6, a.k.a. 225kWh battery.
225 is 22.5 * 10.
22.5 * $3500 = $78,750.
Model 3 is supposed to be $35,000.
I believe in Elon Musk completely and I want nothing more than to see him succeed and I have been blown away by what Tesla Motors and SpaceX accomplish at every turn.
But even so, I will be amazed again if the Gigafactory can truly make the price point feasible. I really believe they'll do it, I just don't see how.
Can the factory's massive gains in efficiency really change things by such a huge factor in 2 years? (Model 3 targets 2017, doubtful.)

Your battery sizes for the cars is way off. The Model S has come with a 60 (no longer available), 70 and 85 kWh battery. The 240 mile vehicle is the newer 70 kWh battery.
70 is 7 * 10. 7 * $3500 = $24,500.

Yeah I have no idea how I managed to add 200kWh in there. Thanks for pointing that out. Wow.

I am not really sure what you are calculating here. That being said I am pretty sure that the model s has a 270mi RANGE, not a 270kWh battery. It has a few options, like 85kWh or 70kWh. It has been published that the model 3 will have a smaller battery, and be a smaller car. Being more efficient at the vehicle level, coupled with cost savings of vertical integration, will allow use of a smaller and cheaper battery.

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