Why batteries both thrill and terrify the U.S. utility industry | Hacker News Reader

Why batteries both thrill and terrify the U.S. utility industry

bloomberg.com

159 pointsdotluis190 comments

From the article:

...said Ellen Hayes, a PG&E spokeswoman. “Having a solar panel that isn’t connected to the grid is like having a computer that’s not connected to the Internet.”

Patently false. It's a great way for them to rationalize their continued existence. But as rooftop solar takes off and the "smart grid" fails to materialize I suspect that you're going to start to see federated neighborhood grids running at 48VDC.

Anything less than 50V isn't regulated by the NEC which is why you're supposed to hire an electrician for new or major upgrades to your house wiring but nobody cares if you put in low voltage pathway lighting, doorbells, networking, etc.

That means that although you'll have to buy thick copper wires, people can wire themselves up with their neighbors LEGALLY to share power. That's a big deal. It doesn't take all that many people to be connected to substantially smooth out fluctuations. Most A/C doesn't run all the time, it's only supposed to be about 15 minutes out of every hour. So if I and four neighbors team up then we might need 5kW of solar panels between us instead of 5kW each. At least if it's somewhere sort-of temperate where A/C isn't crucial at night.

The power electronics to make this happen are getting cheaper by the day. Sure it means having to talk to your neighbors and some retrofitting, but that's doable. And with a lot of new equipment having VFDs in them from the factory (refrigerators, mini splits, even a lot of A/C compressors) it means that the cost of converting them drops even more.

I might be mistaken but I think 5KW can power your whole AC and a few other appliances, no?

Yes, most of the time. My small house routinely exceeds 5 kW though.

What appliances/devices are you using when that happens?

Think about anything with a heating element in it (if electric): * Water heater * Dryer * Oven/range * Microwave * Coffee pot * Toaster [oven]

Those can get "spiky" depending on who is in the house.

I just started monitoring my electricity but I believe any two of these would do it: AC (electric), Dryer, Dishwasher

Air conditioning is my guess. Ours burns about 4kW by itself.

It doesn't take much. A fan heater in a bedroom 2kW, a small heat pump / reverse cycle AC in another room 1kW, a couple of computers 0.5kW - 1kW, the fridge-freezer 0.5kW, hot water system 3kW - 6kW. A large AC could be 3 - 5 kW alone, not at all uncommon in Australia. Houses here are notoriously poorly insulated.

I'm in a rental sharehouse, there's a 6kW electric heater fixed to the wall in the kitchen / dinning room / lounge area. I suggested to my housemates perhaps we don't want to pay to run that thing, followed by $1200 winter power bill. Maybe next winter they'll think twice about running it so much.

My morning routine uses about 6-8 kW just in the kitchen for a small period of time:

1. Tea kettle, 2 kW

2. Microwave, 1 kW

3. Oven (cooking parbaked rolls for 8 minutes), 3-4 kW

4. The refrigerator may or may not go on during this period, ~0.5 kW if it does

Of course if really necessary I could be more careful with staggering my appliance usage. But as it currently stands I don't worry about using those kinds of power loads for short periods of time.

Not the original poster here, but I've got 5kW on my roof and it can often out generate the house load but there are times when it cannot.

There are interesting "moments" when my house spikes in power usage. One is a combination of 'freezer compressor' + 'refridgerator compressor' + heater fan + oven + microwave. (I don't have whole house AC but do have it in one room). I'm getting better at monitoring individual circuits in my house to understand exactly where power goes.

Generally an 'average' day in Northern california my total usage for the day is 25kWh

The NEC doesn't do any regulating nor do they have any authority. They write standards that states may or may not adopt and use for their own enforcement. That's why Romex is illegal in Illinois and New York has it's own code.

You're right, of course. But given how many people/counties/cities/etc just accept NEC recommendations, it's functionally equivalent for a huge portion of the US.

In a single building DC could work. Thick wires are expensive (and always will be), so in a neighborhood it's probably best to just go ahead and hire an electrician if you need one. EDIT: actually I believe the cutoff at 50V isn't because it's safe to be shocked by current below that, but because phone line voltage is 48V and the NEC doesn't want to step on the phone company's toes.

I've done a fair amount of line-voltage house/business wiring myself, and I've never taken any electrician's tests, but then again this hasn't been in highly unionized/severe inspection locations.

You can kill yourself with a single 9 volts in theory http://www.darwinawards.com/darwin/darwin1999-50.html

I was told in introduction to electronica that sadly it's terribly easy, and the teacher claims he has seen it happen. If you manage to take a 9 volt battery and scratch yourself with it (very easy with the negative contact, not so easy with the positive one), and both sides contact blood directly, the current may flow through your hart and may stop it (CPR will restart it, but that of course assumes someone's there to do it, and that people realize what's happened in the first place).

I can't believe someone actually stuck essentially needles connected to a power source into his blood. What. The. Fuck.

Correct. It is total power delivered. You can still short 48V wires and start a fire with high enough current.

Yes, most car-battery injuries are burns from inadvertent tool shorts. Always disconnect the negative post first, and connect it last.

EDIT: yes I'm sure. As wtallis suggests, isolation is important. But while the battery is still connected, there is no isolation. In that configuration, if you have a tool on the positive terminal connector and it strikes any other conductive component of the car, that's a short, which could heat the tool and burn you (among other things). If instead you follow my advice and disconnect the negative terminal first, when striking e.g. a fan pulley your tool is simply an additional connection from the frame to ground, which has no effect. (After you've disconnected negative, a connection from positive to the frame is not a short.)

Are you sure that isn't backwards?

I was thinking that too, until I remember that current flows from the negative terminal. Electrons have a negative charge. Because when Ben Franklin was deciding what to call things, and made a guess about which way it flowed, he guessed wrong.

Negative vs. positive doesn't matter. What matters is that you isolate one of the battery terminals before doing further work. If you've got a single wire attached to the negative terminal and several attached to the positive, then the breaking the negative connection gets you the most safety in the least steps. If there's only one wire to each, it doesn't matter.

Yes thick wires are expensive, but there are plenty of places where houses are only 50 feet apart.

That means your round-trip run is only 100 feet so you can look at this chart (http://en.wikipedia.org/wiki/American_wire_gauge#Tables_of_A...) and divide the Ohm/kfoot by 10. If you used 4 gauge that would be 0.24 ohm/kfoot or 24 milliohms per 100 feet. 24 milliohms on 100 amps is 2.4 volts of droop or a 5% loss. Not awesome, but as an engineer, acceptable.

The 4 gauge is available in quantity for less than $1/ft. 1 gauge is available for about $2/ft neither of those prices are all that daunting.

If you lived on the ideal setup where you have neighbors on either side and off the backyard you could wire 6 houses together for less than $1000. Divided 6 ways that's $160 as a one-time cost to be able to be a lot less careful about your power usage. Hell everyone could net-meter with each other and settle up occasionally if someone's consumption got severely out of balance.

The thing that I really like about this (and which perhaps makes me overly optimistic) is that it would spur a lot of neighborhood engagement and re-forming of communities in the suburbs, which is somewhere that's severely lacking in a lot of places. Perhaps that desire is clouding my rationality; I can't say for sure. But I can say that with the population's general mistrust of large institutions growing by the year idea like this are going to look more and more attractive as time goes on.

https://www.google.com/search?q=millennials+distrust+institu...

My impression, from a number of years in suburbia but admittedly still with a limited slice of it, is that a lot of people who like to live in suburban areas find a need to coordinate with neighbors over resources actively distasteful, and would rather buy them in an impersonal sense from a general provider. I.e. it's not just that they prefer the physical form-factor of a house to an apartment, and would otherwise be fine with some of the communal resource-negotiation that goes on in apartment (central heating, common maintenance of the electrical system, etc.). Rather, one of the things they prefer about suburban houses is that there isn't much need to coordinate with your neighbors, over anything more important than maybe trimming your common hedge at the property line.

5kW at 48V is over 100 amperes - absolutely no offence to you personally, but anyone handling this without training and precautions is absolutely stupid, no matter how thick the cables are.

100 amps deserves to be treated with respect, yes. Just try and break the circuit and you'll see why.

It's basically like a welder. I did some welding a couple weeks ago, right around 100 amps. The output voltage of that machine is probably less than 48 V. Still makes a very pretty arc. :)

While you are correct that 48V is definitely sufficient to cause injury/death in certain circumstances, it's not the current that matters here (e.g. a 1V/5000A supply would have a lower risk of shock).

What will hurt/kill you is the amount of current passing through your body (in particular your heart) and that is determined by the resistance of your body and the potential difference of where it's flowing from/to (I = V/R).

Interestingly, the current required for ill effects is significantly higher for DC vs AC (at lowish frequency) [1]:

  BODILY EFFECT     DIRECT CURRENT (DC)    60 Hz AC     10 kHz AC
  --------------------------------------------------------------- 
  Slight sensation     Men = 1.0 mA         0.4 mA        7 mA 
  felt at hand(s)    Women = 0.6 mA         0.3 mA        5 mA 
  --------------------------------------------------------------- 
  Threshold of         Men = 5.2 mA         1.1 mA       12 mA 
  perception         Women = 3.5 mA         0.7 mA        8 mA 
  --------------------------------------------------------------- 
  Painful, but          Men = 62 mA           9 mA       55 mA 
  voluntary muscle    Women = 41 mA           6 mA       37 mA 
  control maintained                                           
  --------------------------------------------------------------- 
  Painful, unable       Men = 76 mA          16 mA       75 mA 
  to let go of wires  Women = 51 mA        10.5 mA       50 mA 
  --------------------------------------------------------------- 
  Severe pain,          Men = 90 mA          23 mA       94 mA 
  difficulty          Women = 60 mA          15 mA       63 mA 
  breathing                                                    
  --------------------------------------------------------------- 
  Possible heart        Men = 500 mA        100 mA             
  fibrillation        Women = 500 mA        100 mA             
  after 3 seconds                                              
  ---------------------------------------------------------------

The linked article suggests an across the chest current of at little as 17 mA could potentially induce fibrillation. At 48V, this is equivalent to a hand to hand (assuming the second hand is the exit point) resistance of ~2,823 Ohms.

While is this a very low resistance for the body, it's possible with wet hands and a large surface area in contact with the voltage source.

[1] http://www.allaboutcircuits.com/vol_1/chpt_3/4.html

Fibrillation is a problem, but so are electrical burns. 5kW is going to cause a lot of tissue damage.

Your body does not let the 5kW go through it.

While I believe that precisely 5kW will not travel through your body, considering you can arc weld with 48V/100A and your household 120V/10A (1.2kW) sockets can cause severe burns, I think it's safe to say this hypothetical 5kW source could do a lot of damage.

Unfortunately I specialize in low voltage, not high voltage power electronics.

Does not matter if your hand, for example, is in contact with any of the exploding material that comes from a short in a high-current situation.

100A out of 48V requires a resistance of 0.48 Ω.

http://en.wikipedia.org/wiki/Electric_shock#Body_resistance

Amps, as such, are not dangerous unless we are talking about a current source. But practical current sources regulate their output to a given current value by varying their voltage (so it's back to voltage again).

That said, 48V is high enough to be dangerous. See Oli Gaser's answer:

http://electronics.stackexchange.com/questions/19103/how-muc...

> "You can see that as low as 20V may be dangerous given the right conditions."

None taken, but I'm afraid that you don't seem to know exactly what you're talking about either.

Just because something CAN supply 100 amps doesn't mean it WILL supply 100 amps. I can touch both terminals of my car's battery with my hands and very little happens. That's because V = I * R, V = 12 and R ~= 100k so I = 0.12 milliamps or 120 microamps.

Now of course we're talking about 48V not 12V but that's still less than half a milliamp, unless of course you have both of your hands drenched in saltwater and you grab as much exposed wire as you can, in which case the body's resistance is going to be much less than 100k. But for any reasonable adult it's fairly difficult to kill yourself with 48V.

Will people still need to be careful? Absolutely. But the idea is that at least at first, it's much easier to get around codes requiring permits and inspections and whatnot that make it much harder for individuals to do without explicit approval of the government (know how to file a permit? great. are you a certified electrician? sorry...). Given that in many places the government owns, regulates or otherwise has a substantial interest in the electrical utility company this at least temporarily would allow people to do this on their own. The laws could always change, but it tends to take a while at which point there might be enough people doing it that it wouldn't get passed.

It seems good to note that neighborhood power co-ops would smooth out demand fluctuations, but not necessarily supply fluctuations.

Batteries for the supply slack, hot water heater elements to dump excess power into. Concerned about enough supply? Oversize your systems.

Oversizing doesn't help when it's cloudy or the wind stops. You need diversification, which isn't always possible over small (neighborhood-sized) areas.

Oversizing is expensive unless you have a large enough group to distribute the burden. Neighborhoods might not be big enough; they would have to expand to city or county size.... but we already have a system for spreading out the demand and supply balance to larger groups.. it is called the power company.

Depending on how much diversity you need, your neighborhood could add an on-site natural gas or propane generator to the mix.

TL;DR You need to do the cost benefit on a case by case basis.

There's only so much they can do about demand correlation. Electric stoves, for instance, are likely to be used at the same time by most households. That's one reason why really good batteries would be such a benefit.

Having a Leaf EV, I'd very much like to have a 2kWh panel not connected to the grid. Selling power back is uninteresting relative to keeping a 30kWh buffer battery topped off, charged during the day while the car's away, and passing the charge to the car in the evening (ideally at 220V, charging the EV within 4 hours). Other than perhaps being physically located in the garage, it would have nothing to do with house wiring.

the NEC does cover low voltage systems

Federated neighborhood grids could further smooth out large demand fluctuations by networking their cycling devices together so they take turns. The biggest power demands like heaters/AC units/refrigerators/water heaters all cycle on and off, and these cycles could be coordinated so that they wouldn't all be on throughout the neighborhood at the same time.

Smart water heaters could also smooth out some excess supply. The water heater would mix cold water with its' stored hot water in different ratios (depending on how much excess electricity there was and therefore how hot the water is) to provide a constant temperature output.

Yeah, at scale this kind of coordination is really, really difficult. With only 10 houses it's pretty easy.

At scale it becomes easier, since with 10 houses each house represents 0.1 of maximum load, and with 100 houses each house represents 0.01 of maximum load, so there are more opportunities for any particular device to draw power from the grid since there will be more other devices ready to turn off at that time.

Upgrading to city-scale means that the individual consumer will be less likely to have to wait for their electricity ration.

The hard part is defining the system for such a "smart grid" to safely coordinate activities while being resistant to tampering, spoofing, or other cyber warfare.

As an example, a smart grid will be able to deal with "time of use" charging, meaning that solar electricity produced during the early morning or late afternoon will be far more expensive than what is produced at noon/zenith. A malicious party might attempt to fake the production of electricity in order to get third parties to "buy" electricity that was never produced. This will lead to brown-outs as there is more demand than generation, while the fraudster "selling" the fake electricity will be quite hard to catch.

Even worse, a fraudulent network company might decide to under-meter your production so they can make a profit from the extra electricity that you produced that they aren't paying you for.

Starting at the "four neighbours build a DC network" level, how do you determine which of your three neighbours is not producing electricity when they claim they are?

I guess what I meant by "difficult" is from the algorithmic side of things. Let's suppose that scheduling demand is NP hard. For N of 6 this is trivial. For N of 100,000 this is a nightmare, so you end up not with ideal demand scheduling but a bunch of heuristics and approximations.

I can think of a bunch of ways to handle the honesty problem. If it was just say 6 houses I'd probably wire the whole thing as a star and put a current measurement device on each of the 6 hot wires that all connect at the central location. It's then very easy to tell where power is coming from and going to.

Each person could also install their own current measurement device where the power attaches to their in-house system and monitor internally and compare so that way if the central unit gets compromised any individual knows it and can stop participating until it's fixed.

Rather than lots of difficult coordination, why not go a simpler route and make it based on the last digit or two of the street address? It's not a perfect plan, and some smoothing out may be needed to account for the distribution of addresses in a city / state / region, but the plus side is it can be done immediately and without need to figure out what others are up to.

Or maybe not the street address ... use the lat-lon, or phone #, etc.

This is what you want http://en.wikipedia.org/wiki/Vanadium_redox_battery

The extremely large capacities possible from vanadium redox batteries make them well suited to use in large power storage applications such as helping to average out the production of highly variable generation sources such as wind or solar power, helping generators cope with large surges in demand or leveling out supply/demand at a transmission constrained region.

At ~$5/foot for sufficient gauges, this sounds like a rather expensive project.

It's not $5/ft, see my other post: https://news.ycombinator.com/item?id=8706592

Further, even if it was $5/ft that eventually starts to look good compared to a $20/mo charge to have the privilege of being connected to the power grid. This is a concept that utility companies are actively discussing and implementing: https://www.google.com/search?q=power+grid+monthly+connectio...

If it costs $400 to hook up to a neighbor and it smooths supply/demand enough to where you could forgo the hookup fee you get paid back in less than two years.

Is the $20 number reasonable? Maybe or maybe not. The first article in the results is Arizona where the utility asked for $50/mo and got $5/mo. But I pay $15/mo to be hooked up to natural gas and nobody seems to think that's robbery at least where I live. I suspect that politicians might accept $25/mo or more as reasonable with enough campaign donations.

Yes, on the third day, boost converters, buck converters, and wiring with a higher voltage rating would arrive via UPS and that would be the end of the "safe" low voltage neighborhood grid idea; replaced with the much more efficient high(er)-voltage neighborhood grid.

Actually that's a great point! If you're not grid connected I don't think you have to deal with inspections and the like anymore; the inspections are regulations are usually tied in (hur hur) with the idea of being allowed to hook up to the utility company.

Welp, I guess I have to take my stupid idea back then huh?

In some places that'll get your house condemned as "unfit for habitation" or the like.

That's really interesting. Not being connected to grid power means that your house gets condemned.

A part of me wants to believe that there's a justification for most if not all of the laws on the books. I wonder what the justification for condemning an off-grid house is. There are places where it's sufficiently expensive to bring grid power in that people will have solar, wind and generators and that's cheaper at least for any given decade. Should those houses get condemned too?

Or are you talking about in big cities where the house is already hooked up to the grid? Have you got any links? I'd be interested to read about it.

Try this Google fu: https://www.google.com/search?q=house+condemned+off+the+grid

Jesus that's fucking depressing. I knew of the lady in FL but that was just for water; I didn't realize that people were getting condemned for not having what the city considers to be enough electricity.

I can't believe that the hypocrisy of the government officials isn't blatantly obvious to all. Lady can't afford electricity so they kick her out of her house to sleep in her car. Disgusting.

> ...said Ellen Hayes, a PG&E spokeswoman. “Having a solar panel that isn’t connected to the grid is like having a computer that’s not connected to the Internet.”

... "still useful". Is that the rest of the quote?

No, the quote ends. It's hilarious how wrong this lady is. Internet access multiplies the utility of a computer by what, infinity percent? I don't know, but it's a huge freaking number. How much extra utility do you get from having a solar panel grid connected? Maybe 20% to 200% more useful? Certainly not 10x as useful.

http://www.goodreads.com/quotes/21810-it-is-difficult-to-get...

> "Having a solar panel that isn’t connected to the grid is like having a computer that’s not connected to the Internet."

"...it keeps the NSA from spying on you."

There is so much market segmentation potential in that one sentence.

Extrapolating a bit, I'm guessing that she means that it doesn't make much sense for most individual homeowners to manage their own electricity production and storage. Instead what you'll see is more communities adopting Microgrids 'behind the meter'.

It makes sense to be connected because any excess can be sold back to the distribution company at the feed-in-tariff rate. Plus, what happens when a local power system fails?

This is something I've been considering of late. I was an 'early adopter' for Solar and have had 5kW of panels on my roof for 14 years now. Initially we were on a 'watt for watt' type rate schedule with a flat true up at the end of the year (basically net usage would be billed every 12 months). This was a good deal for me, and a bad deal for PG&E apparently. Over the years they have morphed that into something much more in their favor and with the help of "smart" meters have factored in various timing aspects which all work toward increasing how much I pay PG&E even though I am using about the same amount of power that I was before.

The only answer then is to go 'all in' and just cut them out of the equation. But battery maintenance is a huge challenge with lead-acid packs, a fire risk with lithium ones. I'd love to have a locally owned and operated 'storage depot' where I could shove my excess power to the depot, and pull power when I needed it (like being grid tied) but consolidate and amortize the cost of maintaining the power storage component across a bunch of customers.

Can you legally do something like use the solar power for your lighting or small appliances and use the company's electricity for your heating? With different sockets and wires?

Why wouldn't you be able to?

If you are asking why I don't end up with a $0 bill it is because PG&E builds a per kwH 'cost' schedule that includes various tiers of usage. But they don't adjust how much credit I get by baseline usage.

As a contrived example, let's say Baseline is 200kWH and .10 per kWH, and I use 300kWH which is billed at 200kWH at 'baseline' rate, and 100kWH at 'premium' rate of .125 per kWH. My "billed" cost is $32.50, If I then generate 300kWH I get "credit" for 300 baseline rate kWH or $30.00, and have to eat the difference between the baseline rate and the premium rate or generate and extra 25 kWH to cover the difference. I've had extended phone conversations with them and they completely understand that this is exactly the situation, they are pretty pleased with themselves for getting it through the regulators.

Yes, I could do that.

What I can no longer do is come out revenue neutral if I generate exactly the same number of kwH that I consume in a 12 month period.

I don't think that would be fair anyway. There is more value in electricity than net kwH used in a year. Ignoring other value that power companies provide (such as supplying for large demand fluctuations over days and seasons) and asserting that you should get them for free seems disingenuous at best.

Interesting use of the term fair. If I had 'super capacitors' or pretty much any 98% or better charge storage device I could take my house off the grid and give the power company zero dollars for power. In my ideal world I would set up solar to nominally charge the base load charge supply for my house, and power the house from the base load charge supply. In the event my base load charge supply dropped below a set limit, I'd use natural gas to run a fuel cell for some number of hours to get the base load charge supply back into the right zone. I continue to use gas for heat applications (stove top, dryer, house heater, water heating) but would be no longer part of the electricity grid.

Right now, to do this costs more than the 'surcharge' I'm paying PG&E to be a utility with electricity on demand. But once the economics switch I'm going to kick their electricity service to the curb. And I consider that both right and fair.

> I'd love to have a locally owned and operated 'storage depot' where I could shove my excess power to the depot,

I don't understand why the utility companies can't convert some of their regional substations to local grid level storage locations, to counter this trend. They have the scale to utilize larger scale banks of batteries, hire people to manage them, and even exploit more dangerous technologies (like the emerging molten salt batteries).

Simple: Most established companies don't have the stomach for that kind of innovation. They've been delivering their product for basically the same way for over a century, and their shareholders don't see the upside to changing.

Of course, that leaves them ripe for disruption, but the nature of local monopolies makes that somewhat less likely.

Alternative Hypothesis: Large battery banks are uneconomical compared with existing generation mechanisms. Coal/Gas/Hydro are much more efficient and cheaper stores of energy than batteries. This is a major factor is not adopting solar much earlier.

The cost of battery maintenance might benefit from some economies of scale, but even if it did, they'd still pass those costs on to the consumers.

Absolutely. But even when/if we get to cost parity, I doubt we'll see utilities scrambling to adopt the new ideas.

What's frustrating is that many utilities are actively trying to preserve the status quo through legislative maneuvers.

Yeah, that kind of thing sucks.

On the other hand, I think some utility providers are investigating alternative battery tech. Look into Vanadium flow batteries as one option.

The problems with lead acid and Lithium are better handled by Liquid electrolyte batteries, which can scale better and seem to be much more stable in storage scenarios. The downside is that they can be huge, so they'll never be any good in cars, but might be great in warehouses.

The article suggests that solar panels could be an "existential threat" to power companies. For those of you who are familiar with the math of solar panels, how realistic is that prediction? How much of a normal home's energy needs could be supplied by solar panels, assuming the panels covered the entire surface area of the roof? How much is the ROI on solar panels likely to improve in the foreseeable future? (I've heard estimates of 5-8% annual return for 2014.)

I installed a 10kw system ~15 months ago on my 3600sq ft house. Average electricity costs was ~$6k/year before the panels, the first year on solar to total cost for the year was $300.

That $300 worth of electricity for the year is before I've been able to talk the wife in to replacing our incandescent bulbs, swapped out our old pool pump, etc etc - I could easily get that down to below 0 with a small investment in bulbs. So in my case at least, it was trivially easy to get to a net-zero usage.

A few $$ notes - the system cost $37k, I got 11.1k of that in a tax credit from the feds, so my net cost was 26k. I'm saving 5.7k/yr, which means my break even point for the system is 5 years. In 5 freaking years I'm making money from my solar panels! And I don't have to write a $500 check to PG&E every month. It's a beautiful thing...

BTW - the above numbers (plus my severe aversion to debt) are why I'm so against solar leases. If we had a solar lease, we'd still be stuck with monthly payments, would have trouble selling our house, and would be stuck for 20 years.

Where you located? Are we talking Texas or Michigan?

How many units does $500 fetch where you live? Would be curious to know a breakdown of the bigger portion of the pie in those units.

$6K/year sounds really high no? My neighbor pays $100-150/month for a 3200 sqft house.

Yea a $500 per month electricity bill sounds steep to me. When my bill hit $400 in the winter, I realized I had a problem with my water heater.

That's what I thought. My house is about the same size as his and completely exposed to weather. While I live in not-so-balmy Minnesota, it does get well above 90F and humid regularly in summer. Not to mention that the only non-electric heating appliance is the furnace.

I get irritable if my bill hits $250, I'd be freaking out at an average of $500/month.

He says he has a pool and if he lives in california then that pump is probably running all year, probably adds a few hundred a month to his bill.

How much power do you consume a month? Pool heaters can really kill your electric bill.

Welcome to a fully regulated rate structure, throw in the combined weight of years and years of "its for the environment" and the costs go to the people who have the least voice and for many the least ability to pay.

The have so regulated pricing and punitive structures into service there that they have to have assistance programs just to alleviate the burden on middle income and lower consumers.

Where do you live?

Where I live, in SW Missouri, capital and maintenance costs might be higher due to weather (e.g. high winds, hail), and it would be useful during the summer---which the electric company would be generally thankful for, less $$$ peaking power needed---but much less so in fall and winter when it's frequently overcast.

Also, if you live in a place with high electricity rates, like California, the case elsewhere is less compelling. I probably pay on the order of 1/2 of your savings for the total power to handle a building that's almost certainly bigger and thirstier than your's (numbers on request).

Hawaii?

Where do you live? Do you use electricity for heating? I'm in California and for a 1500 sf house, it costs us roughly $600 in electricity and $600 is gas per year. This actually an old house with some insulation. I think it would be more efficient for me to improve the insulation and water heater/furnace before even considering solar panels. I wish they would subsidize these other improvements as much as solar panels.

I'm in an unfortunate area of California where my tier usage is tied to parts of the bay area, but the weather is closer to the central valley.

Our AC and pool pump are big parts of that $6k/year usage, and while AC is a luxury, when it's 105* for a week or two straight and you've got little kids around, it sure is nice.

There are also 2 other factors that feed in to our electrical costs - I work from home, and we have 2 little kids. That means our home doesn't get to shut down during the day. AC, fridge door opening, lights, etc., it all adds up when 4 people live in a house 24/7 instead of being gone during the hottest parts of the day.

You mention the AC and pool pump- and then state that the AC is a luxury :)

I'm in NJ and my numbers are the same. I think it's because we use gas for heating/cooking/hot water. If everything was electric, I can imagine things costing almost twice as much, if not more.

Like "djrogers", I also live under (let's name names) PG&E and their "infernal" tiered pricing. Try paying 30 to 40 cents a kW/h, and also working from home with kids running around during the summer. I live in the Sacramento area, but outside of "SMUD" coverage, so I have to have PG&E. When it is about 100 degrees +/- for 3 months solid, A/C is "life support", not a convenience.

$400/month electric bill, very typical for summer.

I'm absolutely shocked at the PG&E pricing. I'm in Chicago buying power from a 3rd party provide delivered via ComEd, and I'm only paying 8-9 cents/KwH, and that's more than from ComEd directly so I can buy wind power exclusively.

Is it integresys? If so I opted out of that and saved quite a bit of money. (It's the fee that gets you) Going direct with ComEd has it's advantages. Also Chicago has a lot cheaper power than other areas.

FirstEnergy. There was no additional fee in Schaumburg to use them, and I pay 6.65 cents/KwH for 100% wind power (until 2017, at which point I expect the price to plummet).

Northern Illinois has extremely cheap power due to Exelon's nuclear generation capacity (Ameren in downstate us primarily coal-fired). I expect the price in IL from ComEd direct to start going up, as they're going to use their smart meter rollout to start pushing time of day metering (as they should) vs flat rate per kwh pricing.

Yep. That's the standard power pricing throughout California. SCE and PG&E are trying to flatten the tiers somewhat, which will reduce costs for high-end users, but a $300/mo bill is not uncommon for a large house.

Well, PG&E pricing starts at around 10 or 11 cents KwH, but once you plug in a refrigerator (or so), that tier is pretty much used up, and you start sliding up the scale.

Have you investigated the insulation/sealing status of your house?

he said $.3 or $.4 per kW/h. It's not his insulation. That's super expensive.

A high price of power would magnify the effects of poor insulation.

Someone paying $5,000 a year for electric has strong incentives to make improvements, so I was wondering about the specifics, not trying to make a brilliant suggestion that all they need to do is put up some pink foam.

You're partially right: the house is a long "strip" shape that has the living room facing south. We moved in about a year and a half ago, and the back yard needs landscaping to put in some trees on the south side of the house. (shade in the summer, drop leaves in the winter) Now if I can only talk my wife into having something that blocks all the sun coming in that she loves so much...

I grew up in Sacramento and that's completely absurd. Our electric bills topped out at around 200, with 7 people, living in a ~3,000 ft^2 house, and someone was always home running the A/C. $400/month is insane.

How long ago did you electric bills top out at $200?

Good point, that was a while ago. 2008 was the last year I lived in Sac, so around then.

Another thing - in Sacramento county, you probably had SMUD, but Placer, Yolo and El Dorado have PG&E, like most of the rest of Northern California.

California does subsidize upgrades to gas and water heaters and insulation. Check out https://www.energyupgradeca.org/en/save-energy/home/take-con...

I'm in the bay area just replaced my furnace, water heater, and insulated ducts (an 11k job), and I'm expecting a $2800 rebate from the BayREN program (the local program that implements Energy Upgrade California).

https://www.bayareaenergyupgrade.org/program-overview

How long are your panels expected to last, and how much maintenance do they require? Is the 5 year break even point pretty much guaranteed, and considering those things?

They've got 20yr warranties, and require zero maintenance where I live. If you have more rain/snow than I get, or perhaps salt spray etc, you may need to do some cleaning.

Once every few months the monitoring doohickey needs a reboot, but the panels work with or without that.

For my personal situation, unless PG&E reduces their power rates over the next 5 years, I'll absolutely hit that break-even point.

Panel production will degrade over time - the warranty covers something like 3% the first year, and 1% every year after that. So at 5 years I will have less than an 8% reduction in output from the panels. That 8% will be made up by that time with LED bulbs, a variable speed pool pump, etc. Heck, right now out of the ~30 ceiling cans in my house, only my office (4) and front porch (3) are LED. The rest are full 60W sucking incandescent bulbs. The chandeliers are also 60W bulbs too, accounting for another dozen or so lights that are on quite frequently.

What can I say - my wife hates CFLs and barely tolerates LEDs.

You mentioned the reduction in your energy bill, but do you happen to track how much of that comes from selling back to the grid and how much comes from you using your solar power directly? If you're generating 10kW a few hours each day, I would guess that's the only time you're selling back. Would there be any point in an energy storage system for you? I've always had this fanciful notion of having a solar array and building an underground flywheel for storage, but only because I'm riveted by flywheels.

I haven't looked into the ROI of CFLs or LEDs vs. incandescents in a while. I imagine they have improved. Lately, I've even seen some LED bulbs in stores that don't look horrible. Of course, I would buy them anyway just to save time changing bulbs!

I have a similar system, and I sell back for about 80% of daylight hours. That credit covers all of my other needs in the summer (and then some), and about half of my usage during the winter months. When you originally design the system, you use current rates and policies to create a system that generates at most a net zero usage.

I swapped all of the incandescent bulbs that run for more than ~ 15min/day out in our house for some 80+ CRI "warm white" LEDs I got off Amazon. My wife didn't even know I'd changed them till I told her. I noticed the difference for the first day or so, but I got used to it really quickly. I wouldn't hesitate to do it again, and any bulb that fails in my house will be getting replaced with an LED from now on.

Maybe you could slowly transition... replace one bulb a week over the span of a year and she may not even notice :)

Wholesale panels are $500 a kW. That's a lot of markup you had to pay. Definitely much room for improvement on margins.

Labor is a big cost, as well as permitting and the like. It's certainly a business with a lot of profit in it now. As long as the marginal rates of power are high, it's still break-even for the customer fast enough that they don't mind. The feds and the utilities pay the costs.

Well, one of my friends in Arizona has not necessarily his whole roof covered, but he is able to generate about 90% of his yearly energy usage. The only problem is that he doesn't have batteries installed, so he's selling his electricity to the local power company and buying it back. With batteries and a slightly larger system, he'd meet all his energy needs himself. It's definitely possible. One thing that helps is the hot water heater is solar powered as well.

I believe there was a report from US utility companies saying that solar will severely impact their revenue.

http://www.eei.org/ourissues/finance/Documents/disruptivecha...

Without directly answering the question of total capacity, solar does have a few problems that are unlikely to ever make it an "existential threat" to commercial power generation, especially when done at home.

1. It is highly dependent on the amount of sunlight an area gets. This might seem obvious, but is also problematic in that it is difficult to build the correct capacity for climates that vary significantly over seasons. Solar is well and good in Los Angeles, since the weather is very consistent, and the amount of sunlight doesn't vary hugely over the year. In Seattle though, if you were to install enough capacity to be useful in the winter, you would drastically over-produce in the summer. Over production of solar is currently a problem, and can have significant detrimental impact on the overall power grid. Typically, when it drastically over-produces, it can cause blackouts. This is amplified by the fact that solar produces its maximum amount of output at a time when people don't consume the most electricity. This may eventually be mitigated by better batteries, and alternative power storage systems like Vanadium Flow systems.

2. Solar has a maximum capacity, and will likely always need to be mixed with other "on-demand" power generation systems. At present, these are Coal or NatGas generation stations that can be ramped up to meet spikes in demand. Effectively, these plants allow us to store energy chemically in the gas/coal and burn it on demand. very few renewable energy sources have the ability to be ramped up to greater production over short period of time. Again, this problem could be mitigated by substantial battery installations, where a small amount of excess generation from solar could charge batteries that could be drawn on to deal with spikes in demand.

3. Power transmission is always going to be a problem. Solar is less and less viable the further toward the poles you go. Though we could generate power in the southwest, there are practical limits to how far power can be transmitted over existing lines without too much loss.

In all, though it would be possible for Solar to operate a given house or building with on-site generation. It is very unlikely to threaten the power companies, which give us a low-cost, reliable, and simple solution that is capable of meeting our needs.

Is it not possible to "turn off" a solar panels? Worst case, you have to throw a tarp over some of your panels for summertime.

It is certainly possible. The challenge when doing this is that the solar installation that you put in to be able to generate during the winter months ends up being MUCH bigger, and more costly. Most of the ROI models on solar assume that when you do this, you'll be able to "sell" your excess capacity back to the grid.

Many/Most systems I have seen in southern California contribute energy to the grid directly, and power is still purchased through the grid like normal. When your panel is generating, the power you generate and consume balance out and your power is "free", but you don't consume power straight from your panel (a flawed representation of how electric flows, I know).

The challenge with these implementations are that the grid itself handles the power generated by panels, and can't turn them off. The reason they do the installations this way is so homeowners stay connected to the grid to even out their energy spikes, but also to save the homeowner the cost of battery storage systems. In this case, the grid acts as "storage" by accounting, rather than by real storage of energy.

This is easily solved if the utilities get properly involved.

My utility has been pushing a thermostat that they provide at no cost and will even give you a bit of cash for installing. The reason is that this thermostat is hooked up to the utility through the internet and can be shut off by them during a spike or an emergency.

I just got new smart electric meters installed too.

If those meters were a little bit smarter, connected over the net, and had the ability to restrict flow ... they could easily install devices on a per house basis that would protect the grid. That would put the ball back in the homeowners court and the homeowner can implement a solution to shut off the panels when the utility isn't interested in purchasing power back.

Just install an outdoor radiator (electric heater), perhaps with fans if outdoor temperature is very high, and burn off the excess electricity. Switch the radiator on or off by computer. Dirt simple and cheap.

<quote> Typically, when it drastically over-produces, it can cause blackouts. This is amplified by the fact that solar produces its maximum amount of output at a time when people don't consume the most electricity.</quote>

This is a pretty regionalistic viewpoint - in many parts of the world the peak solar production and peak electrical usage are highly correlated due to air conditioning use.

That is very true - I should have been more specific. Solar doesn't generate in the evening hours, when everyone is still consuming their AC, their Lights, their TV and many home appliances.

Pumping workloads (AC, Refrigeration) are fairly static loads on the grid though and don't account for very much (~7%) of the overall energy consumption (http://www.eia.gov/consumption/residential/).

The trouble with solar only really happens when their are spikes, either in over production, or over consumption.

This is where on-site battery storage "fixes" the issue.

Most people are away from home during the day while their battery charges and then come home for a few hours at night when the battery powers the house.

Now, there are certainly cases, perhaps even many of them, where it wouldn't really work out. But for me it's the ideal setup. My wife and I live in a 1300ft2 house and use 250ish kwh a month in electricity including recharging an electric car a couple times a week. A 1.6 kwh system would cover almost all of our energy needs. Couple that to battery storage so we could use the energy we generate during the day when we are at home at night? Perfect!

Is there any region of the world that uses more energy during non-daylight hours? Everywhere I've lived, peak demand is daytime.

You'll see many power companies that offer incentives like this - https://www.pacificpower.net/ya/po/otou/ooh.html

it is still daytime, but typically not peak solar hours.

Where I'm at, today the sunrise was at 09:10, and sunset at 14:30. Peak energy usage is in the evening.

Re #2: is it be possible/feasible for panel owners to sell the extra electricity back to the grid?

This is precisely how most home solar installations work. They provide power directly to the grid and offset the power that they still draw from the meter. Most solar installations feed power to the grid at the meter, so the power company still knows how much power you consume, they just also see how much you provide and then only charge you the difference.

it is this setup in particular that is problematic for spikes in generation, since the power company can't just disconnect your solar array if it is adding too much power at a low demand time.

There's a lot of parameters (load, location, roof size, season), but I think the answer is generally > 100%.

On the other hand, cities don't have the surface area to account for industrial consumption.

I'm making a lot of assumptions here, as I'm not an expert on solar panels (took a class that touched on them once, but I'm mostly just Googling here):

* Typical efficiency of a consumer solar panel to day is about 12%

* Average of 6 hours of sunlight a day over a year, sunlight providing 120 W/m^2 [1]

* Rooftop of about 80 m^2

Total energy over a year comes out to about 2500 kWh.[2] Apparently the average household energy usage in the US is about 10000 kWh[3], which would imply that you could get about a quarter of your energy from solar.

A few caveats:

* Apparently some places get up to 2200 kWh/m^2 per year of sunlight[4], which would bring your solar panel total to about 21000 kWh a year.

* Not entirely sure how big your average rooftop is.

* Solar panels have been created with efficiency in the 40s of percent[5]

Hopefully I'm not completely off with some of these, but it seems reasonable that a rooftop system can provide most or all of your power in the near future, depending on how sunny it is where you live. If it's not sunny, you might have a lot more problems, though.

[1] According to https://en.wikipedia.org/wiki/Sunlight, the World Meteorological Organization defines sunshine as a state of receiving at least 120 W/m^2

[2] http://www.wolframalpha.com/input/?i=365+days%2Fyear+*+6+hou...

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

[4] http://www.nrel.gov/gis/images/map_pv_national_lo-res.jpg

[5] http://www.sciencedaily.com/releases/2013/09/130923204214.ht...

Power is quite a lot higher:

http://en.wikipedia.org/wiki/Insolation#Earth.27s_insolation

(the 250 W/m^2 there is the 24 hour average)

From the link

>> Ignoring clouds, the daily average irradiance for the Earth is approximately 250 W/m2

Emphasis added. Seems like clouds might be a non-trivial factor, yes?

Yeah, clouds matter (obviously, locations vary). GP used an extremely conservative value for the energy available, I was just pointing to a less conservative value.

(The difference between the values is ~8x, I doubt clouds have that big an impact in very many locations)

This doesn't answer your question about residential solar, but it's a useful primer on economic analysis for utility-scale operations.

http://www.eia.gov/forecasts/aeo/electricity_generation.cfm

The interesting bit here is how wind is already cheaper than any other option save combined cycle natural gas, and wind is on track to surpass natural gas.

I've been interested in the viability of those wind towers. The ground is blanketed with plastic tarp about 10ft above ground. It slowly tapers to vertical (approximates y=10^x curve). In the vertical section, there is a scaffolding with wind turbines.

The idea is that the sun heats up the ground. When the wind starts moving, it goes up the chute, spinning the blades.

It was theorized that a 1mile diameter ground cover + tower would give 500 MW of power.

I have a 4.8kW system on my 1700sqft home here in rainy Portland OR and I am net-zero (and that's with everything electric - heating and cooling, water heater, cooking, etc.). But I am also in a certified Passive House, which makes it quite a bit easier...

Building passive houses makes so much sense. Did you build it yourself or buy it?

Bought - I was very, very lucky to have gotten it. But the builder/architect who made mine have built six so far in Portland, none of which have sold for much more than market prices. There's a lot of debate about how necessary going all the way to PH is, there's a "Pretty Good" house movement of just doing more generous insulation / other efficiency improvements, which is also much better than doing the bare minimum required by code. Less is more, either way.

To further comment on djrodgers:

His ROI in 5 years but can possibly be less. Depending on the state/market/utility, the owner qualifies for local rebate incentive, homeowner solar water heating rebates, local labor substantability rebates and SRECs. SRECS are energy credits that are similar to forwards contracts that can be traded on an exchange. The federal tax credit (ITC) is 30% of the purchase price but expires in 2017 to 10%. But, forecasted solar cost drop to 2017 would far cover the itc.

I would point out that most ROI models for solar look so good because of very generous subsidies. If subsidies aren't counted, the ROI time is not nearly so good.

Additionally, the Total Cost of Ownership of Solar will be higher in areas where panels/solar systems are prone to damage from weather etc. Wind, Rain, Snow, freeze/thaw, dust can all damage solar arrays, or negatively impact their performance.

If there are batteries involved, those will likely also need to be replaced before the system has initially paid itself off. Even if batteries get cheaper and better every year, the disposal fees for old batteries and their current inability to deal with house-sized loads well can easily add significant cost.

I don't want this to sound like I am anti-solar. I am a big proponent of solar, but there are many problems with the current system. It is a somewhat unfair comparison no matter what, since the energy we buy from fossil fuel generation does not accurately reflect the cost of the pollution it makes or the environmental harm it does.

"I would point out that most ROI models for solar look so good because of very generous subsidies. If subsidies aren't counted, the ROI time is not nearly so good."

True, without the 11k rebate, my break-even point would have been 7 years instead of 5. I'd still have done it...

Thats pretty good - You also have the benefit of getting alternative return on that 11K upfront, which helps.

Depending on whether you sell your house or not, I assume that the solar system will also generate a reasonably high ROI as an improvement to the home? It would be interesting to see what the real payback time period would be if you were to try to sell the house before its usage ROI were realized.

i.e. could you buy a house, add solar, get the rebate, sell the house after 2 years and still get a return on the solar investment money because you'd improved the value of the house?

A big portion of the existential threat to power companies is the possibility of price-spirals.

The cost of maintaining all of the power infrastructure for a region is relatively fixed, especially if people don't disconnect completely when they add renewables. This cost is generally recouped by a small surcharge to every kWh that's provided to customers. The possibility of a spiral arises when customers start purchasing significantly less power from the utility, which means the per-kWh cost for the remaining customers will have to increase. As this cost increases, the ROI of adding solar panels improves, so more people add solar. As more people add solar, the utility must increase prices to the remaining customers.. etc. etc.

There's also pressure on this spiral from solar installers since the 'soft costs' make up the majority of new installations. As more people purchase systems, the per-installation price will decrease due to installers getting bulk discounts for materials, efficiencies (physical and bureaucratic - dealing with permits, etc.) from previous experience, and a bigger base to spread out the costs of their own capital equipment.

Detractors think that utilities are fear-mongering to increase their operating and price flexibility, which would likely result in higher profits in the near-term. I don't think I buy this theory though, looking at my last bill of about $50, $28 was generation and about $25 was transmission & distribution (T&Ds). PG&E bills T&Ds based on system costs / proportional usage, so if I cut my power, my T&Ds would drop to almost 0, increasing the cost on everyone else.

Here's a pretty balanced article about the issue;

http://www.renewableenergyworld.com/rea/news/article/2014/04...

It seems like the obvious solution is to make transmission and distribution a flat amount rather than trying to amortize it per KWh.

It will likely come down to that but since utilities are typically government-granted monopolies, it will take legislative action to allow changes. It will be a tough political sell since it would actively discourage new investment in distributed renewables and socialize the costs so that the people who used the most energy (and therefore drive most of the demand for T&D) will pay the smallest proportion of their upkeep.

So if the power companies are worried about people buying less electricity, why do they constantly send out power saving tips, and push things like CF and LED bulbs, etc? Is that only because they are required to by law?

Its cheaper to reduce consumption than build additional power plants. The cheapest watt is the one you never needed to generate.

The EPA and various utility commissions mandate efficiency programs, and efficiency improvements are often tied to promises of allowed rate hikes, but utilities also want to shave demand where possible.

An ideal world for a utility would be one where everyone used a moderate amount of energy at all times. The reality though, is that peak consumption is typically 100% higher than the night-time lows. An example from a utility;

http://i.imgur.com/gPR7DNk.png

Most of the efficiency programs are targeted at lowering that daytime peak. You would need less overall generation (saving money on building new power plants) and have a much more stable system if you could flatten that whole curve.

Both increasing and decreasing capacity is expensive. If people use more power, you need to build more power plants, and that costs a lot of money and is politically difficult. If people use less power, you now have excess capital investments in the form of power plants you built in the past.

Their ideal is for power usage to remain exactly constant, or at least grow at a constant pace that matches local realities. The population and their power use wants to grow faster than that. Efficiency helps to compensate for that.

You'll also note that a lot of the efficiency tips are aimed at peak consumption. That's not the case for light bulbs, but there's a lot of stuff around more efficient air conditioning. Peak power is much more expensive than average, and in many places the power company can't charge residential users accordingly. Air conditioners tend to be used at peak usage times, so decreasing that peak usage can save them a lot of money.

I think it's that power companies depend on a very broad customer base to support their substantial capital investments. When you start removing a small portion of customers the cost of power to everyone else starts going up. And if those customers aren't consistently off-grid, i.e. they still need grid power sometimes, that can actually raise power costs.

Increasing generation capacity to meet demand spikes is expensive, and requires having large, expensive power stations waiting at the ready, just costing money.

Kurzweil said their efficiency doubles every two years, and that they would be able to meet 100% of our energy needs by ~ 2030:

http://www.livescience.com/4824-solar-power-rule-20-years-fu...

> Kurzweil said their efficiency doubles every two years

According to that article, he said the "use" of solar energy doubles every two years.

Efficiency has been gradually improving, but it's definitely not doubling every two years. Every few decades would be closer; that said, using an exponential curve to model a function that's capped at 100% doesn't really make much sense in the first place.

http://en.wikipedia.org/wiki/File:PVeff(rev141113).jpg

For people who want to learn more about the complexities in this topic, I highly suggest listening to the Energy Gang podcast[1]. A ‎senior editor at Greentech Media, principal lobbyist at a huge energy lobby firm, and the founder of Sun Edison get together once a week to talk about at latest news. I work in the new energy industry, and everyone I know in this industry listens to this podcast.

For example, a few months ago, they talked extensively about how Hawaii's utility is basically falling apart since it can't find a way to compete with solar now that solar is at grid parity, and solar+storage is on the verge of reaching off-grid parity[2]. What happens when half of your customers simply leave? We're about to find out over the next few years.

Also, if you want to learn more about tech entrepreneurship in the solar, I recommend reaching out to the SfunCube[3].

[1]: https://www.greentechmedia.com/podcast

[2]: https://soundcloud.com/the-energy-gang/can-the-us-government...

[3]: http://www.sfuncube.com/

One thing to note - while this all sounds very exciting and optimistic, a huge percentage of energy is actually generated by coal fueled plants: http://www.worldcoal.org/resources/coal-statistics/ - 40%.

Let that sink in for a while. More than 1 century after the introduction of gas and oil fueled power plants and more than half a century after the introduction of nuclear power plants, coal is still powering almost half of the world. Perhaps even this PC on which I'm writing this comment.

Don't expect a revolution. Expect an evolution that will take another half a century or more :)

For a counterpoint, it should be considered that coal would be a lot more expensive if externalities were accounted for. Coal power poisons the atmosphere, the water, and the land, and kills thousands of people each year. If you account for those costs, coal becomes substantially less attractive, but most places allow power producers to avoid paying for a lot of those costs.

That doesn't mean you're wrong, of course. Coal has tremendous inertia, and accounting for externalities is hard. But the ubiquity of coal is partly due to a cheapness which is somewhat illusory, and we'd be better off if we accounted for it properly which would naturally push alternatives harder.

Only because right now the economics of coal fueled electric plants are favorable.

Coal based plants will die down as cost per kWh of ocean tide, wind, solar, etc are optimized.

Another reason: consumers subsidize industry.

Look up your local utility rates for high demand users. (These usually include things like factories or data centers.)

They pay a lot less for energy than you do at home -- even though the power plant doesn't care if the electricity is used for your hair dryer or smelting aluminum.

If the consumer goes solar, industry will suddenly have to pay their fair share of the bill.

You're ignoring all the ways it's cheaper to provide service to big, compact consumers like factories or data centers, vs. a big branching distribution network, more transformers and metering and billing costs. And then there's math is not optional details like power factor (https://en.wikipedia.org/wiki/Power_factor), although I don't know how they play out for these different sorts of consumers, but it's important to realize the grid past power plants is anything but simple and passively operated.

Plus factories can negotiate schedules of when they're pulling X amount of power, and most of them can shut down during extreme peak demand. It costs power companies a lot to avoid brownouts and blackouts during those worst periods of a year, and most of us home consumers don't have a firm deal to conserve during them.

The biggest devil in the details of all of this is what comes after whatever is producing power, solar cells or conventional power plants, baseline and peaking. That is, after all, what this topic is about.

I experienced the exact opposite with PSE&G in NJ. I had both a residence and an office in the same municipality. I was paying a higher rate per kWh at the office. Almost twice as much. When I asked them about it, they said it was because I was at an address marked as a business.

I think this depends heavily on state-level regulation of the utility and market conditions for your segment.

To be fair, you're talking about a third distinction in the eyes of utilities. They typical tier pricing by residential, commercial and industrial. It's not uncommon for commercial power to be more expensive than residential, but it's extremely uncommon for industrial power to cost more.

Even if this didn't make sense in California (it might), it makes huge sense in Hawaii -- power is $0.30-0.50/KWh, and they're starting to look at higher charges for grid-connected solar users (connection fees), and lower purchase prices for power.

If I could handle peak and steady state loads off-grid there, I'd be very tempted. I was assuming water pumping storage, or scheduling loads, and a diesel or propane generator for extreme peaks (running tools), but this might work too.

This was from last year, I don't know if things are still this way there.

http://www.scientificamerican.com/article/a-solar-boom-so-su...

I learned recently that nearly ideal batteries already exist for the purpose of storing energy from solar: nickel-iron batteries (side note: Edison made more money from selling these batteries than from any other invention). They last a very long time (50 years), are durable (not damaged by full discharge) and can be made from cheap materials. The energy density is not high, but this is probably not a major issue for home energy storage.

Nickel-zinc looks more attractive. What you do need on such application is a fast discharge, and nickel-iron doe not have it.

Now I'm wondering what would it take to create an iron-zinc battery, and how to make it last... Nickel is not a metal you want to waste around.

I didn't know about NiFe batteries. With a long lifetime, deep discharge durability, and cheap non-toxic construction they look quite promising. Except overall efficiency isn't great, and it looks like they require regular maintenance. Of course, maintenance becomes less of a problem at neighborhood/grid-local scale.

Why are they so scary? They're just a whole bunch of 18650's, with integrated cooling chambers and nice chargers.

I just picked up a pack of 10 from ali express for $14. The charger was $10 and can charge 2 batteries in about 1/2 hour. The American markets don't see them unless you crack open dead laptop batteries and test.

I've seen plenty of 18650s outside of laptops. They're extremely popular in the electronic cigarette scene.

Yep, and we inherited them from the flashlight enthusiasts.

Even if individual homes can sustain themselves on solar power, there are many homes and even more businesses that cannot. Even if people are storing power in batteries and charging them up for later use when power is cheap (determined locally) you still need the utility to be that conduit to get the power from the (distributed) sources to the (distributed) consumption.

Can the existing grid handle this kind of workload? Yes, if it is managed well and controls are in place to prevent delivering more power into the network than it can handle.

This is materializing in Australia right now.

My parents just put 5kW of solar on their roof, and are still tied to the grid, selling some back for a tiny fraction of what they buy it for at night.

The government has now mandated that everyone on the grid must pay an "access" fee every month, even if they use nothing, and they are limiting how many people in any neighborhood can go solar and sell power back to the grid.

It's no secret the government are doing this to protect their friends in the coal and electricity industry.

So what would happen, if government did not mandate that? Some people would go completely off grid, this would raise prices for everyone else. In some communities it would not be economical for electric company to operate at all[0]. Moreover they can't just leave this over to the cities because rich communities would go off grid and raise prices for others in the area. While I am sure there is "friendship" angle you are coming from is real issue is far more complex than that and there is no simple solution.

[0] And given utility status of electrical companies they are mandated by the government to do so anyways.

Another issue is sunlight. Most folks own land but not the right for sunlight to fall on it. Someone next door can shade your roof with their large solar collector; now you HAVE to connect to the grid. Such disputes will interfere with the smooth deployment of roof-mounted solar energy panels.

What is the price of a residential battery? Let's say you need 10 kilowatt hours to last from sunset to dawn (you might need more some nights, but if you're still on the grid, 10 kwh might be enough most of the time, which is what matters).

The Tesla model S has a 60 or 85 kwh battery. I don't know what the cost of the battery alone is, but it's probably pretty expensive. For fixed residential, you wouldn't need to use the most energy dense cells available, so it might be cheaper.

Wikipedia has a price per kwh comparison, showing lead acid considerably cheaper, though that might not be up-to-date with the price Solar City and Tesla pay for Lithium Ion cells.

If lead-acid is $250 per kilowatt hour, that puts a 10 kwh battery at $2500. Not too bad, but if they only last six years or so, that's a pretty big part of the ongoing cost of maintaining the system. How does lithium ion compare on price and longevity?

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

> The Tesla model S has a 60 or 85 kwh battery. I don't know what the cost of the battery alone is, but it's probably pretty expensive.

As of 2013, the 60 and 80 kwh batteries are approximately $10k and $12k respectively. [1]

[1] http://www.teslamotors.com/blog/2013-model-s-price-increase

Oh how funny, 130 years ago Tesla scared the hell out of some battery company.

Since they also make stationary batteries I wonder what would it cost to manufacture small flywheel energy storage units for homes instead.

To an extent, those are used in bigger grids to balance out peak production and peak consumption: they rotate in a vacuum on magnetic bearings and require very little if any maintenance.

Those big boys probably cost a lot but a consumer-grade flywheel which could spin for, say, 24 hours and be slightly less efficient (wrt. input-to-output and friction losses) could still be a big deal to even out daily usage.

The interesting situation is that companies regulated as a utility, presumably because a competitive environment for infrastructure isn't always practical (defacto monopolies) is facing competition hence creating some interesting questions.

Thank you for posting this as the print link. Literally a simple task, but again thanks.

This Elon Musk guy sounds more and more like Tony Stark from Iron Man :)

Musk was indeed was an inspiration for the movies (and did a cameo on Iron Man 2) http://content.time.com/time/specials/packages/article/0,288...

It seemed to me that Iron Man (comic) was an inspiration for Elon Musk's persona.

Entropy will increase...

Everything will become increasingly decentralized and democratized thanks to the miniaturization and increasing efficiency of technology. It's all but inevitable. The only thing that can stop it is politics.

Rooftop solar would have a very hard time supplying the same current feed your power company has. A few back-to-nature Californians may be satisfied with the battery-solar combo straw man in this article; most of us want our TV and microwave too.

Really - I am not so sure... my brother in CA tells me after installing solar panels on his home his bill from the power company went from 3 digits to $4 per month. He isn't really a back-to-nature Californian either...

Maybe we need 200 Amps from the power company for peak demand (frozen pizza + ball game + blender) but don't really pull much most of the time. Batteries limit not peak but total draw over the day. Hm.

200 amps even at the ultra low voltage the US has is still 20 kilowatts. That is tumble drier, oven with stove tops, washing machine + everything else in the house and you still have 10 kilowatts to spare.

Also chances are pretty good not everyone will have everything going at the same time, so you would be able to borrow power from your neighbours' systems without needing a big utility with standby coal.

Heat based energy needs are usually cheaper with gas, which is most of what you listed.

The threat isn't that people don't need any power from the electric company, it's that people need very little of it. Demand dropping to 5% of your usual business model might as well be demand dropping to 0%.

Especially when you're dealing with physical infrastructure (like power lines) that has relatively fixed upkeep costs regardless of demand.

Here in NYC ConEd charges a very large fixed fee for that physical infrastructure. Last month I used 96kWh but paid $43.35 (basically $0.45/kwh).

Around $20 of that is fixed fees, to pay for the basic infrastructure, billing, meter reading etc...

Some of that drop can be beneficial to the power company. They are always on the edge of capacity, because building more capacity is very (billions) expensive, and at first you don't need all of it, so the marginal cost of expansion is huge. Deploying solar across the area could postpone the need for generator expansion, and save money for current customers.

Depends on the type of capacity. I gather that peaking power is typically provided by gas combustion turbines (https://en.wikipedia.org/wiki/Gas_turbine#Industrial_gas_tur...), which have much lower capital costs and much higher operating costs (including maintenance). But if you need more baseline, then, yeah, you're going to be spending a lot of money, although I'd expect modern gas powered baseline plants to be relatively cheap (don't ask about nuclear, and fuel handling is much easier than coal, plus coal is nasty dirty stuff that needs exhaust cleaning, and disposal of ash).

I think Joe might have been referring to transmission and switching costs. Adding generation capacity to the grid usually means that you need more substations, and control infrastructure.

But in that case you can downsize a lot, because you only need to produce 10% of the normal electricity, and then charge, say, twice the amount your normally charge for the usage, perhaps reducing it to 8% or so.

That is still a higher rate of return than you would normally get, which makes it a better investment.

The batteries that Tesla uses can far, far surpass what a power company would be willing to provide to a residential unit.

The most powerful model s on the road right now has a ~310kW motor in it. That is an order of magnitude above what most house circuit breakers are rated for (200A-300A, 24kW to 36kW). There are even small RC batteries out there that can push 150A+ for a few seconds on their own.

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