EVs Are Essential Grid-Scale Storage
spectrum.ieee.org
spectrum.ieee.org
New battery for small car costs 13-20k$, so if its lifetime will be shortened from I don't know, say 10 years, to 3 years, then electric company need to compensate owners accordingly and I highly doubt they will pay even 10% of that sum over 3 years.
A 60kwh car battery might cost $10k, and allow 2000 charge cycles. So each kwh cycled into and out of the battery costs 8 cents.
So a smart algorithm can decide it's worth draining the battery back into the grid if the profit to be made is more than 8 cents.
Buuuut... Delaying charging till later is free. So another car owner's car might see on the futures market that delaying charging starting from 6pm till 11pm might save a few cents.
Obviously that means it's most economically efficient for every owner to do grid balancing merely by smartly delaying charges - and in turn price fluctuations will rarely exceed 8 cents.
The component that is missing to make this happen is cars which have code to automate this process, and markets in place that have API's to let the car buy and sell energy, and futures in energy, by the kwh. Users need not understand how it works - they just tick the tickbox which says 'charge and discharge smartly to minimize electricity costs'.
Today, those markets are typically only open to big players, cars don't have a tickbox, and wall chargers typically won't let a car put power into the grid.
In europe (At least) the company Easee makes AC chargeres that are WiFi / 4G enabled. In Sweden (And Norway) you can connect them to a service like Tibber, which allows you to automatically enable/disable charging with the electricity price, assuming you have a spot price electricity contract.
https://tibber.com/en/product/easee
Easee chargers also have a pretty bitching API, so you can also make your own automations using e.g. home assistant or what have you.
This tells me that Li-Ion batteries are far from the ideal medium for grid storage.
If one were to build a "facility" to hold short term load, that's likely what they'd use. They just can't be used in cars because they're incredibly volatile and don't hold a charge for a long period of time.
Edit: to answer my own question, they look pretty good [1]. Significantly lower storage density than batteries (roughly 50Wh/L versus 420Wh/L for Li-ion), but still dense enough for this to be workable at grid level. The linked presentation proposes converting decommissioned power plants into grid-level capacitor storage facilities, since the transmission switchyards are often intact. Furthermore, all the technology is available today, and when built, capacitors require almost zero maintenance.
[1]: https://www.energy.gov/sites/prod/files/piprod/documents/Ses...
For technical reasons, thats because the 'spinning reserve' - which is momentum of every synchronous motor and generator across the nation - already adequately handles this.
Also, large generation stations are required to have a 'load line' which damps high frequency oscillations. The load line can best be described as 'whenever the grid frequency starts slowing down, generators must put more energy in automatically'. Things like wind and solar typically don't have the ability to do that.
For human reasons, it's because electricity markets tend to be minute by minute at most.
For all those reasons, I don't think you'll make any money with capacitor energy storage banks (not to be confused with capacitors for grid scale power factor correction, which can be profitable).
The problem is that capacitors (assuming you mean super and ultra capacitors) don't have much capacity compared to batteries, so their cost per MWH of storage is high even if their cost per MW is low.
If it turns out people don't need all the cycles out their car battery then there's value in capturing that, but new large scale installations will move to other technologies over the next decade or two.
That's on the low end, like if you're fully charging/discharging the battery frequently.
Li-ion are good for frequency stabilisation: initial response times of the order of ten milliseconds, run times up to several tens of minutes maybe.
For longer durations, flow batteries and other chemistries are probably better. They win because of very good cycle life and calendar life (20_000 cycles, 50 years) but tend to take longer to start up.
Flow batteries include vanadium redox, zinc-bromine, iron-saltwater (being piloted). Other chemistries: sodium-sulfur (NaS, developed by NGK and sold by BASF in Europe/NA), carbon polymer based (PolyJoule), and a great number of experimental types.
There are also thermal batteries and compressed air energy storage, and pumped hydro.
Pumped hydro is by far the biggest form of grid storage today and is not as limited by geography or cost as one might think. It can be used in the "hours to months" range of energy delivery durations.
This functionality is already there.
> So each kwh cycled into and out of the battery costs 8 cents.
This is quite much. If you add other infra overhead, feeding power back into the grid is not going to produce much revenue for the individual unless the selling price is maybe 20 cents above the price when charging.
On the other hand, something that MAY make more sense, is if the car battery can be used to provide power to the owner's own house during short price peaks. This might allow some savings even in stable grids, but the killer app would be in grids that have rolling blackouts during high demand periods.
And even for grids where blackouts are infrequent, if your car can serve as large UPS for your house (combined with a large capacitor to keep the power stable), such functionality in the charger may be worth the cost of the hardware for many people. (Bringing the number of units up and hence the cost per unit down over time.)
Still, though, for grid stability it is probably much better to use dedicated batteries as part of the grid itself than to use car batteries.
https://www.tesla.com/sites/default/files/downloads/tesla-ne...
> Warranty Limitations
> This New Vehicle Limited Warranty does not cover any vehicle damage or malfunction directly or indirectly caused by, due to or resulting from normal wear or deterioration, abuse, misuse, negligence, accident, improper maintenance, operation, storage or transport, including, but not limited to, any of the following:
> ...
> Using the vehicle as a stationary power source
https://www.theverge.com/2022/9/12/23349971/nissan-leaf-bidi...
> Ideal for companies with fleet vehicles, the Fermata Energy Demand Charge Management application, along with the FE-15 charger, continuously monitors a building’s electrical loads, and may draw on the Nissan LEAF’s energy to provide power to the building during more expensive high-demand periods. In states with utility demand response programs, bi-directional-enabled Nissan LEAF vehicles (MY2013 and later) are able to safely send energy stored in the battery to the grid during peak energy demand times, such as in summer months.”
> The downsides to V2G tech are that it must degrade your battery (to some extent or another) to be discharging and charging more frequently, and it leaves your battery with less charge at times when you may wish you hadn’t discharged at all. Some people will always take that tradeoff, though, and it is great to simply have an option on the table for consumers who really want V2G tech. Stay tuned and watch this space.
> The article on the Fermata Energy/Nissan announcement is not quite correct. It’s for commercial use only – not residential. The Nissan-approved FE-15 bidirectional charger is available for commercial and government fleet owners. https://www.fermataenergy.com/fe15-sales
---
The other part is that this is grid supplemental charging where there is already a steady main current to be matched. If you are using it to power an island (home or similar disconnected from the grid), it is a different situation and would require completely disconnecting from the grid with safety cutouts to make sure that when the grid comes back on that the systems are not out of phase and damage equipment.
Grid storage is a different (and arguably easier) problem than home backup in the case of a blackout.
There needs to be a specialized charging (and discharging) setup in the garage. People who charge using a regular extension cord without installing additional hardware will not be able to do V2H or V2G.
The charging setup needs to be able to cut off power from the grid to the home. This involves a more extensive modification to the home's electrical setup. Note that there's a different culture with housing in Japan.
https://en.wikipedia.org/wiki/Housing_in_Japan
> An unusual feature of Japanese housing is that houses are presumed to have a limited lifespan, and are generally torn down and rebuilt after a few decades, generally twenty years for wooden buildings and thirty years for concrete buildings – see regulations for details. Refurbishing properties, rather than rebuilding them, is a relatively uncommon practice in Japan, though its prevalence is increasing, indicating that attitudes towards older houses may be changing.
> ...
> The taxable value of a house is controlled by its building material. Wooden houses are considered to have a lifespan of twenty years, and concrete ones to have a lifespan of thirty years, and the assessed price depreciates each year contrary to housing markets in other nations.
This means that basically every 20 years the house is rebuilt and you've got more recent electrical setup. If you're building/buying a new house in Japan and had an EV, the incremental addition to the cost of building the house isn't significant.
The house I am living in was built before electricity was available, had gas pipes to each room for lighting (though not in use), and had functioning knob and tube wiring as recently as 2010.
I do look at a home generator (and the corresponding changes to the electrical wiring needed) - but that's not a small change. If I was getting an EV, and considering V2H as an add on, it would likely not be something I'd do.
Simple delayed charging with a timer is common, yes. The grid interactivity part? Much less so.
The few V1G pilot programs out there have been very encouraging.
>better to use dedicated batteries as part of the grid itself than to use car batteries
Fortunately, it's not an either/or. We can better optimize the total system cost by doing both.
Why? Every kwh we can store using car batteries is a kwh of dedicated grid storage we don't need to purchase. It can increase the speed we add new storage on the grid. It is a more efficient use of lithium and other precious metals. This "smart charge" or "flex EV" is the type of incentive utility companies can push, and something that would decrease the amount of capital investments they need to make.
I can imagine a few counter arguments for why dedicated batteries are better, but nothing that convinces me. This claim that dedicated batteries are better than car batteries has little support in your comment and I would like to understand why you believe this claim.
Then there are the efficiency downsides. Storage "at the edge" means more transmission infrastructure is needed, on average, compared to more centralized storage. Also, grid batteries can be optimized for number of charge cycles, not for charge amount per unit weight. Finally, servicing individual cars is probably more expensive than replacing batteries in a storage facility.
And this is before going into inconvenience aspects, such as risking that your car doesn't have a near-full charge when you need to go on an unexpected trip, or the hazzle of handling the payment agreements, etc, just for a couple of dollars per day in potential revenue.
In computer terms, it's kind of running mining software on your computer GPU at night. For those especially interested, it may be fun, but for the average consumer, probably not worth bothering with.
So you can forget about your car (or even most solar inverters) to work during blackouts unless a couple of things are present:
- a automatic grid disconnection switch (aka a transfer switch)
- special firmware to allow the inverter to operate in 'off grid' mode
Both Xantrex and Victron have inverters that can do this but they are not normally deployed for such installations and they wouldn't know what to do with your car battery (voltage much higher than the ones that they require, typically 48V max).
Growatt has some off-grid units too, but those still won't satisfy the impedance requirements of your cars inverter (the grid is 'too small' so it will fluctuate too much due to high impedance).
Personally having an EV and a Victron inverter with batteries and same vendor car charger I HATE the fact I can't even adapt charging amps depending on p.v. available power in AC charging.
With HA and a bunch of scripts you can actually get quite far in automating all this, but when the grid fails everything will shut down.
I'd love to see these babies become more easily (and cheaper!) to source:
https://en.wikipedia.org/wiki/Lithium-titanate_battery
The energy density isn't super but for stationary applications that's fine. 6K+ cycles, fast charging, what's not to like?
Beside modern water heater nothing else is available on sale and even to simply "trigger switches by software" means pay not marginal prices for IoT devices like Shelly ones, who have simply too much stuff, starting from a webui, to justify their costs.
Even the simple, decades old modbus, is BADLY spoken just by few devices, MQTT even less...
I can definitely recommend the 'Shelly' stuff, it's been absolutely problem free and super reliable, they have a nice range of sensors and controllers.
Some actually have happened, like minisplit with optional remote control module to be installed easily lifting the front top and some hot water heater, but such controls are still very rare and damn limiting...
A small example, I cite it because it's not on sale anymore (there is a slightly updated version, with a different name) my home hot water is made with a Daikin/Rotex M2O EKHHP it feature a "renewable integration" witch consist in two dry contacts who allow just to tell the machine:
- do not run
- run as you want
- run full power (heat pump, if possible PLUS classic resistive stick)
- run for an hour with heat pump only, then full power.
Those who design such logic have NO IDEA about domestic p.v. self consumption. Why the hell such logic instead of:
- do not run, except antifreeze
- do run full power (heat pump and resistance)
- do run ONLY in heat pump mode if possible
- do run ONLY with resistance
My actual "solution" is:
- knowing the outside temperature in HA, so being able to decide if I can run the heat pump or not
- decide to trigger the "run for an hour with heat pump only, then full power", switching to "do not run", switch again to "run for an hour with heat pump only, then full power"
just to limit the load to ~600-800W of the heat pump, BUT for instance sometimes I can use more, like the 2kW resistive stick BUT NOT 2kW+600-800W and for that I have no option. Sure it does not change my life, but it's absurd. Why not give such simple controls?
My VMC is even nicer: it have a range of ModBUS controls, with some registers badly enough documented I can't understand what they mean, some not documented but understandable through observation manually command the machine via it's own keyboard/display.
I've decided to buy an absurdly expensive EV domestic charger from the same vendor of my main home inverter, a Victron EVC. It claim formally to be integrated. Actually in p.v. mode all it do is staring a charge at 6A if there is at least them available from p.v. of course if there is room to more amps no way to change them, it seems to be hardcoded. Only option use the manual mode driven via ModBUS from Home Assistant. At that point I do not even understand the dams logic, the only thing better than a far cheaper charger is that it's three-phase, I have a 3-phase 36kVA domestic contract so if I need a quicker charge I can run around 7*3kW from grid. But that's all. Other domestic chargers for EVs are not better and still with absurdly high price for a simple metered socket with some extras on a mini-board computer, something who can cost around 30€...
That might just inevitably conclude in "OK, I guess others are willing to ask a lower price than I am, so I won't be in a position to participate in a V2G scheme."
That seems more reasonable for the owner, but no utility co would pay it.
If you can really treat the whole cost of the battery as X cents per charge cycle, disregarding the lifetime of the car/battery, this won't work at grid scale. Someone else will build a storage facility that just charges and discharges batteries, and they will outcompete rational EV owners, because they will have economies of scale and battery banks designed for this use. It only makes sense if the EV owner can somehow get charge capacity "for free" - eg the car will be EOL after 1000 charges but the battery lasts 2000 - he should sell the extra 1000. Or alternatively if getting 8c now is better than getting 1 charge in several years time (plausible if interest rates, energy futures prices etc are right).
However, this could be wrong. The same logic says rooftop solar can't exist without special subsidies, and a lot of people disagree with me there.
If someone builds that storage facility to do it commercially then great.
> rooftop solar can't exist without special subsidies
Yet it does
https://www.seia.org/initiatives/solar-investment-tax-credit...
> The solar Investment Tax Credit (ITC) is one of the most important federal policy mechanisms to support the growth of solar energy in the United States. Since the ITC was enacted in 2006, the U.S. solar industry has grown by more than 200x - creating hundreds of thousands of jobs and investing billions of dollars in the U.S. economy in the process.
The Section 48 commercial credit can be applied to both customer-sited commercial solar systems and large-scale utility solar farms. The rate is effectively at 30% until Treasury issues guidance on new wage and apprenticeship standards. Two months later, the rate will be at 6%, with an additional 24% (for a total of 30%) available for meeting these new labor standards.
So utility-scale solar farms can get the same 30% credit as rooftop solar. They're both tax-advantaged compared to (e.g.) building a new gas plant, but the rooftop credit isn't any higher, at least not on the federal level. Self-consumption from rooftop solar may avoid other taxes, like sales tax, but in many states there is no sales tax on residential electricity to begin with.
It's part of the "Inflation Reduction Act of 2022" (and at a higher rate than before): https://www.solar.com/learn/inflation-reduction-act/
Rooftop solar is heavily subsidized almost everywhere it’s popular. Rooftop solar isn’t a good deal for utilities or their non-rooftop-solar customers.
I say this as someone who lived off the grid on solar for years; encouraging rooftop solar may have kickstarted the learning curve for the solar panel industry, and as such may have been pretty good social policy.
But it definitely owes its existence to subsidies.
These days grid scale solar makes lots of sense, rooftop solar still doesn’t (and the subsidies are now harder to defend).
> It only makes sense if the EV owner can somehow get charge capacity "for free"
The EV owner has the power electronics 'for free' - ie. they have almost infinite lifespan, and just a capital cost.
Additionally, the variations of energy prices on the grid are really wide. There might be $100k/MWh for 5 minutes per year. It isn't worth a static operator paying the capital cost for the batteries (which also degrade with time) to setup for 5 minutes use per year. But it does make sense for the EV owner to do so, because his marginal cost is tiny.
This depends where you live and the size/efficiency of your rooftop setup, right?
If you completely neglect the installation part, sure. Utility-scale solar farms have massive efficiencies of scale on purchasing panels and on labor-related overhead.
It's not that clear cut, basically.
I think what the EV model allows is for private car owners to essentially sell a part of their car back in increments, if for some reason their driving behavior changes and they don't need to drive as much as they used to.
Plug in the numbers. A charge cycle is probably around 200 miles (not even optimistic). That means that 1000 charge cycles is 200000 miles. That's roughly the lifetime of a car. However, I have heard anecdotes that EVs should last longer, due to a simpler transmission, so this may be a little up in the air.
I already have to own a car for short trips most days and an occasional long trip. And when I'm not going on a long trip I have a lot of extra battery capacity that I can rent to the grid at extremely low (additional) cost to me.
A dedicated battery storage facility on the other hand has to justify the entire price of the battery.
A real deployed algorithm would estimate the "degradation cost curve" over the entire DoD, and stop charging when total (fully-considered) costs exceed revenue.
That milestone has been hit in some places Australia already.
If the system still depends on distribution, someone has to pay for it.
It may be that rooftop solar users will be asked to pay more for that distribution than they think is reasonable.
I’m sure not excited about my grid operator proposing a $50/month minimum for electricity, it makes my panels seem worthless. But there is logic; I was being subsidized by net metering. And in future I may have to pay a cost closer to the true cost of access to the stability of the grid.
The market they can buy and sell this capacity is called an “aggregator”, and they can earn more money on this then selling just power.
Seems quite different from “your household is an autonomous actor and you get almost all of the arbitrage value of reducing peak consumption”, which would be a radically different system (but ignores who’s going to pay for distribution, which is getting closer and closer to being the dominant cost of the grid).
Yeah, I think that's far more likely. I can also see the possibility of a grid-mandated signal for "please, stop charging for five minutes, we're at capacity".
https://news.ycombinator.com/item?id=34518188
If your life is so chaotic that this doesn't work for some reason, don't turn on V1G
After those 2000 cycles is the battery completely dead, or does it still work but at a reduced capacity?
If it does still work at a reduced capacity, does continued use reduce the capacity to 0 after a while, or does is plateau at some fixed reduced capacity and stop further degrading?
This study is great but a energy storage comparison study that calculates total cost would tell us much more. Wouldn't be surprised if the Department of Energy already has or is [1]
[1] They do a lot of these studies already. i.e. https://iea.blob.core.windows.net/assets/ae17da3d-e8a5-4163-...
I think people worry a lot about market access when it doesn’t make sense. The market operators cannot handle the settlement and operations overhead of microscale power generators. They are not offering reliable commitments, and the metering just doesn’t exist at the small scale. Your local PG&E equivalent isn’t equipped to operate an efficient power market, I don’t think.
For context - a “small” scale solar power plant is in the 10s of MWs, which >1000x bigger then a car battery at full output. Utility-scale storage is also in the same ballpark.
Since prices a per day, announced the day before, the algorithm is not that complicated.
Also, if I install solar panels, the electricity just goes back into the grid, and I would get money for it. For the car it would be the same, just reverse the electricity into the grid. So it is mostly just the connecting the day-ahead prices, plus the cars and wall chargers returning electricity of-course.
1. Cars have advanced battery management system with heating and cooling, which noticeably improves the battery life (e.g old Teslas have lost 1%-2% capacity per year over a decade, while Leaf about 3% per year, most likely due to lacking liquid cooling).
2. Cars won't let the battery discharge to 0%. Modern EVs even have an inaccessible reserve, so that when the car shows 0%, it's actually ~5%. Cars with vehicle-to-load/vehicle-to-grid typically stop giving power at 20% state of charge. Slowly cycling around 50% is quite gentle for the battery.
3. The grid just has to pay more for the storage than the cost of battery wear. The "duck curve" means they'll want to pay you to take electricity off of them at noon, and pay you a premium to get it back in the evening peak time.
This is where V1G beats V2G.
V1G (AKA grid-adaptive charging) just chooses when to charge the car, to efficiently spread out the grid load overnight and spatially across the network. No extra charge cycles, in fact it's probably more mild than just charging at full speed.
The key is that you need a UI setting for "Immediately charge to X%" and "Charge to Y% by Z:00." This avoids the problem where you find yourself without enough charge to get to work (or the local hospital).
> you will now see multiple 0%-100% charge cycles daily.
Even for V2G, why wouldn't there be a depth of discharge slider?
> if its lifetime will be shortened... then electric company need to compensate owners
Or better yet, owners set their car to only "bid" for a grid storage job when the cost-per-kWh is greater than the cost of degradation.
This should be the default after enabling V2G.
It would have to be substantially greater. I'm not going to deal with reduced battery capacity and the hassle of replacing it early for a couple of cents here and there.
Considering the extra cost of equipment to allow the EV to send power to the grid, I don't think the economics will ever work out.
The economics don't work out at the monthly average rate. That's why storage only kicks in when spot prices are well above average.
I would be happy to let the grid operator decide when to charge my EV, especially if I could inform them when I wanted charge by and have an override button to be ready for road trip departures.
I wonder how long it will be before the grid operators are subsidizing parking lot operators and businesses to install tons of smart L2 chargers so commuter vehicles are absorbing all the excess solar power available mid-day that would otherwise go to waste.
We move huge volumes of our residential portfolio every day just setting EV schedules - enough that our total residential profile peaks at market bottom price hour nearly every day, even in winter with lots of ”dumb” heating load.
Vehicle batteries have 8 year 100k mile warranties today, and those manufacturers who have spoken on this topic have said that utilizing your battery as grid storage will not violate the warranty (Ford said this about the Lightning, which can do V2G today.)
Please stop spreading misinformation and go do some research before you spout FUD like this.
It’s much more persuasive to allow reasonable-sounding questions to arise and receive polite, well-thought-out answers, as happened here, than to have everyone chanting in unison. The latter looks like a lie even when it’s actually the truth.
Perhaps you should do more research before ending a comment on such a condescending remark next time.
Existing Tesla cars can do V1G (grid-adaptive charging), but not V2G.
I have so far "babied" my battery and max charge at 70% outside of road trips. So far, my degradation is right on track as average, which I assume is people doing the 90% charge trick - so trying to outsmart the battery hasn't worked for me yet.
They're suggesting using these extremely expensive but no-long brand-new batteries for additional grid storage. Take the battery you don't use anymore, and instead of paying someone to dispose of it, plug it into the grid and get paid for its use.
1) The battery gets damaged or the car is totaled (in which case, you might not want it)
2) The car is 20 years old and done with life
EVs have mostly not yet filtered down to the socioeconomic rungs that have reason to be skeptical of things by default.
Based on what we know about EV battery lifetimes so far and how graceful their failure is I think your concerns are unfounded though.
If there's an economic incentive for EV owners to use V2H to reduce their _own_ load during the time of low generation (and thus high prices), then the setup would already do a great job at balancing the grid.
People aren’t dumb and will be able to figure out where the break-even point is and at what price point it makes sense for them to discharge. Today the only problem is the availability of the V2H tech. My belief is that the _only_ important change that needs to happen is a govt. mandate for V2H support in vehicles and home chargers. Supporting this is quite cheap, and today’s implementations of V2L/H are just price gouging on the novelty basis.
For $0.04/kWh, I'm not the least bit interested. For $0.40/kWh, I'm probably indifferent. For $1/kWh, I'll buy another car (or fixed battery) just to participate in this scheme.
As an EV owner, no.
We need to own a car due to having kids, we happen to have gotten one with a pretty large battery so we can easily use it for road trips too. Also because there was only one choice for battery size with the model that suited us (Ioniq 5)
But I live close to work. I fully cycle the battery maybe 2-4 times a month. I could easly double that and still not wear out the battery in the lifetime of the car. If not more.
This is in Norway, so I get that others wouldn't buy an EV with a large battery in that situation. But as EVs/batteries become cheaper in general, this will be the norm elsewhere.
And then you can flip the question on its head: if you expect to only use half of the life cycles of the battery within the lifetime of the car itself, isn't it incredibly stupid and waste of valuable batteries to NOT use it for V2G?
I suspect the cost equation will be benifical for car rental companies too, since they can get economies of scale when replacing the batteries.
> so if its lifetime will be shortened from I don't know, say 10 years, to 3 years
Uh, 3 years? Even my previous EV, a 2015 Kia Soul EV, with a pretty bad battery chemistry, only air cooling, and high cycling rate since the battery was small, is still in very good condition after 7 years. Even Leaf batteries without cooling have lasted 10 years.
First gen Nissan Leafs and Kia Souls are borderline unusable once their battery degrades to 75%, but new EVs with large batteries should still have useful range with 75% degradation, so using up the rated battery cycles (generally specified at the point where degradation reaches 80%) doesn't mean the car is dead.
New rule has been strongly criticized about being more costly and disentivizing solar, but the one thing it does right, is insentivizing end users to do a propertine shifting of their usage.
Very much not likely.
You have to realize how big the batteries are on EVs. It isn't uncommon to have 80 or 100kWh batteries on EVs (and that number is likely to go up.). Even small batteries are around 40kWh.
Average home energy consumption is 30kWh per day in the US. Meaning even for a small battery you are looking at a single extra cycle per day at most. However, if you are pairing your car charging with home solar then you are looking at a more ideal charge/discharge (Possibly keeping the car between 40 and 80%)
A more reasonable expectation is that people would lease a portion of their capacity. Say 20% for argument sake. You could even place other limits on it "never below 50% and above 90% on weekdays". In this example the power company gets to use between 50% and 90% state of charge in your battery on weekdays and pays you a small fee or other compensation in return.
Say the lifespan of a battery is 10 years. If you lose 10% of the charges for grid storage you're looking at replacement at the 9 year mark. Until we know that the vehicle itself will be reusable at that point you need to depreciate the battery usage against the cost of the entire vehicle, and be compensated for it.
So no, I'm not really worried as I don't drive a Leaf and my car has industry-standard cooling system for the battery pack.
In short, no. I have a 10 year old Leaf that has been on a V2G trial for the last 3 years. (I also work for the company that built the charger.) The battery is not being deep cycled; it goes between roughly 30% and 90% state of charge. The trial has found no clear evidence that it ages the battery at all. In fact, it appears that this is better for the battery than regularly fully charging it and letting it sit. Calendar age appears to be the biggest cause of battery degradation along with deep discharging and rapid charging (which this isn't doing).
I might use my vehicle to power my house, if the grid is down. But there I would prefer to have batteries inside the house that are used for that purpose, and backed up by a generator.
The power that I would have in the vehicle is my last resort of getting out of the house, if things have gotten bad enough that the household batteries are drained and the generator is down.
Some cars have > 100 kWh capacity. Why do I pay > 1000$ per kWh for a house battery? At some point it is cheaper to just buy a car, even if you would never drive it. A Tesla Powerwall has 13 or so kWh? Why don't they use the car battery with nearly 10 times as much capacity?
It is just unit prices that are far better for cars? Is the charge/discharge speed relevant? Is the technology different? Are the capacities for cars just fake? Preferably I would want 200kWh or more capacity for my home.
You can use your car battery - though you will degrade that car battery much faster which is probably the battery you want to have better performance.
Home solar + storage adds community-level resiliency in disasters and will reduce the grid load needed for home EV charging and industrial level charging used by electric tractor trailers. It should be a major complimentary effort of governmental policy along with grid scale solar/wind, grid scale storage, and whatever load leveling we can effectively decarbonize.
Good luck getting that through our deadlocked government.
Especially since
E.g. https://signaturesolar.com/eg4-ll-lithium-battery-24v-200ah/
Perhaps 200kWh is a bit exaggerated. And yes you also need a good quality inverter for your home that synchronizes with the net, but I actually don't believe this to be expensive high tech...
Ideally I wouldn't want to put the energy I generate with solar, wind or differently back into the power net. In my country you basically give that away for free. There are reasons for that, but the most efficient way would be to use the energy yourself as much as possible.
Sure, 5kWH is enough to soften peaks and there could already be huge benefit to this. But a bit more capacity would be really nice to really safe the energy of sunny days. Reminds me if disappointing USPs that let me play Tetris for an additional 7-8 minutes before I feel like civilization has broken down completely until power comes back.
But it is only ever meaningful if you have the respective fixed voltage and it often make sense for a batteries to quickly calculate how long they should last if you know how much ampere a device draws. It could also become a sensible metric if we always talk about 120V/240V for general household appliances of course.
As a chemical battery discharges, the voltage drops, so at the same load in amps you get less watts later.
Your numbers are a little bit off though. I just googled some power bank (which is supposedly better than smartphone). It claims to provide 20 000 mAh at 5V. So it's 20 Ah at 5V or 100 Wh. I think most smartphones are around 10-20 Wh. Far from 5 kWh. But this discrepancy was already noted in other comments.
citation needed
I didn't know they could last as long as LiFePo though. Is this really true?
If this is true, why don't we just use more lead-acid batteries then?
LiFePo has a very high maximum cycle count. But after ten years, they'll die anyway. The only way that you can actually achieve a cycle count as high as the specification says is if you're cycling the battery two or three times a day, which I can believe if you're doing grid-levelling, but not if you're providing backup for your solar panels.
For lead-acid batteries, be aware of the difference between normal lead-acid, which are optimised for standby operation, and deep-cycle lead-acid, which are optimised for long life under regular cycling. Normal lead-acid batteries will die very quickly if cycled - they're designed to be charged all the time, and drawn on for very short period, like a car battery or a UPS.
Deep-cycle lead-acid batteries age by cycling, in contrast to LiFePo, which age by elapsed time. Their maximum cycle count is much lower than LiFePo, but if you're cycling them every couple of days, like in an off-grid solar project, and you're avoiding draining them below around 40%, then they can last 10 years.
So, if you want to cycle your batteries two or three times a day, then LiFePo is going to last a lot longer than Lead-Acid. But if you're cycling every couple of days and limiting the drain, then they can last about the same amount of time. It depends on the usage.
What helps with Lead-Acid is because it is that much cheaper than LiFePo, you can buy a larger capacity Lead-Acid battery for the same or less money, and then for the same performance requirements that larger battery will be drained less and at a lower rate, and therefore be less stressed and even last longer.
I think we don't use Lead-Acid as much as we do for several reasons:
1. Lead-Acid batteries have a reputation of flaking on us after a depressingly short amount of time. But that reputation has been earned from normal Lead-Acid batteries, not deep cycle ones.
2. People get scared by the lead in them, and how lead is toxic and we should be stopping using lead in everything. But really, lead in these batteries is not a danger to us, and Lead-Acid batteries are one of the best recycling success stories in the world. That lead isn't generally getting out into the environment. LiFePo batteries are much harder to recycle.
3. Electricians recommend installing expensive stuff, because then they get a bigger commission.
4. Lead-Acid batteries are commodities, but LiFePo batteries are new and exciting, and have aggressive marketing.
5. Lead-Acid are bigger and heavier for the same capacity than LiFePo. So, a LiFePo installation is going to look prettier in a nice consumer unit and be easier to install. They're heavy enough as it is.
[Citation needed]
Typically lead acid lifespan is around 10x less than lifepo4, even if kept within spec.
But in practice it's hard to keep them in spec too, shit sulphates immediately when you look at it wrong.
LiFePo is maybe 10x the lifespan of a normal Lead-Acid battery, if you're cycling it several times a day. A car battery for instance will not do very well in this test. But I'm talking about deep cycle Lead-Acid batteries, cycled every day or couple of days down to 70% capacity (so using 30%). This is a fairly typical workload if you're (for instance) using it as a backup for solar panels. Under those circumstances, the LiFePo battery will die from time elapsed probably about the same time as or maybe even earlier than the Lead-Acid battery dies from cycle count.
In that case, they cost about $413/effective kWh.
In this situation, a Lead-Acid will have the full capacity that you bought, but will age like you're using 30% of the capacity most of the time.
Still, I would've expected that ever increasing self discharge would've made them far worse in comparison since it gets worse as the batteries age and you can end up losing major amounts of charge to it. Not sure if that's not as much of a problem for flooded as it is for AGM but I haven't heard it mentioned in the rundown.
There are cheaper products, but reliability and trustworthyness is an issue. A good budget offering may decide to sell out their rep or start charging premium prices.
Budget offerings are about $250/kWh right now, or there are some for about $350 with cold weather protection.
In a few more years markets will mature a little and the price gap will be smaller.
With sodium ion the cost should drop to 50$/kWh.
I guess what might happen in a decade or so with EVs with "obsolete" batteries in the used market is that you just get a used EV and you have a powerwall and a secondary/tertiary city car.
NEM3.0 doesn't make a battery a requirement to break even on costs, it just extends the payback time of solar without batteries by 3-5 years. It reduces the still absurdly long payback time of home battery storage somewhat, though. Only when you can sell power back to the grid with batteries at peak wholesale rates will batteries have anything like solar's payback time.
I haven't done the math yet to figure out how that variance relates to payback time for batteries, but would be a fun exercise.
Hopefully, 200-230 wh/kg LFP and 150 wh/kg sodium ion batteries should be a revelation in all use cases of batteries in the next year or so.
Tesla gets to operate at the extremes of volume, so they get to demand the best prices I would imagine, but the markup still seems astronomical in other things (like tools, home powerwalls, etc).
IMO there needs to be some governmental nudge. Battery prices (in theory) should be dropping in price such that many ICE-based tools will be fundamentally cheaper as batteries. An electric lawnmower shouldn't be more expensive than a very very dirty two stroke ICE lawnmower with the LFP/Sodium Ion that is coming to market.
But a lot of electric tool makers are using the reduced sound and superior torque abilities of electric tools as a price premium product. Things like lawnmowers and leaf blowers and snow blowers being high performance electric tools is like a "starter EV" for millions of Americans: it teaches them about recharging batteries, how EVs are better than ICEs in many ways (quieter, better torque, less smelly, no gasoline to spoil over winter) and how to deal with the annoyances (recharging).
Why the complexity? It should be easy to install batteries on a house, right? In reality, every house has an idiosyncratic set of challenges and decisions that need to be made when integrating battery storage: What loads do you want to back up, and for how long? Where will the backup sub-panel be installed, and how can the backup circuits be routed to it? Where is a safe location for the battery and the automatic transfer switch to be installed? They are all answerable, but there is no general solution and each one is on a case-by-case basis.
And yes, this all does have to meet electrical codes (which exist for a reason), and needs sign-off by local building authorities, but they are not the main cost obstacle any more than they are for any major electrical upgrade to a house.
Take away the "luxury premium" part, and this also explains why home rooftop solar will always be much more expensive on a per-watt basis than utility scale solar (and yes, utility scale solar doesn't include the cost of transmission, as with any grid scale generation source).
Compare that to an EV, where thousands are assembled with predefined requirements, a known set of inputs, all in a purpose built environment (a factory).
And even better, they come with a standard plug interface that we can use to send power back to the house or the grid! But hold on: if you want power when the grid goes down, you're going to need an islanding transfer switch and perhaps decide which loads to back up. I mean, do you really want to run your 40A jacuzzi heater or your 50A air conditioner off you car battery?
In an ideal future, every house would be built with a standard connector (analogous to USB for phones or EV charger standards) that you could just plug a stationary storage system into. The houses would also be built to include an automatic transfer switch that islands the house during a power outage, and a smart load panel that dynamically decides what loads to back up based on battery capacity and user preferences. But right now, no such standards exist, and no house is built from the start that way, so everything is an expensive retrofit.
If we reach a point where there is an actual secondary market for used EV batteries, the house battery market will start to boom. But 10+ year old batteries are still 85-90% healthy mostly, so it might take a while...
E.g. a NMC battery has a lifespan of around ~2000 cycles, a model S 90 D has a 90 kWh battery. That's around 180 MWh of total energy that can be moved through the battery before it is dead.
On Reddit, a tesla user reports (https://www.reddit.com/r/teslamotors/comments/v4dqkp/19000_n...) it costing him 19 000 USD to replace a 90kWh battery in his model s.
This means that the replacement cost of the battery for the owner costs ~ 106 USD per MWh hour, which is more than most generation sources (https://en.wikipedia.org/wiki/Cost_of_electricity_by_source#...). In other words, it's cheaper to build and run a natural gas power plant than to pay EV owners for the grid-scale storage capacity from the NMC batteries in their cars.
And the price of the battery does obviously not include the generation costs of the energy needed to charge it, any charging/discharging losses, nor the infrastructure costs of a V2G setup.
So it's a very simplistic and incomplete comparison that gives a rosier picture of V2G MWh price than reality would.
Most batteries, if charged and discharged slowly, in the right temperature range, and while keeping the charge between 40 and 60% capacity, get far higher lifetime than the advertised 'cycles' number.
The damage and degradation happens mostly near 0%, near 100%, when charging/discharging fast, and when excessively cold or hot.
Cell balancing becomes less important when you're not nearly full or empty, and balancing wastes quite a lot of energy - making the battery more efficient when used between 40-60% too.
Minute by minute electricity prices vary really widely. It isn't unusual for prices to spike up 10x briefly at peak times.
Most power stations have too high a capital cost to only run 2% of the time... whereas your tesla battery has no capital cost, so using it to power the grid 2% of the time when the prices are sky-high is very attractive.
Since they are providing power on demand in a way that doesn't have upfront costs, that should mean that car-based power demands a cloud-like premium (10-50x over traditional servers) over traditional power plants.
They are getting a little premium today, but likely won't once this practice becomes normal.
Purely from a theoretical perspective, anything that can generate power at lower prices than the current market rate will be financially viable. With this past winters prices in Europe, it means literally anything. Even at times a diesel generator from your local hardware store would be a good idea (~.60 EUR per kWh).
But these prices won't last, in a few years we will be already back down to manageable price fluctuations.
It's pretty easy to see though that if battery based grid storage is going to be a big thing, it is not going to be EV batteries. The chemistry used in them is not optimized for life cycles (at least currently). LFP chemistry batteris that are in some Teslas has bettery cycle duration. Sodium Ion batteries will most likely be the choice for grid-scale deployment if they can be commercialized.
- replacement battery costs will probably drop a LOT in the next ten years. that quoted cost is $200/kWh, but Tesla is at $100/kWh (possibly less). That is a hell of a markup, probably reflects battery supply prioritization to new cars (Tesla gets more money if you buy a new Tesla rather than keep an old one running). So lets not treat this as some permanent condition. Sodium Ion batteries should stabilize at somewhere around $50/kWh I would guess, especially if they can get them close to 200 wh/kg, which is on the roadmap. And in 5-10 years there will be some solid state, sodium-sulfur, or lithium-sulfur battery that is even cheaper.
- Gas turbines still externalize their carbon emissions aka they don't pay for them. When will that madness change? Who knows. Another example of false economics. The only way I see gas turbines as a good thing is if it keeps the oil wells from burning off their excess methane for absolutely no benefit.
Maybe you are some astroturfer or not, but it is really frustrating talking about energy policy over the next 5-10 years and counterarguments are:
- this guy for this car got charged this price this one time anecdote that you know perfectly well is not representative of future costs and availability
- dude, lets burn more fossil fuels, it's "cheaper", which you know it really isn't
- let's talk about essentially outmoded chemistries and their problems, and ignore both current ones and ones that are scaling up production
I seriously doubt that V2G will cause a lot of people to have to replace their EV battery in the lifetime of the car. People who drive their cars the most will not use V2G because they won't have spare battery capacity. It might trigger one battery change, but then an EV might need a battery change at one point in its lifetime anyway.. and so it doesn't mattery unless V2G triggers the need for a third replacement. (In 10 years batteries might have longer cycle life too).
There are plenty of scenarios where the EV makes more sense than a dedicated battery for it.
In my case, I live on a very shaded property; no solar for me. I also live next to an electrical substation, so extended outages from storms is highly unlikely; I'm first on the fixed list every time. In my case, the home battery doesn't make sense, but the EV might still.
EVs as grid storage is an option that may be compelling in some areas and for some people. I think that's worth exploring.
It already has an EV charger plugin, so I'm in complete control of my selling energy back to the grid if I want to use it.
Some of the comments on this post feel like the "government is coming for your guns" level of foaming-at-the-mouth.
Remember the ultimate aim is to use energy more efficiently and reduce our dependency on fossil fuels, not make it pointless or difficult to live life.
Also note you'll still have fast-chargers, you don't always need to charge immediately at full capacity at home, just as you wouldn't always top up on gas after every drive.
https://www.ofgem.gov.uk/energy-policy-and-regulation/policy...
don't want to be part of that? run your house off your EV and charge it back up at night. my house takes about 6KWh a day, so I could run it for almost a week from my car even if I didn't charge it.
Maybe the utility companies could do their job and provide a reliable electricity source, instead of outsourcing it to customers.
This is quite a naive view of how the world works.
Their actual “job” is to make the most amount of money possible.
A realistic option has to be one that is both technically superior and something a company is incentivised to do.
That is generally true, but not of quasi-public utility companies. The government controls the price utilities charge, and could force them to invest in storage.
I don't think this whole EVs-as-grid-storage really makes sense. When the EVs go into the scrap market, the batteries will likely still have 80% of their range left (if not more, based on what folks have been reporting). If it's as low as 80%, it would be a huge detriment in the used market, but that much is still fine and dandy for grid storage. Just wait 10-15 years and use them then, if this is supposed to be a strategy.
Or better yet, keep investing in other non-lithium chemistries, like those involving sodium, and then cost per kwh will go down significantly.
Having chargers at the office is a thing. You could imagine grid operators subsidizing setting up EV chargers at office parking lots on the condition that they're V2G capable.
I wouldn't mind letting my EV charge at home at night and discharge down to, say 50%, at work.
Also, there's generally a big peak just as people come home from work. I could charge at night, discharge the first couple of hourse right after I come home, and then charge again.
I don't always drive to work either, I hope to take the bus or train more when kids are done with kindergarten (they can walk to school on their own). But this is Europe, I get that this is less realistic in USA.
You have some good points, but I think the next 10-20 years will be so critical for the switch to renewables that we can't afford to wait. If we can get some help from V2G until more permanent solutions are in place, why not?
Also, some of us work from home, or commute by public transit, or whatever, and only use the car on weekends.
The "gas station" model of battery swapping has a number of features: lower sticker price on cars, key for mass-market adoption; expert battery pack charge and diagnosis, maintenance and repair; extension of pack lifetimes by offering cheaper rates to drivers who only want to go short distances and therefore can use old battery packs with only 65% of original capacity; easier power planning and control for distribution grid operators with smoothed electricty consumption and abillity to return energy to the grid in peak demand/low supply hours; easy revenue collection for local governments.
If anything is very much anti-fragile. Decentralized batteries would only make the grid more resilient both to outages and overloads.
a stationary distributed system seems superior in many ways to the mobile version (more capacity, more predictable in both charging and discharging schedules, potentially less costly battery technologies etc). if such a system happens anyway, I'd see the issue of linking the EV fleet as secondary
The simple fact is that these static larger installations should be better, but they're not happening at nearly high enough rate, and so there is still benefit to be had by individuals installing smaller less efficient systems.
People drive during the day, and charge at night. So you could use EVs as a buffer during the night, but they still need to be charged. So EVs are still going to be a net energy consumer during the night, when you need the storage the most (no solar production).
I think the best course of action is to load shift charging of EVs and use it as "storage" in that way. Its an easy load to shed when needed, and an easy load to ramp up when renewables are plenty.
Huge citation needed.
> most cars are parked during the day
Yes, parked somewhere where there is no V2G infrastructure. By the time we pay millions of V2G charging stalls, we would be better off just buying actual grid scale storage.
> this suggests an average of just under 18 trips per car every week.
So cars on average are used multiple times a day. OP's claim that most cars aren't used is ludicrous.
Solar isn't the only green energy source, there's also wind, hydro, nuclear...
Historically, electricity consumption is low at night. With the conventional grid, nighttime charging is a net boom because it brings load when the grid has excess capacity.
This made me wonder why new houses don't come with a battery built in, thereby making power outages obsolete. A battery that could withstand a 48-hour power outage without the occupants even realizing anything had happened seems like it would give the power grid a lot more flexibility and could be a real lifesaver in the case of natural disasters and other emergency situations.
Adding a battery would probably add $10k to the cost of a house, but for a home that costs $400,000, that is only 2.5% of the price. A smaller battery that just provided 12 hours of power might only cost $3k.
I'd be interested to hear from knowledgeable people what the downsides to this idea are. I suppose the battery might degrade over time, and it is likely it would go for several years at a time without being called upon.
Here's an interesting example where a new housing development in Las Vegas built all the houses with battery storage as well as solar generation for the entire neighborhood[3]
[1] https://na.panasonic.com/us/energy-solutions/battery-storage...
[2] https://enphase.com/store/storage/iq-battery-10
[3] https://electrek.co/2022/12/08/tesla-neighborhood-launches-p...
More importantly, they'll be grid scale responsive demand. They're basically internet connected batteries so they can charge whenever suits the grid best.
The UK has been explicitly planning for this as a way to enable the further roll out of renewebales for about a decade so it's hardly news. The new bit is someone doing some sums and putting numbers on it with recent estimates.
That is also usually a market - ie. power stations can bid to provide that service, and the lowest bids are selected.
The only thing missing is that little residential guys usually aren't welcome to bid... Usually there is something like a 5MW minimum to play the game.
Likewise, even disabling charging for a short-term, emergency 10-60 second period might be more practical. Feeding back into the grid requires additional complexity / hardware that could add cost to the consumer.
For day-to-day storage: As soon as someone goes to use their EV in the morning, and they find out that the battery isn't full, they're going to turn it off.
This strikes me as the opposite of "planting trees whose shade you'll never sit under." If the latter makes civilizations great, where does the former attitude lead?
Concerns such as, "will my car be charged in the morning -- or for that emergency hospital run?" are considered, I believe, and you can set things like a "minimum charge" with smart chargers.
yes, but because nobody is deploying V2G at high density housing, and also because the grid doesn't have the capacity
This approach though presupposes that everyone lives in suburban dwellings with garages/driveways, which is at odds with the more sustainable, higher density living scenarios (eg, urban centers) where public transit / alternate transportation usage is higher, and there is less space for personal cars. Eg someone on the 5th floor of a walkup is not going to run a cable from their window to their car parked at the other end of the block.
I think solutions like the Powerwall (or other brands' equivalents) might be a better way to go.
So I will be surprised if this happens on large scale. This is an idea that sound great on paper but there are really a lot of practical issue between where we are now and in this ideal future.
> The US’s transition to electric vehicles could require three times as much lithium as is currently produced for the entire global market, causing needless water shortages, Indigenous land grabs, and ecosystem destruction inside and outside its borders, new research finds.
> It warns that unless the US’s dependence on cars in towns and cities falls drastically, the transition to lithium battery-powered electric vehicles by 2050 will deepen global environmental and social inequalities linked to mining – and may even jeopardize the 1.5C global heating target.
We definitely need to figure out grid scale storage. But I'm not convinced Lithium Ion batteries are the answer. And I strongly disagree with the idea that electric car batteries are the solution.
Arguing for car batteries to be a primary means of grid storage basically presupposes we fail to make the transition away from cars, which means we're committing to a much more difficult and expensive path to the carbon cuts we need to make.
Pumped hydro is a practical grid-scale storage solution that doesn't need lithium.
[1] cost $4B for 24Gwh of storage. That's about the same as the cost of an equivalent amount of batteries. But it has run for 37 years. A battery installment would have had to be replaced at least twice.
[1] https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta...
- have large mass and purchasing power, optimizing their battery purchasing and operational costs;
- have grid-scale storage oriented solutions tuned for maximum charging cycles and lifetime-storage
- use stationary batteries with no mass penalties, affording them the use of low density exotic chemistries (Na-ion) or non-battery storage systems.
Meanwhile, the EV owner has a mobility-optimized battery that is tuned for maximum density that still results in a cycle count comparable with the lifetime of the car. At market equilibrium, any revenue he extracts while serving the grid will reduce the useful life time of the battery and therefore depreciate his capital, and make his battery a "spare parts consumable" which is a major profit driver for most auto-manufacturers, especially a custom form factor battery for a 5 year old vehicle that is no longer sold.
Never mind that the whole operational cost, changing the meter to a bidirectional one, making sure the vehicle is connected for extended periods of time etc. is probably not going to be worth the pennies you will earn.
Grid storage is EVs is a decade old pipe dream, it will never make sense economically, it has been attempted multiple times and always failed, just let it die.
It is fungible, but prices can vary according to limitations on supply. If the big company's capacity is maxed out and demand continues to increase, energy already acquired at lower cost and stored in the car can be sold for profit.
Basically, the next-day / week energy markets, where EV owners can compete, will be saturated by grid-scale battery operators. Renewables will leave large gaps for seasonal energy needs - for example two weeks of winter with no sun and no wind - but EVs cannot help there. So some spin on-demand non-renewables will need to cover that (i.e., the current main providers, after becoming too expensive to run due to carbon pricing).
So, EV owners may use their cars to help reducing their energy costs and supplementing their PVs and fixed batteries (if any), but shouldn't expect a car to pay for itself like that.
And no, using cars for grid-scale storage has not been tried multiple times. The technology has never been available/feasible at a large scale before.
There exist large scale trials for this idea, you never heard of them because (aside from the fact you are arguing on a subject you know little about) they failed or are barely limping along.
If you consume what you store, then you will charge up at low (production prices + distribution fees) for the times when (production prices + distribution fees) are high. The second term is constant so you are arbitraging on production prices.
https://zecar.com/resources/which-electric-cars-have-bidirec...
If they want to use my car as grid storage, then the power company better pay to replace my battery, plus compensate me for the added inconvenience of having to perform that maintenance far more frequently.
Even with just fossil fuels, it's preferable to build a smaller power plant that runs 24/7 than invest bigger money in a bigger power plant and then operate it only some of the time.
See "duck curve".
Storage will waste massive amounts of energy through conversion