9 ms·

Aren't people wary about using their very expensive car batteries for the grid? E.g. imagine you plug in your phone for the night, but instead of a single top u

by Yizahi 4y ago

Aren't people wary about using their very expensive car batteries for the grid? E.g. imagine you plug in your phone for the night, but instead of a single top up change it is now constantly discharging and charging again. Lifetime of pocket sized batteries is not too great even now, and in such scenario they will go bust 2-3 times faster, in year instead of 3 or so. Also discharge swings would be probably much bigger. Instead of using say 30% of the battery per day in normal use cycle, maybe not even every day, you will now see multiple 0%-100% charge cycles daily. 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.

moffkalast 4y ago
Well the ones with li-ion batteries ought to last at least 2000 cycles, or about 6 years with a cycle each day, but there are lots of mid tier models being made with lifepo4s now, and those last like 6000 cycles, so there is far more breathing room. They're also cheaper so you may be able to more easily break even.
- manholio 4y ago
  That just means people will buy daily drivers with small batteries and charge them nightly. 15 years out of a cheap compact car with near zero operating costs sounds like a good deal, still does not make sense to waste a cycle for $1 = 20kWh fed into the grid.
ramraj07 4y ago
depends on how much the demand is. If all they have want is (collectively) a small drain (less than 1-2%) once or twice a day then why not? Especially if there are some incentives provided for the same.
- Yizahi 4y ago
  I admit I don't know much about power grids, but I heard that they are structured in a lot of smaller zones, so if there is a local drop in the generation due to accident then probably only close EVs will be discharged, but by a lot, to compensate.
londons_explore 4y ago
Luckily, any degradation can all be predicted ahead of time. 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.
- Yizahi 4y ago
  Now that's an interesting idea. Let's see how it will unfold globally. Maybe it will indeed be painless feature.
- Maxion 4y ago
  This can be done by using a smart AC charger. 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 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.
- danuker 4y ago
  It worries me that if industrial-purpose batteries cost the same and have similar degradation, grid services will also decide not to charge/discharge if the profit is less than 8 cents. This tells me that Li-Ion batteries are far from the ideal medium for grid storage.
deleted 4y ago
[deleted]
pornel 4y ago
Car batteries are not really comparable to cellphone batteries. Even among "lithium" batteries in cars there are multiple chemistries with different longevity and trade-offs (e.g. LFP can be kept charged at 100%, while NMC would rather not). 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.
schiffern 4y ago
> instead of a single top up change it is now constantly discharging and charging 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.
- dahfizz 4y ago
  > 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. 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.
  - schiffern 4y ago
    That's the great thing about choice: you can choose your price! But it sounds like V1G might be a better choice for you instead of V2G. 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.
- theluketaylor 4y ago
  > 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). 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.
greenthrow 4y ago
We are not talking about multiple 0-100% cycles daily. The places where pilot programs have been run always left the car with some amount of charge so it can be driven, and you don't normally charge NMC car batteries to 100%. 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.
- zopa 4y ago
  Posting a question in an internet forum counts as doing research, surely? 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.
  - greenthrow 4y ago
    Starting paragraphs of misinformation with a vague question is not a get out of jail free card. That comment was full of misinformed nonsense.
- noptd 4y ago
  Excluding Tesla: https://news.ycombinator.com/item?id=34518608 https://news.ycombinator.com/item?id=34518608 Perhaps you should do more research before ending a comment on such a condescending remark next time.
  - schiffern 4y ago
    V1G to the rescue! Existing Tesla cars can do V1G (grid-adaptive charging), but not V2G. https://news.ycombinator.com/item?id=34518188 https://news.ycombinator.com/item?id=34518188
- Gordonjcp 4y ago
  How far down do they discharge the battery, then? Like, how much range would you expect to have at the deepest part of the discharge cycle?
bluGill 4y ago
You are missing something: lifetime depends on how much you cycle the battery. If you take the battery from 80% to 50% 5 times feeding the grid you do a lot less damage to the lifetime than just one 100% to 0% cycle, even though the first supplied more power overall to the grid. Smart management of batteries can ensure that this happens.
- smileysteve 4y ago
  For some really complex lithium battery theory, if you have no long trips planned, the battery will have less wear sitting at 80% than it will sitting at 100%.
  - brianwawok 4y ago
    Tesla UI in fact warns you if you set the charge level to more than 90% for more than 1 day in a row. 90% is the value they suggest. 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.
    - dr-detroit 4y ago
      [dead]
nickelcitymario 4y ago
The way I read it, the paper is more interested in what happens to EV batteries when they drop to 80% of the maximum storage capacity. If I understood them, they're saying that at this level, the battery is no longer suitable for transportation purposes. So what do you do with the old battery when you replace it? 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.
- brianwawok 4y ago
  Modern fluid cooled batteries (Basically anyone but Nissan I believe?), the battery should last the life of the car. You would only really have a spare if 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
- mnw21cam 4y ago
  The reason they use the 80% mark is that Li-ion batteries tend to rapidly degrade after they reach that point, so once they get there it's best to replace them.
dsfyu404ed 4y ago
>Aren't people wary about using their very expensive car batteries for the grid? 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.
nagisa 4y ago
The important part is that it isn’t necessary for people to use their cars for the _public_ good for this idea to work. 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.
sokoloff 4y ago
If V2G is economically unattractive for car owners to participate, they won't. That's fine but everyone involved knows that. Peak power costs the utilities a substantial factor over base load power generation. There's no reason to think that the market will settle on "a retail kWh plus 20%" rather than on "2-4x a retail kWh". 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.
jackmott 4y ago
[dead]
audunw 4y ago
> Aren't people wary about using their very expensive car batteries for the grid? 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.
- brianwawok 4y ago
  Do the newer batteries even degrade past 50%? The first 10% happens pretty fast, but then the curve seriously flattens. I am not sure I could get to 75% degradation before the battery just gives up and dies of old age.
sonarone 4y ago
In California, recently approved NEM3 makes people involved in the energt market - paying or earning rounded rate for that specific hour. Few hours during summer months can earn you $1-2 per kW, so single discharge of EV at that time would earn you $100-200, easily outweighing the cost of degradation. 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.
cogman10 4y ago
> you will now see multiple 0%-100% charge cycles daily. 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%)
RetpolineDrama 4y ago
Well they're paying you. In the recent tesla powerwall virtual grid experiment people were printing like $60/day
torpfactory 4y ago
You're making very aggressive assumptions about amount of use the EV battery would be subject to, to the point of this being a straw man. You're right that people wouldn't agree to have their expensive EV battery trashed by multiple 0-100% discharge cycles daily. You wouldn't get any takers if that was your offer. 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.
fwungy 4y ago
The problem is that the battery is not the only expense on the car. You have to depreciate the vehicle's value too, because there is a good chance a BEV will be disposed of rather than have a battery replacement. 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.
r00fus 4y ago
I have a 6 year old EV with very minimal degradation doing all sorts of stuff that is frowned on: charging up to 100% all the time, using fast chargers regularly, and even letting the car sit outside on hot days (it does warn me if it's >100F to get it into the garage). 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.
goodcanadian 4y ago
Aren't people wary about using their very expensive car batteries for the grid? 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).
bradknowles 4y ago
I would never voluntarily use my vehicle to charge the grid. 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.

by Yizahi 4y ago

moffkalast 4y ago

Well the ones with li-ion batteries ought to last at least 2000 cycles, or about 6 years with a cycle each day, but there are lots of mid tier models being made with lifepo4s now, and those last like 6000 cycles, so there is far more breathing room. They're also cheaper so you may be able to more easily break even.

manholio 4y ago
That just means people will buy daily drivers with small batteries and charge them nightly. 15 years out of a cheap compact car with near zero operating costs sounds like a good deal, still does not make sense to waste a cycle for $1 = 20kWh fed into the grid.

ramraj07 4y ago

depends on how much the demand is. If all they have want is (collectively) a small drain (less than 1-2%) once or twice a day then why not? Especially if there are some incentives provided for the same.

Yizahi 4y ago
I admit I don't know much about power grids, but I heard that they are structured in a lot of smaller zones, so if there is a local drop in the generation due to accident then probably only close EVs will be discharged, but by a lot, to compensate.

londons_explore 4y ago

Luckily, any degradation can all be predicted ahead of time. 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.

Yizahi 4y ago
Now that's an interesting idea. Let's see how it will unfold globally. Maybe it will indeed be painless feature.
Maxion 4y ago
This can be done by using a smart AC charger. 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 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.
danuker 4y ago
It worries me that if industrial-purpose batteries cost the same and have similar degradation, grid services will also decide not to charge/discharge if the profit is less than 8 cents. This tells me that Li-Ion batteries are far from the ideal medium for grid storage.

deleted 4y ago

[deleted]

pornel 4y ago

Car batteries are not really comparable to cellphone batteries. Even among "lithium" batteries in cars there are multiple chemistries with different longevity and trade-offs (e.g. LFP can be kept charged at 100%, while NMC would rather not). 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.

schiffern 4y ago

> instead of a single top up change it is now constantly discharging and charging 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.

dahfizz 4y ago
> 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. 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.
- schiffern 4y ago
  That's the great thing about choice: you can choose your price! But it sounds like V1G might be a better choice for you instead of V2G. 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.
theluketaylor 4y ago
> 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). 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.

greenthrow 4y ago

We are not talking about multiple 0-100% cycles daily. The places where pilot programs have been run always left the car with some amount of charge so it can be driven, and you don't normally charge NMC car batteries to 100%. 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.

zopa 4y ago
Posting a question in an internet forum counts as doing research, surely? 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.
- greenthrow 4y ago
  Starting paragraphs of misinformation with a vague question is not a get out of jail free card. That comment was full of misinformed nonsense.
noptd 4y ago
Excluding Tesla: https://news.ycombinator.com/item?id=34518608 https://news.ycombinator.com/item?id=34518608 Perhaps you should do more research before ending a comment on such a condescending remark next time.
- schiffern 4y ago
  V1G to the rescue! Existing Tesla cars can do V1G (grid-adaptive charging), but not V2G. https://news.ycombinator.com/item?id=34518188 https://news.ycombinator.com/item?id=34518188
Gordonjcp 4y ago
How far down do they discharge the battery, then? Like, how much range would you expect to have at the deepest part of the discharge cycle?

bluGill 4y ago

You are missing something: lifetime depends on how much you cycle the battery. If you take the battery from 80% to 50% 5 times feeding the grid you do a lot less damage to the lifetime than just one 100% to 0% cycle, even though the first supplied more power overall to the grid. Smart management of batteries can ensure that this happens.

smileysteve 4y ago
For some really complex lithium battery theory, if you have no long trips planned, the battery will have less wear sitting at 80% than it will sitting at 100%.
- brianwawok 4y ago
  Tesla UI in fact warns you if you set the charge level to more than 90% for more than 1 day in a row. 90% is the value they suggest. 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.
  - dr-detroit 4y ago
    [dead]

nickelcitymario 4y ago

The way I read it, the paper is more interested in what happens to EV batteries when they drop to 80% of the maximum storage capacity. If I understood them, they're saying that at this level, the battery is no longer suitable for transportation purposes. So what do you do with the old battery when you replace it? 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.

brianwawok 4y ago
Modern fluid cooled batteries (Basically anyone but Nissan I believe?), the battery should last the life of the car. You would only really have a spare if 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
mnw21cam 4y ago
The reason they use the 80% mark is that Li-ion batteries tend to rapidly degrade after they reach that point, so once they get there it's best to replace them.

dsfyu404ed 4y ago

>Aren't people wary about using their very expensive car batteries for the grid? 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.

nagisa 4y ago

The important part is that it isn’t necessary for people to use their cars for the _public_ good for this idea to work. 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.

sokoloff 4y ago

If V2G is economically unattractive for car owners to participate, they won't. That's fine but everyone involved knows that. Peak power costs the utilities a substantial factor over base load power generation. There's no reason to think that the market will settle on "a retail kWh plus 20%" rather than on "2-4x a retail kWh". 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.

jackmott 4y ago

[dead]

audunw 4y ago

> Aren't people wary about using their very expensive car batteries for the grid? 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.

brianwawok 4y ago
Do the newer batteries even degrade past 50%? The first 10% happens pretty fast, but then the curve seriously flattens. I am not sure I could get to 75% degradation before the battery just gives up and dies of old age.

sonarone 4y ago

In California, recently approved NEM3 makes people involved in the energt market - paying or earning rounded rate for that specific hour. Few hours during summer months can earn you $1-2 per kW, so single discharge of EV at that time would earn you $100-200, easily outweighing the cost of degradation. 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.

cogman10 4y ago

> you will now see multiple 0%-100% charge cycles daily. 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%)

RetpolineDrama 4y ago

Well they're paying you. In the recent tesla powerwall virtual grid experiment people were printing like $60/day

torpfactory 4y ago

You're making very aggressive assumptions about amount of use the EV battery would be subject to, to the point of this being a straw man. You're right that people wouldn't agree to have their expensive EV battery trashed by multiple 0-100% discharge cycles daily. You wouldn't get any takers if that was your offer. 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.

fwungy 4y ago

The problem is that the battery is not the only expense on the car. You have to depreciate the vehicle's value too, because there is a good chance a BEV will be disposed of rather than have a battery replacement. 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.

r00fus 4y ago

I have a 6 year old EV with very minimal degradation doing all sorts of stuff that is frowned on: charging up to 100% all the time, using fast chargers regularly, and even letting the car sit outside on hot days (it does warn me if it's >100F to get it into the garage). 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.

goodcanadian 4y ago

Aren't people wary about using their very expensive car batteries for the grid? 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).

bradknowles 4y ago

I would never voluntarily use my vehicle to charge the grid. 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.