[HN Gopher] EVs Are Essential Grid-Scale Storage
___________________________________________________________________
EVs Are Essential Grid-Scale Storage
Author : rbanffy
Score : 161 points
Date : 2023-01-25 11:35 UTC (11 hours ago)
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| jononomo wrote:
| When the Ford F-150 Lightning came out I was interested to learn
| that the battery was powerful enough to power a standard American
| house for over two days.
|
| 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.
| ccheney wrote:
| I'm curious to see what comes of V2G tech and other home
| battery systems. I know that Panasonic[1] & Enphase[2] have
| their own systems rolling out. Adding these systems to new home
| builds makes a lot of sense to me in the interest of future-
| proofing.
|
| 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...
| locallost wrote:
| It's a well known fact that cars stay parked for over 90% of the
| time, so this idea has been floating around for a while. The wear
| and tear issue is only a concern if nothing changes in the way we
| currently charge for electricity, e.g. a fixed price that gets
| adjusted from time to time. But I don't think we will -- even
| today we have more and more providers that charge with prices
| fluctuating hourly to reflect wholesale market prices. Thus if
| you can charge dirt cheap and sell it later for a large multiple
| more, you have a big incentive to do that. With the rise of
| renewables that basically looks unstoppable this will become a
| reality a lot quicker than I think a lot of people anticipate.
| manholio wrote:
| This is never going to happen at scale. Energy is fungible: one
| cannot compete on "quality" of energy, just on price, a kWh is a
| kWh and the provider with the cheapest energy will always win in
| the marketplace. So this means any EV owner looking to make a
| profit is competing against large scale industrial storage
| entities that:
|
| - 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.
| DeRock wrote:
| My electricity cost currently is split around 1/3 generation
| (~10C//kWh) and 2/3 distribution (~20C//kWh). If the power from
| this scheme can avoid most of the costly distribution, eg. I
| use it directly in my house and neighborhood, then it's an
| economic win. This would be true even if the centralized
| generation was free.
| manholio wrote:
| It can't, because the distribution fee is an amortized cost
| of having distribution infrastructure built. Since that
| infrastructure still needs to exist regardless of where you
| get your energy (and in fact needs to be upgraded to handle
| bidirectional consumer/producers), EV storage won't bypass it
| regardless of where the EV and the consumer is physically
| located.
|
| 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.
| rbanffy wrote:
| > Energy is fungible: one cannot compete on "quality" of
| energy, just on price
|
| 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.
| manholio wrote:
| But if that limitation is repetitive to the point of
| investing in infrastructure to use EVs, then some other
| large-scale investor will close that arbitrage opportunity.
|
| 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).
| rbanffy wrote:
| It'll always be some marginal utility - the main purpose of
| the EV will always to be a car. You can use it to store
| energy purchased at non-peak hours so you can avoid using
| the grid at those times, something that'll probably raise
| peak prices, because if you need the energy right then, you
| _really_ need it.
|
| 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.
| manholio wrote:
| But you will not use it if the depreciation on your car
| vastly exceeds what you could earn from the scheme.
| 1234letshaveatw wrote:
| I see, renewables will only leave gaps that fit your
| argument. You don't see any scenario where there could be
| brownouts during the day, say in the summer when AC usage
| is high?
|
| 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.
| manholio wrote:
| There is an economic case being made above that explains
| why, you might want to try and follow that and respond on
| point instead of mindlessly nitpicking.
|
| 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.
| throwawaaarrgh wrote:
| > Before long, there will be more EV battery capacity than the
| grid can use
|
| yes, but because nobody is deploying V2G at high density housing,
| and also because the grid doesn't have the capacity
| ZeroGravitas wrote:
| The original report is more like "we're going to have grid scale
| storage as a side-benefit of EV rollout", which this headline
| kind of twists.
|
| 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.
| Maxion wrote:
| Unless the $/kwh or lifecycle count of EV batteries change
| significantly, using them as a grid-scale storage is just not
| financially feasible.
|
| 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_sou
| rce#...). 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.
| londons_explore wrote:
| Battery lifespan in 'cycles' is kinda simplifying things too
| much.
|
| 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.
| AtlasBarfed wrote:
| - Read up on LFP. their cycle counts are far higher. and newer
| high density stuff is coming to market that competes with NMC
| chemistries from just a few years ago, and they are safer and
| more stable chemically, so less safety systems, so any density
| difference gets made up at the pack level
|
| - 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
| londons_explore wrote:
| > 106 USD per MWh hour, which is more than most generation
| sources
|
| 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.
| pclmulqdq wrote:
| So people being asked to discharge their Tesla into the grid
| should be paid a significant premium, right?
|
| 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.
| londons_explore wrote:
| It's a market - so whoever is willing to do the task for
| the smallest premium gets the business...
| locallost wrote:
| During most of last year prices in Europe were routinely over
| 300, 400 even occasionally over 1000 per MWh because there was
| an energy shortage. At the same time the prices can easily go
| negative if the conditions are favorable for renewables. It's
| not crazy to think that you would be paid to charge your car
| when there is an excess and then get paid a lot when there is a
| shortage. I don't know who would say no to this deal.
| mhandley wrote:
| Of course at some point in the future if a lot of people with
| EVs say yes to this deal, the price range will narrow
| significantly, and eventually stabilize to the point where
| it's only just profitable given battery degradation costs.
| But it may take a long time to get to that stage.
| Maxion wrote:
| My point is mainly that there are plenty of options available
| to stabilize grid prices that are way cheaper than using
| EV's. Europes energy crisis is temporary, over time the price
| fluctuations will go down.
| locallost wrote:
| That's actually not true. Let's say your calculation of
| ~100 per MWh for batteries is correct, we've seen that the
| wholesale prices were a multiple of that basically this
| whole year. Nuclear is above that price. I don't think
| anybody is seriously planning to use car batteries as the
| backbone of the grid, but as one of the last resorts yes.
| It makes sense for everybody.
| dtech wrote:
| which other options are feasible today outside hydro
| pumping?
| Maxion wrote:
| Isn't that the big question? Whoever is confident that
| they have correct answer to that question should invest
| any coin they can get their hand on right this second.
|
| 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.
| VadimPR wrote:
| Does the cost of the natural gas power plant include the green
| house gas costs it is emitting?
| Maxion wrote:
| There are many estimates for the generation cost on
| wikipedia, at least the IPCC one does not try to estimate
| what the costs of the emissions would be.
|
| 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.
| adrianN wrote:
| It's not cheaper to run a natural gas power plant if you want
| to be carbon neutral. Then you have to run it with hydrogen,
| which is quite expensive to make. It also gets more expensive
| if you only want to run the gas plant a couple of hours per
| month because at all other times renewable power is sufficient.
| fcantournet wrote:
| It is cheaper to run a nuclear power plant though. Like a
| lot. Also uses about 50x less material per MWh
| audunw wrote:
| 1. A battery isn't completely dead when it reaches its cycle
| life. It's often defined as the point where the capacity
| degrades to 80% of its initial rated capaity. For an EV with a
| large battery, most of them will be able to continue to use the
| battery for a good while after that. A Model S 90D is still a
| very usable car for many people with even 50% range. 2. You
| assume that every EV owner will use many cycles. That's
| generally not the case. I use at most 2-3 gentle cycles
| (charging to 80%, never discharging below 20%) in a month on
| our EV. I have plenty of spare cycles in the lifetime of the
| car. 3. Time degrades batteries as well. For EVs with low
| mileage, you could be throwing away useful battery cycles by
| not using it for V2G. 4. Most batteries, by far, will not have
| to be replaced until the vehicle is over 10 years old. In 10
| years, it might be far cheaper to replace EV batteries.
| Batteries will be cheaper and you'll have better economies of
| scale for replacements. You might get a better battery with
| longer range than when the car was new too.
|
| 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).
| dtech wrote:
| $0.11/KwH is super doable. Keep in mind that discharging is
| only necessary and profitable during peak demand, when prices
| are much higher than that. $0.50/KwH is far from uncommon. E.g.
| today energy peaks at EUR0.28/KwH in my area. It dipped at
| EUR0.17 so it would've already broke even.
| btbuildem wrote:
| Decentralized energy storage does seem like one solution to the
| mismatch between renewable energy inflow, and energy usage. EV
| batteries certainly have the capacity (har har) to support a
| household during the low-generation times or to "cut the tops"
| off peak demand.
|
| 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.
| vardump wrote:
| Soon enough (2030+) someone's going to solve NIB batteries
| (mainly sodium refining, I guess) and a bit heavier, but dirt
| cheap sodium ion batteries are going to be _everywhere_.
|
| https://en.wikipedia.org/wiki/Sodium-ion_battery
| GaryNumanVevo wrote:
| Another olive branch extended to the auto industry
| dahfizz wrote:
| This boils down to "There are lots of EV batteries, we can use
| them as storage!". It seems to ignore practical issues:
|
| 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.
| gwbas1c wrote:
| > So EVs are still going to be a net energy consumer during the
| night, when you need the storage the most (no solar production)
|
| 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.
| dtech wrote:
| Every ignoring that most cars aren't used every day, most cars
| are parked during the day and peak solar generation time.
| dahfizz wrote:
| > most cars aren't used every day
|
| 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.
| ffmpegy wrote:
| https://www.reinventingparking.org/2013/02/cars-are-
| parked-9...
| dahfizz wrote:
| From your source:
|
| > 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.
| raxxorraxor wrote:
| I don't understand the discrepancy between EV kWh and house
| battery kWh.
|
| 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.
| Schroedingersat wrote:
| Part of it is cars get a bunch of free tax money, but most of
| it is that cars were at the front of the queue and locked
| prices in ahead of time (before the self same orders pushed
| prices up) and they have actual pressure to compete.
|
| 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 $350 with cold weather protection.
|
| In a few more years markets will mature a little and the price
| gap will be smaller.
| AtlasBarfed wrote:
| They had better, with 230 wh/kg LFP and 150 wh/kg lithium-
| free sodium ion coming to mass production, and those
| chemistries are far safer than nickel/cobalt chemistries
| because they don't catch on fire, the "OEM" cost of a large
| battery pack will certainly drop under 100$/kWh, if it
| already hasn't.
|
| 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.
| Schroedingersat wrote:
| What a wild and ironic twist if we actually get some
| increase in transit use because leaving the car at home
| pays for the ticket.
| AtlasBarfed wrote:
| Either Chinese companies are reaping huge profits on batteries,
| or the American companies that repackage them into their
| bespoke platforms (EGo batteries don't work with greenworks or
| ryobi AFAIK because they put different plastic shapes around
| the battery cells so you're locked into their ecosystem for
| example) are reaping the profits.
|
| 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).
| theshrike79 wrote:
| Car manufacturers are buying every battery they can.
|
| 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...
| csours wrote:
| My guess is supply constraints. Tesla would rather sell cars
| than Powerwalls; other suppliers can't make a dent in the
| market because EVs are slurping up all the capacity at every
| level of the supply chain. This really is only a guess though.
| Isinlor wrote:
| Tesla is supply limited, so they can put prices high. That's
| probably about it.
| sharemywin wrote:
| State level regulations around installation driving up prices?
| [deleted]
| danans wrote:
| Nope, not that. See my sibling response above.
| sgerenser wrote:
| House batteries are a much smaller market than batteries for
| EVs (at least right now). They also have other supporting
| components, safety features, etc. that add to the price. Since
| they're normally installed as part of a solar install, they
| also usually qualify for a tax credit (between federal and
| state this can be over 50%) which further drives up the price
| because the vendor is able to capture a large chunk of the tax
| credit as profit.
| zihotki wrote:
| Actually they require less safety features (they don't need
| to be crash-safe) and can use heavier batteries and
| components. Which should make them cheaper than EV's
| batteries in theory. But that market is in early stages with
| all associated downsides of early adoption, I agree with
| that.
| boringg wrote:
| There are other features for a home battery. There are
| shutoffs. Each job is a bit custom on the install +
| electrician work. Retail markup.
|
| 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.
| AtlasBarfed wrote:
| That's a failure of government with home solar.
|
| 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
| discordance wrote:
| $300/kWh for home storage is readily available.
|
| E.g. https://signaturesolar.com/eg4-ll-lithium-
| battery-24v-200ah/
| raxxorraxor wrote:
| True, there are better prices by now. But 5kWh? I thought my
| smartphone would have that by now...
|
| 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.
| vbezhenar wrote:
| Phone battery is something like 4V. Watts depend on
| voltage. I guess home batteries use other voltage so their
| watt actually provides more electricity.
| raxxorraxor wrote:
| No, Watts should be independent of voltage, it is the
| product of voltage and ampere (don't know the exact
| English terms here). You perhaps mean ampere hours, I
| think that is often used for phones.
|
| 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.
| beckingz wrote:
| Voltage isn't fixed across a discharge cycle.
|
| As a chemical battery discharges, the voltage drops, so
| at the same load in amps you get less watts later.
| thehappypm wrote:
| I think what they're talking about is the amp-hour
| measure of battery capacity, which is common in
| electronics, but converting to actual energy requires
| knowing the voltage.
| pjc50 wrote:
| Phones are more like 10-15 _watt_ -hours, not kWh.
| mnw21cam wrote:
| Deep cycle lead-acid batteries are available around
| PS100/kWh, and they'll last pretty-much as long as a LiFePo
| if managed sensibly.
| moffkalast wrote:
| > they'll last pretty-much as long as a LiFePo if managed
| sensibly
|
| _[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.
| mnw21cam wrote:
| https://www.youtube.com/watch?v=LPPUqLZOqCQ
|
| 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.
| thescriptkiddie wrote:
| > they'll last pretty-much as long as a LiFePo
|
| citation needed
| sgt wrote:
| Managing lead-acid sensibly in my experience means never
| letting levels go below 40%. Temperature too I suppose.
|
| 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?
| mnw21cam wrote:
| LiFePo can last longer than Lead-Acid. It depends on the
| usage.
|
| 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 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.
| coding123 wrote:
| Those 5kwh "server" batteries are overpriced compared to
| prismatic cells and a bms.
| driverdan wrote:
| They aren't when you factor in labor and the other
| components involved (wiring, breakers, terminals, steel
| box, etc). I've built my own system in my RV but will be
| going with racked batteries for my house due to how much
| time and effort they will save.
| ajross wrote:
| House batteries are never purchased in isolation. They're what
| amounts to a luxury add-on to a much bigger solar system, so
| you'd expect to see a "markup". That may change with the recent
| rollback of net metering in CA, which is making a battery
| system a requirement to reach break even on cost.
| danans wrote:
| > That may change with the recent rollback of net metering in
| CA, which is making a battery system a requirement to reach
| break even on cost.
|
| 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.
| ajross wrote:
| I've seen a lot of different numbers thrown around (and to
| be clear: I'm in Oregon and not part of the fight). Let it
| suffice that NEM3.0 makes the relative benefits of a
| battery for time shifting (and thus the costs of a solar
| system without a battery, as was typical for early
| installations) much, much higher.
| [deleted]
| fsh wrote:
| The explanation is quite simple. Electricity from the grid is
| still very cheap. It therefore makes no economical sense to buy
| huge batteries for buffering your home solar panels. Since
| there is no demand, there are no products.
| danans wrote:
| As someone who recently self-installed home batteries (LiFePo),
| I learned quite a bit about what drives up prices. It's not
| regulation. If anything state incentives in California can
| drive down the prices (if you qualify for them), and federal
| incentives drop the price by 30%, thanks to the Inflation
| Reduction Act. In my experience, the big cost with home
| batteries are the same things that make artisinal custom
| designed and built homes expensive: the labor cost of the
| complex system design, installation and integration, and the
| premium charged because they are still marketed as a luxury
| product, not as a basic home appliance.
|
| 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.
| [deleted]
| dbingham wrote:
| Counter point, getting the resources for those batteries and
| building them has no small environmental impact - including
| carbon impact: https://www.theguardian.com/us-
| news/2023/jan/24/us-electric-...
|
| > 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.
| coffeebeqn wrote:
| It's not just cars. How would homes store energy overnight
| without lithium? The current best available home storage is
| still lithium based (lithium iron phosphate).
| dahfizz wrote:
| Why do houses need storage? Why can't the grid operators do
| their job?
|
| 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...
| panick21_ wrote:
| This would require quite a bit of hardware on both cars and
| houses to work. And in many ways doing both backup to the house
| and being able to feed into the grid is pretty damn hard.
|
| 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.
| tboyd47 wrote:
| So not only do the batteries lose 2.3% capacity each year, and
| lose up to 40% of their range in cold weather, but now the power
| company wants to drain your car battery at night to power other
| people's homes. What a comedy of errors!
| baq wrote:
| Au contrarie, it's a solution to bring grid storage online to
| offset some wind and PV intermittency.
| tboyd47 wrote:
| That's just saying what I said in a different way.
| 1970-01-01 wrote:
| Let's get ISO15118 working at scale before we declare it
| essential. I'm not aware of any EV for sale today that uses it
| for V2G.
|
| https://en.wikipedia.org/wiki/ISO_15118
| r00fus wrote:
| You might want to take a look at this - several production
| vehicles that are available near me have V2L (similar to V2G)
| support already.
|
| https://zecar.com/resources/which-electric-cars-have-bidirec...
| babypuncher wrote:
| This sounds like a great way to destroy the longevity of my
| battery.
|
| 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.
| college_physics wrote:
| This feels gimmicky and fragile. If distributed / decentralized
| storage is required (sounds like a good idea overall) it is
| surely better to have stationary installations, with larger
| batteries and connectivity optimized for that purpose, not using
| the EV batteries currently developed for moving these two-ton
| exosceletons to random places... In fact you want to have the
| option to significantly reduce EV usage as other, more
| sustainable overall, mobility modes become available and/or
| popular.
| goodpoint wrote:
| > This feels gimmicky and fragile
|
| If anything is very much anti-fragile. Decentralized batteries
| would only make the grid more resilient both to outages and
| overloads.
| college_physics wrote:
| my comparison is between EV batteries and stationary
| batteries, not a system without batteries (which is in any
| case unworkable if input is solely based on renewables).
|
| 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
| tuatoru wrote:
| Battery swapping allows you to have both EVs and the benefits
| of decentralized stationary installations.
|
| 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.
| chipsa wrote:
| Battery swapping has a number of disadvantages: forcing all
| the cars to use a specific size and shape battery, which may
| not be great for packaging efficiency. Battery has to be
| physically more robust to be able to withstand regular
| handling. It has to be designed to be quickly detachable,
| because if the battery takes 20 minutes to take out, it's
| definitely not faster than just charging the thing.
| coffeebeqn wrote:
| It is gimmicky but the batteries in EVs are really big and
| especially in the US everyone has a car. I don't see a large
| amount of houses getting a 30-70kWh battery unless they install
| rooftop solar. So what are the realistic options ? Other than
| large infrastructure spend to get grid batteries which is
| probably what will happen in the end
| dahfizz wrote:
| > So what are the realistic options?
|
| Maybe the utility companies could do their job and provide a
| reliable electricity source, instead of outsourcing it to
| customers.
| j245 wrote:
| > Companies could do their job
|
| 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.
| dahfizz wrote:
| > Their actual "job" is to make the most amount of money
| possible.
|
| 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.
| lambdasquirrel wrote:
| I came on here to comment that if you do this, it requires that
| the EVs be connected to the grid. How is that going to happen
| during the day when a lot of folks are at work, or out and
| about, and there aren't that many public chargers?
|
| 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.
| audunw wrote:
| > I came on here to comment that if you do this, it requires
| that the EVs be connected to the grid. How is that going to
| happen during the day when a lot of folks are at work
|
| 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?
| dTal wrote:
| Yeah, the utility of smoothing grid demand overnight seems
| limited. Nighttime is when demand is _least_ peaky. And if
| you commit to having the EV charged in the morning, you can
| 't get net energy out which means it can't be used to
| compensate for lack of sun either. It doesn't seem to solve
| any problems that we actually have.
| bluedino wrote:
| Doesn't the average US household have 2 cars? And probably
| higher in the households that can afford a new Tesla?
| greenthrow wrote:
| Peak grid load is not during the day when people are at work.
| It is right after they get home when their EVs would be
| plugged in. EVs can be used to soften this demand's load on
| the grid.
| goodcanadian wrote:
| Peak electricity demand occurs in the evening when people
| come home from work and start cooking and watching TV and
| giving the kids and bath and so on. Bring your car home, plug
| it in, and it supplies the grid at this peak time. Then it
| charges up again overnight when demand is otherwise low, and
| it is ready for you to go to work in the morning. As long as
| you have some charge left in your battery at the end of the
| day, it can work out fine.
|
| Also, some of us work from home, or commute by public
| transit, or whatever, and only use the car on weekends.
| mnw21cam wrote:
| I made this argument a few years ago when my wife asked me if
| it was a good idea for us to get solar panels for the house. My
| reply was that solar farms get economy of scale and would out-
| compete us, plus our roof views East/West, not South. Now that
| electricity prices have trebled, I have changed my mind.
|
| 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.
| Cthulhu_ wrote:
| Cool, but will the energy company pay for the wear and tear? Do
| you get paid extra if you promise to not use your car between
| hours X and Y?
| throwawaaarrgh wrote:
| an energy company paying _customers_ extra? lolllllll. if
| anything they 're gonna find a way to charge you for the
| privilege of giving them power
| dismalpedigree wrote:
| This is completely accurate. Often done by shifting the
| reported cost structure to claim transmission is vastly more
| expensive than generation. You are not doing transmission,
| they are so you pay them more.
| londons_explore wrote:
| The way most energy companies work, they do indeed 'pay for
| readiness' - ie. they'll give you money simply to be available
| to deliver power, even if you are never asked to deliver power.
|
| 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.
| Mrdarknezz wrote:
| This seems like a massive waste of energy, why not just produce
| the amount of energy we need?
| pornel wrote:
| The demand for energy is highly variable. Without storage, the
| production capacity has to be overbuilt to match the peak
| demand, and then sit underutilized for the rest of the day.
|
| 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".
| Mrdarknezz wrote:
| No you don't have to overbuild? Just build enough load
| following.
|
| Storage will waste massive amounts of energy through
| conversion
| Yizahi wrote:
| 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.
| cogman10 wrote:
| > 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%)
| r00fus wrote:
| 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.
| torpfactory wrote:
| 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.
| jackmott wrote:
| [dead]
| moffkalast wrote:
| 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 wrote:
| 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.
| nickelcitymario wrote:
| 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 wrote:
| 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 wrote:
| 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.
| audunw wrote:
| > 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 wrote:
| 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.
| ramraj07 wrote:
| 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 wrote:
| 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.
| [deleted]
| nagisa wrote:
| 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.
| dsfyu404ed wrote:
| >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.
| sonarone wrote:
| 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.
| fwungy wrote:
| 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.
| greenthrow wrote:
| 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 wrote:
| 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 wrote:
| Starting paragraphs of misinformation with a vague question
| is not a get out of jail free card. That comment was full
| of misinformed nonsense.
| Gordonjcp wrote:
| 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?
| greenthrow wrote:
| This is something pilot programs are helping to figure out.
| The ideal case is the driver can set minimum discharge as
| they can set a maximum charge (that's how it works on the
| Ford Lightning.) on top of that many EVs have the ability
| to set a departure time and the vehicle will ensure it is
| charged to your maximum level at the departure time.
| noptd wrote:
| Excluding Tesla:
| 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 wrote:
| V1G to the rescue!
|
| Existing Tesla cars can do V1G (grid-adaptive charging),
| but not V2G.
|
| https://news.ycombinator.com/item?id=34518188
| pornel wrote:
| 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.
| goodcanadian wrote:
| _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).
| schiffern wrote:
| > 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.
| theluketaylor wrote:
| > 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.
| dahfizz wrote:
| > 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 wrote:
| 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.
| jakewins wrote:
| Thank you for posting this. This focus on V2G is nuts.
|
| 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.
| RetpolineDrama wrote:
| Well they're paying you. In the recent tesla powerwall virtual
| grid experiment people were printing like $60/day
| sokoloff wrote:
| 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.
| bluGill wrote:
| 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 wrote:
| 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 wrote:
| 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 wrote:
| [dead]
| londons_explore wrote:
| 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.
| punnerud wrote:
| This already exist in Norway with the company Tibber, that
| have more than 400.000 users. They do just that, let you
| connect your EV so they adjust the charging and guarantee a
| lower price.
|
| 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.
| mercutio2 wrote:
| This is "let a large entity suck up much of the arbitrage
| value, with a small fraction going to you", and already
| exists in most countries.
|
| 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).
| dmurray wrote:
| > 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.
|
| 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.
| scythe wrote:
| >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.
|
| 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.
| bryanlarsen wrote:
| Power has two big costs: generation and distribution. Once
| rooftop solar power is below the cost of distribution it
| doesn't matter how much it costs to generate power; rooftop
| solar is always going to be cheaper.
|
| That milestone has been hit in some places Australia
| already.
| mercutio2 wrote:
| I don't quite buy your argument.
|
| 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.
| iso1210 wrote:
| This does work today at grid scale, people use their home
| batteries (either on wheels or not) to charge/discharge to
| the grid in the UK all the time.
|
| If someone builds that storage facility to do it
| commercially then great.
|
| > rooftop solar can't exist without special subsidies
|
| Yet it does
| [deleted]
| sokoloff wrote:
| There are special subsidies for rooftop solar here in the
| US (Solar Investment Tax Credit). Are there not subsidies
| for solar where you live?
|
| 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.
| philipkglass wrote:
| The same link says:
|
| _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.
| sokoloff wrote:
| The interesting question of there being a subsidy for
| rooftop solar is the difference in subsidy to me between
| my roof having solar panels or my roof not having solar
| panels, not between my subsidy for my roof having solar
| panels or someone else's for their field having solar
| panels on it.
| iso1210 wrote:
| Not any more, other than no sales tax on the panels.
| sokoloff wrote:
| ??
|
| 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/
| fwungy wrote:
| Subsidies are a terrible way to run energy policy because
| they can change quickly with politics. Big players stay
| away from big commitments to subsidy based markets.
| sokoloff wrote:
| Subsidies of "do this this year and we'll pay you $X"
| work and are relied upon. Subsidies like the CF that was
| the SREC market are indeed highly suspect and should not
| be relied upon, as generators of SRECs can attest.
| mercutio2 wrote:
| I think you may have missed the point here.
|
| 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).
| neallindsay wrote:
| "X cents per charge cycle" is a bit simpler than the
| reality. The actual wear cost of charging/discharging a big
| EV battery is cheaper in the middle and more expensive at
| the extremes.
|
| 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.
| schiffern wrote:
| I took their numbers only as a simplified illustrative
| example to teach the idea.
|
| A real deployed algorithm would estimate the "degradation
| cost curve" over the entire DoD, and stop charging when
| total (fully-considered) costs exceed revenue.
| londons_explore wrote:
| Rooftop solar outcompetes solar farms because energy from a
| solar farm pays taxes and distribution costs before it is
| delivered to a user. Whereas rooftop solar energy is
| untaxed when it powers your laptop.
|
| > 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.
| est31 wrote:
| This reminds me of how in Germany, before there has been
| a value added tax, there'd been a revenue tax. It was
| lower, but you had to pay it on every $ of revenue, even
| if your profit margin was very small. So a lot of
| businesses started to vertically integrate. Once the
| system switched to one where you get back the tax for the
| things your business buys, businesses got broken up or
| grew in only one of the steps of their supply chain.
| onlyrealcuzzo wrote:
| > Rooftop solar outcompetes solar farms because energy
| from a solar farm pays taxes and distribution costs
| before it is delivered to a user.
|
| This depends where you live and the size/efficiency of
| your rooftop setup, right?
| thrashh wrote:
| It may be calculable, but is it economical? That 8 cents
| isn't free. If the power company pays, that means customers
| pay. If customers don't pay, society has to pay. There are
| other power storage solutions like pumped hydro that don't
| have to deal with battery chemistry degradation, for example,
| but they have higher investment costs.
|
| 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-...
| staringback wrote:
| Let's hope you don't need to go anywhere urgently in the
| middle of the night... oops not enough battery to make it!
| schiffern wrote:
| This is why you have an "always charge immediately to X%"
| option in the UI. You set this to whatever range an
| unexpected trip might require.
|
| 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
| svggrfgovgf wrote:
| People value things differently. You'd have to pay me way
| more than the 8 cents/kwh it cost me to use my battery. I'd
| want to be heavily compensated for the inconvenience of
| replacing the battery or car prematurely.
| bryanlarsen wrote:
| If I had a LiFePo4 battery that's good for 750,000 km I'd
| be willing to accept less than 8c because there's no way
| the rest of the car is going to last 750,000 km.
| sokoloff wrote:
| You'd be willing to take around a penny per km of battery
| lifespan? I accept your decision at face-value, but it
| hardly seems worth it to me.
|
| 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."
| martin-adams wrote:
| Plus the reduced range between new and replacement.
| weard_beard wrote:
| Plus my time and inconvenience of not having full range
| transport at all times. The time of someone who can
| currently afford an EV is more expensive than the time of
| someone who cannot.
| japaneseminisub wrote:
| From GPs post its actually $5 plus 8c per KW.
|
| That seems more reasonable for the owner, but no utility co
| would pay it.
| tzs wrote:
| > A 60kwh car battery might cost $10k, and allow 2000 charge
| cycles
|
| 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?
| Maxion wrote:
| 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
|
| 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 wrote:
| 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.
| theluketaylor wrote:
| Most cars use NCA or NMC chemistry which has 500ish cycles.
| Grid storage will soon use LFP which is cheaper to begin
| with and has 5000+ cycles. It has a lower density than
| other chemistries and very poor cold weather performance,
| making it less ideal for vehicles (though Tesla is using it
| in the standard range model 3 now). Those downsides don't
| matter for grid storage and really change the economics of
| charge/discharge.
| appletrotter wrote:
| > has 500ish cycles
|
| That's on the low end, like if you're fully
| charging/discharging the battery frequently.
| wongarsu wrote:
| For grid scale storage Li-Ion is a transitional technology
| at best. It sees interest right now because it's quick to
| deploy (unlike the much cheaper pumped hydro), and because
| so much money had been pumped into Li-Ion research and
| production that other battery technologies have a hard time
| competing.
|
| 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.
| tuatoru wrote:
| There are various niches in grid storage.
|
| 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.
| mnw21cam wrote:
| These up and coming battery types look fantastic, but
| everyone seems to forget that lead-acid batteries are
| already way better than Li-ion or LiFePo for non-mobile
| energy storage, in terms of price per kWh stored.
| devmor wrote:
| Batteries are extremely inefficient. Capacitors are much
| more resilient in terms of charge cycles (by orders of
| magnitude).
|
| 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.
| kragen wrote:
| capacitors are very low energy density and very high cost
| per joule of storage so they are never used this way
| antipotoad wrote:
| The idea of super-capacitors in cars is positively
| horrifying, knowing how explosive just the small ones can
| be. At grid level though, is there anything that speaks
| against them?
|
| 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/docum
| ents/Ses...
| londons_explore wrote:
| Todays grids don't have much need for energy storage on
| the sub-10 second timeframe. Ie. there is rarely any
| money to be made by taking power from the grid now and
| returning it in 10 seconds.
|
| 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).
| danans wrote:
| > Batteries are extremely inefficient. Capacitors are
| much more resilient in terms of charge cycles (by orders
| of magnitude). If one were to build a "facility" to hold
| short term load,that's likely what they'd use
|
| 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.
| pjc50 wrote:
| > 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.
|
| 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".
| trashtester wrote:
| > Buuuut... Delaying charging till later is free.
|
| 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.
| jacquesm wrote:
| For a blackout situation your car won't be of much help:
| any inverter that is grid tied will refuse to come on as
| long as there isn't a low impedance _functioning_ grid
| connection present. Typically they 'll measure the
| conditions for a minute or two, then make the connection
| (you'll hear a relay trip) and then bit by bit the inverter
| starts pushing power by advancing its on phase relative to
| the grid. If that doesn't stay within very precise
| parameters it will switch off, wait for a bit and try
| again.
|
| 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).
| [deleted]
| kkfx wrote:
| Fronius have hybrid inverter for 400V lithium batteries,
| witch are essentially the same used in cars, the missing
| part is the integration p.v. inverter-car's BMS.
|
| 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.
| [deleted]
| shagie wrote:
| > 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.)
|
| 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
| ben-schaaf wrote:
| > All model year 2013 and newer Nissan Leafs are approved
| for use with the FE-15 bidirectional charger, and the
| automaker states that battery warranties will not be
| affected.
|
| https://www.theverge.com/2022/9/12/23349971/nissan-leaf-
| bidi...
| shagie wrote:
| https://cleantechnica.com/2022/09/09/a-nissan-leaf-can-
| power...
|
| > 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.
| foobazgt wrote:
| V2X (vehicle to grid, home, or load) is pretty new, but
| there are some vehicles out there with it. Tesla is not
| one of them. They seem to be more focused on solving
| storage with powerwall. I don't know where that's good or
| bad, but I do wish I could use my Tesla to jump another
| dead EV.
| [deleted]
| htag wrote:
| > 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.
|
| 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.
| schiffern wrote:
| >This functionality is already there.
|
| 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.
| cogman10 wrote:
| We really just need a standard. The j1772 includes data
| lines. V2G is would literally be just controlling when
| the cars battery is connected to the charge circuit.
| EGreg wrote:
| People measure stuff in terms of $ when they should be
| looking at the global resources on the planet, the garbage
| and the externalized costs. Until we move to a resource-based
| economy that takes these into account, we'll be destroying
| the planet while on paper the carbon credit accounting looks
| perfect.
| whazor wrote:
| Here in EU, day ahead prices that are available to me as
| consumer are now ranging from EUR0.18/kWh to EUR0.34/kWh in
| the same day (winter). So that is 16 cents per kWh diff to
| profit from. I guess there is some energy loss with charging
| and de-charging.
|
| 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.
| Yizahi wrote:
| Now that's an interesting idea. Let's see how it will unfold
| globally. Maybe it will indeed be painless feature.
| singhrac wrote:
| The spread between wholesale energy prices between high and
| low renewable times (with low-compared-to-future renewable
| penetration) is around $20/MW (it's not $2 and it's not
| _usually_ $200), or about $0.02 /kwh, so this isn't a viable
| return. I doubt selling into the grid will ever get you
| retail prices in return (someone had to maintain load power
| lines).
|
| 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.
| coding123 wrote:
| Someone else's EV is going to charge mine at night
| thehappypm wrote:
| Yup. They'll be getting paid a nice markup to charge their
| batteries cheaply during the day and sell it to you at night.
| TheLoafOfBread wrote:
| What a joke. Renewables intermittency is not a problem of a user,
| but problem of the operator of renewable power plant. Government
| should mandate that any renewable power plant must provide
| installed power (i.e. 100MW) for at least 24 hours without
| interruption, independently on weather and if it can't because
| operator cheapen out on power plant's energy storage, sanction
| them until bankruptcy.
| KingOfCoders wrote:
| What a joke. Every candy store should provide insulin free of
| charge for 1% of customers.
| TheLoafOfBread wrote:
| We already have that, like when store have obligation to take
| old electrical appliance for recycling when you buy new one.
| NDizzle wrote:
| ...grid scale?
|
| Reminds me of CLOUD SCALE.
|
| Avoid.
| joshuanapoli wrote:
| I'd guess that vehicle-to-grid will get not get past small-scale
| trials. Not because of wear-out, but because the vehicles are
| probably not located at the most ideal locations for the grid
| operator.
| gwbas1c wrote:
| This really only makes sense for _short-term, emergency_ storage:
| IE, if a major power plant suddenly goes offline, calling on EVs
| to push power back into the grid for 10-60 seconds. This is
| enough time for things like pumped storage and quick start
| generators to come online. (It also wouldn 't cause noticeable
| wear.)
|
| 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.
| TheLoafOfBread wrote:
| Exactly. This is just offloading of expensive energy storage to
| consumers, so energy company can show bigger profits.
| schiffern wrote:
| "Quick, don't make the world more efficient! The _wrong
| people_ might also benefit... "
|
| 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?
| TheLoafOfBread wrote:
| There is no reason to subsidize energy companies. They are
| operating renewable power plants, which have intermittency
| issues, they should be solving this problem. I don't see
| any reason why I should be part of their problem of their
| own making.
| bryanlarsen wrote:
| They solve their problem by paying me money. I'm fine
| with that. You don't have to get paid if you don't want
| to.
| causi wrote:
| Even if you completely do away with concerns of battery wear, I'd
| only be willing to participate in this as long as my household
| still had an ICE vehicle to fall back on. When I get home and
| plug the car in I don't want to have to think about whether I
| might want or need to leave the house at a particular time with a
| particular charge; I just want the charge to be as high as
| possible as soon as possible.
| dtech wrote:
| That is going to be an expensive habit in the future once time-
| variable pricing is the standard, which I think is inevitable.
| Charging your car at 6PM is going to be super expensive
| compared to 3 AM or 1 PM.
|
| 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.
| ffmpegy wrote:
| Just a note for any UK readers that this is coming in sooner
| than you think. There are already proposals on the Ofgem[1]
| site to force mandatory half-hourly meter reads that mean
| energy companies can offer pricing that more closely matches
| demand.
|
| 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.
| jonplackett wrote:
| All you need is a 'no selling electricity today please' button.
| ceejayoz wrote:
| Or "always leave me 150 miles of range".
| gwbas1c wrote:
| At that point it's cheaper to buy a car with a smaller
| battery and use a stationary battery for grid storage.
| goodpoint wrote:
| No. You are going to charge up for longer trips e.g. on
| holidays.
| ceejayoz wrote:
| I might want a car with 300 miles charge for vacations,
| but most of the time be making trips to the grocery
| store. The grid might only dip into my car's battery for
| a 15-30 minutes at a time to prevent brown-outs while
| power plants spin up.
|
| There are plenty of scenarios where the EV makes more
| sense than a dedicated battery for it.
| guruz wrote:
| You might be at work (away with car) while the midday sun
| is filling your home battery.
| ceejayoz wrote:
| Sure, if you have solar, by all means get a home battery
| and enroll it in the same grid backup program. Makes
| plenty of sense.
|
| 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.
| tsimionescu wrote:
| How do you know when it is safe to activate?
| ffmpegy wrote:
| I use an app for my home heating that lets me define a
| schedule every day. If I'm going out I can turn it down or
| off, and if I have guests over I can boost the hot water.
|
| 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.
| numbasys wrote:
| If you're a consumer in the UK, and thinking about an EV,
| consider Octopus Energy's Go tariff: https://octopus.energy/go/.
| They also offer a salary sacrifice scheme to buy EVs:
| https://octopusev.com/, because this grid-supplementing storage
| is part of their offering, I think.
|
| 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.
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