Returning Power From Electric Cars To the Grid

Has potential, but... by Smidge204 · 2011-09-27 02:12 · Score: 3, Insightful

This idea is kicked around a lot, and there are some pros and cons.

The intention is obvious: use stored energy in parked vehicles to help smooth spikes in demand and evenly distribute the load on the grid. But the difficulty is that people will want their cars to be charged when they leave work or the train station to head home, and peak demand is usually during those hours. Not only will a lot of cars be getting unplugged right when you need them, but few people will be willing to part with charge they might need to get home.
=Smidge=

Re:Has potential, but... by SrJsignal · 2011-09-27 04:23 · Score: 2

Hundreds of dollars per month. You are either purposely making stuff up, or horribly bad at math.
I suppose you could be spouting off someone else's fake numbers, which would just make you ignorant.

Anyway, lets do some math:
24KWh battery (Nissan leaf, and we'll give you the entire battery, just for grins).
I'll even grant you a ridiculous number for power cost (average wholesale energy cost in TX $0.045 / KWh) we're talking peak so lets go with $0.10 / KWh
24KWh*$0.10/KWh*30days = $72.00 Oh and by the way you can't drive your car now, because it's going to take 6 hours to charge back up.
Nissan said the cost for the battery is $18K (not $9k as widely reported) http://green.autoblog.com/2010/05/15/nissan-leaf-profitable-by-year-three-battery-cost-closer-to-18/
So to break even is 20 years (or 10 if you assume the cost ends up dropping to $9K).
Neat that's to break even, no where near an order of magnitude.... And now you can't drive your car because it's an expensive battery...

Both by hackertourist · 2011-09-27 02:13 · Score: 3, Insightful

It's genius in that it allows load levelling without much investment by the power company, it's silly because the investment will just be moved to the user: Adding one charge cycle per day means that battery life is halved.

The only way this will take off is for users to have a financial incentive to allow the power company to do this, ie the power price during peak demand must be so high that it's cheaper to deplete your EV battery rather than draw from the grid.

Re:Both by ITShaman · 2011-09-27 02:28 · Score: 2

Yeah, it's genius for the electricity generating companies, they can get the car owner to pay for the fuel to generate the electricity to charge their car.

--
I can no longer read Dilbert. It's too depressing, because it is too real. -- Hyperhaplo
Re:Both by Anonymous Coward · 2011-09-27 04:05 · Score: 2, Interesting

Exactly, the only thing holding EVs back is battery prices. There's no way you let someone borrow your $10-30k battery to run their AC.
Current batteries cost $0.13/kwh over their lifetime, which means you need to pay me $0.20/kwh plus the regular utility rate if you want that power. If you're in a high demand area, you're up to half a buck / kwh. Might as well just keep burning gasoline to meet the demand.
Re:Both by Spoke · 2011-09-27 04:35 · Score: 3, Interesting

It's genius in that it allows load levelling without much investment by the power company, it's silly because the investment will just be moved to the user
Users will only allow this if they are compensated appropriately.

Adding one charge cycle per day means that battery life is halved.
Typical use case won't involve anywhere close to a full cycle. Today, typical use of an EV involves a partial cycle - probably 1/3rd to 1/2 cycle. 2 half cycles is easier on a pack than one full cycle - you can probably get 2-3x more "full" cycles by only half-cycling a modern battery pack. Limit depth of charge/discharge even more and you'll get even more use out of the pack.
That said - the real value won't come from performance large charge/discharges. It will come from many small charge/discharge events to provide grid regulation services. If a big load pops on, draw a bit of juice from batteries while conventional generators spin up. When it turns off use the excess juice to charge batteries.
Conventional generators are not good at spinning up and down quickly to match changes in load - by buffering this load and allowing the big generator to run closer to constant load you can significantly improve it's operating efficiency. Very frequently this inability to quickly match changes in load is what causes black outs (the recent San Diego blackout is a good example).
Worst case you're looking at a really hot or really cold day and you want to be able to draw 5 kW from storage during peak. This can go a long ways. I know that some utilities will pay ~$50/year just to have the option of being able to remotely control your air conditioner to keep it on a 50% duty cycle for one hour - they'll pay up to $200/year to have the option of being able to keep it off for a whole hour - and they may never need to use it!
So imagine being paid to simply leave your car plugged in to the grid just so the utility has the option of drawing power from it - and then being paid more if they actually use it. Having these resources available at little cost can be worth their weight in gold when they are needed.

Is it really worth the investment? by damn_registrars · 2011-09-27 02:13 · Score: 2

It seems like the energy loss of moving energy from the grid to the cars, then back to the grid, could potentially be too great to justify the investment. I would think large arrays of dedicated stationary batteries might be a better choice.

--
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.

Re:Is it really worth the investment? by skids · 2011-09-27 02:39 · Score: 2

It seems like the energy loss of moving energy from the grid to the cars, then back to the grid, could potentially be too great to justify the investment.
It's offset by the inefficiency of suddenly having to fire up coal plant turbine or keep a gas turbine in spinning reserve mode just to handle a temporary peak. Which is why storage facilities like those built by Beacon Power/A123/VRB systems can turn a profit.

I would think large arrays of dedicated stationary batteries might be a better choice.
No argument there. Car batteries are optimized for weight and the extra electronics for grid feedback are better bought/installed in bulk. A dedicated stationary facility can use battery/storage technology that doesn't have this restriction, and use more efficient power conversion systems designed for larger loads.

--
Someone had to do it.

This raises a question I've always had by elrous0 · 2011-09-27 02:15 · Score: 2

Considering how much rechargeable batteries "leak" energy when they sit, does anyone take this into account when they're touting all these great energy savings that electric cars are supposed to provide? I mean, I drive very little. Most of the time my car is just sitting around. But with a gas-powered car, it's not like I'm losing gallons of gas letting it sit for a few days (or even a week). With an electric car, even with one of the newest batteries, I would be losing power even if I'm not driving it, right? Yet I never hear any of these green types addressing that. Just think of all the power that would be wasted just in long-term airport parking.

--
SJW: Someone who has run out of real oppression, and has to fake it.

As a prius driver by Gideon+Wells · 2011-09-27 02:18 · Score: 4, Insightful

Silly as hell for now.

I can't count how many times I parked my car with my battery being "full". I mean, if surplus energy were such a huge issue then why is Toyota releasing models now you can plug in for extra "fuel efficiency". For hybrids there can't be that much of a demand. I mean, this means I would need to use more gas to charge my car more to get my good fuel efficiency, partially defeating the purpose of the car.

This seems even sillier for pure electric cars. You might as well argue that each home should have a pipeline to gas stations to siphon off their gas, in exchange for money, which you can buy back at the gas stations.

That hybrid and electric car batteries may need tapped enough to use in this system is a more worrying scenario for me. What the bleep is wrong with the local grid that we are that pinched for energy? There are fluke events that make this impractical, or it happens enough which means to me there is something wrong with the regional system that needs fixed. Not my car drained of "fuel".

Now, solar cars (maybe even cars with mini wind turbines?) I can see being part of this if you leave your vehicles outside. Once, if, your battery fills up you can sell surplus energy back as your car could be generating power during non-use unlike current electrics or hybrids.

--
by Anonymous Coward: I, for one, welcome the shift from car analogies to pizza analogies. um.. overlords?

Re:As a prius driver by angel'o'sphere · 2011-09-27 02:59 · Score: 2

Silly as hell for now.
Hm, perhaps you should elaborate more?

I can't count how many times I parked my car with my battery being "full". I mean, if surplus energy were such a huge issue then why is Toyota releasing models now you can plug in for extra "fuel efficiency".
Because plugging your Hybrid into the Grid let you load it for less than a 4th of the price (than burning your own gasoline) and with perhaps 5 to 6 times the efficiency regarding CO2.

For hybrids there can't be that much of a demand. I mean, this means I would need to use more gas to charge my car more to get my good fuel efficiency, partially defeating the purpose of the car.
Sorry, I don't get it. This only would hold true if you would allow the battery to more or less completely depleet so you have to relaod it with gasoline again. Obviously it is _not_ done that way.

This seems even sillier for pure electric cars. You might as well argue that each home should have a pipeline to gas stations to siphon off their gas, in exchange for money, which you can buy back at the gas stations.
The articel and most people miss one important point: being able to regulate how much power a loading car is draining from the grid allows a better power plant controll. Instead of firing up the plant when the demand increases, you throttle the load of the electric car.

That hybrid and electric car batteries may need tapped enough to use in this system is a more worrying scenario for me. What the bleep is wrong with the local grid that we are that pinched for energy?
If you keep your grid like it is, then nothing is wrong. However the grids are changing. E.g. more wind and solar power.

There are fluke events that make this impractical, or it happens enough which means to me there is something wrong with the regional system that needs fixed. Not my car drained of "fuel".
This are not fluke events. Usually a power company knows in advance that wind power will increase, lets say in 2h, and will stay at a higher level for 3h e.g.
During that time energy prices will drop. Electric cars that are not in use, or do not need to be fully charged all the time, will now start loading with that (cheap) surplus energy.

Now, solar cars (maybe even cars with mini wind turbines?) I can see being part of this if you leave your vehicles outside. Once, if, your battery fills up you can sell surplus energy back as your car could be generating power during non-use unlike current electrics or hybrids.
Well in this case it is not the car producing power but the Wind turbine or Solar panel ;D
Bottom line: I'm surprised about this anti technology attitude you see on /. lately so often.
Everything that is new and green is evil .... why?

--
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Re:As a prius driver by Kyont · 2011-09-27 04:20 · Score: 2

'Tis nothing of the sort. What's "wrong" with the grid is that demand is higher during the day than at night. This is a well-understood condition that we've had pretty much since air conditioning was invented. We frequently have so much cheap power available at night that the wholesale (hourly or 5-minute) price paid to generators goes negative (i.e. you are charged for burdening the system with your extra energy). On the flip side, we have expensive generators sitting around all year for the peaks, that only get to run for a few hours on hot afternoons. Charging cars (or anything else) at night when it's cheap and paying them to retrieve power during the day (when it's expensive) is simply a way of postponing or eliminating the need for that next super-expensive power plant that you use only at peak times. Sure, you lose some of that power in the round-trip, but if the price difference from night to day is large enough, you come out ahead.

--
You shall see a cow on the roof of a cotton house.

Step 4: Profit? by sureshot007 · 2011-09-27 02:18 · Score: 2

As long as I get paid for giving electricity back to the power company. Maybe then I could make back the cost of the car by charging it at night at my house, and then plugging it in at work and selling it back at a high cost per kwh.

This is not about you by Anonymous Coward · 2011-09-27 02:24 · Score: 3, Funny

As a Prius driver, obviously this is not relevant to you, because you do not drive an electric car. You drive a gasoline car.

(Unless you've got one of the very latest Priuses, or you've modded your car.)

Capital Costs by alexander_686 · 2011-09-27 02:28 · Score: 3, Insightful

So we have a expensive capital good laying around doing nothing most of the time – car batteries.

We have a variable energy source (wind or solar, take your pick) which do not necessary correlate to peak energy usage. If one were to run solely off of these 2, energy companies would have to invest in a lot of batteries, unless

Also, one could delay additional investments into the power grid by levering out the usage, where the energy Is coming from, etc. This assumes you don’t lose too much energy by taking electricity out of the battery again.

Re:Capital Costs by Dr+Max · 2011-09-27 13:27 · Score: 2

Renault and betterplace are releasing a car where you lease the battery from betterplace and they refill the battery (when you plug into one of their outlets they will install) which still works out cheaper than gas, the initial cost of the car is reduced to the same as its petrol brethren, performance is practically the same, battery swapping stations assure extended range and it's due out next year.
http://www.betterplace.com.au/
http://www.renault.com/en/vehicules/renault/pages/fluence-ze.aspx

--
Rocket Surgeon.

Re:Silly. by MarkGriz · 2011-09-27 02:52 · Score: 2

Depends on perspective.

Silly, if you own the car.
Genius, if you sell car batteries.

--
Beauty is in the eye of the beerholder.

Not gonna work. by whitelabrat · 2011-09-27 02:59 · Score: 2

I thought the point of having an electric car was to avoid using gasoline? If I have a drained battery at the end of the day and you assume that I have a combustion engine as a standby, I'd have to use petroleum to get home. FAIL. If the car is electric only and relies on the grid to charge, I'd end up walking home. FAIL.

Now if we were talking about some sort of super capacitor that can drain and then be quickly replenished this may have a useful effect to normalize daytime power usage, but only for short durations. An extended drain would be unacceptable. I don't think the monetary reimbursement would entice folks at all because vehicular range is king.

Overall I think this wouldn't work well.

Re:Silly. by Tanktalus · 2011-09-27 03:30 · Score: 2

My car has a range of x km, based on a full charge. I need to travel .4x km and back today. The grid took off the top 20% of my battery. Do I make it all the way back into my driveway?

Planning road trips, even if the trip is only downtown and back, gets trickier when you don't know how much energy (range) you have before you climb in to the vehicle. Other trips, of course, are going to be moot - getting to the local grocery store and back is unlikely to be a significant issue.

When we drive a 350km-each-way trip to visit my grandmother, we know exactly where we need to fill on gas. We can plan how long we'll be in the vehicle before mandatory stoppages. We can load up on gas the day before the trip and know how much will be in the tank when we depart the next day.

If the power companies want to shave their peaks, they should provide the power storage. And batteries may or may not be the most effective ways to do that.

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Returning Power From Electric Cars To the Grid

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