Saturday, May 26, 2012

FEV2Gen to support V2G

To translate, corporate Fleet Electric Vehicles could add power To backup Generators and push Vehicle-To-Grid technologies along.

V2G involves drawing power from electric vehicle batteries to supplement the power grid, instead of connecting the EVs to the grid solely for the purpose of charging up the EV to drive around (great info at University of Delaware).  This could have a lot of economic value by timing when you charge and release power from the batteries, and go a long way to support renewable power by providing power storage.  A related idea would take old EV batteries when they're no longer reliable enough for vehicles, but still have significant storage capacity, and using them as power backup.

For decades, people in developing countries have used regular car batteries for power supply.  In recent years, hobbyists have modified hybrid cars to power homes, and EV carmakers are finally starting to make that option available to individual buyers.  V2G experiments are happening, but we've got miles to go.

The water district that I help direct is considering spending $700,000 to $1 million to buy/upgrade two generators (100kw and 650kw) for our buildings.  We have to have power 24/7, especially when the Big One hits or if a major storm takes out power at the same time that it causes a flood.  We have a significant vehicle fleet of our own, and 700 employees who mostly drive to work.

If much of our vehicle fleet were to be converted to EV and networked to add to the power we'd receive from our generators, then we could either use less-powerful generators or extend the time that we can operate without system power.  As an additional step, we would also have a financial incentive to work out deals with our employees, providing them with financial incentives if the EVs they drive to work could be used to supplement generator power while they're there.

This is a miniature version of the V2G solution for broader society, operating in a situation where having the power would be extremely important and otherwise hard to obtain.  Other government agencies could be in a similar situation - they own a substantial vehicle fleet and need generator power.  Other places like hospitals may not have much of a fleet but would have employees there 24/7.  I think using your own fleet may be simpler at first, but working with employees is the next logical step.

Another advantage this system might have would be for transitory blackouts.  Backup generators are inefficient and polluting, while most blackouts are short.  Maybe we could have enough EVs attached so that for an initial period of 30 minutes or so, they provide all the backup power, and only if the power is still off does the generator kick in to stop battery depletion from happening too fast.  With luck, the generators would never be used at all except for testing and maintenance, something that California's air quality regulators might appreciate.

Having these systems might be good practice for and help acceptance of larger scale V2G, as well as being an additional incentive to just get more EVs on the market.

Just an idea at this point though....


very1silent said...

What exactly are the water district's needs for backup power and vehicles during the aftermath of a major earthquake? I've got a funny feeling that you will need to send an unusual number of personnel out into the field to carry out emergency dam inspections and keep the power on for your office staff at the same time.

Dealing with transitory blackouts is another story entirely.

tonylearns said...

this does sound rgreat and I have been hearing more and more about this.
Do you know much about other storage options like molten salt?
I have always felt that the arguments about inefficient storage were missing the point, since solar energy is effectively limitless. Even mechanical storage would seem practical (i.e. pumping liquid slowly uphill) to me in certain situations. And the only reason petroleum is so efficient is because it took millions of years to concentrate it.


Current electric car batteries offer so limited a number of charge cycles - roughly 1,000, at such a high replacement cost as to greatly inflate the cost of withdrawing stored power from them.

Really robust electrochemical cells , like the Al/SbCl3 ones under development could change matters, but current lithium battery cycling costs render such proposals unattractive

Anonymous said...

I really like the idea of V2G but as Russell points out, the current state of battery technology means that it is not viable. Also the costs of a two way power supply that enables V2G are quite high.

I have little doubt that they'll be able to lick both cycle life and cost though and would be surprised if we didn't have V2G before too long.

A recent report looking at the situation in the UK found that there is something to EVs supplying grid balancing services (e.g. frequency control) which are currently supplied by power stations, but V2G isn't doable now:

Anonymous said...

Apologies, looks like the link I gave above doesn't go through to the report. See:

David B. Benson said...

Yes, using auto batteries is a loser for the vehicle owner. Used as described by void the warrenty on the auto batteries.

Anonymous said...

I'm not a big fan of V2G, especially for backup applications. There are simply too many variables to consider it a reliable backup solution.

A different creative approach to backup power is installing a combined heat and power (CHP) microgeneration system. That way you get some return on your capital cost even when the grid is up. A properly designed CHP system makes very efficient use of source energy. In fact, since you are looking at putting money into upgrading your backup power anyways, I would recommend investing a few hours looking into microgeneration. Maybe call Ballard (fuel cells) or Capstone (turbines).


Brian said...

very1 - yes, that's true. Some vehicles may not be useful though. You might have triage the others, but this would create the triage option.

tony - I don't know a lot, but I know someone working in that area. I tend to go for a "try everything and see what works" solution, so I'm all for trying molten salt. The inefficiency issue to my mind is all about cost.

Russel- I've heard of that objection. I'm not certain it's a deal killer, or that it's as bad a problem as some say. Might depend partly on the economic payoff/value of storage. Also read anon's pdf:

"the degradation
cost associated with the expected additional battery
“cycling” is likely to be very low. A more thorough analysis
of the trade-of between utilization rates and value of
balancing provided could be performed to optimize the
‘response function’ for a maximum net rate of return to the
vehicle owner, taking account of battery depreciation" (p. 11)

Anon - seems like a mixed bag, but they do like the possibility for fleet vehicles. Getting to the limits of my knowledge here, but more smart metering may be necessary anyway, so the assumed infrastructure costs might not be right.

David- see above.

Brian said...

Also David - new legislation trumps warranty limitations. California did it in 2004 for hybrid batteries, so it can be done again.