Future Toyota Highland to be equipped with fuel cell
Powered by a fuel cell, vehicles like this Toyota Highlander could become the distributed power plants of the future.

Get Ready For V2G

Willett Kempton, professor, College of Marine Studies and Center for Energy and Environmental Policy, University of Delaware.

By Bill Moore

Advocates of electric-drive vehicles point to their quiet, low-cost operation and near zero emissions as two of the strongest arguments for EVs, including battery, fuel cell and hybrid electric-vehicles.

Now there is a third, perhaps even more compelling reason supporting the adoption of electric-drive technologies, the energy crisis. As strange as this might sound, the electric-drive automobile could just be the answer to helping meet growing energy demand.

EV World has previously interviewed Dr. Steve Letendre and Dr. Alec Brooks on the concept of using the electricity generated by an electric-drive vehicle to help power homes and businesses in the future. Their colleague in this research is Dr. Willett Kempton.

Kempton, Letendre, Brooks and others, incuding Dr. Jasna Tomic, also with the University of Delaware and Dr. Timothy Lipman with UC Davis, recently issued June of this year a white paper commissioned by the California Air Resources Board, the California EPA and LADWP. That paper, entitled, "Vehicle-to-Grid Power: Battery, Hybrid and Fuel Cell Vehicles as Resources for Distributed Electric Power in California," investigated in some detail the potential implications of connecting the tens of thousands or hundreds of thousands of EVs to the State's power grid.

"People think of a car as a lot smaller than a house and maybe think of it as having less power, but electric vehicles put out from 10 kilowatts up to the EV1 that puts out 100 kilowatts. So, that compares with an average consumption of a house at one kilowatt. A vehicle puts out quite a bit more than a house requires," Kempton pointed out. This means the average electric-drive vehicle could easily power several homes, he added.

"But the question is, is there use for this (EV-generated electricity) besides just emergency power on a one-by-one, switch-it-on-manually kind of basis?" he asked. "That's what we've investigated in a study we did for the California Air Resources Board and the Los Angeles Department of Water and Power."

What the Vehicle-to-Grid study found was a very real opportunity to provide the power grid in California with high-quality electric power during times of peak demand. Under this scenario, a participating EV owner could net as much as $3,000 a year in extra income, a sum that would go a long ways towards paying for the vehicle.

Of course, a number of not insignificant changes would need to be implemented in terms of both technology and policy. Carmakers, utilities, regulators and consumers would have to become committed stakeholders in such a far-reaching infrastructure change.

"There is a quick way to get it, some of it done with minimal changes," Kempton told EV World. "And then if you wanted to get full use of it, full potential, then it would require more of the types of changes we're talking about, both technical and regulatory."

When EV World first discussed the concept of Vehicle-to-Grid or V2G with Dr. Steve Letendre several years ago, few thought the concept practical, but that now appears to be changing. Kempton stated that before the end of 2001, several experimental vehicles capable of sending electric power to the grid will debut. "So, it's not something that requires a great deal of change to get some operational."

The most logical first vehicles to experiment with are battery electric vehicles like the GM EV1, Toyota RAV4 EV or even the Ford Th!nk city. Kempton explained that this is because the electric drive systems on these vehicles operates on alternating current -- the same type of current used by the power grid -- but that they already have a grid-to-vehicle connection that is used to recharge their batteries. With some relatively small changes to the power electronics, it would be possible to send electricity the other direction, from the vehicle to the power grid.

Dr. Kempton added that this proposal really only starts to make sense with vehicles above the Neighborhood Electric Vehicle (NEV) class. This is because NEVs and golf cars simply don't store enough energy onboard to make utilizing their power worth the cost of setting up the necessary accounts and integrating the necessary hardware. In addition, most of these vehicles operate on DC power and have to have expensive inverters installed to make them compatible with the AC power grid.

"We tried to look just briefly at that size of vehicle (and) its probably not worth it. But the Th!nk (city), which is a relatively small battery pack and all, that's quite good as far as having the amount of power to make it worth doing, " he said.

"We did specifically calculate for the Th!nk (city) and for one type of electric power market, "regulation services," we calculated that a Th!nk could generate $4,400 dollars of revenue per year at a cost to the owner of $1,900. So, that's about a $2,500 dollar profit to the owner for that relatively small electric vehicle.

What about hybrid-electric vehicles like the Honda Insight and the Toyota Prius? It turns out that Kempton and his colleagues did take a look at both of these vehicles and while the Prius would work as long as the gasoline engine was running in generator-mode, neither vehicle is suitable using just the energy from their battery packs along.

The most promising of the four major types of electrical services studied in the California utility market was "regulation services." Kempton explained that on the typical power grid, there are momentary energy peaks and valleys as large electricity users turn equipment on and off. While a consumer's hair drier barely causes a ripple in the grid, a large electric plating machine at a factory can cause a significant spike in demand that is felt across the grid.

What the V2G proposal envisions are tens of thousands of BEVs and FCEVs connected to the grid and available to help even out these energy spikes by putting electricity into the grid and absorbing it back when demand drops. All these EVs would act like a giant surge protector and backup battery supply for the grid. And because "regulation service" is one of the most costly kinds of power a grid operator can purchase in terms of capital expenditures, buying a comparable service from EV owners seems to make a great economic sense all the way around. Kempton also pointed out that conventional nuclear and coal-fired plants simply aren't respond in this way.

The entire system would be regulated electronically so power demands would be met almost instantaneously. The grid and the EV would be in continual communication as long as the vehicle is plugged in. EV owners would have control of how much power the grid could take from their vehicle so they wouldn't come out after work some evening and find their battery pack drained of power.

Another advantage of this approach is its distribution flexibility with power demands being regulated in the vicinity of the load, rather than scores or hundreds of miles away at a central power plant. "We think that it can respond more quickly," Kempton stated, "And also it can do it in the area where the power's required, because as EVs start to move into the market, they're going to be distributed all over."

He continued, "Battery vehicles sort of get double dipping here because regulation down is charging your battery. Regulation up is discharging your battery. So there are two benefits that are there. One is you are getting paid to charge your battery. The second is you don't have an overall discharge over a period of time because there will tend to be a balance between regulation up and regulation down."

"You've got some losses because of inefficiencies, but it's different from the other situations we look at: peak power, base load and spinning reserves. In all of those cases you're sending power out and not taking any in."

For V2G to work, someone needs to aggregate the tens of thousands of EVs that will someday populate the market.

"Most utility and grid operators are not really set up to deal with thousands or tens of thousands of generators. So that means there will be an aggregator, that is a business that does the marketing, gets people to sign up, tabulates who's being plugged in when and credits on that basis.

"It's looks a lot like the cell phone business," Kempton continued. "If you think of a cell phone business, they're communicating with dispersed mobile units and those mobile units are doing micro-transactions and the cell phone business is charging each of thousands of them for fifty cents here, twenty-five cents there, a dollar fifty there... plus a monthly fee, whatever. Maybe that's a aggregator."

Kempton also thinks third-party Internet service providers to the large carmakers could fill a similar role as EV power aggregator. "It's a business that looks a little different from generator or utility distribution, but it could be a distribution company who has accounts with all these millions of homes. Somebody like Southern California Edison or Pacific Gas and Electric."


Times Article Viewed: 12587
Published: 26-Aug-2001


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