Saturday, April 14, 2007

Vehicle-to-Grid is such a strange idea, why are people pursuing it?

"Vehicle-to-Grid" is a kind of reverse plug-in hybrid electric. The idea is some kind of poppycock wet dream that I don't understand the purpose its development. This idea comes around occasionally and involves some overly hyped breathless descriptions of the possibilities inherent in a car that has an onboard electricity generating plant. I've seen this idea applied to fuel cell cars and now to hybrid-electric cars.

PG&E Demonstrates Vehicle-to-Grid Technology and PG&E demonstrates first ever vehicle-to-grid charging and PG&E sees plug-in hybrids as potential profit centers discuss a recent showing by Pacific Gas and Electric of a modified Prius that has vehicle-to-grid capabilities. "The basic principle here is that electric cars charged at night while electricity is cheap can actually give some of that power back during the day when electricity costs more, and the owners of the vehicle that is giving that power back can get a credit towards the purchase of electricity when the car charges back up."

That's the idea .. that a hybrid electric car, or for that matter a fuel cell car, contains on board the car equipment capable of generating electricity. So why not, these people suggest, connect the car to the grid and use the onboard generator to generate electricity and sell it to the power company. And then the article suggests that time-of-use metering will allow the car owner to buy that electricity back in the evening when rates are cheaper.

Since the articles linked above are doing such a good job of portraying this as a positive thing, I want to list out some alternative points of view.

First is the cost and effort to load power into a car. For a hybrid car that means making a stop at a gasoline station, or for a fuel cell car it's a stop at a different kind of gas station. The use of the onboard generator means depleting that fuel, which then decreases the range of the car requiring the driver to make a stop at the gas station (of either kind) more frequently.

Second, time of use metering is rarely available to consumers. Instead consumers most often see flat electricity rates. The advantage accrues only when time of use metering is available.

Third, it's especially egregious to tie vehicle-to-grid to a gasoline burning vehicle. The goal is to reduce gasoline usage to zero, not to continue gasoline usage.

Fourth, a comprehensively installed vehicle-to-grid system means electrical intertie points at most or every parking spot in a parking lot. This would drastically increase the cost of building parking lots ... think, do you see power outlets installed in parking lots today? No. And we're not talking normal power outlets, but one capable of accepting power as well as sending power. This sounds like complexity, and would we trust average consumers to properly operate a power intertie system connected to their cars?


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