So, you’re thinking of buying one of those gas-electric hybrid cars like the Toyota Prius or Honda Insight. They’re trendy, conserve fuel, and reduce pollution. But to really go “green,” some entrepreneurs and academics say, you should try a Volkswagen Jetta.

Not just any Jetta. A dark blue one that a California electric-car company has modified so that it not only uses electricity but generates it for other purposes. So, once it’s parked, you plug it in and sell excess electricity to a utility.

It sounds like a good way to meet car payments. But don’t start counting the cash just yet.

Neither big auto-makers nor utility companies have yet seized on the idea, known as “vehicle-to-grid,” or V2G. Still, V2G is an idea waiting to happen – and the push toward hybrids today is making it ever more likely, say scientists, entrepreneurs, and economists.

“As electric-drive hybrids begin to penetrate the auto market, you now have distributed power generation on wheels,” says Stephen Letendre, an economist at Green Mountain College in Poultney, Vt. “You also have an asset that’s sitting idle most of the time – just waiting to be connected.”

Of the more than 235 million vehicles in the United States today, only a few thousand are hybrids. And these lack the extra internal circuitry and external plug necessary to give electricity back.

More here.