Researchers at National Renewable Energy Laboratory (NREL) in Colorado have added solar panels and a bigger battery to a Toyota Prius and achieved 100 mpg. The cost: a surprising steal at $70,000 (and that’s a costly prototype).

With gas over $4, there will now be a market for innovation like this. In fact, it’s not really all that innovative. The NREL (which says Detroit is interested) was beat to the punch by the Ewart brothers in Chicago who claimed earlier this year to have coaxed 100 mpg out of a Prius, too. And you can bet the Ewart brothers used more duct tape than dollars.

Let’s review the parts list: Solar panels, batteries, and a hybrid car already in production. The other day, I was talking to my 7-year-old about gas prices and the various ways we generate power and electricity, and he suggested just such a combination, based on a little 2-inch x 2-inch solar panel that runs an electric motor in a science kit he likes. “Just put a bunch of them on the roof,” he said.

Thing is, Detroit has long relied on modest mpg laws and failed to employ fuel-saving technology that’s already available. Perhaps we are on the threshold of a new era — driven by the rising price of gas instead of any legislation — in which small car companies or aftermarket producers pop up to fill a need not met by major car manufacturers.

• Hybrid Cars: How They Work