That may be possible in about three years if a retrofit kit invented by a former IBM engineer pans out in prototype testing.

This development is probably a more attainable (and affordable) set-up than the one reported earlier this year about an inventor near Boston converting Ford Explorers into electric vehicles for a mere $15k.

The hybrid concept developer, Charles Perry, is looking for doubling vehicle mileage by putting electric motors on each wheel, between the brake and hub. Batteries to drive the motors would be installed in the trunk, which prompts the question of impact on the car's weight and balance. Handling may also be affected because the unspring weight increases by adding the 10-15 hp motors on each wheel.

Perry says at 40 mph or less, a car equipped with his Plug-In Hybrid Retrofit Kit could go 30 miles on battery power alone. Target kit cost is $3,000 to $5,000—so you figure out the payback period for your car.

Perry's invention received first prize in a green energy competition at the Tennessee Technology Development Corp. The patent pending kit will be developed into a commercial product by Palmer Labs (Reston, VA). To aid in that effort, Perry has partnered with the Tennessee Technological University (Cookeville), which will build a working prototype within a year with about $100,000 in existing funding. The next step will be to retrofit the kit on 30 state-owned vehicles for testing. If all goes as planned, Perry estimates that within three years the final kits will be manufactured by Palmer Labs in a new Tennessee facility that would employ about 2000 workers.