Photos: Speedy sports car powered by batteries

The X1's license plate, which makes the car street-legal in California, indicates how it compares in energy consumption with a regular car. The car uses about 200 watt-hours to go a city mile. A gallon of gas contains an energy content equivalent to 33,705 watt-hours. Divide 33,705 by 200 and you get 168.5 miles per gallon. But 170 reads better on a license plate.

The Wrightspeed X1 was designed by Simon Saunders, who has worked at Aston Martin and Porsche. The heads of the driver and passenger are about level with the middle of a sport-utility vehicle's tires. People tend to react positively to the design, founder Wright said. When he's driving around, people lean over and talk to him.

Riding in the car, driver and passenger are secured with five-point restraint systems. Minimalism aside, Wright has installed a Pioneer navigation system and a device that captures how many G-forces the car pulls. (During a recent test drive, the car pulled 0.8 Gs going straight and more than 1G in the turns.)

Air rushing into the airfoil in the back keeps the car's lithium-ion polymer battery cool. The commercial version of the car will likely sell for around $120,000.