Early next year, U.K. automotive start-up Riversimple will introduce a radically new, environmentally friendly vehicle. With a body made of lightweight composites, the two-seat electric vehicle will be powered by hydrogen fuel cells. The company is aiming for fuel efficiency of more than 200 mpg, a range of 300 miles, acceleration from 0 to 30 mph in 5.5 seconds, and a cruising speed of 55 mph.