This month, Louis Palmer, a 37-year-old substitute teacher and adventurer from Switzerland, will complete his 18-month trip around the planet in a solar-powered car, becoming the first person to drive the 30,000-mile distance without using a single drop of gasoline. His ride, the Swiss-built SolarTaxi, is a two-seater run by a pair of fully recyclable sodium-and-nickel batteries and 65 square feet of solar panels in tow. Palmer hopes his journey will inspire more eco-friendly driving. "The technology is here," he says. "It's affordable, it's reliable, and it's ready."