China, guzzling petrol at a furious pace amid breakneck economic growth and car buying, should wean itself off oil by promoting vehicles powered by hydrogen, General Motors executives said. Executives from the U.S. auto maker will show off their latest concept cars to Chinese officials including Zeng Peiyan, minister of the powerful State Development and Reform Commission. The centerpiece of the GM Tech Tour that has included stops in San Francisco and Tokyo is the Hy-wire concept car that is powered by a hydrogen fuel and uses electronic steering, acceleration and braking.