Toyota, Daimler, Hyundai and Honda have all committed to producing hydrogen-powered fuel-cell vehicles by 2015. However, few hydrogen stations, costing more than $1 million to build, exist in the U.S. Hydrogen advocates say that an adequate number of stations will be ready in step with the cars, by 2014 or 2015. Japan, Germany and South Korea have all committed to substantial fueling networks for hydrogen cars in the future.