General Motors is building a prototype for a home hydrogen refueling unit in hope of selling fuel-cell cars by 2011, says a report in USA Today. The concept would avoid the need for expensive centralized hydrogen refueling stations, a major stumbling block for the use of hydrogen as a fuel. The automaker’s goal is an affordable, compact unit that would allow customers to fill their cars overnight in their own garages, says a GM spokesman. GM would join Honda, which has already created a model for a home refueling hydrogen unit. GM is starting to seriously plan a business case for hydrogen vehicles, which up to now has been a long-range research project eclipsed by more market-ready fuel-saving alternatives, such as gas-electric hybrids. And, while gas-electric hybrids and fuel cells have gained much press over the past few years, BMW has had a hydrogen-fueled combustion engine program in development for years. Using liquid hydrogen, the conventional engine approach allows for a flex-fuel approach, and tailpipe emissions when hydrogen fuel is used are water vapour and carbon dioxide. In the U.S. there continue to be very few fueling stations however. California has 23 and the USA Today report says that Shell spent $2 million U.S. to build its lone facility in Washington D.C.