In a European study that parallels one done in the U.S. in 2001, researchers found that fuel cell vehicles using hydrogen produced from natural gas could present an attractive solution to cutting greenhouse gas emissions. The study, produced by General Motors with input from various energy companies and a leading research institute, assessed fuel sources, processing techniques and propulsion systems. A principal finding of the study was that fuel cell vehicles using hydrogen could be the solution, depending upon the source of the natural gas. Optimum results are achieved when renewable energies such as biomass or wind power are used to produce the hydrogen. The project was a sequel to the North American Well-to-Wheels study published by GM, BP, ExxonMobil, Shell and Argonne National Labs last year analyzing the impact of energy sources and alternative propulsion systems in North America. In that study, a Chevrolet Silverado pickup was used as a reference vehicle. The results of the current study, based on European driving conditions and the Opel Zafira minivan, were that: -- On a well-to-wheel greenhouse gas emissions basis, the best use for natural gas was to reform it to obtain hydrogen for use in hydrogen fuel cell vehicles. -- To a lesser extent, natural gas offered improvements relative to conventional gasoline and diesel systems when used to fuel compressed natural gas vehicles. -- The use of hydrogen from natural gas in internal combustion engines actually produces poorer well-to-wheel results than do conventional gasoline engines. -- When natural gas was used to produce methanol for an on-board reformer fuel cell vehicle, no well-to-wheel benefits were seen relative to conventional gasoline or diesel internal combustion engine vehicles or gasoline reformer fuel cell vehicles.