This is an excerpt from EERE Network News, a weekly electronic newsletter.
GM Study Examines Greenhouse Effects of 36 Fuel Technologies
A study released on May 21st by the General Motors Corporation (GM) examined the greenhouse gas emissions resulting from 36 fuel pathways and 18 propulsion concepts that ranged from conventional engines to fuel cells. The study found that greenhouse gas emissions are lowest overall when renewable sources such as biomass or wind power are used to generate hydrogen, which then fuels a fuel-cell-powered vehicle. Fuel cell vehicles using hydrogen produced from natural gas could also reduce greenhouse gas emissions, according to the study.
The study also found advantages for compressed natural gas vehicles, but found that producing hydrogen from natural gas and burning it directly in a combustion engine would be inferior to using conventional gasoline engines. Likewise, methanol produced from natural gas and used to power a fuel cell vehicle provided no benefit over conventional vehicles.
The study included a "well-to-wheel" analysis of the complete fuel chain, from the production of fuels from their basic feedstock components to the actual consumption of the fuel in the car. It focused on European driving conditions and looked toward technologies likely to be in use by 2010. The study examined fuel efficiency and greenhouse gas emissions but did not consider cost or other air emissions. See the GM press release.
A similar study released last year examined the North American market. That study, prepared with the help of DOE's Argonne National Laboratory, is posted on Argonne's Transportation Technology R&D Center Web site.