May 21, 2002

Opel/GM/Energy company research team submits initial study for European conditions

Fuel cell cars offer solution to curtail greenhouse gas emissions

The effect of various propulsion systems and fuels on global warming potential analyzed

Rüsselsheim/Brussels. Opel and GM's Fuel Cell Activities Center presented initial results from a comprehensive study assessing the greenhouse gas emission characteristics of a wide range of potential fuel and propulsion systems for the car of the future at the "Hart World Fuels Conference" today in Brussels. Experts examined the complete chain from the production of fuels from their basic feedstock components to the actual consumption of the fuel in the car ("well-to-wheel").

A total of 36 fuel pathways and 18 conventional and alternative propulsion concepts were examined for the 2010 timeframe assuming European conditions for both fuel and vehicle. A highly reputed research institute, LBST (Ludwig Bölkow Systemtechnik) from Ottobrunn near Munich, acted as scientific advisor and consultant, with additional data and analysis provided by energy companies BP, ExxonMobil, Shell and TotalFinaElf. A principal finding of the investigation was that hydrogen fuel cell vehicles come out best in terms of well-to-wheel greenhouse gas emissions. This also applies even if the hydrogen required to operate them is obtained from reformed natural gas. However, optimum results are realized when renewable energies such as biomass or wind power are used to produce the hydrogen.

This project is a sequel to the North American Well-to-Wheels study published by General Motors and Argonne National Labs in the spring of 2001 and which is now regarded as a reference work in worldwide discussions on transport-related greenhouse gas emissions and energy consumption. In the new study, the original methodology was applied in a European context for both fuel and vehicle: "We based our additional research work, which took over a year, on the Opel Zafira, European driving conditions, and our understanding of the European energy supply situation," explained Raj Choudhury, who was project manager for the study at the German Fuel Cell Activities Center in Mainz-Kastel, Germany.

The vehicle data for the European study were generated by means of mathematical modeling and simulation by GM scientist, Trudy Weber: "The Zafira proved to be the ideal reference vehicle, since it already exists with gasoline, diesel, compressed natural gas (CNG) and fuel cell propulsion systems. We forecasted the powertrain system characteristics for the 2010 time frame and imposed the constraint that all 18 vehicle variants examined be able to meet the same set of stringent, customer-based performance criteria over the European drive cycle (EDC). This provided us for the first time with a realistic and comparable basis for energy utilization and net greenhouse gas emissions in a European context."

On the fuel side, a variety of different pathways were considered. They can be put into four basic groups, based on their source of feedstock: crude oil, natural gas, electricity – from both traditional power stations and renewable sources – and biomass. Results to emerge from the study 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 CNG 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.

"The best alternative, however, is to produce hydrogen from renewably generated electricity – e.g. wind power – and use it in a fuel cell. This will essentially eliminate well-to-wheel greenhouse gas emissions," says Dr. Erhard Schubert, Co-director of the Fuel Cell Activities Center.

The complete study will be concluded and published this summer. The focus for the Opel/GM team now turns to addressing commercialization challenges faced by fuel cell vehicles and the hydrogen infrastructure, including cost and availability issues. "However, it is already clear that the future belongs to the fuel cell, especially if renewable energy is used in the production of hydrogen as a suitable infrastructure becomes available," says GM Vice President Larry Burns, responsible for research & development and planning at General Motors. "That is why we intend to do everything we can to produce a fuel cell car that is both affordable for the customer and economically viable for us by the end of this decade."

There are more than 400 scientists and engineers working at Opel and GM on the development of fuel cell propulsion systems and their commercialization. The center in Mainz-Kastel was established jointly by Opel and GM at the end of 1997 and GM has two sites in the US, in Rochester, New York, and Warren, Michigan.