2nd International Workshop on Oil Depletion
Paris, France, May 26-27 2003
Organized by the Association for the Study of Peak Oil and Gas
The workshop was held at the Institut Francais du Pétrole, Rueil-Malmaison, Paris.
If information and other material from this proceeding are used the following reference should be given:
Proceedings of the 2nd International Workshop on Oil Depletion, Paris, France, May 26-27 2003,
Edited by K. Aleklett, C. Campbell, and J. Meyer
Options for Future Transport Fuels
by Jörg Wind
Modern civilization is based on an economy which widely depends on communication technologies, sufficient energy supply, and unrestricted individual mobility. Up to now, the energy supply for industrial and household use as well as for transport largely relies on resources of fossil fuels, such as coal, natural gas, and crude oil. These resources are limited, and there is some discussion about the timeframe when these fossil resources will be reduced significantly. To assure fuel supply for sustainable mobility of all citizens and reduce CO2 and pollutant emissions, use of alternative fuels has to be increased.
In the last years, a variety of fuel options for transport of the future has been discussed and produced. Today, cars are fuelled with diesel, gasoline (up to three different qualities), natural gas (NG), gas to liquid fuels (GTL), fatty acid methyl ester (FAME), ethanol and some drivers even use plant oils. Additionally, there are a small number of cars powered by electricity. Methanol and hydrogen are also tested as fuels for cars with an internal combustion engine (ICE). In the last ten years, the development of fuel cells for transport application made a big step towards commercialisation of fuel cell cars with very high efficiencies, which are fuelled with hydrogen, methanol or even gasoline or diesel.
The European Commission has announced numbers for alternative fuels, in a communication paper on alternative fuels for road transport, as a proposal for a Council directive. For 2020, 8% biofuels, 10% natural gas and 5% hydrogen are suggested. The best alternative fuel would be one which is environmentally benign to produce, not emitting any greenhouse gases during growth of the biomass and subsequent fuel production, and at low cost. Additionally, this fuel should have favorable properties in ICEs and fuel cells, even improve performance and regulated emissions.
Hydrogen has a very high potential to fulfill all requested requirements. Especially in combination with fuel cells, which provide for a very high efficiency, this fuel option would be preferable. Hydrogen production by steam reforming or electrolysis is a well-known industrial process, but storage in cars still does not yet allow for sufficient travel distances. The building of a hydrogen infrastructure is very costly and will not take place until a significant number of cars need to be fuelled by hydrogen. The open issues for implementation by the end of the next decade are vehicle production costs and onboard H2 storage, efficient H2 production and installation of a fueling infrastructure, as well as the need for attractive subsidies or tax incentives. These can be resolved by a joint effort of governments and the auto and oil/energy industries. If successful, it is likely that by 2020 2-3% of the overall European vehicle fleet will be fueled by hydrogen, and that in the subsequent decade the use of H2 fuel will sharply increase.
In the next 20 years, the ICE will dominate the market for new cars, and it will remain a major technology beyond that period. A significant reduction of greenhouse gas emissions could be achieved by the introduction of fuels based on biomass in the next two decades. From all options for biofuels, synthetic fuels from biomass (BTL) seem to have the best potential to fulfill all requirements. Such fuels have similar properties as the gas-to-liquid fuels which are currently produced by some oil companies. The first process step is the production of synthesis gas (CO and H2). The second step is synthesis of hydrocarbons, like methanol or diesel fuels, by Fischer-Tropsch synthesis.
Currently, some research groups and small companies are working mainly on the gasification step. In 2001 DaimlerChrysler started a joint project with the Choren company to investigate in a pilot plant the feasibility of producing synthetic renewable Methanol and BTL Diesel from wood and using it in road vehicles. Since June 2002, DaimlerChrysler and Volkswagen have been pursuing this pathway jointly.
In conclusion, it seems likely that synthetic biofuels will play a major role in fuel supply for transport applications in the future. Hydrogen, which is the most favorable fuel on the reduction of CO2 emissions and diversity of primary energy sources, remains the most promising candidate for future fuels, especially in combination with fuel-cell powered vehicles.