Title

ENVIRONMENTAL BENEFITS OF NATURAL GAS FOR BUSES

Authors

A RABL

Document Type

Journal Article

Publication Date

2002

Subject Area

planning - standards, planning - environmental impact, land use - impacts, land use - planning, policy - environment, economics - benefits, place - europe, mode - bus, mode - bike

Keywords

Trade off analysis, Toulouse (France), Standards, Social costs, Sensitivity analysis, Pollutants, Paris (France), NGV powered buses, Natural gas buses, Life cycle planning, Life cycle analysis, Filters, Externalities, European Commission, Environmental impacts, Environmental effects, Emissions, Diesel motor exhaust gas, Diesel exhaust emissions, Diesel engine exhaust gases, Diesel buses, Cost benefit analysis, Comparison studies, Comparative analysis, CNG powered buses, Benefit cost analysis, Alternatives analysis, Air pollution, Air pollutants

Abstract

In comparing the environmental benefits of two technologies, a life cycle assessment can be useful since it takes into account all the effects that are relevant for the comparison. This paper uses a life cycle assessment to compare diesel buses with buses fueled by natural gas. The data for the emission of pollutants are based on the MEET Project of the European Commission (EC), supplemented by data measured for diesel and gas buses in Paris. The benefits of the gas-fueled bus are then quantified using the damage cost estimates of the ExternE Project of the EC. A diesel bus with emissions equal to the Euro2 Standard of the EC is compared with the same bus equipped with a natural gas engine, for use in Paris and Toulouse. The damage cost of a diesel bus is significant while natural gas allows an appreciable reduction of the emissions, lowering the damage cost. An approximated rule is provided for transferring the results to other cities. The effect of the evolution of the emissions standard towards Euro3, 4 and 5, as well as the effect of uncertainties, are evaluated using sensitivity analysis. A comparison is also presented between a Euro2 diesel bus with particle filter, which has very low emissions, and a gas fueled bus with a multipoint engine that offers a more advanced and cleaner technology. Damage costs of the gas-fueled bus using this engine are 3-5 times lower than those of the diesel with particle filter. Overall results show that the damage costs of air pollution are large for the Euro2 diesel bus compared to the market price of the fuel. The numbers here can serve as an input to a cost-benefit analysis for determining if alternatives to the current diesel bus are preferable in terms of total life cycle social cost.

Comments

Transportation Research Part D Home Page: http://www.sciencedirect.com/science/journal/13619209