Environmental Impact of the Hydrogen Fuel Cell Bus (Well-То-Wheel Analysis)

When using hydrogen as fuel, the local emissions of a fuel cell bus consist only of water. However, to evaluate the global environmental impact of this fuel, a complete analysis must be made covering all the steps in the production and use of the fuel, from the primary energy source to the end use – a well-to-wheel analysis. This task is being performed by 1ST together with the University of Stuttgart and consists of two phases.

image245

Fig. 7. Route layout.

Within the first phase, a well-to tank analysis was be performed by the University of Stuttgart. This analysis covers the life of the fuel from the primary energy source (renewable, crude oil or natural gas) to the moment it is filled to the on-board reservoir.

Подпись:
image247"Подпись: Diesel bus Подпись: TOPOGRAPHY STEEP аэ FLAT CLIMATE *1* COLD □ HOT Подпись:image249"Using a Life Cycle assessment tool (GABI Software [1], develop at the University of Stuttgart), the environmental impact of the production of hydrogen was compared with the impact of conventional fuels, as can be seen in Fig. 8.

Подпись: TANK-TO-WHEEL

In the second phase, the Tank-to-Wheel analysis was performed by 1ST in order to quantify the impact of the operation of the fuel cell bus and compare it to conventional Diesel and Natural Gas buses (see Fig. 9).

VEHICLE AND

OPERATION

TAILPIPE

FUEL

PARAMETERS

EMISSIONS

For this purpose three tools were used:

• МоЬіІеб [2], a tool developed by the EPA (Environment Protection Agency, United States) to calculate the emissions of road vehicles;

• Copert [3], which fulfils a similar role and represents the European market;

• EcoGest [4] is a tool developed at 1ST that uses as input the characteristics of the vehicle, driving behavior and topography and, based on those inputs, calculates on a second by second basis the power needed and the resulting emissions and fuel consumption.

These three tools were used in order to ensure reliable results from the simulations: Mobile and Copert are proven tools that calculate moderately accurate results, while EcoGest allows for much more precise calculations.

In addition to the simulations, the vehicles will be monitored during their regular operation. This monitorization will be extended to the conventional Diesel and natural gas vehicles. In this case the parameters monitored will be dynamic performance and fuel consumption.

The combination of the life-cycle analysis of the production and distribution of the fuels, together with the values from the operation of the different technologies produced a well-to-wheel analysis for the fuel cell bus as well as conventional Diesel and natural gas buses, and thus allowing for the completion of the remaining 1ST tasks within the CUTE project:

• Evaluation of the Environmental Impact of the bus operation;

• Compare Hydrogen with conventional Diesel/Natural Gas technologies;

• Contribution to the objectives of the Kyoto Protocol;

• Monitoring of the Energy and Environmental performance of the vehicles.

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