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Social Cost Comparison Among Fuel Cell Vehicle Alternatives (cont.)
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Due to these difficulties in using hydrogen as a vehicle fuel, methanol is considered a promising hydrogen carrier for fuel cell vehicles. As a liquid fuel, the existing gasoline retail distribution system can be adapted to serve methanol with few modifications. Methanol can be easily transported on-board the vehicle. Worldwide, there is a huge reserve of natural gas, the typical feedstock for methanol production. In the future, methanol can be produced from flared natural gas, biomass, or even from reacting solar hydrogen with atmospheric CO2. The later configuration also is a zero emission fuel (Bockris, 1999). The challenge for methanol is that it must be reformed into hydrogen on-board the vehicle to be used by a hydrogen fuel cell stack, making the Indirect Methanol Fuel Cell Vehicle (IMFCV) "near" zero emissions. Also, the on-board reformer adds cost and complexity to the vehicle design. A long-term solution is the Direct Methanol Fuel Cell Vehicle (DMFCV), where the methanol is oxidized inside the stack, eliminating the necessity of reformers. The DMFCV is the most elegant solution associating the simplicity of direct reformation with the ease of using liquid fuel on-board. It also can be a zero emission vehicle if a closed system is used to eliminate evaporative emissions. DMFCV research is currently focusing in reducing the cross-over of methanol through the PEM, which reduces the efficiency of the stack, and the overall efficiency of the DMFCV. This efficiency has historically been much lower than that of HFCVs, but new developments with very highly-diluted fuel flows are motivating researchersand major developers (Moore, 1999).
Gasoline internal combustion engine (ICV) vehicles have responded over time to social requirements related to pollution and safety concerns. Improvements to catalytic converters, fuel injectors, fuel composition and vehicle efficiency can, in the short-term, further alleviate some of the problems associated with conventional vehicle engines. Hybrid vehicles with batteries and an electric motor used in combination with a small internal combustion engine have been seen as an interim solution for reducing vehicle emissions. Gasoline fuel cell vehicles (FCVs) are considered a long-term option to improve emission performance. Due to the presence of heavier hydrocarbons in the gasoline, partial oxidation reformers operating at high temperatures have been developed with some success. Complexity, cost and onboard size of the gasoline reformer are challenges that must still be overcome.
SOCIAL COST APPROACH:
Using the social cost approach, various concerns can be transformed into a single value, allowing for broad comparisons to be made. However, each concern is established separately making it possible to view them individually in context with the overall value. The use of alternative technologies will change the social cost in different ways as shown below. This classification methodology is based on DeLucchi (1998).
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