Most alternative fuel vehicles on the road today were originally designed for gasoline, but converted for use with an alternative fuel. Because the petroleum industry has successfully responded to the competitive threats of alternative fuels by developing reformulated gasoline that burn much cleaner, the conversions are typically performed more for economic reasons (when the alternative fuel is less expensive, which has occurred with propane) rather than environmental reasons.
It is likely that technical advances will continue to permit petroleum refiners to meet the increasingly more stringent environmental regulations imposed on gasoline with only minor increases in the retail price. And since petroleum reserves will be abundant at least through 2020, gasoline promises to dominate automotive transportation for the foreseeable future.
However, fuel cell vehicles, which are designed to generate their power from alternative energy hydrogen, pose a major long-term threat to the preeminence of gasoline. Automakers believe the best solution is to extract hydrogen from a liquid source because hydrogen has a low energy density and is expensive to transport and store. All the major automakers are developing fuel cell vehicles powered by hydrogen extracted from methanol because reforming gasoline into hydrogen requires additional reaction steps, and a higher operating temperature for the reformer. Both requirements are likely to make the gasoline reformer larger and more expensive than the methanol reformer. Moreover, the sulfur content of gasoline is another major reason that automakers are leery of developing gasoline reformers for fuel cell vehicles. Quantities as low as a few parts per million can be a poison to the fuel cell stack.
There are no gasoline reformer fuel cell vehicles in operation, so an acceptable level of sulfur has not been determined. If it is determined that an ultra low-sulfur gasoline blend can be developed specifically for fuel cell vehicles, it would be a far less expensive solution than developing the fuel production, delivery and storage infrastructure that would be needed for methanol-powered fuel cell vehicles.
