Fuel cells are electrochemical devices that turn hydrogen directly into electricity without combustion, at high efficiency and with emissions only of water. For a fuel cell-powered vehicle, the hydrogen can either be carried onboard or produced from a hydrogen-rich fuel such as methanol. 50 Although there are several types of fuel cells, most analysts consider the proton exchange membrane (PEM) fuel cell as the best candidate for vehicle applications, because of its low-temperature operation and expected potential to achieve high power density and low cost.
Achieving low cost and small size and weight remains a substantial development challenge, however. Current fuel cells cost thousands of dollars per kW and are too large to fit comfortably in a light-duty vehicle; researchers hope to reduce their costs to less than $40/kW and shrink their size to fit into a car without usurping its cargo space. In fact, recent fuel cell prototypes have demonstrated substantial success in size reduction.
While longer term prospects show promise, OTA considers it unlikely that a PEM fuel cell can be successfully commercialized for high-volume, light-duty vehicle applications by 2005, although fuel cell developers are hoping for early commercialization in larger vehicle applications (buses, locomotives); 2015, or perhaps a bit before, seems a more likely date for commercialization, if the many remaining development challenges are successfully met. By that year, an aluminum-bodied mid-size PEM fuel cell vehicle with methanol fuel and a bipolar lead acid battery for high power needs and cold start power might be capable of achieving about 80 mpg.51 The price of such a vehicle is extremely uncertain. With current fuel cell designs, assuming that substantial cost reductions from current values are achieved and the designs are optimized and produced in large quantities, a mid-size car could cost $40,000 more than an equivalent baseline car. If fuel cell
developers can cut costs to $65/kW or below for both fuel cell and reformer, the incremental price could be $6,000 or less. The incremental vehicle price could also be reduced substantially by relaxing the maximum continuous power requirement, thus allowing a smaller fuel cell to be used.52 This conceivably might be a reasonable tradeoff for an urban commuter vehicle, but not for an all-purpose vehicle.
Small vehicular fuel cells are still at a relatively early stage of development, and system improvements have come rapidly. Successful commercialization, however, will depend on great improvements in a host of separate development areas—size and cost reduction of methanol reformers, development of low-cost, high-energy-density, onboard hydrogen storage; shrinkage of fuel cell “balance of plant”; reduction of platinum catalyst requirements53; and a good many others. Differing degrees of optimism about the likely success of these R&D efforts explain most of the differences among the various estimates of future fuel cell performance and cost. In OTA’s view, the most optimistic estimates, such as fuel cell costs at well below $65/kW, are certainly possible but require a substantial degree of good fortune in the R&D effort-and the progress
needed is unlikely to come quickly.
Advanced Automotive Technology: Visions
of a Super-Efficient Family Car
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