Civil Engineering Reference
In-Depth Information
FIGURE 12-9
Fuel cell principle: hydrogen and oxygen in, electrical power and water out.
stack up in series-parallel combinations for the required voltage and current,
just as the electrochemical cells do in the battery.
The low temperature (250°C) fuel cell is now commercially available from
several sources. It uses phosphoric acid as the electrolytic solution between
the electrode plates. A typical low temperature fuel cell with a peak power
rating of 200 kW costs under $1,800 per kW at present, which is over twice
the cost of the diesel engine. The fuel cell price, however, is falling with new
developments being implemented every year.
The high temperature fuel cell has a higher power generation capacity per
kilogram at a relatively high cost, limiting the use in special applications at
present. Solid oxide, solid polymer, molten carbonate, and proton membrane
exchange fuel cells in this category are being developed. The industry interest
in such cells is in large capacity for use in a utility power plant. The Fuel
Cell Commercialization Group in the U.S.A. recently field-tested molten
carbonate direct-fuel cells for 2 MW utility-scale power plants. The test
results were a qualified success. Based on the results, a commercial plant is
being designed for a target date of operation by the year 2000.
Solid oxide fuel cells of several different designs, consisting of essentially
similar materials for the electrolyte, the electrodes, and the interconnections,
are being investigated worldwide. Most success to date has been achieved
with the tubular geometry being developed by the Westinghouse Electric
