Gaining Perspective on Fuel Cells

by Robert L. Mauro, Executive Vice President, National Hydrogen Association

Next year it will be 160 years since Grove invented the fuel cell. While great progress has been made in the technology, it is still not commercial. This was evident from the presentations and comments by the attendees at the recent joint U.S. Department of Energy/Electric Power Research Institute/Gas Research Institute annual program review held in San Francisco, California, U.S.A., in mid-May.

Coming away from the conference, there is a sense that a large amount of field experience has been developed, particularly on phosphoric acid fuel cells, which now have almost two million hours of operating time. This provides a level of confidence that a fuel cell that operates with predicted performance and life can be produced. The issue is that, in the current energy market, fuel cells are not economically competitive for stationary applications unless other forms of generation cannot be sited.

Application interest for fuel cells has shifted from bulk power and even distributed power to transportation because the large number of units involved are expected to drive costs down. Interest in residential power has developed because half of the new homes in the United States are heated with natural gas, which can be reformed into a hydrogen-rich gas. In addition, the replacement market for natural gas is even larger than the new-home market. Other small power applications include power for recreational vehicles and communications. Photovoltaics have been rather successful at penetrating the small power market and fuel cells may also be successful. These comments are focused primarily on PEM fuel cells.

Solid oxide fuel cells are potential competitors to PEM in residential and some of the remote power applications. The advantages of solid oxide fuel cells over PEM fuel cells include efficiency and cost for the same production levels. PEM advantage over SOFC is operational flexibility and fast start-up time. The future role of phosphoric acid is unclear, given its production costs and relatively low power density.

Molten carbonate fuel cells would seem to have a market in certain applications, such as using a hydrogen-rich gas stream from biomass. Its principal competition is SOFC.

Molten carbonate fuel cells would seem to have a market in certain applications, such as using a hydrogen-rich gas stream from biomass. Its principal competition is SOFC. Costs are competitive and each technology has advantages and disadvantages with respect to materials. The key factor for high-temperature fuel cells may be whether or not there are rapid successes in developing and demonstrating a low temperature (600°C to 650°C) SOFC.

Transportation efforts focus on PEM that Daimler-Benz, Ford, and Ballard are poised to produce and PNGV PEM efforts by AlliedSignal and Plug Power, a joint venture between Detroit Edison and MTI. There was little detail about Ballard’s performance and life numbers except that the units will operate for the 3,000-plus hours required over the 10-year average life of a vehicle. The information that both AlliedSignal and Plug Power presented indicated that they are approaching acceptable fuel cell power density levels for vehicle operation. Their cost information presented indicated that they would have to be reduced by 50% for commercial introduction.

Ballard presented some results of its 250-kW PEM fuel cell demonstration. They said that the unit operated at 34% efficiency with a peak output of 213 kW. The design targets were 31% efficiency with a design output of 190 kW. The target efficiency number for production units will be 40%. The unit price for the 250-kW with support and other unspecified benefits was US$2 million. The first field unit will go to CINERGY in 1999.

Another interesting factor for transportation fuel cells that are not operating on hydrogen is that all the fuel reformation systems require about 10 minutes to warm up from a cold start. Right now this appears to be a significant commercial barrier to widespread use of fuel cell power vehicles. All presenters of on-board reforming systems mentioned this problem.

To sum up the state of fuel cell technology, I would say that at least one manufacturer of PAFCs and SOFCs can produce units with 40,000 hours of life. The jury is still out on PEMFCs and MCFCs as to their ability to produce units with 40,000 hours. PEM fuel cells can produce transportation units with sufficient life for automobiles and probably buses (20,000 hours). MCFCs operated as a megawatt or more unit at Santa Clara for about 5,000 hours. There are good prospects that in the next seven years all the technologies will achieve the 40,000 hours of operation threshold.

Cost is another matter. PAFCs are going to have a difficult time reducing their cost to US$2,000/kW. The cost targets for automobiles with fuel cells are fuel cell systems under US$50/kW. Buses require fuel cell system costs under US$500/kW. Stationary power can have costs which vary from US$500/kW to US$2,000/kW, depending on application and the value of the power. Most manufacturers are looking to produce power from stationary fuel cells at about US$.05/kWh. We need a similar number for transportation vehicles in cents/mile based on vehicle life.

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