To the Editor: We respectfully take issue with an article in your May issue ("Beginning the Transformation"), which inaccurately represented competing fuel cell technologies. The authors apparently decided to tell only one side of the fuel cell story and inaccurately concluded that so-called "high-temperature" stationary fuel cells were superior to other technologies, including phosphoric acid. They further suggested that these technologies would be the only solution in the future. Publicly available data and statistics prove that conclusion wrong.
UTC Power, which was credited in the article with leading the commercial deployment of stationary fuel cells, produces phosphoric acid fuel cells for stationary applications. We are the only fuel cell company in the world that has actively worked in all fuel cell technologies and that provides fuel cells for large commercial stationary as well as transportation applications. We pursued and were a leader in developing both molten carbonate and phosphoric acid fuel cell technologies until the late 1980s, at which point we made a strategic decision to commercialize only phosphoric acid due to its superior durability, reliability, and lower life-cycle cost.
The phosphoric acid technology is by far the most durable and reliable fuel cell technology of any commercially available fuel cell system. The installed base of our PureCell 200 phosphoric acid fuel cells has consistently demonstrated a cell stack life of 40,000 hours. In addition, our phosphoric acid fuel cell power plants have a demonstrated reliability, as measured by unit availabilities that exceed 95 percent. We are now actively working to develop an advanced phosphoric acid fuel cell stack with a design life of more than 80,000 hours and significantly reduced life cycle cost.
Further, when discussing efficiencies, it is important to distinguish between beginning of life and average over life. Today's phosphoric acid power plant provides electrical efficiencies of 42 percent at beginning of life and 37 percent average over its proven 40,000-hour life. This compares to a mid-40s range for high-temperature units at beginning of life. Comparisons of average efficiency over life are not possible with high temperature, since their "life" is only 10 to 15 percent that of phosphoric acid.
MICHAEL O. BROWN
South Windsor, Conn.
Editor's note: The author is vice president for business development and general counsel for UTC Power, the fuel cell subsidiary of United Technologies Corp.