Development of the Commercial SOFCs
Westinghouse continued SOFC research during the late 1950's and early 1960's. In 1962 the newly-formed Office of Coal Research in the Department of the Interior began 40 years of funding SOFC development by awarding one of the first fuel cell research grants to Westinghouse. By late 1962 researchers at Westinghouse had developed a cell made up of zirconium oxide and calcium oxide that overcame many of the problems that had plagued SOFCs. Current SOFC's use a variety of materials to withstand high operating temperatures.
During the rest of the 1960s and 1970s Westinghouse continued to develop SOFCs and by 1980 the process was found promising enough for the U.S. Department of Energy (DOE) to award Westinghouse a development contract. During the remainder of the 1980's Westinghouse continued to develop the design of tubular SOFCs, starting with very short cells built on a porous support tube. Later, with Tennessee Valley Authority sponsorship, a stack of tubes with 400 watt output was developed and demonstrated.
By the 1990's Westinghouse had achieved long cell lifetimes, developed a commercially viable stack of cells, and entered into a cooperative agreement with the DOE's Advanced Power Technology Program to commercialize tubular SOFCs. Subsequently, SiemensWestinghouse Power Corporation built a demonstration SOFC that was started up in December of 1997 at a power plant in Westervoort, The Netherlands where it ran "virtually unattended" for 4035 hours or almost six months. The system was found to be so reliable that technicians from the local utility, NUON, typically checked the unit only one day each week during the test run. After this initial run the unit was rebuilt and re-installed in The Netherlands where it operated for an additional 12,600 hours and was shut down when it completed its contracted operating period. By producing 110 kW at the end of the test run, slightly above the "name plate capacity" of 109 kW, the unit showed no output degradation and met a key technological challenge facing fuel cell development. In addition, at the end of the run the unit was sustaining an electrical generating efficiency of more than 46 percent, well above the 33 to 35 percent efficiencies of conventional combustion-based power plants. The unit also produced the equivalent of 65 kW of thermal energy as hot water used in the local district heating system. Air emissions from the unit: nitrogen oxides, sulfur oxides, carbon monoxide and volatile hydrocarbons, all measured less than 1 part per million (by volume) significantly below the most stringent clean air standards. In March 2001 the system was moved from The Netherlands to a site in Essen, Germany where it was operated by the German utility RWE. As of January 2002 the system has operated an addition 3700+ hours, for a total of 20,000+ operating hours. DOE is funding additional development of SOFCs with electrical efficiencies greater than 50%, these systems operate above atmospheric pressure and are fitted with microturbines.