Siemens-Westinghouse - Permanent operation of high temperature fuel cell successful

The Siemens-Westinghouse high temperature fuel cell prototype in Westervoort (Netherlands) has been in permanent operation since 1997. The long-term project expired at the end of 2000, which makes the 100 kW site (SOFC = Solid Oxide Fuel Cell) available to take up its duty elsewhere. Until now the system ran for more than 16000 operation hours without any significant flaws or losses in performance, with only the stacks renewed in March 1999. System efficiency recently ranged at 46 %.

A second project started in their technology center in Pittsburgh (USA), then went to California. Similar to the model in the Netherlands, this SOFC fuel cell was combined with a gas turbine. Here, pressure was increased to 3 bar. This modification makes it possible to utilize the 850 °C exhaust temperature by using heat and pressure loss from 3 to 1 bar to again produce electricity in an additional turbine.

Hereby the 220 kW power plant uses almost 60% of the energy contained in gas to produce electricity. Single-sided closed cavity tubes constitute a significant difference to traditional fuel cells with even slabs (planar). The ceramic parts (tubular), which remind of broom sticks (1,5m long, 2,2cm wide) separate fuel from air and at the same time enable spatial thermal expansion.

A 320 kW hybrid site (SOFC plus gas turbine) is already planned for North-Rhine-Westfalian (Germany). The first plant to work in megawatts is expected to start operation mid of next year. By 2004 the system will have gone commercial.

Source: H2Report, S. Geitmann, Feb. 2001