EnBW and Siemens team up to construct an efficient megawatt-class gas-fuelled fuel cell-hybrid power plant.

EnBW Energie Baden-Wuerttemberg AG and Siemens Power Generation (PG) are joining forces to build a fuel cell-GT hybrid power plant, in the hope of converting up to 70% of the fuel energy into electricity.

The necessary groundwork is scheduled for completion by 2008, and will provide the basis for construction of a small pilot plant. It is anticipated that a planned hybrid plant with an installed capacity of 1 MW would follow in 2012, although initially Siemens is to supply a high-temperature SOFC fuel cell with a capacity of 5 kW. By combining a high temperature fuel cell with a gas turbine, it is hoped that the more efficient use of the fuel and minimised emissions compared to modern gas and steam turbine plants, will be achieved.

The project is scheduled to run for an extended period, and involves background research to optimise operation of stationary fuel cells in conjunction with gas turbines making hybrid SOFC’s a viable alternative for commercial plants. Should the project be completed successfully then hybrid technology could become available roughly a decade earlier than expected by experts.

Since 2001 EnBW has operated a statewide programme to provide funding for a variety of fuel cells. The company has gained technical experience from the use of these fuel cells in more than 20 plants.

During the initial phase of the project, which is scheduled to run for three years, the individual components will serve as the basis for development of an operating concept and a corresponding simulation model. The associated control concept will be developed by the Institute for Aviation Engineering. The test components will be coupled together in the next phase of the project starting in 2009, and the configuration will be optimized from 2012 onwards.

To serve this project a special research working group was established at the University of Stuttgart. With the continued support of the Helmholz Association of German Research Centers it combines the resources of the German Aerospace Center in Stuttgart and the University of Stuttgart.

In a hybrid power plant, the hot exhaust gases exiting the fuel cell are fed into a gas turbine, thereby reducing or totally eliminating the turbine’s fuel consumption. The gas turbine makes it possible to operate the fuel cell at increased gas pressure, which increases efficiency.