A cogeneration plant belonging to RWE Power in Dortmund, Germany could be the potential site of a novel heat storage project which aims to maximize efficiency for combined cycle gas turbine CHP units.

RWE Power says it is starting to develop a high-temperature thermal storage technology specifically for this application under a co-operation agreement with ThyssenKrupp Xervon Energy, Paul Wurth Group and Deutsches Zentrum für Luft und Raumfahrt.

The project development is expected to take approximately two and a half years and once the development phases have been concluded successfully, the co-operation partners intend to erect a pilot facility with a capacity of 10 MWh from around 2011.

RWE adds that preliminary studies already conducted confirm the general technical and economic feasibility, however, they add that the practical development of a CCGT power plant with integrated thermal storage depends on the availability of a commercial-scale, cost-efficient, reliable and long-lived high-temperature thermal storage facility.

The company says that by integrating storage, the supply of electricity and heat to be decoupled from the demand profile, allowing surplus heat produced during the day to be delivered at night when electrical demand is low and the gas turbine is not normally operating.
Dr. Johannes Lambertz, chief executive officer of RWE Power explains: ‘CCGT power plants operated in the combined heat-and-power mode are often no longer driven by the power market, but usually by the heat market. Owing to this disadvantage, power plants with heat extraction have to continue operating even when demand for electricity is low in the public grid, for instance at night.’

‘We are confident to develop highly flexible thermal-storage CCGT power plants to commercial maturity in this cooperation in a foreseeable period of time. Apart from new-build projects, the retrofitting of existing facilities is also an important option for us,’ added Hans-Josef Sandkaul, managing director of ThyssenKrupp Xervon Energy in Duisburg.

Together with the companies in the alliance, the Institut für Technische Thermodynamik des Deutschen Zentrums für Luft und Raumfahrt (DLR) will also be involved in the development.