Thermal storage

German energy giant RWE Power is developing a high-temperature thermal-storage system for combined-cycle power plants (CCGT).

The integration of such a storage system into a CCGT power plant would enable the supply of electricity and heat to be decoupled, permitting surplus heat produced during the day to be provided during the night when the gas turbine is not operating.

This is currently not possible in CCGT power plants, which are operated in the combined heat-and-power mode (CHP).

The company will work on the system over the next few years together with ThyssenKrupp Xervon Energy, the Paul Wurth Group and the Institut für Technische Thermodynamik des Deutschen Zentrums für Luft und Raumfahrt (DLR).

The project itself is expected to take approximately two and a half years to complete. Once the development phases have been concluded, the partners intend to erect a pilot facility with a capacity of 10MWh; the co-generation plant of RWE Power in Dortmund could be one potential site.

‘We are confident that we can develop thermal-storage CCGT power plants in a foreseeable period of time. Apart from new-build projects, the retrofitting of existing facilities is also an important option for us,’ said Hans-Josef Sandkaul, managing director of ThyssenKrupp Xervon Energy in Duisburg.

The new system will use high-temperature thermal-storage technology from the Paul Wurth Group. ‘We have already applied similar schemes to supply hot air for the metal and glass industry. However, they [now] have to be tailored to the specific requirements of a CCGT combined-cycle power plant,’ said Dr Manfred Möller, managing director of Paul Wurth Refractory and Engineering in Wiesbaden.

Under the agreement between the outfits, DLR will be responsible for the thermal design of the heat storage facility, investigations into potential storage inventory materials in the laboratory, and the operation of the small pilot-scale prototype.

‘The development and testing of technologies for high-temperature storage using innovative materials is one of our core areas of expertise,’ said Dr Stefan Zunft of DLR in Stuttgart.