Storing electricity from renewable energy sources.

Better utilization of the fluctuating energy production from renewable sources like wind turbines and photovoltaic systems becomes more and more important since these sources constitute a growing part of the Danish energy system. Moreover, integrated smart-grid solutions with high load-leveling capabilities are much desired since these will contribute to a far more efficient and well-balanced energy production. Consequently, this induces a high demand for efficient high capacity energy storages and underpins the great significance of this project.The concerned technology is based on the storage of electricity as heat at a constant high temperature. This is made possible by utilizing a phase change material (PCM). The R&D activities in the field of high temperature PCMs are concentrated on various types of salts. The proposed project will investigate the use of metals as PCMs. Contrary to salts, metals have the advantages of high latent heat capacity, long term stability and a much better thermal conductivity. In general, fabrication of tailored PCM materials with specific thermal properties is possible by choosing the proper metal or alloy. The high operating temperature during storage discharge ensures an efficient conversion of the accumulated heat back to electricity (higher round trip efficiency).