The role of large-scale hydrogen storage in the power system

Abstract

In order to reach national and international climate targets and to reduce the dependency on fossil fuels, the share of electricity generation from renewable energy sources has to be further increased. As this will require the integration of high shares of fluctuating generation, a more flexible power system is needed. The temporal balancing of production and consumption, which is essential to utilize surplus generation, can be achieved by large-scale energy storage as well as by load management and additional flexible loads. A new option to enhance the flexibility of load is the production of hydrogen by electrolysis. At times of surplus generation from renewable energy sources electrolyzers could produce hydrogen, which has a high storage density and can be utilized for various purposes. Within this chapter it will be discussed to what extent the intended expansion of electricity generation from RES and the associated requirements of integration will impact the profitability of large-scale storage and the electrolytic production of hydrogen. For this purpose, the model IMAKUS is used, which allows to optimize the expansion and dispatch of conventional power plants and storages in the German power system. The sale of electrolytically produced hydrogen to other areas of application competes with the possible use as a storage medium for electrical energy in the power system. A sensitivity analysis of electrolyzer costs and market prices of hydrogen is conducted. Based on this analysis, the main drivers for the potential of electrolytically produced hydrogen until 2050 are identified. Under the given assumptions the sale of hydrogen to other areas of application exhibits seasonal characteristics, which correlates with the strong seasonal characteristics of wind generation. Whereas the cost assumptions for electrolyzer units have a significant effect on the volume of hydrogen utilization, the proportion of hydrogen sale to the total production is only affected to a small extent. The analysis furthermore suggests that the amount of hydrogen required in Germany today can also be produced by using electrolysis to integrate renewable electricity generation into the power system.