Energy storage systems in the future German electricity system: A foresight approach

Germany has ambitious targets to produce 35 % of the needed electricity from Renewables mainly based on wind and solar power by 2020 and over 80 % by 2050 within the so called “Energiewende”. Energy storage is seen as a potential option to assure the safe RES system integration to achieve these goals. There is a high uncertainty and the resulting public discourse about the future demand and the most suitable type of storage technology is driving further development of these technologies. A literature review of 9 studies and 10 expert interviews are carried out in line of a foresight exercise on to tackle these uncertainties. The estimations of reviewed studies are based models with a market perspective on energy storage demand. Most model-based scenarios are built on top down logics, where processes at lower levels (technology, micro-economic sphere) are determined by dominant macro dynamics. Different technologies are only considered partially or in an aggregated way. The reviewed studies showed that there is a high potential storage on every time scale starting from the year 2030 to 2040. Analysed potentials vary depending on RES diffusion and excess rate assumptions between 0 to 44 GW. Reviewed studies strongly integrate shared visions about system developments and formal analyses and provide important and valuable information about potential future implications. But they only partially account, due to practical reasons, wider benefits, stakeholder opinions and continuous changes. They account also discontinuities in the technological innovation process of energy storage. Stakeholder interviews provided additional and helpful insights to the literature review. The stakeholders framed alternative potential future developments that could influence the market success and need for energy storage until 2050. Most important factors named where policy measures, new market models and decentralization of the energy system. As in literature there is a big uncertainty among experts about the right storage technology and if energy storage is in general the best option among other measures as grid reinforcement, flexible demand and flexible power plants. It remains impossible to provide suggestions regarding the development of single storage technologies.Karlsruhe Institute of Technology