. Évora: CICS.NOVA/Universidade de Évora, 2017.
Germany has ambitious targets to produce 35 % of the needed electricity from Renewables (RES) 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 this goals. There is a high uncertainty and the resulting public discourse about the future demand of different storage technologies is driving further development of these technologies. A literature review of 9 studies and 10 expert interviews is carried out in line of a foresight exercise to tackle these uncertainties. The estimations of reviewed literature are based on models with a market perspective on energy storage demand. Most scenarios used in this models are built on top down logics, where processes at lower levels (technology, micro-economic sphere) are determined by dominant macro dynamics. Different storage technologies are only considered partially or in an aggregated way. The reviewed studies show that there is a high for potential storage on every time scale starting from the year 2030 to 2040. Analysed potentials vary depending on RES diffusion scenarios and excess rate assumptions which are estimated to be between 0 to 44 GW in 2050. Reviewed studies strongly integrate shared visions about system developments and formal analyses and provide important and valuable information about potential future implications regarding energy storage. But they only partially account, due to practical reasons, wider benefits, stakeholder opinions and continuous market and system changes. It is also not possible to account for discontinuities in the technological innovation process of energy storage within this quantitative approaches. Stakeholder interviews provide thus additional and helpful insights to the literature review. The stakeholders frame 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 importance of different storage technologies and if energy storage is in general the best option among other flexibility measures as grid reinforcement, flexible demand and flexible power plants. It remains thus impossible to provide suggestions regarding the development of single storage technologies.
