On the day (October 11, 2017) that the EU together with German French and Polish  announced the European Battery Alliance, with the EU pledging 2.2 bln, the Energy Storage Technology Development Roadmap 2017 was published, that the European Association for the Storage of Energy EASE together with the European Energy Research Alliance (EERA) compiled. Installed large-scale energy storage capacity world-wide in 2015 was estimated at 150 GW with approximately 96% of this capacity consisting of pumped hydro storage (PHS) (IEA Tracking New Energy Progress 2016). The massive increase of renewable power plants is having a big effect on the stability of electricity networks and the IEA estimates that limiting global warming to below 2°C will necessitate globally installed energy storage capacity to increase from 140 GW in 2014 to 450 GW in 2050. This threefold increase is necessary because, as the European Commission underlines, “energy storage can support the EU’s plans for Energy Union by helping to ensure energy security, a well-functioning internal market and helping to bring more carbon-cutting renewables online. By using more energy storage, the EU can decrease its energy imports, improve the efficiency of the energy system and keep prices low by better integrating variable renewable energy sources”. This means that the energy storage market will see rapid expansion in the next years and decades: the global market is forecast to grow to at least $250 billion by 2040 (Bloomberg New Energy Outlook 2016).