<P> The economic valuation of large - scale applications (including pumped hydro storage and compressed air) considers benefits including: wind curtailment avoidance, grid congestion avoidance, price arbitrage and carbon free energy delivery . In one technical assessment by the Carnegie Mellon Electricity Industry Centre, economic goals could be met with batteries if energy storage were achievable at a capital cost of $30 to $50 per kilowatt - hour of storage capacity . </P> <P> A metric for calculating the energy efficiency of storage systems is Energy Storage On Energy Invested (ESOI) which is the useful energy used to make the storage system divided into the lifetime energy storage . For lithium ion batteries this is around 10, and for lead acid batteries it is about 2 . Other forms of storage such as pumped hydroelectric storage generally have higher ESOI, such as 210 . </P> <P> In 2013, the German Federal government has allocated € 200M (approximately US $270 M) for advanced research, as well as providing a further € 50M to subsidize battery storage for use with residential rooftop solar panels, according to a representative of the German Energy Storage Association . </P> <P> Siemens AG commissioned a production - research plant to open in 2015 at the Zentrum für Sonnenenergie und Wasserstoff (ZSW, the German Center for Solar Energy and Hydrogen Research in the State of Baden - Württemberg), a university / industry collaboration in Stuttgart, Ulm and Widderstall, staffed by approximately 350 scientists, researchers, engineers, and technicians . The plant develops new near - production manufacturing materials and processes (NPMM&P) using a computerized Supervisory Control and Data Acquisition (SCADA) system . Its goals will enable the expansion of rechargeable battery production with both increased quality and reduced manufacturing costs . </P>

The processes that can transfer energy from one store to another