Technical and financial benefits of electrical energy storage

Traditionally, electricity networks are dimensioned on peak demand. This is inevitable due to the fact that storage of substantial amounts of electricity is technically and economically infeasible. As a result, a vast amount of currently unused network capacity is available. When this could be used, much more energy could be transported with the same network so that investments on network reinforcements could be postponed or omitted. To this end, it must be possible to shift demand for electricity in time or, more precisely, to shift the transport of electricity in time. In principle, this can be done by incorporating (distributed) electricity storage in the networks. This paper attempts to summarize the current state of knowledge regarding energy storage technologies for electric power grid. It is intended to serve as a reference for policymakers interested in understanding the range of technologies and applications associated with energy storage, comparing them, when possible, in a structured way to highlight key characteristics relevant to widespread use.