Energy storage for grid-scale applications: Technology review and economic feasibility analysis

Non-dispatchable Renewable Energy Sources (RES) changed energy production from being centralised and fully dispatchable, to be more decentralised and less predictable. Despite the substantial growth, RES must be increased to fulfil the power production decarbonization targets set by several countries. In several countries, Italy included, RES development must be based on solar PV. Thus, relevant energy quantities will be shifted from day hours to night hours. Such “Load Shifting” is done with energy storage technologies. A few technologies suited for this task are already available, whereas several others have been proposed, but not tested in the practice. In this paper, such storage technologies are reviewed focusing on the performance and costs. Based on the review, current and future storage economic outlooks are assessed by focusing on the Italian scenario. In the paper, the storage operation is optimized at the hourly level to calculate the maximum achievable annual revenue. The optimisation is performed with a linear programming (LP) approach. Since none of the reviewed storage is economically feasible, the energy price modification required to achieve feasibility are estimated. Based on such results, the distance between the current situation and the one favourable to storage is assessed. In this way, the future outlook of each storage technology is discussed.