Energy storage as part of electricity distribution asset management

Energy storage (ES) is part of modern power system providing benefits for the distribution system operation. In this paper, the storages have been considered as back-up supply of the distribution substation to ensure that medium-voltage network faults do not cause long interruptions in the considered substation. The paper presents a case study of a Finnish rural area electricity distribution system where feasibility of energy storages is analyzed. In the best case by using energy storage system (ESS) the expensive underground cable investments can be avoided and high local electricity supply security can be ensured with ESS in the low-cost overhead line network.The paper shows that unit costs of the energy storages should be below 200 €/kWh to enable wide use of the storages. In addition, the size of the storage plays the key role and if a storage with low-energy capacity fulfils the criteria, the storage system can be feasible with higher unit costs.