Benefits of battery energy storage system for system, market, and distribution network – case Helsinki

Abstract

This study presents the first performance results of a large battery energy storage system (BESS) that is connected to a medium-voltage distribution network and used simultaneously by multiple stakeholders. This study presents the background of the purpose of a BESS as part of the Nordic power system and markets, and the functionalities it is able to perform. The first test cases ran in the fall 2016 included simultaneous controls of frequency, reactive power, and voltage according to the requests from transmission and distribution system operators. The results showed that the first functions of the BESS performed were successful. Valuable experience has also been reached when observing, e.g. the energy capacity limits of the batteries.