Cost-benefit Analysis for Using the Li-ion Batteries in Low-voltage Network for Decreasing the Outage Time Experienced by Customers

Battery energy storage (BES) installed in the low-voltage busbar of a secondary substation can prevent part of the customers’ interruptions in a low voltage (LV) network that would happen due to failures in the supplying medium voltage (MV) network or rarely in the high voltage network (HV). In fact, over 80% of average customer outage time comes from the interruptions in the MV network [1]. One way to improve the network reliability for decreasing the interruption time of customers is to focus the investments on the MV network (e.g. network automation or cabling). The other option is to develop local solutions at LV network level by energy storages.

This study compares the life-time costs of Li-ion batteries against the benefits achieved by decreasing the customer interruption costs (CIC) defined by the Finnish network business regulation model. The analysis is done by using the interruption and network data of Elenia Oy consisting of 13,867 LV networks in rural areas. The results indicate profitability in the interruption prone LV networks.