Techno-Economic Assessment of Using Utility Scale Battery Storage to Facilitate Variable Renewable Energy (VRE) Integration in Sri Lanka

Sri Lanka has envisaged an ambitious target for renewable capacity integration to the power system as indicated through favorable government policy targets and long-term generation expansion planning studies carried out by Ceylon Electricity Board. These renewable capacity additions are mainly comprised of wind and solar, both of which are variable renewable sources (VRE) which affect the operation and stability of the power system due to the inherent intermittency and variability of the sources. This rapid increase of VRE integration to the power system, calls for a more flexible power system and battery storage systems are emerging as one of the potential solutions to increase system flexibility. A technical and economic evaluation was carried out through the study on the use of battery storage compared to thermal generators in providing operational reserves to the system and reducing VRE curtailments which in turn support VRE integration. For technical analysis, dispatch simulation using Stochastic Dual Dynamic Programming (SDDP) was used and a cost benefit analysis based on the dispatch simulation results for 2022–2031 horizon were used for economic evaluation. It was observed that compared to thermal generators, battery storage contributed favorably in reducing VRE curtailments and providing operational reserves.