Publication

Abstract : At higher penetration levels of intermittent electricity generation on to powergrid the utility operation invariably calls for inclusion of grid-connected energy storage system from the point of view of the power system reliability. The paper studies the storage requirements of a bulk electricity generation scheme connected to the grid and examines the suitability of various storage systems developed or demonstrated. In the absence of a single storage system that satisfies all the requirements of a generation scheme a combination of different types of storages can be thought of. Also an attempt has been made to estimate the power capacity and size of storage required for a grid-connected windfarm located at a proven Indian site. Costs of generation with and without the storage have been compared. The result shows that inclusion of a pumped hydro storage causes a 68% increase in generation cost along with a 11% reduction in the annual energy production by the wind farm. On the other hand large scale grid integration of a renewable source like wind without storage demands a spinning reserve which if provided on thermal plants through part load operation the overall system efficiency will decrease and cost of operation will increase. A storage scheme is therefore to be selected based on the overall economics and quality of performance of the entire power system. The paper also observes that a storage scheme aptly suited for intermittent generation of bulk electricity is yet to be developed.