Pumped Energy Storage Systemfor the Randenigala Hydropower Plant in Sri Lanka

Abstract: The main focus of this work is to introduce a pumped storage system to an existing hydro power plant located on the Randenigala reservoir in Sri Lanka. The selected power plant is located in an area where farming is done extensively, therefore electrical power generation and release of water to the downstream is to be properly coordinated with relevant authorities. The solution for this situation can introduce a wind powered pumped energy storage power plant to the Mahaweli hydro cascade for the purpose of saving peak power for around half an hour. A feasibility study was carried out on the utilization of wind energy and excess power to drive the motors of the pumped storage system.Three versions with different numbers of pump motors and wind turbines have been considered to meet the half hour peak demand of the energy storage system. The optimum number of turbines and motor capacities and their number and brand have been selected with view of both energy and water management system.Finally, the selected system case has been compared with the function of pumped hydro storage using excess power from the national electricity grid. The annual savings to the Ceylon Electricity Board using the most optimum system configuration was found to be Rs. 55 million per year.