Hydraulic design and performance analysis on a small pump-turbine system for ocean renewable energy storage system

Korea has a myriad of islands in the south western coast that extensively rely on diesel generators for power production, which increase cost and environment pollution. The small hydro pump-turbine system for ocean renewable energy storage system is a kind of hybrid system that can reduce the usage of diesel generators and help to contribute to the environment in a positive manner by helping to reduce carbon emissions. The study focuses on initial hydraulic design and numerical analysis of a 30 kW-class pump-turbine system for energy independent islands in South Korea. The purpose of the study is to propose an ocean renewable energy storage system using a small pump-turbine system working with seawater. A 30 kW-class pump-turbine does not require a large head; approximately 30 m is sufficient for the design and application. Several other renewable energy systems like wind turbines, tidal turbines, wave energy converters and solar energy could be used to make a hybrid system with pump-turbine. The initial design achieved more than 85 % efficiency in both pump and turbine modes. However, further optimizations of the impeller blade shape and number of guide vane and stay vanes could improve the overall efficiency of the system.