Performance of a wind-turbine-driven compressor for lifting water

Energy storage is important for renewable energy systems. Compressed air storage is an attractive alternative to pumped water storage. It is suitable for use with wind-energy systems. We have studied a system consisting of a wind turbine, compressor, storage tank, and air-lift pump. The output power and capacity factor were accurately determined. Characteristics of the air-lift pump were investigated by using a numerical model. Wind turbines with compressed air storage and capacity factors greater than 40% are feasible with air-lift pumps. With air-lift pumps, increases of air-flow rates were accompanied by corresponding increases in water-flow rates, up to maximum outputs. The efficiency of the system reaches 22% when the ratio of water to air flow rate equals 2.15 and decreases thereafter.