ABSTRACT
Energy storage technologies are of great interest to electric utilities, energy service companies, and automobile manufacturers. Flywheels store their energy in their rotating mass, which rotates at very high speeds, and are made of composite materials instead of steel because of the composite’s ability to withstand the rotating forces exerted on the flywheel. In order to store energy, the flywheel is placed in a sealed container which is then placed in a vacuum to reduce air resistance. As the name implies, the compressed air energy storage plant uses electricity to compress air, which is stored in underground reservoirs. When electricity is needed, this compressed air is withdrawn, heated with gas or oil, and run through an expansion turbine to drive a generator. The compressed air can be stored in several types of underground structures, including caverns in salt or rock formations, aquifers, and depleted natural gas fields.
