The electric power grid operates based on a delicate balance between supply (generation) and demand (consumer use). One way to help balance fluctuations in electricity supply and demand is to store electricity during periods of relatively high production and low demand, then release it back to the electric power grid during periods of lower production or higher demand. The most common methods of energy storage include pumped hydroelectric, compressed air, flywheels, batteries, and thermal energy storage.

Geothermal 101

Check out this infographic