To ensure a functional and reliable grid, the Independent System Operators (ISOs) that operate the various regional grids must maintain their electric frequency very close to 60 hertz (Hz), or cycles per second (50 Hz in Europe and elsewhere). When the supply of electricity exactly matches the demand (or "load"), grid frequency is held at a stable level. Grid operators, therefore, seek to continuously balance electricity supply with load to maintain the proper frequency. They do this by directing about one percent of total generation capacity to increase or decrease its power output in response to frequency deviations.
The Smart Energy 25 flywheel is a 4th-generation advanced energy storage solution designed to meet the requirements of demanding utility grid applications. It features a long-life, low-maintenance design, highly cyclic (charge-discharge) capability, and zero fuel consumption or CO2 or other emissions. An array of Smart Energy flywheel units can be configured to form a Smart Energy Matrix plant, which can store and return megawatts of energy to maintain grid reliability and stability.