Giant Flywheel Battery System Under Construction

A USD $43 million loan guaranteed by the U.S. Department of Energy has been announced for a  20 MW flywheel energy storage plant.
We’ve mentioned flywheel “batteries” in the past – a system that works by accelerating a rotor (flywheel) to very high speeds and maintaining the energy in the system as rotational energy, which is converted back by slowing down the flywheel. 
The storage plant, now under construction in Stephentown, New York, is being developed by Beacon Power Corporation. The plant will provide frequency regulation services to help improve and maintain stability of the New York mains power grid and also allow greater use of wind and solar power. 
Frequency regulation is a service that maintains a balance between electricity supply and demand. The flywheel batteries will absorb electricity from the grid when there is too much and when there’s not enough; will inject energy back into the mains grid.
Beacon Power Corporation says that a 2009 study found that 30 to 50 MW of fast-response energy storage can be expected to provide the same or greater regulation effect as a 100 MW combustion turbine.
The 20MW facility will cater to around 10% of New York’s total frequency regulation capacity on an average day. The $43 million loan will cover 62.5% of the plant’s estimated USD$69 million cost. 
Four MW at the plant is expected to be online by the end of this year, with the remainder being available by the first quarter of 2011.
Beacon Power is also developing two more 20 MW flywheel-based energy storage plants; one in the PJM Interconnection grid operating region and another in Glenville, New York.