One of the energy storage systems being developed to support the electric grid is the flywheel. Beacon Power Corporation, a company based in Tyngsboro, Massachusetts, is building a 20 MW flywheel energy storage plant in Stephentown, New York. The project, partially funded with a $43 million loan guarantee from the U.S. Department of Energy was pointed out as one of the 100 Recovery Act Projects that are Changing America, a report issued by the office of Vice President Joe Biden. According to the report, the plant will reduce carbon dioxide emissions up to 82 percent over its 20-year life compared to a coal, gas or pumped hydroelectric plant.
Beacon Power explains that flywheel energy storage consists of a type of kinetic or mechanical battery. A cylindrical assembly, or flywheel, is accelerated to a very high speed and the energy is maintained as rotational energy. A carbon-fiber rim is supported by a metal hub and shaft, with a generator mounted on the shaft. When the cylinder is charging, the flywheel motor draws power from the grid to accelerate the rotor. When the motor is switched to generator mode, the inertial energy drives the generator, creating electricity that is fed back into the grid.
Beacon Power’s Smart Energy 25 flywheel spins at between 8,000 and 16,000 rpm and can store up to 25 kWh of energy. The rotor assembly is sealed in a vacuum chamber and levitated with magnets and an electromagnetic bearing to reduce friction and energy losses. The Smart Energy Matrix, which is used on an electrical grid scale, consists of multiples sets of 10 Smart Energy 25 flywheels that are interconnected for storing energy for utilities.
According to Beacon Power, its flywheel energy storage systems do not use any fossil fuel or produce any CO2 or other emissions during operation. The flywheels require little or no maintenance and can operate reliably for many years.
In September, 2010, Beacon Power announced on Globe Newswire that the company had signed a $2.8 million contract with the U.S. Department of Energy to develop components of an advanced “flying ring” flywheel energy storage system under the Advance Research Projects Agency. Beacon would contribute 20% of the total cost of the program. The goal is to store up to four times as much energy at one-eighth the cost compared to Beacon’s current Smart Energy 25 flywheel system. Beacon points out that an area of special interest is for the flywheel system to support wind and solar power facilities. The energy stored in the flywheel system would compensate for the intermittent nature of wind and solar power, rather than using backup energy generated from fossil fuels.
100 Recovery Act Projects that are Changing America – The Whitehouse
Beacon Power Flywheel Plant Named as One of “100 Recovery Act Projects That Are Changing America” – Globe Newswire
Beacon Power Signs ARPA-E Contract to Begin Developing Long-Duration Flywheel for Renewable Energy Integration – Globe Newswire