Developed by Beacon Power, the Smart Energy Matrix system is a prototype for the company's planned 20-megawatt (MW)-level commercial system.

"The application of new energy storage technologies is a high priority as California upgrades its electricity grid system. The Energy Commission is pleased at the results of Beacon's testing and the potential for use of this technology in California," said Energy Commissioner John Geesman. "California has made a significant commitment to deploy renewable energy -- placing greater demands on the state's electric grid. Technologies such as Beacon's flywheel-based energy storage system provide attractive options to address these emerging issues."

A flywheel energy storage system draws electrical energy from a primary source, such as the utility grid, and stores it in a high-density rotating flywheel. The flywheel system is actually a kinetic, or mechanical battery, spinning at very high speeds (>20,000 rpm) to store energy that is instantly available when needed.

Upon power loss, the motor driving the flywheel acts as a generator. As the flywheel continues to rotate, the generator supplies power to the customer load. Performance is measured in energy units indicating the amount of power available over a given period of time.

Typical single-flywheel systems are intended for standby power applications. The Smart Energy Matrix flywheel design proposes an integrated system of 10 higher-power (25 kWh) flywheels, interconnected in a matrix to provide energy storage for utility-grade applications.

"We're grateful for the consistent and effective support we've received from the Energy Commission throughout the project," said Bill Capp, Beacon Power president and CEO. "We're also very pleased that our technology has been certified by the California ISO, which we announced [last week]. These two important authorities, in conjunction with the U.S. Department of Energy, are demonstrating energy policy leadership and vision. They understand that new technologies will be required to maintain grid reliability while achieving ambitious goals for the deployment of renewable energy and the reduction of carbon emissions."

In addition to the environmental and transmission benefits of flywheel technology, current research at Lawrence Berkeley National Laboratories indicates that 10 MW of fast-responding flywheel energy could provide the grid with the equivalent energy of 20 MW or more of traditional slow-responding power plant energy.

The California Energy Commission contracted with Massachusetts-based Beacon Power in 2005, to develop and install a system to demonstrate the potential benefits of using flywheel energy storage for frequency regulation of the grid, a service required by all grid operators. The Department of Energy (DOE) Energy Storage Systems Program Office, through Sandia National Laboratories, is also providing technical assistance to the Energy Commission for this contract.

The system first became operational in 2005 and completed a series of performance tests and technical assessments prior to a six-month field trial phase on August 1, 2006.

Field demonstration testing of the Smart Energy Matrix will continue until January 31, 2007. After that, the CEC and DOE will review all the performance data collected over the last six months period and release a public report summarizing the testing program, results and recommendations.