The Beacon Power Stephentown – Flywheel Energy Storage System is a 20,000kW energy storage project located in Stephentown, New York, US.

The electro-mechanical energy storage project uses flywheel as its storage technology. The project was announced in 2007 and was commissioned in 2011.


The Beacon Power Stephentown – Flywheel Energy Storage System was developed by Beacon Power. The project is owned by Rockland Capital Energy Investments (100%).

The key application of the project is frequency regulation.

Contractors involved

Beacon Power and Rockland Capital Energy Investments have delivered the energy storage project.

Additional information

The Storage system has been funded by Federal/National Debt, US Department of Energy – Loan Guarantee. The facility sits on five acres and is comprised of 200 flywheels each with a peak power capacity of 100kW and storage capacity of 25kWh.


All publicly-announced energy storage projects included in this analysis are drawn from GlobalData’s Power IC. The information regarding the projects are sourced through secondary information sources such as country specific power players, company news and reports, statistical organisations, regulatory body, government planning reports and their publications and is further validated through primary from various stakeholders such as power utility companies, consultants, energy associations of respective countries, government bodies and professionals from leading players in the power sector.