US company Convergent Energy and Power has acquired two flywheel energy storage systems totalling 40MW from Rockland Capital.

The projects are located in Stephentown, New York, and Hazle Township in Pennsylvania and have been operational since 2011 and 2014, respectively.

They consist of 400 five-tonne carbon composite and steel flywheels storing electricity as rotational energy, which is released by reducing the speed of the rotor, the company said. 

Convergent said it will continue to operate the flywheels to meet the balancing needs for PJM Interconnection and NYISO grid operators as more wind and solar capacity is connected.

Convergent chief executive Johannes Rittershausen said: “Renewable energy capacity in the US has tripled since the year 2000, and we see these flywheel assets as crucial to integrating more such energy in the future.”

Image: Convergent Energy and Power