S&C Electric Co. deployed six 25-kW PureWave energy storage systems at its global headquarters in Chicago. The 150-kW energy storage system provides fast-response frequency regulation for the PJM market, which serves more than 61 million people in 13 states and the District of Columbia.
Ancillary grid services, such as frequency regulation, are crucial for maintaining the stability and reliability of the power system. Frequency regulation is used to minimize the mismatch between generation and loads by quickly adjusting generation output to maintain the grid's ideal frequency — 60 Hz in parts of the world and 50 Hz in others.
Historically, fossil-fueled fired generating plants have provided a majority of such services, but response times often exceeded 20 minutes. In 2011, the Federal Energy Regulatory Commission (FERC) issued Order 755, which mandated higher rates for fast-responding frequency regulation sources.
S&C is selling its CES-stored electricity to PJM through Intelligent Generation, which offers a networked software platform that facilitates optimization and bidding of distributed energy resources into wholesale electricity markets.
To sell into the fast-response frequency regulation market, PJM requires systems to pass a series of tests that measure the accuracy, delay and precision between PJM's regulation signal and the system's output. PJM rejects any system that does not meet a minimum of 75 percent; S&C's system passed with an average performance score of 97 percent.