"The battery was deployed at the site to provide energy storage for the wind farm, helping to stabilize its output to the grid. Such battery systems are being considered for solar installations as well. “Battery storage is an important innovation to address the variability of wind and solar energy generation,” said Duke Energy Renewables President Greg Wolf. “Developing an expertise in this advanced technology will enable us to expand the use of renewable energy, better integrate it into the power grid and become even more efficient at serving our customers.”"

"The project has been in the works for a while, at least since 2009 when Duke Energy matched a $22 million grant from the DOE to install large-scale batteries. The grant came from the American Recovery and Reinvestment Act of 2009 (ARRA). It was one of 16 grants totaling $185 million that the DOE’s Office of Electricity Distribution and Energy Reliability made for such storage projects. Each project is cost-shared with the project owners, with the DOE making no more than half the investment. Other projects that received grants included compressed air energy storage, flywheels and advanced batteries. The devices being installed help with frequency regulation, smoothing of a photovoltaic installation, ramping for wind, and time shifting for a fossil fuel plant."