Notrees storage system in service

Duke Energy Renewables has completed its 36MW energy-storage and power-management system at its Notrees wind farm in west Texas using technology supplied by Xtreme Power.

In late 2009, Duke announced plans to match a $22m grant from the US Department of Energy (DOE) to install large-scale batteries capable of storing electricity produced by the 153MW Notrees facility.

 Xtreme Power, based in Austin, Texas, designed and installed the system, and will continue to operate it.

"Battery storage is an important innovation to address the variability of wind and solar energy generation,”says 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.”

Imre Gyuk, programme manager for energy storage at the DOE, says completion of the project represents a “singular success” for the partners and the US energy-storage community.

In addition to increasing the supply of renewable energy during periods of peak demand, the system will help stabilise the frequency of electricity travelling throughout the grid.

Duke Energy is working closely with the Electric Reliability Council of Texas (Ercot), which signals to the battery-storage system either to dispatch stored energy to increase frequency, or to absorb energy to decrease frequency.

ERCOT dispatches about 85% of electric load in Texas.

The Electric Power Research Institute will collect performance data from the storage system and help assess the potential for broader adoption of energy-storage throughout the industry.

Xtreme Power,a privately held company, has raised more than $90m since its founding. Current investors include SAIL Capital Partners, Bessemer Venture Partners, Dow Chemical, BP and Fluor.