Duke Energy Renewables recently announced its acquisition of three new 1-megawatt solar plants in North Carolina.

The energy company purchased the turnkey solar plants from Spain-based ESA Renewables, which will continue to maintain the arrays. Duke has also arranged to sell the power the three plants produce to the Tennessee Valley Authority. TVA, a public utility that serves several southeastern states, signed a 10-year, power-purchase agreement with Duke, according to a press release from the company.

Duke has two arms. It is a regulated utility which provides power in five states, and it has commercial operations like those advanced through its Duke Energy Renewables business, said Duke spokesman Greg Efthimiou.

The commercial branch of Duke commissions builds and buys renewable energy generation facilities including both solar and wind and typically sells that power to other utility providers and cooperatives.

“We made these purchases as part of our commitment to sustainability,” Efthimiou said of the three new solar installations.

Duke is dedicated to bringing a mix of renewable energy sources online over the coming years, Efthimiou said.

The company has been in business more than 100 years and has been building power plants from the beginning, Efthimiou said. But it didn’t get into the renewable energy line until 2007 when it built 107 megawatts of wind generation.

It has since gotten into solar. In North Carolina alone, the company owns about 20 megawatts of solar generation, Efthimiou said.

The three new solar plants that Duke purchased include 4,298 panels at the Murphy Farm Solar Project on eight acres, 4,340 panels at the Wingate Solar Project on seven acres and 4,242 panels at the Holiness Solar Project on nine acres. All three started producing power between May and November. They all use Canadian Solar panels.

While the company’s solar portfolio is slowly growing, it has an even greater concentration on wind.

Duke built almost no wind generation plants in 2011 because power-purchase agreements were stalled in 2010. But the company already has agreements to build wind plants that will generate more than 700 megawatts of power in 2012.

“We’ll more than double our wind capacity,” Efthimiou said.

Image courtesy of Advanced Energy.