On June 7, General Electric (NYSE: GE) said it sold its first power plant that integrates solar and wind power with its newly released FlexEfficiency 50 combined-cycle gas turbine. At 530 megawatts, it’s not small. Developer and investor MetCap Energy Investments already said they plan to double the plant’s size.

The news follows June 6’s announcement that GE entered into an investment and licensing agreement with solar thermal company eSolar. The California-based company has developed modular tower-based solar thermal technology, which GE will integrate into its turbine system.

“GE is now able to deploy integrated solar. We will combine it with our FlexEfficiency plant. The integrated system will provide more than 70 percent efficiency,” said Paul Browning, CEO of thermal products for GE.

“eSolar’s techology is modular,” said eSolar President John Van Scoter. “Owners can scale up or down. It’s tested and field-proven solar technology,” he said.

The company designed its towers to be 4 megawatts each, much smaller than tower systems being built in the U.S., like SolarReserve’s 110-megawatt Crescent Dunes Solar Energy Project, near Tonopah, Nev. But it also allows buyers to add in more of the towers as they need to.

“Today, we have an order from MetCap for the world’s first integrated renewables combined cycle power plant. This will be a plant that combines, wind, solar thermal and gas at one plant and takes it well beyond 70 percent efficiency,” Browning said.

The power plant, which will be built in Karaman, Turkey, will feature GE’s 510-megawatt FlexEfficiency power plant, 50 megawatts of eSolar’s solar towers, which will provide additional steam for the FlexEfficiency turbine, increasing its overall efficiency.

The site will also include 22 megawatts of GE wind turbines. The company said all the sources will be integrated by a GE Mark VIe plant control system.

The power plant, which is slated for completion in 2015, is expected to pay for itself in about 10 years, without incentives, said Dr. Celal Metin, chairman of MetCap.

“Our total investment at this point is 400 million euros.” he said.

“The beautiful thing about combining them all is you’ve already paid for the steam generator [and] the connection,” Browning said. Adding the eSolar to the turbine, doesn’t add that much more. “It adds up to a very attractive number.”

Other potential markets for the technology include Italy, Spain and India, Browning said during the webcast. Don’t expect to see this incarnation in the U.S., however. The FlexEfficiency turbine produces electricity with a frequency of 50 hertz, which is used in most of the world. But the U.S. uses electricity with a frequency of 60 hertz.