The 299 MW Kay Wind facility comprises 130 wind turbines manufactured by Siemens.
The power generated from the turbines helps meet the electricity consumption of about 100,000 average U.S. homes.
The Kay Wind project assists Southern Power to grow its wholesale business through the acquisition and construction of generating assets substantially covered by long-term contracts.
Southern Power president and chief executive officer Oscar C. Harper said: "The completion of Kay Wind – Southern Power’s first wind project – marks an important milestone for our company.
"Renewables remain a central focus as we continue developing sustainable energy solutions through projects that align with Southern Power’s conservative business model."
The electricity and related renewable energy credits (RECs) derived from the project will be sold under 20-year power purchase agreements with Westar Energy Inc. in Kansas and Grand River Dam Authority (GRDA) in Oklahoma.
The contract with Westar Energy involves approximately 199 MW and that with GRDA involves about 100 MW.
The companies can either sell or retain the RECs.
The facility has been developed and will be operated by Apex Clean Energy.
Blattner Energy Inc. was the engineering, procurement and construction contractor of the project.
Southern Power has also signed a contract to acquire the Grant Wind facility, a 150 MW project in Grant County, Oklahoma.
The Grant Wind project is expected to utilise 66 wind turbines manufactured by Siemens.
