Allete Clean Energy announced it purchased a 300-megawatt wind farm under construction in Oklahoma, and plans on selling the energy to corporate customers.

The project, in southern Oklahoma's Caddo County, was previously owned by Apex Energy and is expected to be operational by the end of 2021. Allete Clean Energy, a subsidiary of Duluth-based Allete, Inc., said the energy will be sold to three Fortune 500 companies. Company names were not released.

“Our total wind capacity also will have nearly tripled in four years," Allete Clean Energy President Al Rudeck said in a news release. "We’re honored to help corporate customers reduce their carbon footprint and reach their clean energy goals."

Rapidly-growing Allete Clean Energy now owns, operates or is building 1,340 megawatts of wind power, the company said.

Last year, the company announced it bought a different wind farm in southern Oklahoma, Diamond Springs, and would be selling all 300-megawatts to Walmart, Starbucks and Smithfield Foods.