Atlantic Power bought the interest from Canadian Hills’ developer, Virginia-based Apex Wind Energy Holdings, which will retain a 1% stake in the project. Apex will continue in its role as asset manager for Canadian Hills, managing construction and overseeing operations.

The deal follows Atlantic Power’s entry into the US$410 million project in February, when it bought a 51% stake for US$23 million. The company has not disclosed the value of the latest purchase.

Construction on Canadian Hills, which is located near El Reno, will start immediately, and the project is expected to be fully operational by November 2012.

Atlantic Power also secured a US$310 million financing facility for the construction of the wind farm, arranged by Morgan Stanley.

"Our investment in Canadian Hills is a significant milestone in the continued growth of the company", said Barry Welch, chief executive of Atlantic Power, adding that the purchase increases the contribution of wind to the company’s generating capacity from 3% to 15%.

Canadian Hills has long-term power purchase agreements in place for 100% of its output. The power will be delivered to local distribution networks owned by Southwestern Electric Power Company, Oklahoma Municipal Power Authority, and Grand River Dam Authority.

The project will use a combination of Mitsubishi 2.4 MW MWT102 turbines and and REpower 2.05 MW MM92 wind turbines, which Atlantic Power said were well placed to take advantage of Canadian Hills’ “strong wind regime”.

Atlantic Power has interests in 31 operational power generation projects across 11 US states and two Canadian provinces, with a total capacity of around 2.1GW. The portfolio includes a 53 MW biomass project under construction in Georgia, and an 84 mile 500kV transmission line in California.