Westar Energy plans to purchase 200 megawatts of electricity from a northern Oklahoma wind farm expected to begin operating in late 2016.

The Topeka-based utility announced Wednesday that it had reached purchase agreement with Virginia-based Apex Clean Energy.

Westar already has about 700 megawatts of electricity from renewable resources.

Apex plans to start building the 18,000-acre wind farm in 2015. The site is about six miles south of Arkansas (ahr-KAN’-zuhs) City, Kan., where city manager Nickolaus Hernandez says the project is expected to boost the local economy.

Westar is the largest electric utility in Kansas, with about 700,000 customers.