Xcel Energy Tuesday announced the prime contractors for four Upper Midwest wind energy projects, and Golden Valley-based Mortenson landed two of the deals.

The projects are part of Xcel's plan to add 1,850 megawatts of wind energy in the Upper Midwest over the next four years, enough power for nearly one million homes. The contracts unveiled Tuesday cover 750 megawatts of generation capacity. (A megawatt is one million watts).

Mortenson, one of the largest U.S. wind energy contractors, won bids for the Blazing Star 1 and Blazing Star 2 wind farms in Lincoln County in southwestern Minnesota. Each Blazing Star project will have the capacity to generate 200 megawatts of power, utilizing about 100 turbines a piece.

Construction on the Blazing Star wind farms will start by 2019.

Wanzek Construction of West Fargo won contracts for the Foxtail Wind Farm in southeastern North Dakota and the Freeborn Wind Farm, which would be partly in Minnesota's Freeborn County and partly in Iowa. Wanzek is a subsidiary of a publicly-traded Florida company, MasTec.

The Foxtail and Freeborn projects together will have the capacity for 350 megawatts, using about 175 turbines. Foxtail is scheduled to be built in 2018-2019; Freeborn in 2020. All construction dates are contingent on regulatory approval of the projects.

Minneapolis-based Xcel has been the largest wind energy provider among U.S. utilities for over a decade.