PIGEON, Mich., Oct. 23, 2013 /PRNewswire/ -- The first 13 wind turbines at DTE Energy's (NYSE: DTE) Echo Wind Park have been commissioned, with the entire facility set to begin commercial operation by the end of November. The 70-turbine Echo Wind Park in Huron County will be operational by the end of 2013 and add another 112 megawatts (MW) to the DTE Energy's renewable energy portfolio. The wind park, primarily in Oliver and Chandler townships, is sited on nearly 16,000 acres. The Echo Wind Park is the third to be owned and operated by DTE Energy. The 110-MW Thumb Wind Park reached commercial operation in December 2012. In addition, DTE Energy has an ownership stake in the Gratiot County Wind Park. The Gratiot wind park is a 212.8 MW project. Sixty-four of the turbines are owned by DTE Energy, while 69 turbines are owned by Gratiot Wind LLC, an affiliate of Invenergy Wind LLC. DTE Energy purchases the power from Invenergy's turbines under a 20-year power purchase agreement. DTE Energy also announced recently it will purchase the energy from the 20-MW Big Turtle Wind Farm, which will cover 2,800 acres in Rubicon Township in Huron County. The Big Turtle Wind Farm, expected to be operational by late 2014, will comprise a minimum of 50 percent Michigan content and feature new technology advanced by Ventower Industries of Monroe and other Michigan suppliers. The Big Turtle Wind Farm will have 10 2-MW turbines and will be the first wind park in Michigan to incorporate all Ventower towers. The owner, Big Turtle Wind Farm LLC, is a subsidiary of Heritage Sustainable Energy, a Michigan wind energy producer. The Big Turtle contract is part of DTE Energy's efforts to expand the company's renewable energy resources and meet the state's renewable energy goals. DTE Energy expects to add more than 900 MW, or 10 percent of its power, by 2015. The Big Turtle contract will bring DTE Energy's renewable energy portfolio, with contracts signed or projects in operation, to 9.8 percent.