Invenergy, LLC develops, builds, owns and operates power generation and energy storage projects in North America and Europe. Its portfolio includes wind, solar, and natural gas-fueled power generation and energy storage facilities. It is one of the six largest owners of wind generation plants in the United States and is North Americas largest independent wind power generation company. According to Invenergy, the company has developed 5,539 MW of wind farms in operation; 3,159 MW of natural gas-fueled facilities in operation; 144 MW of solar projects in operation; and 88 MW of energy storage facilities in operation. At least 3,982 MW of renewable and clean energy projects are under contract or in construction. Wind production is spread over 56 operating projects, with several others currently in development and construction. Founded in 2001 after the sale of SkyGen Energy to Calpine Corporation by energy veteran Michael Polsky who also serves as president and CEO, Invenergy is based in Chicago, Illinois. Invenergy also has North American offices in Denver, Toronto, and Mexico City. European activity is centered in Warsaw. The company also has an office in Tokyo.