Distributed Energy Systems Corp. (Distributed Energy) operates through two subsidiaries: Proton Energy Systems, Inc. (Proton) and Northern Power Systems, Inc. (Northern). Proton is engaged in designing, developing, selling and manufacturing on-site hydrogen gas delivery systems. Northern has a range of businesses, including the design and sale of power generation equipment, engineering, procurement and construction of distributed power systems, the design and sale of direct drive wind turbines, and the servicing of fossil fuel power generation equipment. In June 2008, it announced that the Company and its wholly owned subsidiary, Northern Power Systems, Inc., filed voluntary petitions under Chapter 11 of the United States Bankruptcy Code. In July 2008, pursuant to a previously disclosed Stock Purchase Agreement between the Company, its Proton Energy Systems, Inc. subsidiary (Proton) and F9 Investments, LLC, dated as of June 4, 2008, it completed the sale of Proton to F9 Investments.