Tecogen 

Tecogen Inc produces commercial and industrial, natural-gas-fueled engine-driven, combined heat and power (CHP) products that reduce energy costs, decrease greenhouse gas emissions and alleviate congestion on the national power grid. Its products supply electric power or mechanical power for cooling. The company has three business segments: Products Segment, Services Segment, and Energy Production Segment. The majority of the company's revenue is derived from the Services segment, which provides operations and maintenance (O&M) services for its products under long term service contracts.