NEW YORK ( TheStreet) -- American DG Energy (AMEX: ADGE) has been downgraded by TheStreet Ratings from hold to sell. The company's weaknesses can be seen in multiple areas, such as its weak operating cash flow, poor profit margins and generally disappointing historical performance in the stock itself. American DG Energy Inc. distributes, owns, and operates on-site energy systems that produce electricity, hot water, heat, and cooling. It offers natural gas powered cogeneration systems, which produce electricity from an internal combustion engine. American DG Energy has a market cap of $105.5 million and is part of the utilities sector and utilities industry. Shares are down 15.5% year to date as of the close of trading on Tuesday. You can view the full American DG Energy Ratings Report or get investment ideas from our investment research center.