Ten Eco-Friendly Companies

Candy lovers know that M&M's don't stick to your hands. The reason: palm oil, which is used in the candy's coating. One company that makes the palm oil used in M&M's, Aarhus of Port Newark, N.J., pays hundreds of dollars to send some of the 900 gallons of palm-oil waste that it generates daily to a landfill. But starting next month, the company won't be paying any disposal costs. Instead, it will turn that palm oil into energy, using a new technology developed by an Ann Arbor, Mich., company, STM Power.

STM's technology, which generates electricity on-site, is based on the Stirling cycle engine, which was invented in 1816 as a cooler alternative to the hot-burning steam engine. The process can harness the power of a variety of fuel sources, including methane gas and environmental pollutants to run an external combustion engine. The burning takes place outside the engine, and the heat is then transferred to a small amount of hydrogen stored in tiny, semicircular tubes inside the Stirling engine. The heated hydrogen drives the pistons, to create new energy, and is then cooled and transferred back to be reheated, where the cycle repeats itself.

STM's units are expensive at $65,000 apiece, but each of its 4,000-pound power plants generates 55 kilowatts of electricity, enough to power 11 homes. Over the past year, STM has shipped 31 of its units to a wide variety of customers, including EcoMEET Solutions in Tokyo, which is using gas from chicken manure as a fuel source for STM's technology. In August, Ford Motor Co. started running one of STM's units for its truck plant in Wayne, Mich. It's converting paint emissions containing volatile organic compounds into an electricity source, in a project it's calling "Fumes to Fuel." "It's a great thing," says Mark Wherrett, Ford's principal environmental engineer. "We turn an environmental issue on its head and now use those environmental emissions to make electricity.''

--Julie Halpert

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