This is an excerpt from EERE Network News, a weekly electronic newsletter.

May 29, 2002

Companies Developing Alternative Home Power Technologies

Two new technologies for distributed generation — Stirling engines and liquid-injected cogeneration — have recently appeared on the horizon, although commercial plans for both technologies remain several years in the future.

Ocean Power Corporation claims to have developed a home energy system that uses a Stirling engine to generate up to 3 kilowatts of electricity while also providing hot water, space heating, and air conditioning. The company claims to have established the conditions for the sale of 10,000 units to a private real estate management company. Upon completion of performance and code compliance certifications, Ocean Power intends to install the units in late 2005, at a cost of about $3,800 per unit. Ocean Power currently has a unit being tested in Norway and plans to have tests performed by EPRISolutions, a subsidiary of the Electric Power Research Institute. See the press release, unit description, and frequently asked questions on the Ocean Power Web site.

Stirling engines are a form of external combustion engine. Since they can be driven by a wide range of external heat sources, they are also known as heat engines. For more information, see the California Energy Commission's Distributed Energy Resource Guide.

The second technology, liquid-injected cogeneration, is being developed by the U.S. Army Soldier Systems Center and Yankee Scientific, Inc. It involves pumping water to a high pressure, heating it with a conventional oil or gas burner, and then expanding it to steam, which is used to drive a turbine. The exhaust steam from the turbine provides the energy for space heating and hot water. Although the Army developed the system for its field kitchens, a spin-off company plans to invest $5 million over the next three years to develop a residential version of the system. See the U.S. Army press release.