Michael Kanellos 11 17 09, 8:23 PM

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Renewable Energy for $1 a Watt? Yes, Says Alphabet Energy

SAN FRANCISCO -- Alphabet Energy, a Lawrence Berkeley National Labs spin-out with a semiconductor that converts heat directly into power, says it can make devices that will produce power at close to $1 a watt.

Traditional waste heat converters cost around $20 a watt and are made out of bismuth telluride. Alphabet won't say what it's semiconductor is made from, but sources say it is silicon nanowires.

The company, one of the finalists for the Cleantech Open, hopes to get a prototype plant running in about 18 months. Potentially, it could move into mass manufacturing 18 months to two years after that. The chips will be bought mostly by industrial manufacturers first, where the material could be wrapped around hot steam pipes. Later, it could move into the auto industry, but the amount of heat and often lower temperatures could make that a challenge.

The U.S. consumes around 100 quads (100 quadrillion BTUs) of energy a year and 55 to 60 quads get dissipated as waste heat, according to Arun Majumdar, the UC Berkeley professor who came up with a lot of the technology behind Alphabet. He now runs ARPA-E, the advanced projects group inside the Department of Energy.

GMZ Energy, Promethean Power and Cypress Semiconductor are all also experimenting with thermoelectric devices and various semi materials like gallium. GMZ and Cypress want to turn heat into power while Promethean converts electricity from PV panels directly into heat.

MC10 and Photonic Devices recently received grants from ARPA-E to develop, respectively, waste heat semiconductors from silicon nanotubes and what silicon nanowires.

Companies such as Recycled Energy Development (RED) and Ormat have successfully retrofitted factories to capture waste heat, but they largely rely on mechanical engineering. Heat is captured and then channeled into productive uses. One of RED's showcase projects coming next year is a system at West Virginia Alloys, a silicon manufacturer, that will generate 45 megawatts of electrical power from the waste heat generated by factory operations. The company uses 120 megawatts right now: The waste heat system will effectively allow Alloys to recover about one-third of the power it now buys but wastes.

Replacing mechanical systems with semiconductors, potentially, will be the next wave for the industry.

Waste heat – we love it around here.