A Thermoelectric Generator That Runs on Exhaust Fumes

Alphabet Energy ships a generator that runs on waste heat from industrial operations

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A Thermoelectric Generator That Runs on Exhaust Fumes
Image: Alphabet Energy

Alphabet Energy has designed a generator that uses no fuel. Instead, it uses racks of thermoelectric modules to convert the waste heat from industrial machines into electricity.

The Hayward-California based startup earlier this week introduced the E1, claiming that it is the first large-scale commercial thermoelectric generator on the market. The company is already taking orders from mining companies that have large amounts of waste heat and no use for it.

To set it up, a mining company needs to connect a flexible tube to direct exhaust from an engine into Alphabet Energy’s generator, which is packaged in a shipping container. The gases flow through 32 racks of thermoelectric modules that produce a direct current, which is inverted to alternating current and fed to the site’s breaker. A radiator cools the modules because they need a difference in temperature to produce current.

Alphabet’s generator can produce 25 kilowatts from the waste heat given off from an engine that generates 1000 kilowatts of electricity from fuel, such as diesel. The solid-state modules are designed to work for ten years and can be replaced as better materials are developed.

The company plans to target other industries with copious amounts of waste heat, including oil and gas as well as steel and glass manufacturing. 

Alphabet Energy originally set out to use a silicon nanowire material licensed from Lawrence Berkeley National Laboratory as the core material for its thermoelectric modules because it promised higher conversion efficiency than conventional materials, such as bismuth telluride. Earlier this year, though, it licensed a different class of materials called tetrahedrite from Michigan State University. Tetrahedrite is an abundant, naturally occurring mineral, which the company expects will work well over a broad set of temperatures, Alphabet Energy CEO Matthew Scullin told me earlier this year. 

Alphabet Energy also spent a number of years deciding on how to use thermoelectrics, which convert any source of heat into electricity. It decided to target large industrial companies because there’s the potential for substantial fuel savings, Scullin said in a statement

For the field of thermoelectrics, the release of the E1 is significant. Thermoelectric materials have been used for niche applications, such as portable coolers or in spacecraft, for many years, but waste heat as a power source offers much more potential. Automakers, for example, have researched thermoelectric modules to improve the fuel efficiency of cars by attaching thermal electric devices to engines and exhaust pipes.

Alphabet Energy is not the only company making progress in thermoelectrics. GMZ Energy, based in Waltham, Mass., last month introduced its first products which are based on a half-Heusler material. Rather than make its own generators, though, GMZ has development programs with different industries, including one with Honda for passenger cars.

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