A Thermoelectric Generator That Runs on Exhaust Fumes

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

2 min read
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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Smokey the AI

Smart image analysis algorithms, fed by cameras carried by drones and ground vehicles, can help power companies prevent forest fires

7 min read
Smokey the AI

The 2021 Dixie Fire in northern California is suspected of being caused by Pacific Gas & Electric's equipment. The fire is the second-largest in California history.

Robyn Beck/AFP/Getty Images

The 2020 fire season in the United States was the worst in at least 70 years, with some 4 million hectares burned on the west coast alone. These West Coast fires killed at least 37 people, destroyed hundreds of structures, caused nearly US $20 billion in damage, and filled the air with smoke that threatened the health of millions of people. And this was on top of a 2018 fire season that burned more than 700,000 hectares of land in California, and a 2019-to-2020 wildfire season in Australia that torched nearly 18 million hectares.

While some of these fires started from human carelessness—or arson—far too many were sparked and spread by the electrical power infrastructure and power lines. The California Department of Forestry and Fire Protection (Cal Fire) calculates that nearly 100,000 burned hectares of those 2018 California fires were the fault of the electric power infrastructure, including the devastating Camp Fire, which wiped out most of the town of Paradise. And in July of this year, Pacific Gas & Electric indicated that blown fuses on one of its utility poles may have sparked the Dixie Fire, which burned nearly 400,000 hectares.

Until these recent disasters, most people, even those living in vulnerable areas, didn't give much thought to the fire risk from the electrical infrastructure. Power companies trim trees and inspect lines on a regular—if not particularly frequent—basis.

However, the frequency of these inspections has changed little over the years, even though climate change is causing drier and hotter weather conditions that lead up to more intense wildfires. In addition, many key electrical components are beyond their shelf lives, including insulators, transformers, arrestors, and splices that are more than 40 years old. Many transmission towers, most built for a 40-year lifespan, are entering their final decade.

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