Waste heat from combustion could power 11.4 million U.S. homes a year

alphabet energy waste heat
Video screen capture Alphabet Energy / YouTube

Engineers at Berkeley, California start-up Alphabet Energy have developed a cutting-edge renewable energy device that taps the energy from an often over-looked source: waste heat.

Now, we've definitely seen technologies before that harness energy from waste heat, but according to Berkeley Engineer, Alphabet's devices are the most efficient thermoelectric devices ever created and the company is setting their sights on major sources of waste heat -- combustion exhaust from power plants and vehicles.

“Waste heat is everywhere,” said CEO Matt Scullin. “It is an absolutely huge opportunity.”

Approximately two-thirds of all energy produced is lost as heat. Global energy consumption is around 104,000 terwatt hours, which means 208,000 terwatt hours are lost as heat. Scullin estimates that if even just 5 percent of that waste heat was converted into electricity at the cost of 10 cents per kWh, that's a $1 trillion a year industry.

Just in the U.S., if waste heat recovery devices were used at every oil, gas and manufacturing plant, 11.4 million homes could be powered by the electricity produced and it would have the bonus benefit of offsetting the need for the same amount of energy to be produced using fossil fuels.

The cornerstone of Alphabet's technology is the PowerCard, a small device the size of a tortilla chip that contains a common and cheap mineral called tetrahedrite. The PowerCard is made to be used with heat exhaust at temperatures between 572 and 1112 degrees Fahrenheit. One PowerCad can generate 9.2 watts of power simply by being exposed to pressurized hot air.

The PowerCards can be used individually, but they also come together up to 100-strong in the company's PowerModule, which is a fully-enclosed thermoelectric generator about the size of an extra-large pizza box. The PowerModule can be used in vehicles or for industrial use. In a vehicle, the device could be placed directly in the exhaust system with hot air going in one end and out the other all while it converts the waste heat into electricity that is fed back into the vehicle, bumping up the mileage by 5 percent.

Alphabet has already signed a commercial contract with an automaker to provide waste heat recovery for its vehicles, though the deal is still under wraps.

For larger applications, the company has the E1 system that is built into an ocean freight-sized container and suited for heavy manufacturing and larger industrial waste heat conversion. The PowerCard design allows Alphabet to create modular and customized devices for different uses.

The big task ahead for Alphabet is to get the technology to an efficiency and at a scale where the cost of generating electricity from waste heat is cheaper than the cost of retail electricity.

Tags: Renewable Energy | Technology | Waste


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