The result is more energy for every dollar spent on fuel or utility-provided electricity.
Waste-heat recovery is part of a basket of technologies that harvest “opportunity fuels” — usually byproducts of the energy-consuming firm’s main product.
Aside from systems like RED’s, methane from farms and wastewater treatment plants that is used for powering turbines, as well as refining plant and animal fats from food processing into transportation fuels, could be considered “opportunity fuels.”
Unlike installing rooftop solar panels, each potential waste-heat reduction project is different and requires different technology.
“You need to get the modeling right,” says Anissa Dehamna, an analyst with boutique cleantech research firm Pike Research. “A lot of these projects are going to be bespoke.”
“It’s not really a [single] technology, it’s more of an approach,” Casten says, and often means more time spent on making sure heat isn’t lost in the recovery process, rather finding the right turbine.
He adds that every project ultimately depends on the primary use of the energy. “Do you want to do one job with each fire, or do we want to do two?” he asks.
Waste-heat solutions firms like Casten’s see the biggest benefit to the heaviest industries first — steel, glass and cement producers, for example.
But utilities and power-plant operators could also benefit. RED competitor Echogenis currently working on a test facility to harvest 250 kilowatts of energy from a power plant in Columbus, Ohio, owned by AEP.
The U.S. Department of Energy estimates that each year the nation’s power plants lose over 200 gigawatts of energy from wasted heat — about the equivalent capacity of 100 Indian Point, N.Y.-sized nuclear power plants.
Payback time would vary greatly; firms like Echogen, for instance, say they can recover costs in under three years.
That short time frame is critical, says Dehamna, because “if the payback period is over five years, as a business owner I’m likely not going to consider it.”
But Casten says the real benefit to energy-intensive commodity producers, like steel or glass, could be in their margins.