Clean Energy’s Best-Kept Secret: Waste Heat Recovery
Recycling the heat that spews from industrial smokestacks may be one of the biggest opportunities for reducing greenhouse gas emissions, yet not many climate-savvy entrepreneurs are aware of it. When it comes to energy conservation, “[b]y and large, the world ignores the biggest, single most cost-effective, most profitable thing to do, which is recycle the energy that we’re wasting,” says Thomas Casten, chairman of the Illinois-based company Recycled Energy Development (RED).
Of the 500,000 smokestacks in the United States, the 47,500 stacks that produce waste heat above 260 degrees Celsius (500 degrees Fahrenheit) could produce at least 50,000 megawatts of power, says Casten. That’s almost half the energy produced by the U. S. nuclear fleet, he notes. Companies like RED and its competitors, Cain Industries and GTS Energy, Inc., all work to help develop waste heat recovery in the United States.
RED retrofits smokestacks with “waste-heat recovery boilers” that use the stack’s heat to produce steam to spin a turbine and generate electricity. The company uses similar technology to develop new, localized power plants that are at least two times as efficient as the average U.S. electric utility plant. According to Sean Casten, president and CEO of RED, the United States could conceivably continue producing the same amount of energy it does now, with half the fossil fuel, by recycling the waste heat from its factories and electric generating stations.
Thomas Casten says most people think of vehicle emissions as the leading driver of global warming, but in reality 69 percent of U.S. greenhouse gas emissions come from heat and power production, and a mere 18 to 19 percent from vehicles. The heat and power sector is so inefficient, he explains, that it is like being “in the forest products business, and you just leave every fourth tree in the forest. Cut it down and just leave it there to rot.”
It typically takes three to four years for RED’s projects to make back their initial investment in the heat-recycling equipment, a roughly 35 percent return. But the practice is not widespread, Casten says, because most businesses do not take time to consider what they can do with their waste products—in this case, heat. In many states, there are also barriers to selling electricity back to the grid or directly to another business, so if a factory uses its waste heat to produce more power than it can use, it can be difficult to sell the excess, making the process less lucrative.
“We have gotten caught up in yesterday’s technology, yesterday’s rules, and yesterday’s goals,” Casten says, stressing the imperative of informing more people about the obstacles to waste heat recovery. Changes in state and national legislation that promotes recycled energy are also necessary, he says. “Climate change mitigation is a huge economic opportunity. Our trading partners are pursuing greater efficiency, and they’re finding that in the process they’re becoming more competitive and taking manufacturing jobs away from the U.S.”
This story was produced by Eye on Earth, a joint project of the Worldwatch Institute and the blue moon fund. View the complete archive of Eye on Earth stories, or contact Staff Writer Alana Herro at aherro [AT] worldwatch [DOT] org with your questions, comments, and story ideas.