U.S. manufacturers rely on more than 30,000 small industrial boilers to make a large number of things: foods, drinks, paper, chemicals, clothes, electronics, furniture, transportation equipment, and more.
The vast majority of these smaller boilers burn fossil fuels — mostly gas, but sometimes coal or oil. Their emissions contribute not only to climate change but to smoggy skies and elevated asthma rates, too.
Swapping out such boilers for electric industrial heat pumps would be a quick win for communities and regulators looking to improve air quality, said Hellen Chen, industry research analyst at the nonprofit American Council for an Energy-Efficient Economy, or ACEEE.
Only about 5% of process heat in industry currently comes from electricity, but industrial heat pumps are gaining some momentum. They’ve already been installed in at least 13 American factories, helping reduce pollution from brewing beer, pasteurizing milk, and drying lumber. Kraft Heinz, the famed ketchup and mac-and-cheese maker, plans to install heat pumps at 10 factories by 2030. Oat-milk producer Oatly is considering one at a New Jersey plant. And policymakers in Southern California passed a rule last summer to phase out industrial boilers, a move that will likely boost heat-pump replacements.
Industrial boilers spew a panoply of air pollutants as byproducts of combustion, including nitrogen oxides, or NOx. NOx is harmful in itself but also contributes to the formation of ozone, a key ingredient of smog that can inflame airways and cause a range of respiratory problems, especially in children whose lungs are still developing.
To identify opportunities to clean up air quality, Chen and ACEEE colleagues recently mapped areas where ozone levels exceed the U.S. Environmental Protection Agency standard, the number of small industrial boilers in each area, and the fuel they use. In total, they found that more than 5,400 boilers currently burn in 174 counties. The team focused on smaller industrial boilers, defined as having capacities up to 50 million British thermal units per hour, because their emissions are often overlooked, yet the equipment is the easiest to switch out for heat pumps, Chen said.
“In areas where the baseline community pollution burden is already high, there is a really important opportunity,” Chen said. Heat pumps are “a cleaner and more efficient technology that is ready for adoption today.”
Depending on the boiler size, fuel type, and other aspects, the reduction in onsite NOx emissions from swapping just one industrial boiler for a heat pump is equivalent to taking 400 to 10,000 cars off the road, by Chen’s calculation.
The industrial emissions reductions would add up. Some counties host large stocks of these smaller boilers: Cook County, Illinois, has 297; Philadelphia County, 127; Harris County, Texas, 123; and Los Angeles County, 111, per the ACEEE map.
Heat pumps are available now for low-temperature industrial processes, making them well-suited to industries like food and beverage manufacturing, which relies almost exclusively on heat below 266 degrees Fahrenheit (130 degrees Celsius). Low-temperature heat also plays a significant role in areas like chemicals and paper production.
