Lasers could help cut CO2 emissions from Maine’s paper and pulp mills

This story was first published by Energy News Network.

A Massachusetts university is developing technology that aims to use lasers to drastically cut emissions and energy use from Maine’s paper and pulp industry.

Worcester Polytechnic Institute recently received a $2.75 million U.S. Department of Energy grant to help ready the industrial drying technology for commercial use.

“We are all excited about this — this is potentially a groundbreaking technology,” said Jamal Yagoobi, founding director of the institute’s Center for Advanced Research in Drying.

In Maine, the paper and pulp business generates about 1 million metric tons of carbon dioxide emissions each year, roughly half of the state’s industrial emissions. Much of these emissions result from the process of drying mashed, pressed, and rolled wood pulp to yield paper products. The emissions come mainly from three major operations across the state; three additional facilities contribute smaller amounts.

These plants’ emissions will need to be addressed if Maine is to reach its goal of going carbon neutral by 2045. Furthermore, each of these plants is located in an area with an above-average population of low-income residents, according to data assembled by Industrious Labs, an environmental organization focused on the impact of industry. And two are located in areas with a higher-than-average risk of cancer from air toxins, suggesting a correlation between their operations and the incidence of cancer in the area.

At the same, the paper and pulp industry remains economically important to Maine, said Matt Cannon, state conservation and energy director for the Maine chapter of the Sierra Club.

“It’s got real union jobs — the paper industry is still very important to our community,” he said.

Worcester Polytechnic’s drying research center has been working on ways to dry paper, pulp, and other materials using the concentrated energy found in lasers. The lasers Yagoobi’s team is using are not the lasers of the public imagination, like a red beam zapping at alien enemies. Though the lasers are quite strong — they can melt metal, Yagoobi says — they are dispersed over a larger area, spreading out the energy to evenly and gently dry the target material.

Testing on food products has shown that the technology can work. Now, researchers need to learn more about how the laser energy affects different materials to ensure the product quality is not compromised during the drying process.

“For paper, it’s important to make sure the tensile strength is not degrading,” Yagoobi said. ​“For food products, you want to make sure the color and sensory qualities do not degrade.”

Therefore, before the system is ready for a commercial pilot, the team has to gather a lot more data about how much laser energy is present on different parts of the surface and how deeply the energy penetrates different materials. Once gathered, this data will be used to determine what system sizes and operating conditions are best for different materials, and to design laser modules for each intended use.

Once these details are worked out, the laser technology can be installed in new commercial-scale drying equipment or existing systems. ​“This particular technology will be easy to retrofit,” Yagoobi said.

Industrial sources were responsible for about 1.3 billion metric tons of carbon dioxide emissions in the United States in 2023, about 28% of the country’s overall emissions, according to the U.S. Energy Information Administration. Heating processes, often powered by natural gas or other fossil fuels, are responsible for about half of those emissions, said Evan Gillespie, one of the co-founders of Industrious Labs. Many industrial drying processes require high temperatures that have traditionally been difficult to reach without fossil fuels, giving the sector a reputation as hard to decarbonize, Gillespie said.

“The key challenge here is: How do you remove natural gas as a heating source inside industrial facilities?” said Richard Hart, industry director at the American Council for an Energy-Efficient Economy. ​“The scale of what is happening in industry is enormous, and the potential for change is very powerful.”

To make the new technology effective, industry leaders and policymakers will need to commit to reinvesting in old facilities, Gillespie noted. And doing so will be well worth it by strengthening an economically important industry, keeping jobs in place, and creating important environmental benefits, he added.

“There’s often this old story of tensions between climate and jobs,” Gillespie said. ​“But what we’re trying to do is modernize these facilities and stabilize them so they’ll be around for decades to come.”