Big Plans for Biochar

At a repurposed 27-acre former U.S. Steel facility in the Iron Range town of Coleraine, researchers for the the University of Minnesota’s Natural Resources Research Institute, which is dedicated to tackling economic and environmental challenges, are producing biochar, a special carbon-rich charcoal. Dubbed the “Swiss knife” of climate tools by some, biochar has many environmental benefits including keeping carbon dioxide from entering the atmosphere, where it contributes to climate change.

“It’s a negative emissions technology that takes carbon out of the atmosphere, and then it’s sequestered and stored in an inert form—charcoal,” says Eric Singsaas, director of the NRRI materials and bioeconomy research group. Minnesota is a recognized leader worldwide in biochar research and usage, he says.

Biochar is created by heating organic waste in a low-oxygen environment, such as the industrial-size kilns used by the NRRI in Coleraine. The method limits emissions from the process while retaining much of the carbon in the biochar.

Biochar has many known uses and more under exploration. When added to the soil, it increases organic matter and helps the soil hold more water—a good thing for commercial crops and natural restorations alike. It can reduce greenhouse emissions in the steelmaking process. It shows promise in filtering stormwater.

One way the NRRI uses biochar is to support wildfire mitigation. In the Superior National Forest, balsam firs are thinned to cut fire risk. If left on their own, those piles of slash present their own fire hazard and slowly emit carbon. When turned into biochar, however, the carbon remains in the charcoal, which can then be used to enrich the soil.

Over at the city of Minneapolis, Jim Doten, carbon sequestration program manager, is a biochar evangelist spearheading the creation of one of the country’s first municipally owned biochar plants. When up and running, the new $1.5 million biochar plant near the University of Minnesota will process 3,600 tons of wood feedstock—sourced in part from trees trimmed by utility companies, including ash trees affected by emerald ash borer—to produce 500 tons of biochar annually.

Doten, who first used biochar to improve soil for farmers in Afghanistan when he was stationed there with the Army National Guard more than a decade ago, says that Minnesota’s experience with biochar is drawing attention from around the globe. In September, the U.S. Biochar Initiative will host the North American Biochar Conference in Minneapolis.

“What we’re doing has catalyzed urban biochar across the country,” says Doten, a member of the USBI board of directors. “It’s great to see approaches other major cities are starting to take. They’re coming to us to learn from what we’ve accomplished.”