The City of Minneapolis has officially begun construction on North America's first city-owned biochar facility. The project aims to transform 3,000 tons of wood waste annually into 500 tons of biochar while sequestering an estimated 3,700 tons of carbon dioxide, the equivalent of removing nearly 800 cars from the road.
Expected to become operational in fall 2025, the facility represents a significant investment in urban climate resilience and sustainable waste management.
From concept to construction
The facility, located at 670 25th Ave. SE, marks a culmination of years of planning and collaboration, led by James Doten, Carbon Sequestration Program Manager for the City of Minneapolis. Doten's work on biochar began during his time as a hydrologist in Afghanistan, where he explored soil restoration techniques using biochar to improve agricultural outcomes.
Upon his return to Minneapolis, Doten proposed biochar as a solution to urban environmental challenges, particularly in the city's Green Zones, where food insecurity and degraded soils are prevalent. In collaboration with the Shakopee Mdewakanton Sioux Community (SMSC), the city conducted early biochar trials, mixing biochar with compost to rejuvenate nutrient-poor soils in community gardens.
"We worked with community groups to grow pre-European contact seed lines following native traditions," Doten said. "The biochar mix helped retain moisture and nutrients, reducing the need for synthetic fertilizers and supporting crop health."
Biochar's potential as a substrate additive in vertical farming systems
Biochar shows potential as a substrate additive in vertical farming systems, particularly those using hydroponics or soilless growing methods. A recent study in Mexico demonstrated how a 50% biochar mix in hydroponic systems significantly improved yields in habanero chili cultivation.
Doten acknowledges biochar's broader potential. "We plan on using biochar in urban agriculture, green spaces, forestry, and wastewater projects, but expanding its use to other controlled environment systems is a potential consideration as production scales up."
Urban feedstock and sustainable supply chains
The Minneapolis biochar facility will source its feedstock from local partners, including Xcel Energy, Hennepin County, and the Minneapolis Parks Board. These partnerships ensure a sustainable supply of woody biomass, addressing the influx of tree waste caused by the Emerald Ash Borer crisis.
"We have a feedstock agreement with Xcel Energy for line maintenance waste and are negotiating similar arrangements with other regional entities," Doten explained. "Even with the Emerald Ash Borer crisis, we have a sustainable source of woody material."
Environmental benefits and climate action
Beyond agriculture, biochar's porous structure makes it effective for stormwater filtration, capturing pollutants and excess nutrients from urban runoff. This application complements the city's efforts to enhance urban water quality and build climate resilience. This facility serves as a model for other cities looking to integrate biochar into urban waste management and climate resilience strategies. Doten sees this project as a blueprint for municipal innovation. "This facility shows that cities can take meaningful action on climate change while creating green jobs," he said. "We're not just reducing emissions, we're building climate resilience and enhancing local food production."
The broader implications of biochar's carbon-sequestering properties are emphasized by Myles Gray, Executive Director of the United States Biochar Initiative (USBI). "This project represents something tangible that cities can do to mitigate climate emissions while also more effectively managing biomass waste," Gray said. "Tree pruning material is a major source of biomass waste in most US cities. While some of this material is used locally as mulch, most of it is sent to landfills, biomass energy, or composting facilities, where it is eventually converted back into carbon dioxide in the atmosphere. By converting this material into biochar, the carbon is sequestered for thousands of years."
The upcoming 2025 North American Biochar Conference, hosted by USBI, will further explore these applications, highlighting biochar's evolving role in carbon markets, infrastructure, and advanced agricultural systems.
For more information:
U.S. Biochar Initiative
www.biochar-us.org
City of Minneapolis
James Doten, Carbon Sequestration Program Manager
www.minneapolismn.gov