DUAL BENEFIT

We have not made as much progress towards slowing climate impact as we had hope from years ago so I think [biochar] is gaining attention because of the climate impact.”

Eric Singaas

Audio

Dual Benefit_Allie Johnson.mp3

Minneapolis will soon be able to produce its own biochar, bringing the city one step closer to its goal of becoming carbon neutral by 2050.
This spring, the city will break ground on a new biochar facility – the first municipally owned and operated such facility in the U.S.
Biochar production is a carbon-negative process, meaning it removes more carbon from the atmosphere than it releases, said Eric Singaas, leader of the materials and bioeconomy research group at the University of Minnesota’s Natural Resources Research Institute. To limit carbon emissions, tree waste is heated in a low-oxygen environment like an industrial kiln, rather than burned. The result is a charcoal-like material that can store carbon for thousands, if not tens of thousands, of years, he said.
Jim Doten, Minneapolis’ carbon sequestration manager, calls biochar the “swiss army knife of climate tools.”
Biochar production provides a sustainable alternative to dealing with tree waste, which cities like Minneapolis have in oversupply due to things like utility line maintenance and emerald ash borer disease, he said.
But biochar itself has a myriad of different uses. When added to the soil, biochar helps soil retain nutrients and hold water, boosting plant growth and improving drought resilience, according to Singaas. It can also be used for filtering stormwater and in construction materials. For example, mixing biochar with cement can create a more durable concrete, he said.
“In every case, there’s a dual benefit,” said Singaas. “One is that long-term carbon storage and two is some other environmental benefit, whether it’s cleaning water or making materials stronger or some other job.”

EQUIVALENT OF TAKING 789 cars off road
Doten was the first to push Minneapolis to start using biochar. Since 2013, it has been used in various applications throughout the city, primarily mixed with compost in community gardens and boulevards, but also incorporated into stormwater mitigation projects to help prevent pollutants from getting into lakes and rivers.
Doten purchased the biochar for the city from a vendor in Missouri. But for Minneapolis to continue to use biochar, he needed a local source.
“It’s a great way to demonstrate [biochar], but you reduce the climate benefits when you have to truck it across the country,” Doten said.
Enter the city’s new biochar production facility.
Xcel Energy will be the primary supplier of the facility. The company plans to donate the wood waste from its routine tree trimming around power lines throughout the city. Doten said he is also in talks with Hennepin County and the Minneapolis Park Board to take their wood waste for use at the new facility.
Once it is up and running, the facility will have the capacity to process over 3,000 tons of wood waste and produce over 5,000 tons of biochar annually. That amount of biochar production will remove an estimated 3,700 tons of carbon dioxide from the atmosphere – the equivalent of taking over 789 cars off the road, according to a news release.

NOT NEW BUT GAINING ATTENTION
Biochar is not new. The practice can be traced back thousands of years to indigenous communities in regions around the world, said Doten. But biochar is experiencing a surge in popularity as communities seek ways to address climate change.
“We have not made as much progress towards slowing climate impact as we had hoped from years ago so I think [biochar] is gaining attention because of the climate impact,” Singaas said.
Doten said Minneapolis plans to sell biochar produced at its facility to other cities and counties in the Twin Cities metro, as well as state agencies like the Minnesota Department of Agriculture and the Minnesota Department of Transportation to use in their own projects.
“We’re not trying to displace private industry,” he said. “We’d like to get this up and established as a practice so people know how to do it so that there is a demand for private businesses to make biochar and make it into a green industry in Minnesota and better use our wood waste.”
Minneapolis has become a leader in urban biochar application, and cities around the world are taking notice. Doten said he has been contacted by officials in Buenos Aires, Argentina and Nairobi, Kenya who are interested in starting their own biochar programs. Doten also sits on the board of the U.S. Biochar Initiative, which will host its North American Biochar Conference in Minneapolis in September.
Minneapolis’ biochar facility will be located at 670 25th Ave. SE near the University of Minnesota campus. Doten expects biochar production to be underway by late summer or early fall.