Is Biochar a Climate Friendly Solution for Western Fire Protection?
This story is part of The Salt Lake Tribune’s ongoing commitment to finding solutions to Utah’s biggest challenges through the work of the Innovation Lab.
It’s a new technology, but it’s been around for centuries. It is made fiery hot, but not burned. It sequesters carbon dioxide, but you have to release carbon dioxide to make it.
These are the contradictions of biochar. The charcoal-like material continues to fascinate as a possible player in everything from limiting climate change to boosting food production.
Biochar is wood waste or other plant material that has been heated in a low-oxygen environment. The absence of oxygen prevents the material from releasing carbon dioxide, which causes climate change. When producing biochar, the carbon remains locked in the material and the material becomes more useful. In particular, biochar can be added to the soil to make it hold more water and become more agriculturally productive.
“Biochar isn’t a silver bullet, but it’s absolutely fundamental,” said John Webster, communications director for Salt Lake City-based US Biochar Initiative, a nonprofit organization dedicated to advancing the production and use of biochar.
If biochar is a key technology, it is underused. And that prompted biochar advocates to hold a “charpolooza” at the Tooele County landfill on Wednesday to demonstrate three devices used to make it.
In Utah and the west, the greatest opportunity for biochar comes from forests that are crowded with wood that fuels wildfires. More than a century of firefighting combined with a more oxidizing climate makes forested areas vulnerable to massive wildfires.
Forest managers handle hazardous fuels in a variety of ways, including removing vegetation and collecting them in “log piles”. In the past, these piles were either burned, releasing large amounts of carbon dioxide, or left alone, where they slowly rot and release their carbon dioxide over time.
The dumps are still burned to produce biochar from the slash and burn land, but the burning is done in furnaces that limit oxygen. About a fifth of the carbon dioxide is still released, mostly from the top of the burning material. But deep inside the kilns, where there is heat but little oxygen, pyrolysis takes place, breaking down the material without burning it and trapping the other 80% of the carbon dioxide in the charred material left behind. This material is biochar.
From a climatic point of view, biochar represents a compromise. The carbon dioxide released during production is theoretically more than offset by the carbon remaining in the biochar. And it will stay in the biochar for hundreds of years longer than if the material were just left to rot.
“We can find charcoal that’s 400 or 500 years old” left behind by Native Americans, said Debbie Page-Dumroese, a soil scientist at the US Forest Service who has worked on developing biochar. This charcoal contains carbon dioxide that would have been released if it had not been burned.
Biochar has been analyzed for years as a possible solution to not only sequester carbon but also improve soil health. The deep black material is light and porous. When added to soils, it increases water and nutrient retention. It was also added to livestock feed to improve animal digestion.
But there has been much debate as to whether the carbon dioxide in biochar really stays trapped. If not, then it is not an effective climate strategy.
“In reality, the science of biochar is far from a consensus point, with some studies actually challenging the entire premise,” says a report from Desmog, a Canadian website that challenges what it sees as flawed climate solutions . “Additionally, well-meaning biochar advocates have seen their optimism coupled with individuals and companies – including Big Oil – poised to reap big profits before the science settles on the risks and implications.”
Page-Dumroese acknowledges that when using biochar as a soil amendment in agriculture, it is less clear how long the carbon will remain sequestered when the soil is turned over and new crops are planted. But if it’s produced and stored in the forest, she’s confident the carbon will remain locked in.
“In forested areas that’s a settled question,” he said, “the charcoal will stay there for centuries, and so will the carbon.”
And it helps the forest floor much like wildfires do, she adds.
At Wednesday’s event, three different furnaces were used to turn garden waste into biochar at the landfill. All three kilns have one thing in common: they are portable. This means they can take the kilns to waste instead of taking the waste to the kilns.
Page-Dumroese has worked with a Florida company, Air Burners Inc., to develop the “CharBoss,” a truck-sized kiln that can be continuously charged. The machine produces the biochar and then cools it down so that it can be landfilled without the risk of fire. Air Burners has filed patents and begun marketing the CharBoss.
Darren McAvoy, a former “hotshot” firefighter who fought the 1988 Yellowstone Park fires and now a professor at the Utah State University Extension, created the “Big Box” stove, which is small enough to fit behind a man being towed by a pickup truck. The dumpster-sized, low-tech metal box is double-walled to protect workers and increase efficiency. McAvoy, who directs the Utah Biomass Resource Group at USU, said about a dozen kilns have been built to his design, including one used by the Harvard University Arboretum.
McAvoy has no patents on the device and is happy to share the design with others. “I think we need to recognize all the values of biochar. Right now it’s cheaper to burn heaps.”
And for even smaller jobs, another inventor, Kelpie Wilson, made the Ring of Fire stove small enough to disassemble and fit in a truck bed. Their market includes farmers who want to burn their crop residues and property owners who want to clear brush and produce biochar instead of just burning it.
Tim Fitzpatrick is a renewable energy reporter for The Salt Lake Tribune, a position funded by a grant from Rocky Mountain Power. The Tribune retains overall control of editorial decisions independent of Rocky Mountain Power.