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  • Jessica Zimmer

Better Biochar is a Climate Change Antidote

Across the Pacific Northwest, 40 producers, engineers, and scientists are working together to better understand the use of biochar - charcoal produced from plant matter. Their goal is to advance a research and development program to encourage the production and higher use of biochar as it can reduce greenhouse gas emissions and withdraw CO2 from the atmosphere.

In 2022, the U.S. market for biochar is expected to be $341.1 million, according to a report from Global Industry Analysts, Inc., a California-based market research company.

biochar production
Credit: VectorMine

“There are a number of different ways to create biochar. We want to emphasize the need to maximize climate change mitigation with its use,” said Dr. Jim Amonette, geochemist at the Pacific Northwest National Laboratory. Amonette is also an adjunct research professor of soil chemistry at the Center for Sustaining Agriculture and Natural Resources at Washington State University.

The four primary technologies to make biochar are a portable flame cap kiln, a low-tech method with 25% to 55% carbon efficiency, an air curtain incinerator with high throughput but only 5% to 15% carbon efficiency, a slow pyrolysis kiln, which has 50% to 55% carbon efficiency, and gasifiers, with carbon efficiencies that range up to 60%.

“The biochar created from all of these processes is similar. We’re trying to make the best technologies available at the lowest cost to the most people. One way to do that is for people interested in creating biochar to pool resources. They can buy a large efficient system and run it with the material they collect,” said Amonette.

Virtual workshop, real report

In 2020, Amonette and his colleagues organized a virtual workshop with biochar producers and engineers. The group brainstormed how to implement biochar technologies in the Pacific Northwest. Federal and state funding supported both the workshop and resulting report, Biomass to Biochar: Maximizing the Carbon Value.

It can be hard to encourage biochar production because state and federal agencies have trouble regulating biochar processes.

biochar research
Researchers test whether the addition of biochar helps establish vegetation at the Formosa Mine Site in Oregon. Credit: Kristin Trippe

It’s easier to burn a large pile of wood and other plant material than only a little bit at a time. Yet burning that much at once results in soot and methane. In addition, a small-scale producer who wants to create biochar has to get a U.S. EPA Title V permit. Testing for (that) costs up to $50,000 per year, (which) is prohibitive,” said Amonette.

One solution is to get agriculture and forestry producers to sell their residual biomass to larger entities like companies that make and use biochar commercially. For example, biochar is a primary ingredient in many different potting mixes.

“After that, we need to know who buys biochar. The list includes cannabis cultivators, “truck gardeners,” who grow produce on the outskirts of cities, master gardeners, and a few commodity crops, (like) wheat (and) corn, farmers,” said Amonette.

Biochar tends to be alkaline, which is not good for plants. However, composting helps decrease biochar's alkalinity, and in turn, the biochar helps minimize greenhouse gas emissions during composting.

Biochar can also be used in concrete to substitute aggregate materials like gravel and sand. It can be added to asphalt for highway construction too.

“Our workshop recommended a long-term national study involving 20 field sites with several in the Pacific Northwest. We want to see what solutions are financially and logistically feasible to collect and create biochar in Oregon and Washington,” said Amonette.

Amonette said the group is currently gathering support and potentially funding for the study from federal agencies and private foundations.

“The potential cost of a national study would be approximately $150 million a year for ten years. We’d gather crop yield and carbon offset information from growers using biochar. Then we’d follow their progress over the next few decades,” said Amonette.

Amonette said due to the cost, biochar supply exceeds demand. Carbon credits for biochar could help change this.

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“Ultimately, we’re limited by the amount of biomass available to create biochar. Most of it is already spoken for. We have to be careful about how much plant material we take out of the forests, in particular,” said Amonette.


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