Farmers And Environmentalists Alike Are Excited About Biochar
5:34 minutes
This article is part of The State of Science, a series featuring science stories from public radio stations across the United States. This story, by Murray Carpenter, was originally published by Maine Public.
In a former biomass plant in Greenville, wood chips are flowing from hoppers into long tubes about three feet in diameter.
Pat Jones is the president of Clean Maine Carbon, which burns wood in high-temperature, low-oxygen conditions known as pyrolysis.
“It starts out as wood” he said. “And as you can see when we come over here what comes out the other end is biochar.”
In the quest for climate solutions, Jones is among the Maine entrepreneurs banking on this charcoal-like substance. They say it can bind up carbon for decades, and improve agricultural soils at the same time.
The end product has high carbon density, and is very stable, so less of the carbon will be released into the atmosphere than if it were left to decompose. So while Jones is making biochar, his business plan is focused on selling carbon credits to corporations.
“So somebody will say, ‘Would you like to sell credits to XYZ company?’ And we’ll say, ‘Yeah, what’s the price?’ They will pay on a per-ton basis, whatever the agreed value, based on carbon content and everything else,” Jones said. “And that’s the end of it, they never get the biochar and they don’t do anything. They get to use those credits to help reduce their footprint, their carbon footprint.”
Most of the biochar Jones has sold from the Greenville plant has been for agricultural applications. And he’s not yet certified to sell carbon credits, but pending the completion of an audit, he said he’ll be able to sell credits even on the biochar he’s already shipped.
Scientists and advocates debate the true value of carbon sequestration as a response to climate change. Jonathan Foley is executive director of Project Drawdown, a nonprofit that focuses on science-based climate solutions.
Foley says 95% of climate solutions should focus on reducing emissions by driving more efficient cars, for example, or insulating houses. But he said there’s also value in removing carbon from the atmosphere. And while there’s no silver bullet, biochar could be seen as a piece of silver buckshot.
“And we can put that in farm fields, we can bury it in old mines, we can bury it in the ground, and it should last for hundreds, if not thousand of years under the right circumstances,” Foley said. “So it’s a pretty clever kind of hybrid of nature and some engineering that might be a pretty good little piece of silver buckshot.”
And researchers are looking for ways to put biochar to use. As a soil additive, for example. University of Maine associate professor YongJiang “John” Zhang said the physical structure of biochar allows it to hold water like a sponge during periods of heavy precipitation, and release it slowly. It can also hold nutrients, and Zhang said these qualities can be beneficial when applied to the sandy soils of blueberry barrens.
“But if you have the biochar, it can hold more water, and hold the nutrients to increase the water use efficiency, and nutrient use efficiency,” he said.
Zhang said other research is looking at biochar’s benefits to potato crops, and its ability to lock up particles of PFAS in contaminated fields and prevent them from being taken up by plants.
Jones said he plans to produce about 1,200 tons of biochar annually with the current setup. But he’d like to scale up, using more and bigger equipment, to create more biochar and also put the excess heat from the process to work.
“So that it becomes more economical and practical to extract hot air and hot gasses for lumber drying for power generation, any number of things that could be done with this very clean, high-temperature gas,” he said.
Meanwhile, a second biochar facility, Standard Biocarbon in Enfield, hopes to start production in the next few months, and aims to produce about 1,200 tons annually.
Segment Guests
Murray Carpenter
Murray Carpenter is a science journalist in Portland, Maine.
Segment Transcript
IRA FLATOW: This is Science Friday. I’m Ira Flatow. And now it’s time to check in on the state of science.
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SPEAKER 1: This is–
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IRA FLATOW: Local science stories of national significance– on this program, we are always on the lookout for climate change solutions. And we found one way up in Maine, where some entrepreneurs are banking on biochar. This is a charcoal-like substance. It’s been used for centuries to enhance soil. And recently, it’s gained appreciation for its carbon capturing properties.
Joining me to talk about biochar is Murray carpenter, Science Journalist based in Belfast, Maine. He reported this story from Maine Public Radio. Welcome back to Science Friday, Murray.
MURRAY CARPENTER: Thanks, Ira. Glad to be here.
IRA FLATOW: All right. So tell me how you make biochar. What is it?
MURRAY CARPENTER: Well basically, I visited this plant where they’re making biochar up in Maine’s North Woods in Greenville near Moosehead Lake. And what they do is they take woodchips, like low-value wood products that might be left over from lumber production or the tops and limbs from pulpwood production. And it goes into a hopper, and then it goes into an oven. And it’s burned at very high temperatures, like up to 2,000 Fahrenheit and low oxygen conditions. This is called pyrolysis. And so the woodchips go in at one end.
And Pat Jones, President of Clean Maine Carbon– he described it to me this way.
PAT JONES: It starts out as wood, and as you could see when we come over here, you can see what comes out the other end is biochar, which is very high carbon, very porous, very good for agriculture. And so we turn nice white woodchips into black carbon.
IRA FLATOW: And then what do you do with it?
MURRAY CARPENTER: Well, that’s the interesting thing. Biochar seems to have some pretty good agricultural properties. It’s inert, and it’s stable. I mean, scientists call it recalcitrant. So basically, it wants to stay in its carbon form for a long time. But increasingly, people in Maine are looking at it as an agricultural amendment.
IRA FLATOW: So it stores the CO2 that was in the logs or the woodchips. And so a lot of it’s not released back into the atmosphere.
MURRAY CARPENTER: Yeah. You’re basically pulling this carbon out of the carbon cycle for some period. It may be decades, it may be centuries. But you’re pulling it out of the carbon cycle for a long time. It’s not immediately going up into CO2, or at least less of it is. Of course, there’s some CO2 generated in burning and some in transportation.
Yeah, increasingly people are hoping it will be used as an agricultural amendment. And I talked to Jonathan Foley. He’s the director of Project Drawdown. And they’re looking at science-based climate solutions. And he basically thought that biochar– it’s not a silver bullet as a climate solution, but it’s sort of a piece of silver buckshot.
JONATHAN FOLEY: And we can put that in farm fields. We can bury it in old mines. We can bury it in the ground, and it should last for hundreds if not thousands of years under the right circumstances. So it’s a pretty clever kind of hybrid between nature and some engineering that might be a pretty good little piece of silver buckshot.
IRA FLATOW: That’s really cool. As I said, biochar has been around for a long time, just not necessarily known as biochar. I mean, it’s long been used in Indigenous communities to fertilize the ground for planting, right? What are the benefits for the soil?
MURRAY CARPENTER: Yeah. The benefits are that, although it’s inert, it retains water and it retains nutrients. So here in Maine, they’re looking at it for particularly in three different areas, in the blueberry barrens Down East and in potato fields up north, and also as possible remediation for some pollutants.
And so in the blueberry barrens, we’re increasingly seeing, these are sandy soils. And we’re increasingly seeing flashy, heavy rains when they come and then long, droughty periods in between. If you have something that has better water retention, it can improve those agricultural soils. And so the other very intriguing area is the idea of remediating problems from pollutants, such as PFAS. It appears that biochar may bind up pollutants in the soil and make it harder for plants to take up those pollutants into crops.
So there are a number of intriguing areas of research. But basically, it’s really around this idea that it retains moisture and it retains nutrients.
IRA FLATOW: Yeah, well, we know how important blueberries are in Maine, right? So it could be an important useful item for them. But let’s look at the grand scheme of things. How much of a dent could biochar put on our carbon capturing goals?
MURRAY CARPENTER: Well, I think it’s never going to be a huge dent. Let’s say that. We know it can– I mean, it’s definitely locking up, sequestering some carbon. It’s hard to say how much. A place I visited in Greenville is producing about 1,200 tons a year. Another plant that’s coming online soon hopes to produce about the same amount. It’s a small climate solution. It’s definitely sequestering some carbon. And it definitely has some agricultural benefits. So people are pretty excited about this.
IRA FLATOW: And they should be because every little bit helps in this climate crisis we’re in, right Murray?
MURRAY CARPENTER: Every little bit helps, and this is just one more little bit for sure.
IRA FLATOW: Thank you, Murray.
MURRAY CARPENTER: Thank you, Ira.
IRA FLATOW: Murray Carpenter, Science Journalist based in Belfast, Maine. He reported this story from Maine Public Radio.
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