What On Earth28:12This one weird climate fix is like ‘burnt toast’
It might be considered an odd retirement hobby, but Greg Porteous spends his spare time making biochar.
Biochar is a black, charcoal-like substance created by applying high heat to organic materials such as wood, plant matter and even sewage sludge.
He makes it in his own backyard in Courtenay, B.C., where he has a kiln that he bought online. In goes the organic matter, like brush or old wood pallets, high heat is applied with little to no oxygen and, since there is minimal fire, the fuel is turned into biochar.
Porteous got the idea after looking into ways he could help fight climate change and reading that making biochar was a good option. He started doing it for himself and his neighbours.
“It’s just win, win, win. It’s a cascade of positive benefits,” said Porteous.
“The property owner, he gets his woody debris dealt with, the soil gets a beautiful additive put into it, the atmosphere gets the carbon sequestered so it doesn’t go into the atmosphere. It’s great for me, too. It’s a great physical activity to get outside,” he said
It’s a carbon removal tool that has been picking up steam over the past decade. The United Nations has said biochar is a good way to deal with wood waste because it can hold carbon in the soil. Its report on mitigating global warming said biochar can be “used to store carbon away from the atmosphere for decades to centuries.”
That has corporations and countries turning to biochar as they look at their own climate solutions.
What is biochar?
Biochar is made through a process called pyrolysis.
“Think of it as burnt toast,” said Kathleen Draper, who sits on the board of the U.S. Biochar Initiative and is the U.S. director for the non-profit Ithaka Institute for Carbon Intelligence.
“Imagine you put any kind of organic material in an oven, you close the door to limit the oxygen … and if you turn up the heat, what happens? You get this black substance that is very unappetizing.”
Unappetizing to eat, yes, but there are benefits. A plant, for example, absorbs carbon dioxide over its lifetime. When it dies, that carbon is released. But through pyrolysis, Draper says at least half of that carbon doesn’t get released, and instead is put into that “burnt toast”-looking substance.
Benefits of biochar
Biochar has all sorts of uses. Draper says it can be used as an additive to make greener concrete and asphalt or to clean up lakes and ponds that have too much phosphorus.
It’s also very good for soil, according to Annette Cowie, a researcher at the New South Wales Department of Primary Industries and an adjunct professor at the University of New England in Australia.
A Vancouver Island retiree is doing his best to make a difference for the environment by creating bio-char –
the product of partially burned organic material… like tree bark and leaves.
He says he’s created about 20,000 pounds of biochar over the past few years,
which he says can be used in gardening and compost to enrich soil.
Claire Palmer caught up with him up in Courtenay.
It can increase soil alkalinity, moisture content, and nutrient retention, which can improve crop yields and benefit places with poor soil quality.
“If you make biochar from that plant material and put that in the ground as a soil amendment, you can store the carbon effectively for hundreds to thousands of years,” said Cowie, who has been a lead author on some of the UN’s climate reports.
The process of pyrolysis can also be used to deal with dead wood and organic bio-matter that acts as fuel for wildfires.
Dipita Ghosh, a researcher at Northern Arizona University, has been looking into the uses of biochar for the U.S. Department of Agriculture.
Ghosh said in Flagstaff, Ariz., where she works, dead brush and other forest matter don’t decompose because the climate is cool and dry. That means there’s a lot of potential fuel for wildfires.
She’s found that pyrolysis not only reduces that fuel, but once biochar is in the ground, it keeps the soil cooler and adds moisture, further reducing the risk of an out-of-control blaze.
As part of her research, Ghosh has used a kiln on wheels called CharBoss, a product sold by Air Burners Inc. She says it’s great for moving through a forest and converting organic matter to biochar.
Biochar bonanza
More countries and corporations are getting behind biochar. Google has agreed to buy carbon credits from an initiative in India that turns large amounts of agricultural waste into biochar.
“Biochar is a promising approach to carbon removal because it has the ability to scale worldwide, using existing technology, with positive side effects for soil health,” Randy Spock, Google’s carbon removal lead, told Reuters.
In Denmark, the country has developed a pyrolysis work program and strategy to make biochar a key part of reducing agricultural waste.
So how much carbon is that all capturing? Warren Mabee says that’s hard to say, and depends on a number of variables, such as temperature, the kiln itself, and what kind of wood or biomass goes in it.
But once it’s in there, it’s in there, says Mabee, who is the director of Queens University’s Institute for Energy and Environmental Policy.
Mabee says biochar production can be scaled up by using pyrolysis in the places where this waste is being created. That includes wastewater treatment plants, landfills, and industrial operations such as a sawmill. But, Mabee says, scaling past that through bringing in material from large forestry or agricultural operations can be difficult, as you run the risk of actually increasing your carbon footprint.
“If you’re just generating hundreds of tons or thousands of tons or millions of tons of this material and getting it from sources that are actually not appropriate sources and using it in a way that is really carbon intensive … then you’re not really winning,” said Mabee.
Backyard biochar
Ghosh says that open kilns such as the CharBoss or Porteous’s backyard setup aren’t perfect at creating biochar, as the best biochar is made when you’re able to limit the oxygen. But she says it’s better than letting the biomass decompose or burning it.
She also says, for those cooking and then spreading their own biochar at home, “it’s not so simple.”
She says that if your soil is already very alkaline or has a lot of calcium, you need to modify your biochar accordingly.
And those considerations don’t just apply to small producers.
Mabee says there needs to be regulations and clarity around creating biochar. But, he says, that shouldn’t discourage Porteous and others like him from what they’re doing.
“Making biochar at a small scale actually can be the best way to maximize the benefits and minimize the footprints,” said Mabee. “To think that there are Canadians that are working on these kinds of innovative solutions, I think it’s exciting.”
