Fighting Climate Change with Ancient Technology

Used for millennia, biochar is gaining significant market traction for its versatility in dozens of applications and its primary environmental benefit of sequestering carbon indefinitely.
By Ron Kotrba | February 21, 2020

Anthropology demonstrates the first evidence of controlled fire by human ancestors—Homo erectus—dates to 400,000 years ago, but some in the field assert this could span as far back as 1.7 million years. How soon afterward primitive humans developed charcoal is unknown, but experts believe they used it for cave drawings 32,000 years ago. The first documented use of charcoal was nearly 6,000 years ago, when ancient Egyptians employed the material in smelting ores to manufacture bronze from copper, tin and other metals.

“Biochar is not new—it’s been made and used for millennia,” says Melissa Leung, business development and marketing manager for Quebec-based GECA Environnement. “It’s coming back to life, and the industry is growing. Let’s not forget, it’s a known, green product. We know how to make and use it. It’s only a matter of who will do it.”

Biochar is made from a variety of feedstocks through various techniques, such as pyrolysis or gasification, and can be a byproduct, coproduct or main product of a given production process. It is produced in low- or no-oxygen environments with heat through which moisture and gases are burned off, leaving behind a carbon-rich product.

“In more technical terms,” describes the International Biochar Initiative, “biochar is produced by thermal decomposition of organic material (biomass such as wood, manure or leaves) under limited supply of oxygen, and at relatively low temperatures (less than 700 degrees Celsius). This process mirrors the production of charcoal, which is perhaps the most ancient industrial technology developed by humankind. Biochar can be distinguished from charcoal—used mainly as a fuel—in that a primary application is use as a soil amendment with the intention to improve soil functions and to reduce emissions from biomass that would otherwise naturally degrade to greenhouse gases.”

While biochar’s primary application is a soil amendment, Tom Miles, IBI board member and principal of T.R. Miles Technical Consultants Inc., says there are at least 55 documented uses of biochar listed in various articles. “It can be used in cement, or as a filler in plastics, also wallboard, building products, or added to anaerobic digesters to improve gas production at dairies,” he says.

On the surface, having such a broad range of uses for biochar may appear beneficial to its desirability and market value, but this vast list of product potentiality might actually be a detriment, according to Jonah Levine, vice president of development and cofounder of Biochar Solutions Inc. “The challenge for biochar is there are so many different stories to tell that it gets complicated,” Levine says. “People like a nice, neat story. Biochar has a lot of value, and it’s not a simple story to tell.” He adds that, in addition to the breadth of applicability being a challenge for people to understand what biochar is and how it can be used, biochar’s complicated story also “screws up” developing businesses. “Some want to produce biochar and think they’re going to do 10 different things with it, but that’s hard to do,”Levine says. “They should really choose one or two things and run with it, but they can get distracted. It’s important to know who the stakeholders are and give them a nice, neat package. The story of biochar in agriculture is tight. So is one on filtration, or animal feed. Each of those alone is a tight story. But blend them all together and it becomes challenging. The stakeholders are different. It becomes too large and unwieldy. It’s too hard for biochar to be all things to all people.”

Leung says although this may be true, she simplifies the story of biochar by advising that each biochar’s unique set of properties is the best indicator for suitable market applications, thereby narrowing the field of possibilities and uncomplicating the otherwise complex narrative. One type of biochar might work best as a soil amendment while another may be more appropriate for filtration, and another yet as an animal feed supplement—although the latter is not currently approved in the U.S., despite studies demonstrating large increases in daily weight gain and decreases in methane emissions from cattle.

Think of choosing the right potatoes for mashing, Leung says. “Yellow potatoes are the best to make mashed potatoes, more so than other types,” she says. Conversely, one wouldn’t choose cherry tomatoes to slice for sandwiches, but those same tomatoes work well in a garden salad. “It’s the same thing with biochar,” Leung says. “So, it’s important to understand the different types of biochar and assess the properties for each product. Feedstock, temperature, technology, preconditioning—they all affect the end product and its usefulness in certain applications. That’s why we at GECA Environnement do what we do. It’s confusing for those who don’t know about biochar, and they might use the wrong product in the wrong situation.”

Quality
To elaborate on this concept, Miles details three main determinants of biochar quality. “One is feedstock,” he says. “Ag residues, whether field crops or manure, urban residues such as sewage sludge or urban wood waste, or wood residues, whether waste from processing or from the forest—each of those feedstocks has different qualities in terms of the amount and composition of ash.” He says sewage sludge has higher ash and lower carbon content while wood, on the other hand, has much less ash but very high carbon content.

In addition to feedstock, another aspect that affects biochar quality is the design of the device used to carbonize the biomass. “If you take raw biomass and heat it, 80 percent turns to gas and you can recover that gas as steam or heat, but 20 percent remains as char,” Miles says. “If you burn that as a fuel, it’s called charcoal, but if you use it in the soil or for other nonfuel uses, it’s biochar. It retains 50 percent of the energy it had when you started with it.” Several different designs of devices exist to convert biomass to biochar: pyrolizers, which use no air and yield 25 to 30 percent biochar; gasifiers, which use little air and produce slightly less biochar content, perhaps 15 to 20 percent; and combustors, boilers or stoves, which use a lot of air and mostly convert the biomass to energy and yield little char, maybe 5 percent or less, according to Miles.

“The third leg of the stool,” Miles says, “is how you operate those devices and at what temperature. If you want to make a biochar that duplicates an Amazon [rainforest] soil amendment, then take the biomass and combine it with clay, heat at low temperatures and you’ll make a composite material that’s similar to Amazon soil. If you want a high surface area to capture pollutants like heavy metals, then biochar made from a gasifier with higher temperatures gives a higher surface-area material, which makes it good for capturing metal contaminants. In China, 20 percent of agricultural lands are polluted from industrial processes, so they’re using biochar as a growing medium and for filtering water from irrigation to capture pollutants.”

Soil Health
Biochar works best with a partner, Levine says. “Biochar plus compost is the best blended material,” he says. If a farmer wants to upgrade course, sandy soil in order to improve nutrient cycle times and utilize moisture more efficiently, then they should target 5 percent organic matter in the soil profile—but adding 5 percent organic content to soil six inches deep is too much all at once. The farmer could implement a three- or five-year program, adding a biochar-compost mix annually until the target organic content is achieved. “There’s labile and recalcitrant organic matter—or what will and won’t break down,” Levine says. “Biochar will not break down. Compost will. Biochar is more expensive and compost less so.”

Levine says there are layers of carbon value by adding biochar to soil. Biochar interrupts the natural carbon cycle, so the atmospheric carbon retained in the biomass via photosynthesis is not released back into the environment when charred—so long as it’s not set back on fire. “The carbon will remain sequestered permanently,” he says—or at least for thousands of years. He likens it to the reverse of burning coal. “That’s what got me excited about biochar to begin with—it’s coal in reverse,” Levine says. “Frankly, I’m not a coal hater. It’s been a wonderful resource for the time and where we were. Now we know better. I believe in sustainability. It’s what gets me excited to go to work in the morning.” The second layer of biochar’s carbon value to soil, according to Levine, is if one can reduce moisture and nutrient requirements for soil, then by extension this reduces other pollution-emitting inputs needed. And the third is, if that ground is now more agronomically productive, the carrying capacity of biomass on that piece of land is elevated, thus removing more atmospheric carbon through, once again, photosynthesis.

“With all biochar,” Miles says, “you’re increasing carbon content in soil, which is the really interesting part. For every 1 percent organic carbon in the soil, 26,000 gallons of water per acre is available. So, as you increase carbon in the soil, not only does this increase the fertility, but it also increases the amount of water the soil can hold and make available to plants.”

Production
While biochar has its market-related challenges, Miles says an equally encumbering obstacle is helping would-be manufacturers get into biochar production at a reasonable scale. “That’s been a challenge,” he says. “Transportation becomes a big issue. If you’re going to use it, you need to find sources within 30 to 50 miles to be economical. Now biochar is being transported all across the country. We need more decentralized production.” 

Biochar Solutions designs, produces and sells systems to make biochar, and Levine says anyone with excess capacity of biomass such as course, dry wood chips would be a great potential candidate to start manufacturing biochar in order to add diversity to their product line and revenue to their bottom line. This could be feedstock providers, biomass power plants with excess feedstock on-hand, or numerous other players in the biomass space. Levine says the standard base unit costs $400,000 and can process 2,000 pounds an hour of course, dry wood chips. The result is two cubic yards of char per hour and 3 to 6 million Btu on a continuous basis. “It’s exothermic, so you start the process in the morning with a torch and the energy in the chips drives reaction,” he says. “You get 18 to 20 percent by mass char coming out. If you use external energy, which would be endothermic, you could get 40 to 50 percent by mass carbon out. But being exothermic, it consumes carbon in the reaction.” Levine says some energy goes into the process for blowers and augers, “but it only takes 25 kilowatts,” he says.

Certain plants designed to create energy produce biochar on the side, Leung says, and the energy generated from the pyrolysis process can be fed back into the main processing plant for heat or steam. “The feedstock going in so high in energy, and since the actual pyrolysis process releases more energy than it needs, people who already have biomass plants can benefit in multiple ways from incorporating such technology,” she says. “For example, if a sawmill has a bunch of residues and it wants to install a pyrolysis system right next to the mill to transfer extra energy, they’ll be doubling their energy and also producing biochar as a product. Some want residues to heat greenhouses. Pyrolysis works well in different situations in which primary revenue is being generated from another process. As a company though, we always make a point to say, if you choose to make biochar, use residue that would not otherwise be used. We don’t recommend taking a high-value feedstock to make biochar. If someone has wood chips that would rot outside otherwise, then there’s a good opportunity.”

Suzanne Allaire, owner of GECA Environnement, says her company encourages the use of everything that comes out of biomass. “There is always gas coming out of the [biochar] process, so that gas can be used to dry the material,” she says. “If it’s already dried, say at a big sawmill, then the surplus energy can be cleaned and sent to the grid or used to make energy on-site. It fits well in a circular economy.”

Market Value
The value one can expect to receive for biochar depends, again, on many factors such as the quality, type and intended market. “Right now, it’s like the Wild West,” Miles says. “There’s no set prices. Biochar is not viewed as a commodity, it’s still a specialty product.” He says pricing can range from $50 to $200 per cubic yard, or more, depending on the cost of production, and supply and demand. “As we see production grow,” Miles says, “prices will come down to maybe settle down at $50 a cubic yard.”

Allaire says the cost of biochar depends on what the client is willing to pay and in what application they intend to use it. “The range can be $300 to $1200 per metric ton,” she says. “That’s a huge difference. Why? If they want to use it to replace coal, then it’s cheap, but activated carbon is expensive—as much as $3,000 a ton. The same biochar could have one price, but in a different application the price doubles.” Leung adds that the niche markets pay the highest, but the volume is low. Conversely, the high-volume markets typically pay much less. “Finding markets can be difficult for producers,” she says. “That’s what we do to help. We make market studies, determine what markets are the most accessible and which pay the highest revenue.”

In addition to connecting producers to buyers, GECA Environnement also puts biochar seekers in touch with the right supply. “People looking for biochar may not know what they need,” Allaire says, “so they’ll call us and we have so many biochar producers we work with that we can find the right biochar for the right consumer.” 

For the past 16 years, Allaire has worked to build out the biochar industry and market. “Early on, it was like I was coming from Mars,” she says. “The past two years, however, have been very unique. The market is really picking up. Regulations take a long time to change. Biochar is not allowed to be used in concrete, and it takes like 20 years to change these laws. Other industries like steel, agriculture, animal feeding, cannabis—they are willing to use biochar. But this is really new. There’s been a big jump in new markets over the past two years—exponential.”

One reason for this, Leung says, is a better understanding of biochar’s ability to sequester carbon. “In 2019, there was a huge surge in positive, public opinion,” she says. “Enterprises are looking for alternative, new products that are environmentally friendly and sustainable to use or replace current products. This is partly where the surge is coming from. Also, more and more large producers have started making biochar. Before, it was largely small producers, and those larger markets didn’t have access to enough volume to satisfy the need.”

Allaire adds that the volume and quality control for energy, steel and concrete industries was simply not there three years ago. “Now we see it, companies are willing to switch to replace coal, for instance,” she says. “There’s not enough biochar volume for 100 percent replacement of coal, but they can do coal-biochar mixtures. For a coal power plant to switch to wood [pellets], it would cost about $200 million to adjust the equipment. Comparitively, with pyrolyzed wood—pelletized biochar—the modification cost to switch from coal is minimal.” Leung says biochar emits three times less carbon equivalent than coal, and it is an ultra-low sulfur energy source, which is “way better for the environment,” she says, adding that transport costs for biochar are less than wood. “The other thing is, when comparing wood pellets to biochar for a coal replacement, wood pellets are very sensitive to humidity and make a lot of dust.” Conversely, she says, pelletized biochar isn’t affected as much by humidity and doesn’t create the same amount of dust.

GECA Environnement currently has access to a total volume of 230,000 metric tons of biochar per year, according to Leung, to which the company can refer clients. “That’s a significant amount—more than half of the biochar in North America,” she says. “In the next two or three years, we’ll double that in our agreements. A lot more plants are going to be built in the next few years.”

Allaire says, “Through our agreements with producers and others building plants for which we don’t have agreements yet, we could probably reach 1 million tons in the next two or three years.” That is significant, impressive growth considering 10 years ago, according to Levine, the market was essentially “zero.”

Author: Ron Kotrba
Senior Editor, Biomass Magazine
218-745-8347
rkotrba@bbiinternational.com