November 14 – Storing carbon in living biomass has long been touted as a solution to climate change, but as successive scandals and concerns about destruction by wildfires has dampened the market for tree-planting credits, many believe that storing carbon in biomass that is already dead is a safer bet.
Collectively known as biomass carbon removal and storage (BiCRS), the term covers a range of processes that use biomass from plants or algae to remove carbon dioxide from the air and then store it permanently, either underground or in long-lived products.
These approaches have the potential to remove around 5.5 gigatons of CO2 (GtCO2) globally per year, according to the U.S. nonprofit Rocky Mountain Institute (RMI). They can also lock this away for substantially longer periods of time than living tree-based projects, at an average of 100 years, though some techniques such as bio-oil have the potential for 1,000 years of storage, says Rudy Kahsar, RMI’s manager of climate-aligned industries.
The most mature BiCRS technology is biochar, which accounts for more than 90% of credits delivered in the entire carbon removals market. Produced by heating biomass in low-oxygen environments to produce a charcoal-like soil additive that sequesters carbon, biochar has potential to be used on fields to replace nutrients and improve soil health. Read more
The United Nations’ Intergovernmental Panel on Climate Change concluded that biochar “has significant mitigation” potential, though it said there were question marks over just how long it could lock carbon away.
Last summer, global standards body Verra published a methodology for quantifying emission reductions and removals from biochar. And in September, a biochar project in Switzerland became the first ever engineered carbon removal project to receive an A-rating.
An olive farmer holds out a handful of biochar, which as well as improving crop yields locks carbon into the soil. REUTERS/Jon Nazca Acquire Licensing Rights
Carbon credits ratings agency BeZero Carbon awarded the rating after assessing it against a number of rating risk factors, such as additionality, over-crediting, leakage and non-permanence.
U.S.-based Charm Industrial produces both biochar and a carbon-rich bio-oil, heating agricultural wastes and residues such as leftover corn stalks to high temperatures in a low-oxygen environment through pyrolysis.
The pyrolysis Charm uses are small and can be moved from farm to farm on the back of a truck bed for on-site operation. The bio-oil is injected into abandoned oil and gas wells, where it sinks and solidifies in place, out of reach of fires and other climate risks.
Charm began operations in 2020, and has already delivered more than 6,000 metric tons of carbon removal.
The public benefit company Frontier chose Charm for its first offtake deal announced in May, paying $53 million for 112,000 tons of CO2 on behalf of member companies such as Alphabet, Meta and H&M Group. Also in May, JP Morgan Chase agreed to purchase approximately 28,500 metric tons of carbon dioxide equivalent (mtCO2e) over five years from Charm.
Nora Cohen Brown, head of market development and policy at Charm says: “We’ve ramped pretty quickly in terms of actually removing carbon and part of that is because our process combines a number of components that already exist.”
Charm Industrial produces a carbon-rich bio-oil as a product of pyrolysis. Charm Industrial/Handout via REUTERS Acquire Licensing Rights
The startup is working on scaled up versions of its pyrolizer technologies that will be able to process 10 tons of biomass per day, which it hopes to have operational in the next couple of years.
While Charm’s process is currently “pretty expensive”, Cohen is optimistic costs will fall once its machines are being manufactured at scale. “We can get down the cost curve somewhere in between $100-$200 a tonne. Part of the goal for us is to become cost-competitive with natural gas because in a parallel process we’re doing research and development on using our bio-oil to produce carbon negative steel.”
Other co-benefits of Charm’s approach are securing and eventually plugging abandoned oil and gas wells that are at risk of leaking methane and chemicals, and providing jobs – an independent study estimated these at 200,000 by 2040.
An even more novel approach is called woody biomass burials, where dead biomass is buried in vaults or underground. The idea is that wood from forest thinnings or coppiced native woodland species can be dried out to prevent growth of fungi, mould or bacteria, stabilised and stored underground long-term to prevent the release of carbon.
Californian startup Kodama Systems is backed by investors, including Bill Gates’s climate fund, Breakthrough Energy Ventures, and Stripe. Its plan is to bury in the Nevada desert waste biomass that has been harvested from California forests, which are today piled up in cleared areas to rot, or deliberately burned to decrease wildfire risk. The biomass will be buried deep underground in vaults, in a process similar to the first step of coal formation.
Insurance firm Zurich has pre-paid against future carbon removal certificates from West Australia-based InterEarth, sold by Puro.earth, which has piloted a woody biomass burial methodology.
A wildfire in California. Kodama Systems plans to bury waste biomass that is currently deliberately burned in parts of the state to decrease wildfire risk. REUTERS/David Swanson Acquire Licensing Rights
Simon Avenell, the company’s chief operating officer and founder, says his company is planning to harvest varieties of acacia and eucalyptus for burial. These are fast-growing trees that are efficient at capturing atmospheric CO2 and adapted to desert conditions. The repeated cycle of grow-harvest-bury-grow effectively creates a CO2 pump, he says.
“Over 100 years, it’s six to 10 times more effective at removing carbon than just planting trees,” he says.
He adds that InterEarth is targeting marginal farmland, where it will harvest both existing trees that were originally planted for the failed eucalyptus oil industry, and that farmers currently want removed, and trees it plants itself.
The startup is about to sign a contract with a farmer for its first site, and should be operational there in the next 12 months, he says.
The model is highly scalable, according to Avenell. “When I say we can plant at scale, I mean from 1,000 hectares to 50,000 ha at a time to really get this up and running.”
Caitlin Smith, manager of the RMI’s carbon markets initiative, says demand for biomass-removal credits far outweighs supply. “There’s a limited number of companies that are providing those removals, and they are more than oversubscribed into the future.”
Other than biochar, however, these are highly novel technologies, and their potential impacts have not been fully studied. Haley Leslie-Bole, research analyst with The World Resources Institute, points out that “the guidance that Puro has developed for woody biomass burial is still in the pilot phase, and as far as I know, Puro is the only independent verification body working on methodologies for biomass burial.”
Freshly planted eucalyptus trees. InterEarth has piloted a woody biomass burial methodology and plans to harvest and bury the fast-growing trees. REUTERS/Rafael Marchante Acquire Licensing Rights
That means companies are carrying these out according to their own methodology, she says. “I’d hope that they’re accounting for all the energy used to cut down trees and recovering any sort of residue, but there’s no oversight – that’s my concern with any of these emerging carbon technologies.”
She flags up potential issues with using forest thinnings, in that such material should not be completely removed, as it is needed for forest soil and biodiversity.
Another concern is that growing crops for biomass burial could displace food production, or growing timber, she says.
“Then we could see the expansion of plantation forests globally to make up for the reduced supply of wood for wood products. If you’re doing carbon removal in one place, and then releasing its carbon in another, you’re really not doing carbon removal.”
In its briefing note on carbon removals this year, the United Nations Framework Convention on Climate Change (UNFCCC) highlighted another risk, warning that afforestation or biomass crop production for BECCS or biochar, “if poorly implemented, can have negative impacts on local livelihoods and indigenous peoples’ rights, especially when implemented at large scale and where land tenure is not clearly defined”. Read more
Such impacts would be less likely if “free, prior and informed consent of the relevant stakeholders has been obtained before the removal activity is registered and stakeholder consultations are systematically followed.”
RMI’s Kahsar says that though the approaches are still being studied, the expectation is that, if done correctly, the durability of their carbon storage should be fairly high.
This article is from The Ethical Corporation magazine’s in-depth briefing on carbon removals. Click here to download the digital PDF.
Opinions expressed are those of the author. They do not reflect the views of Reuters News, which, under the Trust Principles, is committed to integrity, independence, and freedom from bias. Ethical Corporation Magazine, a part of Reuters Professional, is owned by Thomson Reuters and operates independently of Reuters News.
