Biochar takes carbon that plants pulled from the air and turns it into a form that breaks down very slowly. This page explains how it works, how long the carbon stays put, what it costs and what to check before you buy. It is part of our guide to carbon credit project types.
How biochar projects work
Biochar is made by heating biomass, such as crop residues or forestry waste, to high temperatures without oxygen. Puro.earth describes this process, called pyrolysis, as converting biomass into a stable form of carbon that can store CO₂ removed from the atmosphere for at least 200 yearsSource 2.
The finished char is then put somewhere it will stay. Verra’s VM0044 methodology covers waste biomass turned into biochar at new production facilities and used in crop and grassland soils, or in emerging products such as biochar-amended concrete and building materialsSource 5.
A project earns credits for the carbon stored, minus the emissions from collecting feedstock, running the kiln and transporting the char. Isometric’s protocol also requires projects to check that their feedstock meets its biomass accounting rules, which cover what would have happened to the biomass otherwise and market leakageSource 4.
Matched shop
Buy engineered removal credits
- Registry serial numbers
- Retirement certificate
- Project documentation
Removal or avoidance?
Biochar produces removal credits. Ecosystem Marketplace lists biochar production alongside direct air capture as a technological removal, and counts it as a project type that creates removals onlySource 1. The plants did the removing; biochar is the storage step that stops that carbon going back to the air.
That makes biochar relevant to buyers following the Oxford Offsetting Principles, which ask organisations to raise the share of removals in their credit mix over timeSource 7. Removals are still a small part of what buyers retire. Citing Berkeley Carbon Trading Project data to December 2023, the Oxford Principles report that only 3.3% of credits retired across the four major registries were pure removals, all from afforestation, reforestation and revegetation or biochar projectsSource 7. See removal vs avoidance credits for the wider trade-off.
How permanent is the storage?
Biochar sits between nature-based storage and geological storage.
- Standards’ minimum. Isometric’s protocol requires long-duration storage of more than 200 yearsSource 4, and Puro.earth states 200+ years with a low risk of reversalSource 2.
- Longer estimates. The ICVCM says biochar added to soil acts as a long-term sink, storing carbon for hundreds or even thousands of yearsSource 3.
- Compared with forests. The IPCC finds that carbon stored as biochar is less prone to reversal than carbon stored in vegetation and soils, which human or natural disturbances can releaseSource 6.
Durability is modelled, not measured
Nobody can watch a tonne of biochar for 200 years. Isometric notes that all biochar durability estimates used for crediting so far come from modelling based on the char’s chemistry, such as its hydrogen-to-carbon ratio, or from comparison with stable geological carbonSource 4. Ask which durability model a project uses.
What do biochar credits cost?
Biochar is among the most expensive credits on the market. Ecosystem Marketplace reports that biochar production had an average price of over $160 per tonne of CO₂e in 2024, more than 25 times the total market averageSource 1. It was also one of the smallest clusters by volumeSource 1.
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| Credit type | Average price (USD per tCO₂e) |
|---|---|
| Biochar production | Over 160 |
| All removal credits | 19.50 |
| All reduction credits | 4.05 |
As of Oct 2026 · Source: [1] Ecosystem Marketplace, State of the Voluntary Carbon Market 2025
The figures are averages of deals reported to Ecosystem Marketplace, so individual quotes varySource 1. Our carbon credit price page tracks the latest snapshot.
Risks and integrity issues
Biochar avoids some of the problems of forest credits, but it has its own.
- Feedstock. The Oxford Principles warn that biochar needs biomass feedstock, which can have high land and water requirements and potential negative impacts on food security, biodiversity and resilienceSource 7. The IPCC adds that biomass production for biochar, when poorly implemented, can harm livelihoods, food and water security, and the rights of Indigenous PeoplesSource 6. Waste residues avoid most of this; purpose-grown crops do not.
- Counterfactual. If the waste would have been used for something else, using it for biochar can shift emissions elsewhere. That is why protocols require feedstock and leakage accountingSource 4.
- Durability assumptions. Because permanence is modelled, credits depend on the model and lab tests being rightSource 4.
- Reversals after issuance. Isometric handles reversals that happen after credits are issued through a separate risk-of-reversal assessment, not in the main removal calculationSource 4.
Check the end use
Biochar burned as fuel releases its carbon. A credible project documents where the char ends up, whether in soil, concrete or other materials, and how the standard verifies that.
Standards and methodologies
In August 2025 the ICVCM approved three biochar methodologies to use its Core Carbon Principles labelSource 3:
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| Programme | Methodology |
|---|---|
 Climate Action Reserve | U.S. and Canada Biochar, v1.0 |
 Isometric | Biochar Production and Storage, v1.0 |
 Verra | VM0044 Biochar Utilization in Soil and Non-Soil Applications, v1.2 |
Logos identify the organisations named; no endorsement is implied.As of Oct 2026
Puro.earth also runs a biochar crediting methodology and sells the resulting CO₂ Removal Certificates (CORCs)Source 2.
Buying biochar credits
- Check the methodology and whether credits carry the CCP label.
- Ask about feedstock and end use, and how leakage was handled.
- Confirm retirement in a public registry. Our guide to how to verify carbon credits shows how.
Comparing engineered removals? See direct air capture and enhanced weathering, or the portfolio approach for blending biochar with cheaper credits.