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Biochar carbon removal

United States · $242.86USD per tonne

This project uses a high-heat, low-oxygen process called pyrolysis to convert biomass—like crop residues or wood waste—into biochar, a carbon-rich charcoal that can persist in soil for centuries with minimal decay.

Normally, biomass residues would rapidly decay or be burned to ash, releasing plant carbon into the atmosphere as carbon dioxide (CO₂). Instead, this project turns the biomass into biochar, which is primarily applied to farmland to improve soil quality. In some cases, biochar is used in other carbon-sequestering pathways, such as being applied to landfills to solidify and stabilize waste to prevent hazardous chemicals from leaching into groundwater.

Wren is a proud early supporter of our project partner, Pacific Biochar, as one of the first to pre-purchase verified biochar carbon credits in the United States.

Pacific Biochar delivers biochar to a vineyard in Napa, one of the last steps in removing ~22 tonnes of CO₂e.

Wren subscribers support Pacific Biochar in two ways. The first is funding carbon credit purchases, which count toward the tonnes of carbon dioxide equivalent (CO₂e) offset on Wren dashboards. The second is funding Wren's investment into Pacific Biochar, the company. You can learn more about our different project types here.

How does it work?

1. Form partnership: Pacific Biochar conducts a feasibility assessment for a biomass power plant, seeking opportunities to integrate biochar production into existing operations. This determines whether the collaboration is likely to succeed based on technical, financial, legal, and operational factors. Pacific Biochar then creates a mutually beneficial contract, which outlines biochar production responsibilities, payment conditions, and other terms.

2. Modify infrastructure: The facility modifies its equipment and operating parameters as needed to support pyrolysis, a high-heat, low-oxygen process that burns organic materials to produce biochar instead of ash.

3. Collect biomass: The facility sources biomass, like forest residue, logging debris, sawmill residue, urban wood waste, power line clearings, agricultural residue, and other approved sources of biomass to use as feedstock—the organic input used to create biochar. In many cases, clearing this biomass from the environment helps reduce the likelihood and severity of wildfires by minimizing fuel loads.

4. Complete pyrolysis: The facility places biomass feedstock into the modified system where pyrolysis occurs, transforming organic waste into biochar while also producing steam and electrical energy.

5. Confirm biochar quality: Biochar samples are sent to an accredited lab to confirm that any given batch meets the quality standards required by the World Biochar Certificate.

6. Distribute biochar: Pacific Biochar organizes biochar distribution to its end destination. It is mostly used as a soil amendment to retain moisture, reduce soil acidity, improve crop yields, and increase soil organic matter. Alternatively, it can be used in other carbon-sequestering pathways, such as being applied to landfills to solidify and stabilize waste to prevent hazardous chemicals from leaching into groundwater.

7. Generate carbon credits: Once the biochar passes quality checks and has been applied in carbon-sequestering pathways, with data verified by third parties, Pacific Biochar generates carbon credits. This indicates that carbon is safely stored for centuries to millennia.

Handful of biochar in the foreground, half-full trailer of biochar in the background.

Why this project?

We think this is an excellent project for a few reasons:

• Carbon removal: Biochar is a stable form of carbon. Research shows that industrially produced inertinite biochar is permanent on geological timescales. This means carbon can remain in the soil for centuries to millennia, keeping CO₂ out of the atmosphere.

• Measurability: Carbon removal from biochar is measured by quantifying the amount of stable carbon retained in the biochar, estimating its long-term sequestration potential in the soil, and subtracting from that any greenhouse gas emissions resulting from its production and transportation.

• Scalability: Pacific Biochar has fantastic potential to scale, based on its approach to working with biomass power plants and modifying existing infrastructure, of which there is a lot of opportunity.

• Soil health: When applied to farmland, biochar improves soil quality by enhancing nutrient retention, allowing soils to hold more water, helping neutralize acidic soils, and providing a habitat for beneficial microbes—crucial for nutrient cycling and plant health. These benefits reduce the need for irrigation and chemical fertilizers, lowering costs for farmers.

• Pollution reduction: Biochar can adsorb and immobilize heavy metals and organic pollutants in soil, reducing bioavailability and preventing them from entering the food chain or groundwater. This is especially useful when applied to landfills, where it stabilizes and solidifies waste.

• Wildfire mitigation: Pacific Biochar’s facilities mostly use forest residues as biomass. When this wood is cleared from the environment, it can help reduce the likelihood and severity of wildfires by reducing fuel load. This is particularly relevant in California, Pacific Biochar's home state, which is facing longer and more intense fire seasons due to climate change.

Press mentions

Ancient Farming Practice Draws Cash From Carbon Credits

Combined Biochar and Compost Application Increases Vineyard Yields by Over 30%

What is biochar? Why an ancient farming technique could help fight climate change

BBC’s 39 Ways to Save the Planet: Black Gold

Project updates

Jun2026

How wood residues create clean energy, biochar, and jobs

A new production facility, Hat Creek Bioenergy, is on! Once the commissioning refinements are finished, the project is expected to produce over 5,000 tonnes of bone dry biochar and up to 15,000 tonnes of durable carbon dioxide (CO₂) removal per year....

Jun2026

What our projects are working toward in 2026

Looking to the new year, Wren subscribers will help scale climate solutions, advocate for smart policy, and protect nature-based projects that deliver real, measurable impact....

Jan2026

Preventing wildfires while sequestering carbon with biochar

Clearing forest residues for biochar helps reduce wildfire risk—especially important as California faces hotter, longer fire seasons....

Jul2025

Where is the project located?

Pacific Biochar is headquartered in Santa Rosa, California, and works with biomass power plants across the United States, including:

• Humboldt Sawmill Company in Scotia, California
• Georgia Renewable Power (Madison) in Colbert, Georgia
• Georgia Renewable Power (Franklin) in Carnesville, Georgia
• Shasta Sustainable Resource Management in Anderson, California
• Hat Creek Bioenergy in Burney, California

These facilities vary in their current status. Some, like Humboldt Sawmill Company, actively produce biochar. Others, like Hat Creek Bioenergy, have agreements in place and are set to come online as Pacific Biochar expands.

Who is behind this project?

Pacific Biochar is a public benefit corporation with a team united by its mission to put carbon back in the ground and leave a legacy of fertile soil. Josiah Hunt, CEO and founder of Pacific Biochar, has pioneered carbon removal methods using ecological, sustainable agricultural practices for well over a decade.

Pacific Biochar blends a specialty biochar product, circa 2016.

How is the money spent?

The Biochar carbon removal (Certified offset) and Biochar carbon removal (Investment) fund how Wren subscribers support Pacific Biochar.

Funds allocated to Biochar carbon removal (Certified offset) fund carbon credit purchases that cover Pacific Biochar's carbon removal expenses alongside monitoring, reporting, and verification procedures.

Funds allocated to Biochar carbon removal (Investment) finance Wren’s investment into Pacific Biochar. These funds are used to get facilities accredited and verified, pay facilities to convert biomass into biochar, and transport biochar to its destination. About one-tenth of this investment goes toward Pacific Biochar’s payroll and administration costs.

How did we vet this project?

Wren uses a scorecard to assess project quality and risk. In 2024, Wren re-evaluated this project to ensure continued quality. We worked closely with Pacific Biochar to explore feedstock sourcing, project economics, lab testing, life cycle assessments, and baseline scenarios.

Our scorecard asks over 150 questions to explore project governance, carbon removal efficacy, people and biodiversity impacts, and sector risks. Pacific Biochar met Wren's standards across all categories.

Biochar, up close.

Verification

This project has historically used the European Biochar Certificate C-sink methodology to verify carbon removal, and listed credits on the Carbon Standards International Carbon Sink Registry. Monitoring, reporting, and verification activities were previously supported by Carbonfuture.

Future credits will be generated following methodologies from Climate Action Reserve and/or Isometric, and issued on the corresponding registry. Monitoring, reporting, and verification activities will be supported by Mangrove Systems.

Contact information

Pacific Biochar, info@pacificbiochar.com

Talk to a

Wren team member

If you have specific questions about Biochar carbon removal, our team is here to help answer them.