Bio-oil carbon removal

California · $969.67USD per tonne

Aug 2025: Archived in the Wren Classic Portfolio for strong traction with major carbon credit buyers and high cost, and in the Wren Trailblazer Portfolio to prioritize super-pollutant avoidance.

Climate scientists agree – carbon removal is essential to limit global warming to 2C. Yet, solutions that permanently remove carbon from the atmosphere need help scaling their operations. To support the gigaton-scale carbon removal required to address the climate crisis, Wren pre-purchases carbon removal credits from our project partner, Charm.

This project uses plants to capture CO₂ from the atmosphere and permanently store it deep underground.

Charm collects biomass residues (sustainably sourced from wildfire prevention projects) and converts them into a stable, carbon-rich liquid called bio-oil. This bio-oil is injected into EPA-regulated wells deep underground where it sinks and solidifies in place for permanent storage.

How does it work?

1. Collect biomass residues: Charm works with landowners & local forestry services to sustainably collect excess biomass. There are over 50 million acres across the United States that need wildfire treatment, but due to lack of funding and economic incentives often mean these forests are left untreated and at-risk of wildfire

2. Pyrolyze biomass: By partnering with local communities and forest managers, Charm removes excess biomass and converts it into a stable form of carbon that is sequestered for thousands of years, preventing it from re-entering the atmosphere. This process not only reduces wildfire risk but also avoids the harmful emissions & air pollution of “burn piles”, creating a win-win solution for climate action and community protection.

3. Biomass pyrolysis also creates syngas (a gas composed of H₂ and CO) that is recycled to power the pyrolyzer, and biochar (a form of natural, stable carbon) that is applied back to agriculture fields to improve soil carbon and nutrients.

4. Inject bio-oil deep underground: Charm transports the bio-oil to EPA-regulated wells – some of which are former oil and gas wells. The bio-oil is injected hundreds of feet below the water table, sinks, and solidifies in place, becoming permanent carbon removal.

A sample of carbon-rich bio-oil being tested in the lab.

Why this project?

Here's why we're excited about this project

1. Permanent Carbon Removal: Charm’s approach locks carbon away for millennia. Since bio-oil is not buoyant, once it’s safely injected into rock formations deep underground, there is essentially no chance CO₂ will be re-emitted into the atmosphere.

2. Catastrophic Wildfire Mitigation: Wildfires are becoming increasingly severe, endangering communities, ecosystems, and infrastructure as climate change brings hotter, drier weather to the Western U.S. Traditional wildfire mitigation efforts involve removing excess forest biomass, but most of it is either burned in piles—releasing carbon and smoke pollutants—or left as fuel for future fires. With over 50 million U.S. acres in need of treatment, these methods are neither scalable nor sustainable. Charm offers an innovative, economically viable way to create demand for non-commercial lumber from wildfire treatment projects.

3. Commitment to trust & transparency: Charm is committed to trust & transparency. They publish all of their work on their Public Ledger, for anyone to review and explore. They’ve also partnered with Isometric (registry) who defines science-backed protocols and is responsible for reviewing every step of our process – for every removal – to ensure the credits that customers are receiving are high-quality and permanent. Importantly, Isometric is paid directly by buyers (not Charm), which removes a major financial conflict of interest compared to how verification processes have been conducted in the past.

4. Scalable Impact: Charm is scaling up to remove millions of tonnes of carbon by 2030. Charm has a pathway to reduce the cost of its carbon removal to $45 per tonne of CO₂. What's more, there are billions of tonnes of sustainably sourced biomass available each year that Charm can convert into bio-oil and permanently store.

5. Improving American Agricultural Land: Through the sustainable collection of residual biomass and production of biochar, the project enhances soil quality that can improve water retention and soil nutrition. By incorporating biochar into the soil and returning ash, Charm helps improve soil carbon levels, structure, and nutrient retention, all while minimizing erosion and maintaining a healthy microbiome.

6. Early Progress and Success: Charm is one of the leading carbon removal companies and was the first selected for an offtake by Frontier Climate, a billion-dollar carbon removal buyers club. They also are a semifinalist for the Department of Energy Purchase Prize.

Who is behind this project?

Charm Industrial was founded in 2018 with the goal of returning the atmosphere to 280 ppm CO₂. In 2020 their Chief Scientist and co-founder Shaun Meehan had two breakthroughs (bio-oil intermediate and bio-oil sequestration) that kickstarted the company. Within 10 months they completed their first carbon removal injection and in 2021 completed more than 5,000 tonnes of CO₂e removal for customers like Stripe, Shopify, and Microsoft.

How is the money spent?

Receipts and documents

We keep a public record of all payment receipts we've received from our project partners. The funds are used to scale operations and monitor, measure, and verify the carbon removal. Charm is actively sustainably sourcing biomass and converting it to bio-oil via pyrolysis.

Verification

Charm is committed to next-level transparency in carbon removal. This dedication ensures accountability and trust in every step of the process. To ensure the carbon removed is measured accurately, Charm collaborated with industry leaders Carbon Direct and EcoEngineers to develop a prototype protocol.

✅ Carbon credit insured

Wren partners with Kita, a Lloyd’s Coverholder, to protect subscribers' carbon credit pre-purchases and ensure the promised impact of this project.