Wren | Underground biomass storage

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Underground biomass storage

Arkansas · $251.43USD per tonne

The University of Oxford estimates that the globe needs between 7-9GT of carbon removal annually by 2050 to meet Paris Agreement temperature targets. Unfortunately, existing initiatives and projections fall significantly short of what’s required. That’s why Wren supports carbon removal partners like Graphyte, who need firm demand from buyers to scale their operations.

This project removes CO₂ from the atmosphere by taking residual or waste biomass leftover from timber and agricultural operations and producing carbon blocks that are stored safely underground.

Every year, millions of tonnes of organic material go to waste—from agricultural residues to household yard trimmings to wastewater sludge. When this biomass decomposes, it releases greenhouse gases into our atmosphere.

Graphyte helps to break this cycle by collecting unwanted biomass such as sawmill residues and rice hulls, processing this biomass into carbon blocks, and storing these blocks in a designated site to prevent decomposition and ensure there is no release of greenhouse gas emissions.

Graphyte: Casting the Carbon Future - YouTube

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Graphyte: Casting the Carbon Future Graphyte

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The Roads to Removal report led by the Lawrence Livermore National Laboratory estimates that there is between 500M and 1B tonnes of dry biomass available for this form of carbon removal in the United States each year, and that biomass with carbon removal and storage (BiCRS) has the potential to remove >800M tonnes of CO₂ per year in the United States without impacting food supply. Graphyte is helping scale this critical carbon removal pathway today.

How does it work?

  1. Collect biomass: Graphyte collects sawmill residues and rice hulls that would otherwise decompose. Normally, microorganisms break down the biomass into simpler compounds, releasing carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) into the atmosphere.

  2. Dry biomass: A dryer eliminates moisture content in the biomass, halting microbial activity and preventing decomposition.

  3. Condense biomass: Once dried, the biomass is condensed into blocks for efficient stacking and underground storage.

  4. Wrap biomass: The blocks are wrapped in an environmentally safe, impermeable barrier to further prevent decomposition and ensure there is no release of greenhouse gases.

  5. Store biomass: The wrapped blocks are stored underground in lined cells that are engineered to prevent water and oxygen from reaching the biomass. Graphyte has received a permit from the Arkansas Department of Environmental Quality for its first storage site, ensuring safety and mitigating risk. Once the blocks are buried, the above-ground surface can be utilized for resources like solar farms.

  6. Monitor biomass: State-of-the-art sensors and tracers enable robust, long-term monitoring to ensure the carbon stays underground.

Dried and condensed biomass block.

Why this project?

Here’s why we’re excited about this project:

  1. Durable carbon dioxide removal (CDR): Graphyte Carbon Casting technology locks carbon away for over 1000 years. Dry biomass storage stops decomposition, as microbes need water to survive. Graphyte puts their land under a restrictive covenant to prevent disruptive land use while they monitor their stored biomass.

  2. Scalable impact: Graphyte can utilize billions of tonnes of commercially unviable biomass annually. This CDR pathway is scalable at a low cost per tonne of CO₂ removed due to low energy and technology requirements.

  3. Low energy intensity: Many CDR pathways require large amounts of energy, while Graphyte’s process is designed to use minimal energy—only 10% of what is needed for direct air capture—allowing broad deployment and saving renewable energy for other uses.

  4. Environmental justice: Graphtye’s community benefits plan considers local impacts and benefits, prioritizing communication with nearby communities. They aim to maximize job opportunities and prevent negative externalities, with remediation plans in place in case circumstances change.

Press mentions

This Startup Says It's Figured Out How to Trap Carbon Affordably

The Lego-like way to get CO2 out of the atmosphere

CBS Mornings visits Graphyte plant in Pine Bluff, Arkansas

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Where is the project located?

Graphyte’s first project, the Loblolly Project, is based in Pine Bluff, Jefferson County, Arkansas—a disadvantaged community. The EPA’s Environmental Justice Screening Tool shows multiple environmental justice risks for the local community, including air pollution and wastewater discharge. This makes it essential for Graphyte to provide co-benefits like employment opportunities while ensuring they can also prevent negative externalities.

The project is in Pine Bluff due to biomass availability from nearby processing facilities, such as rice hulls generated as a by-product by Arkansas River Rice. Graphyte’s founder and CEO, Barclay Rogers, is also an Arkansas native, with a deep understanding and passion for the community.