Carbon-trapping bricks created by carbon removal startup Graphyte. The company has support from Bill Gates-led Breakthrough Energy Ventures. (Graphyte Photo)

Graphyte, a startup with backing from Bill Gates-led Breakthrough Energy Ventures, announced Monday that it has developed an affordable, long-term strategy for storing carbon that will keep it out of the atmosphere where it otherwise warms the planet.

The company said it can provide carbon storage for less than $100 per ton — a price point that the Biden administration set as the “earthshot” goal of its climate funding efforts.

Memphis, Tenn.-based Graphyte takes advantage of the ability of trees and plants to naturally capture carbon through photosynthesis. The startup takes unwanted biomass including waste from logging and farming and using a process called “carbon casting” it dries and squeezes the material into blocks. The blocks are stable and won’t decompose, which would release the carbon back into the atmosphere. Graphyte says it can store the bricks in monitored, underground sites.

In addition to providing low-cost carbon removal and storage, the technology can be quickly scaled, according to the company.

“By combining the strength of nature-based approaches with the lasting impact of engineered removal, Graphyte has created a unique solution that accelerates progress toward the billions of tons of carbon removal needed to protect our planet,” said Carmichael Roberts of Breakthrough Energy Ventures in a statement.

Another strategy for plant-based carbon storage uses a charcoal-like substance called biochar to hold on to the carbon. Seattle’s Myno Carbon is among the companies deploying biochar as a climate solution and is building its first facility in northeast Washington state where it will use timber waste as its feedstock.

Other startups are building machines that can vacuum carbon out of the air and either use or store it, but these efforts so far cost hundreds of dollars per ton to remove CO2.

A Pacific Northwest regional consortium recently won a $3 million award from the U.S. Department of Energy to explore the possibility of creating a carbon capture hub in the area. The hub could use a variety of carbon capture and storage technologies, including trapping the carbon in the area’s abundant basaltic rocks.

Microsoft and Amazon this fall signed separate deals with carbon capture startups in which the tech giants are paying the companies to remove carbon on their behalf.

Last week Heirloom, which has a deal with Microsoft, announced that it had started operations at the first commercial direct air capture facility in the U.S.

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