Minneapolis-based carbon removal firm Carba has announced a five-year agreement to deliver 44,000 carbon removal credits to Microsoft, marking a significant step in scaling up biochar-based carbon capture technologies.
Carba’s innovative approach uses a patented pyrolysis reactor and burial method to convert biogenic waste into high-carbon biochar, which is then stored underground in low-oxygen environments. The company’s autothermal pyrolysis technology is designed for high energy efficiency and long-term carbon stabilisation.
Under the agreement, Carba will produce and bury biochar as an alternative daily cover at a local landfill, where the material is expected to be protected from degradation. Preliminary research suggests the biochar may offer additional environmental benefits, acting like an activated carbon filter by reducing odours and absorbing pollutants such as persistent organic pollutants (POPs), dioxins, furans, and PCBs. These co-benefits will be further evaluated during the operational phase.
“We’re thrilled to contribute to Microsoft’s portfolio by providing high-quality carbon removal credits that will begin retiring this year,” said Andrew Jones, CEO of Carba. “Our integrated approach—from biomass sourcing and processing to secure storage—positions us to scale rapidly while potentially delivering wider community benefits.”
Microsoft’s Senior Director for Energy & Carbon Removal, Brian Marrs, added: “Carba’s co-located model for biomass delivery, pyrolysis, and storage offers promise as a scalable and cost-effective climate solution. This agreement enables us to assess the viability of biochar for long-term carbon removal and explore its co-benefits, with a straightforward monitoring and verification process.”
The project has already gained notable recognition. In 2024, Carba received a $7 million grant from the US Department of Energy under the Carbon Negative Shot Pilot initiative (FOA 382). The project’s methodology has been certified by Isometric, which awarded it carbon credits with a 1,000-year durability rating.
Carba’s deal with Microsoft represents a growing trend in corporate investment in durable carbon removal technologies as businesses seek to meet net-zero commitments and contribute to climate resilience.
