Permanent, Affordable and Scalable Carbon Removal through Carbon Casting

H. Murnen
United States

Keywords: carbon removal, biomass


Carbon removal is increasingly being recognized as a critical part of the work needed to avoid the worst impacts of climate change. While decarbonization efforts must be undertaken, significant amounts of carbon dioxide and methane must also be removed from the atmosphere. However, it is thermodynamically difficult to separate CO2 from the air due to its relatively low concentration of approximately 400 ppm. This results in large energy requirements for typical absorption-based Direct Air Capture (DAC) processes. Even if renewable energy is used for directly capturing CO2 from the air, that renewable energy cannot be used for other purposes, like generating power or producing materials like steel or cement, slowing down the overall process of decarbonization. In addition, the resulting stream of captured CO2 must be compressed and transported to a geologic storage location, reducing the feasible project locations and increasing the complexity of those projects. Plants, on the other hand, are designed to capture CO2 out of the air and convert it into solid biomass. They do this using energy from the sun, representing a passive path towards capturing carbon out of air. However, biomass is usually left to decompose naturally or burned, releasing that carbon back into the atmosphere in the form of CO2 or methane (CH4). Graphyte has developed the process of Carbon Casting to take waste biomass, stop the decomposition process, encapsulate the biomass to prevent the reintroduction of water and therefore restarting of decomposition, and to permanently store the resulting inert biomass blocks in a purpose-built storage site. This presentation will share the current operational status of the first Carbon Casting facility in Pine Bluff, Arkansas as well as the experimental data to date validating the durability of the carbon stored. The Monitoring, Reporting and Verification (MRV) system will also be described with a focus on operational deployment.