Graphyte Carbon Sequestration: Empirical Monitoring of Carbon Stability in Dry-tomb Chambers

AUTHORS: RYAN GEYGAN, HANNAH MURNEN 

This white paper presents one year of monitoring results from Graphyte’s inaugural site, Project Loblolly in Sheridan, Arkansas. To date, Project Loblolly has sequestered more than 6,000 metric tons of carbon dioxide equivalent (CO2e) in six sequestration chambers (zones).

Direct gas measurements of carbon dioxide (CO2) and methane (CH4) concentrations within these zones demonstrate that the Carbon Casting system is preserving carbon captured by biomass (i.e., decomposition of sequestered biomass is not occurring).

Specifically, the data show no measurable increases in CH4 in any zone and minimal increases in CO2. The CO2 rates we observe are 50-100x lower than what would be expected from decomposing biomass and are consistent with the slow oxidation of trace organic carbon found within the sand infill material. In other words, the observed CO2 rates show no sign of biomass decomposition and instead indicate sand carbon oxidation. In addition, pressures are stable and temperatures move in line with seasonal variation, indicating that no biomass

decomposition is occurring within the detection limits of the system.

These results provide direct evidence that Graphyte’s Carbon Casting method prevents biomass decomposition at commercial scales for appreciable time periods. The monitoring framework enables ongoing verification of carbon stability with better than part-per-million (ppm) sensitivity, offering high-confidence durability assessments over project lifetimes.

Graphyte’s analytical system can detect anaerobic carbon degradation at sub-ppm levels, and will allow for ongoing direct measurement when all oxygen is depleted from a zone and thus becomes anaerobic.

Download the full white paper:

Graphyte_MRV White Paper_December 18 2025.pdf

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