Methane-to-graphite: A pathway to reduce greenhouse gas emissions in the U.S. energy transition
Santiago D. Salas, Jennifer B. Dunn
Abstract
Graphite, an important ingredient in the energy transition, faces supply constraints in the U.S. Natural gas decomposition (NGD) coupled with graphitization could be an emerging source of graphite. We investigate using abundant U.S. natural gas resources to produce graphite via natural gas decomposition (NGD) coupled with graphitization at the Eagle Ford shale. When NGD uses wind power, it is possible to produce graphite at 94 % less greenhouse gas (GHG) emissions than conventional synthetic graphite and 93 % less emissions than natural graphite. In addition, producing graphite in the U.S. with NGD could meet graphite demand through 2050. The co-produced H2 exhibits life-cycle GHG emissions between 0.71 to 0.78 kg CO2e/kg H2, well below the Inflation Reduction Act's threshold of 4 kg CO2e/kg for tax credit eligibility. Furthermore, decomposing NG to H2 and graphite in the most promising scenario reduces baseline NG system emissions (cradle-to-grave) by 78 %.