Advancing sustainability in subsurface systems for decarbonization

The subsurface is indispensable to deep energy decarbonization, with capacity to store energy on scales necessary to balance renewable grid loads and to sequester carbon on scales relevant to emission reduction targets. Sustainably engineering subsurface reservoirs for energy production, energy storage, and dedicated carbon storage requires an integrated understanding of the geologic and systems-level processes governing performance and environmental impacts. This talk highlights our research on subsurface hydrogen and carbon storage systems at both of these scales. With respect to hydrogen storage, experiments coupled to analytical techniques demonstrate conditions under which biogeochemical reactions compromise hydrogen retention and purity in porous reservoirs, both through microbial H2 consumption and production of harmful byproducts. Techno-economic analyses further motivate continued research to overcome current knowledge gaps in our ability to deploy hydrogen storage in porous reservoirs, demonstrating the cost and efficiency advantages of employing porous storage to support green hydrogen and/or ammonia pathways at the surface. With respect to carbon sequestration, reactive flow experiments coupled with x-ray computed tomography demonstrate how complex interactions among reservoir geochemistry, fracture structure, and transport control carbon mineralization in fractured basalt. Systems-level analyses quantify the inherent value of carbon mineralization across a range of capture and storage scenarios, further motivating research efforts to sustain reactions toward complete mineralization of injected CO2. Collectively, these studies have important implications for designing injection schemes that optimize long-term performance in energy and carbon storage reservoirs, as well as informing policy or incentive structures that guide sustainable planning of subsurface resources to support energy transitions and carbon management.

Speaker: Anne Menefee, Pennsylvania State University