Hydrogen energy and geological carbon retention using a biogas-geothermal wellborereformation tool Enhancing overall resource efficiency contributes significantly to energy security. Biogas serves asa critical energy asset within waste management by converting diverse organic wastes into highervalueproducts. Through the establishment of integrated partnerships, sector coupling underscoresthe synergies among geothermal energy, district heating, industry-related CO₂, urban biowaste, andagriculture. This innovative geothermal approach — applied to wellbore biogas reformation —facilitates hydrogen production alongside point-of-use geological carbon capture and storage (CCS).The Carbon Injection and Gasification Geothermal (CIGG) methodology offers a direct and effectivepathway towards net zero by merging biogas reformation and carbon capture with low-grade districtheat geothermal systems. This approach streamlines the hydrogen generation and CCS systems byeliminating unnecessary surface process steps, while incorporating reservoir heat storage andrecovery, thereby reducing process energy consumption, costs, and material use, and results in anintegrated, more energy efficient and sustainable solution. To realise these synergies, a specialised wellbore tool for biogas (methane) reformation is underdevelopment, designed to leverage the natural properties of a geothermal reservoir formation andits fluids (i.e., heat storage, geothermal pressure, and temperature). The reformation’s resulting hotCO₂ waste stream from this tool is injected into the reservoir, for heat storage and later recovery.This mitigates the reservoir rock’s temperature depletion typically observed from long termproduction of geothermal power fluids. Moreover, this immediate, in situ downhole CO₂ capture willenable improved geothermal power efficiencies through enhanced heat recovery utilising the powerfluid. As geothermal wells generally possess a lifespan of 15 to 25 years, integrating theseprocesses bolsters long-term energy security. Overall, the CIGG process represents a mutuallybeneficial advancement for both energy sectors and environmental stewardship.
Gillick et al. (Wed,) studied this question.