Water-driven geothermal heat extraction with simultaneous CO2 injection: overview of concepts, benefits and challenges

• DOI: 10.5194/egusphere-egu24-10031
• Publication Date: 2024-03-08T19:51:51Z
• Authors: Annick Loschetter; Christophe Kervévan; Rowena Stead; Thomas Le Guénan
• Keywords: Water extraction

Geothermal energy production and CCS (Carbon Capture Storage) represent promising technological solutions to help mitigate climate change aid the current global crisis. In recent years, number of concepts that propose combine mutualize these technologies has risen dramatically. While a (notably CPG CO2-EGS) use supercritical CO2 as heat vector, another route for hybridization is inject dissolved in geothermal brine. This focus our work. An extensive literature review was carried out concepts, complemented by interviews some developers. A few are still theoretical (only described literature), but most ones on way pilot/demonstration projects at progressively increasing scale. The main their associated sites are: CO2-DISSOLVED technology, with potential identified Paris basin (France); AAT-G / Cleag site Croatia; Related CarbFix, GECO SUCCEED, Hellisheidi (Iceland), Nesjavellir Bochum (Germany), Kızıldere (Turkey), Castelnuovo Italy (as case study due permitting issues); Reinjection from brines Ngatamariki Te Huka New Zealand. Despite similarities, differentiated purpose: either store an external industrial emitter CO2-Dissolved concept), thus bringing contribution CCS, or reinject emitted CO2-rich brine during exploitation, near-zero emissions. Because solubility limit brine, performance extraction generally higher than storage. For instance technology particularly well-suited small emitters (ca. <150,000 t CO2/year). Unlike using CO2, those can be deployed much lower depths (no need exceed point). tight caprock, high trapping represents risk leakage. system behaves mainly water-driven system, adjunction cases increase thermo-hydrological (pH decrease might avoid clogging and/or open porosity carbonate reservoirs). challenges addressed, including complexity regulations validation technical aspects. Besides, considering variety underground configurations, there no turnkey solution, which hamper economics such small-scale projects. Acknowledgements: work part taken published report ‘IEAGHG, “Prospective integration Energy Carbon Storage (CCS)”, 2023-02, August 2023’. We grateful IEAGHG, especially Nicola Clarke, proposing funding this topic interesting scientific discussions debates