| Title | Re-assessing the Economic Prospects of Low-temperature Geothermal Resources Through Bioenergy Hybridization and Aqueous Dissolution of Biogenic CO2 |
|---|---|
| Authors | Karan Titus, David Dempsey, Rebecca Peer, Jannik Haas, Rosalind Archer |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Geothermal electricity is mostly generated in a handful of countries endowed with high-temperature hydrothermal systems (>250°C). In these countries, geothermal contributes a valuable role as a source of renewable, baseload generation. However, the most profitable high-temperature hydrothermal systems have largely been exploited, relegating future developments to more challenging and less accessible resources. Here, we propose combining bioenergy hybridization and biogenic CO2 removal with low temperature-hydrothermal systems to improve global geothermal resource potential. Low-temperature systems (<160°C) are far more abundant globally than their high-temperature counterparts. These are typically considered less suitable for electricity production due to diminished thermodynamic conversion efficiencies. Although advances in binary technologies have improved access to low-temperature systems, lower nameplate capacities, and thereby revenue streams, can still raise difficult business case questions. Pairing low-temperature systems with bioenergy hybdriziation and biogenic CO2 removal can bolster revenues through surface enthalpy control and credited negative emissions. Our results show that surface enthalpy control can improve the electricity production of low-temperature resources while requiring fewer wells per MWe. Naturally, such a scheme hinges on the availability of sustainable biomass feedstocks. If said biomass feedstocks are combusted in pure oxygen, a high-grade of CO2 is produced and can be dissolved in the reinjected brine for subsurface storage. If leveraged as revenues on an emissions trading market, this storage presents a secondary revenue stream. At reasonable future CO2 market prices, negative emissions may even carry more weight than electricity production with regards to economic feasibility. |