More efficient power production from geothermal resources could lower capital and operating costs while increasing conversion efficiency.

 In coordination with the Supercritical CO2 (sCO2) Team, the Geothermal Technologies Office (GTO) conducts early-stage applied research to increase the operational efficiency of sCO2 power cycles utilizing geothermal heat. The unique subsurface flow properties of sCO2 suggest that it may also offer potential efficiency advantages as a heat extraction fluid.

Geothermal sCO2 Power

GTO conducts foundational research to explore sCO2:

  • Potential operational efficiencies of sCO2 for fluid circulation through a surface power cycle.
  • Subsurface dynamics of sCO2 as a heat extraction fluid

In a first-of-a-kind field demonstration, Lawrence Berkeley National Laboratory and its partners successfully deployed an sCO2 thermosiphon at the SECARB Cranfield Test Site in Mississippi (2015).

GTO sees commonalities with the long-term development of commercial-scale sCO2 Brayton-cycle power generation and integration with sCO2 as a subsurface geothermal working fluid. In particular, use of sCO2 within enhanced geothermal systems (EGS) is a potentially important long-term goal, pairing transformative heat extraction techniques with unique working fluids.