Hybrid geothermal power plants operate by using geothermal fluid to preheat the working fluid of a higher-temperature power cycle for electricity generation. This has been shown to yield higher electricity generation than the combination of a stand-alone geothermal power plant and the higher-temperature power cycle. Here, we test both a direct CO₂ hybrid geothermal system and an indirect brine hybrid geothermal system. The direct CO₂ hybrid geothermal system is a CO₂ Plume Geothermal (CPG) system, which uses CO₂ as the subsurface working fluid, but with auxiliary heat addition to the geologically produced CO₂ at the surface. The indirect brine geothermal system uses the hot geologically produced brine to preheat the secondary working fluid (CO₂) within a secondary power cycle.

We find that the direct CPG-hybrid system and the indirect brine-hybrid system both can generate 20 % more electric power than the summed power of individual geothermal and auxiliary systems in some cases. Each hybrid system has an optimum turbine inlet temperature which maximizes the electric power generated, and is typically between 100 °C and 200 °C in the systems examined. The optimum turbine inlet temperature tends to occur where the geothermal heat contribution is between 50 % and 70 % of the total heat addition to the hybrid system. Lastly, the CO₂ direct system has lower wellhead temperatures than indirect brine and therefore can utilize lower temperature resources.

混合式地热发电厂通过使用地热流体来预热高温循环的工作流体来发电。与单独的地热发电厂和更高温度的电源循环相结合，这已显示出更高的发电量。在这里，我们测试了直接CO ₂混合地热系统和间接盐水混合地热系统。直接CO ₂混合地热系统是CO ₂羽状地热（CPG）系统，该系统使用CO ₂作为地下工作流体，但在地质生产的CO _2中还添加了辅助热量。在表面。间接盐水地热系统使用地质学生产的热盐水在二次发电周期内预热二次工作流体（CO ₂）。

我们发现，在某些情况下，直接CPG混合系统和间接盐水混合系统均可产生比单个地热和辅助系统总和多20％的电。每个混合动力系统均具有最佳的涡轮机入口温度，该温度可使发电量最大化，并且在检查的系统中通常介于100°C至200°C之间。在地热贡献占混合系统总热量的50％至70％的位置，往往会出现最佳的涡轮机入口温度。最后，CO ₂直接系统的井口温度比间接盐水低，因此可以利用较低的温度资源。