Performance Evaluation of Geothermal Hybrid Systems Under Grid-Connected Operation Scenarios

In the United States, geothermal power generation is primarily concentrated in California and Nevada, leveraging high-temperature hydrothermal resources. However, geothermal energy remains underutilized even within these states and outside the western US, its deployment for power production is limited, largely due to lower-temperature geothermal resources that result in reduced energy conversion efficiencies and high capital expenditures (CAPEX). Hybridizing geothermal power plants with concentrated solar power (CSP) technologies and borehole thermal energy storage (BTES) presents a promising pathway to enhance geothermal competitiveness. This approach can increase operating temperatures while potentially lowering installation costs. Furthermore, integrating geothermal systems with other energy can improve their dispatchability and grid integration capabilities. However, the value of both standalone and hybrid geothermal systems in providing grid flexibility and stability has not been fully quantified or demonstrated. To address this gap, we have developed a digital twin of a 1 MWe hybrid system. This system integrates a 10 MWth parabolic trough collector CSP plant with a BTES unit, which is connected to a binary geothermal plant via a primary heat exchanger. The digital twin has been implemented in a digital real-time simulation (DRTS) environment using a hardware-in-the-loop (HIL) setup at NREL's Advanced Research on Integrated Energy Systems (ARIES) platform. This developed tool is being used to evaluate the potential of geothermal and hybrid geothermal systems to enhance electric grid flexibility under various operational scenarios.