A critical review of technological advancements and challenges in geothermal power generation

Geothermal power generation is regarded as an important pathway for achieving effective utilization of geothermal resources and has attracted increasing research interest worldwide. However, the development of geothermal power generation technologies is still limited by low thermodynamic efficiency. Therefore, a comprehensive review of geothermal power generation technologies is conducted in this study, including flash cycle, dry steam, organic Rankine cycle, thermoelectric generators and combined-cycle. Additionally, future trends and challenges in geothermal power generation are analyzed. Furthermore, the thermo-economic performance and optimization methods for geothermal-driven combined cooling, heating, and power systems are comprehensively examined. Binary-cycle geothermal power generation systems show significant potential for geothermal fluids at 90-150 °C, which effectively mitigate scaling and corrosion issues by preventing direct contact between geothermal fluids and power production components. Future studies are expected to emphasize optimization of geothermal ORC layouts, working-fluid selection, as well as CFD-based turbine design to mitigate irreversible losses and improve geothermal power generation efficiency. A geothermal poly-generation system enhances overall system performance by cascading utilization of medium- and high-temperature geothermal resources. Based on an assessment of existing design limitations, state-of-the-art technologies and optimization strategies are identified to improve geothermal energy utilization, including modular thermoelectric generation, advanced cycle optimization, solar–geothermal hybrid integration, and cogeneration control strategies.