Ground source cooling to increase power generation from geothermal power plants

The utilization of geothermal resources for electricity generation relies heavily on appropriate power plant technology, which is linked to the resource's enthalpy potential. Moderate and high-enthalpy resources often find application in binary (Organic Rankine Cycle) plants, flashing-type plants, or even hybrid configurations. Among the crucial elements determining plant efficiency is the cooling system. By maintaining low turbine exhaust pressure, an effective cooling system facilitates enhanced power output. Traditional options include wet-type and dry-type cooling systems, both with established roles in geothermal applications. This study focuses on mitigating the detrimental impact of high ambient temperatures during summer months on geothermal power plant performance. Specifically, we propose the first-ever implementation of ground source cooling for a combined geothermal power plant in Western Anatolia, Turkiye. This innovative approach aims to counteract the decline in electricity generation observed during summer and maintain stable output throughout the year. The TOUGH + RealGasBrine V1.5 was employed to model the heat transfer dynamics between the buried pipes of the ground source cooling system and the surrounding ground. The simulated system underwent a three-month injection phase followed by a nine-month shutdown period to allow for a return to initial temperature conditions. This comprehensive modeling approach provided valuable insights into system behavior and performance. The simulations revealed a highly encouraging outcome: ground source cooling has the potential to enhance the power generation performance of the geothermal plant by over 10% during summer conditions. This significant improvement underlines the feasibility and effectiveness of the proposed approach. Furthermore, a sensitivity analysis was conducted to assess the influence of pipe diameter on temperature transient behavior and overall system feasibility. This analysis provides valuable information for optimizing the design and implementation of ground source cooling in future geothermal projects.