Assessing the Hybridization of an Existing Geothermal Plant by Coupling a CSP System for Increasing Power Generation

Abstract

Concentrated Solar Power (CSP) and geothermal energy systems are outlined as two of the most promising technologies for sustainable and reliable electricity generation. Several studies in the technical literature have pointed out that the hybridization of solar and geothermal energy sources could lead to a reduction of the levelized cost of energy (LCOE) of geothermal systems, as well as improving the capacity factor of CSP systems. However, the technical literature shows that the integration of solar thermal collectors does not present a positive impact in all scenarios analyzed. The present study aims to further analyze the competitiveness of the hybridization of solar and geothermal systems under high irradiation conditions such as those observed in the Andean region in northern Chile. The evaluation was carried out by coupling a thermodynamic model in Engineering Equation Solver (EES) with a solar thermal model in the System Advisor Model (SAM). The assessment considers the configuration of an existing geothermal plant, considering the design constraints associated with the actual operating conditions of the plant. The analysis is based on an energy and exergy assessment, allowing us to identify the efficiency of the subsystems introduced for the hybridization and assess the competitiveness of the hybrid schemes by an economic assessment in terms of the LCOE. The results show that the hybrid schemes allow a reduction of the LCOE of a geothermal stand-alone plant by about 10 USD/MWh, increasing the competitiveness of the geothermal system. However, a large variation on such a reduction is observed depending on the size of the solar field and the storage tank of the solar system.

Techno-Economic Analysis of Greenfield Geothermal Hybrid Power Plants using a Solar or Natural Gas Steam Topping Cycle

“…In Hu et al [14] and Ghasemi et al [15], solar is used to heat the geothermal brine without a topping cycle, and in Lentz and Almanza [16], solar thermal is used to assist an underperforming geothermal plant. Adding supplemental heat to the geothermal brine was also considered by Hu et [14], [17], [18].…”

“…Thus, investigating a greenfield hybrid system with a solar topping cycle and a geothermal bottoming cycle remains a novel area of research. [7], [17], [20], and annual energy production (AEP), McTigue et al, Tranamil-Maripe et al, and Song et al [7], [17], [22]. Despite a well-established history in the literature, opportunities for novelty in this field still exist in the form of greenfield design and dispatch/design focused on value of the system.…”