A review on geothermal-solar hybrid systems for power production and multigeneration systems

Abstract

Geothermal and Solar are among the renewable energy, classed as low to high-temperature sources which are abundant across the globe. However, geothermal resources surfer extraction challenges as well as resource degradation. On the other hand, solar resources are highly intermittent and unavailable at night. Researchers have proposed hybrid geothermal-solar energy schemes to overcome their challenges and to enhance their energy efficiency. This review presents the directions, challenges, opportunities, and future orientations of hybrid geothermal-solar combinations. An overview of solar and geothermal energy sources applications with main use is presented. The study concentrated on the presented hybrid systems for electricity generation (power systems) and multigeneration systems. It is found that geothermal–solar hybrid applications in power plants involve lower enthalpy and lower cost geothermal heat source combined with higher enthalpy and higher-cost solar thermal heat to achieve better performance, with a reported power production increase by upto 20% in some cases compared to geothermal only power plants. Geothermal–solar hybridization in multigeneration has increasingly been proposed for hydrogen production, electricity generation, clean water production and space heating and cooling, energy outputs in an efficient way. It is indicated that promising performance results with exergy and energy efficiency of 40% and 50% are reportedly attainable. The main challenge of multigeneration schemes is their complexity and their real applications are rare.