Techno-economic feasibility of thermal storage systems for the transition to 100% renewable grids

Abstract

Batteries are often used to overcome the intermittency of renewable energy resources. However, Li-ion batteries are associated with tremendous metal depletion, environmental impact, and human health hazards. Thermal energy storage systems are often disregarded in large-scale plans for direct production of electricity due to the losses encountered in the conversion process. Using Jordan as a case study, six different systems were evaluated, namely Photovoltaic (PV)-thermal storage, PV-wind-thermal storage, PV-concentrated solar power (CSP)-thermal storage, PV-CSP-wind-thermal storage, PV-CSP-Li-ion battery, and PV-CSP-wind-Li-ion battery. Different techno-economic parameters were considered to scan for the installation sites of highest demand-supply matching and lowest levelized cost of electricity. The results showed that when thermal storage is adopted, incorporating wind turbines with the solar system decreases the total installation capacity by about 35%, even though larger thermal storage is required. The optimal configurations of PV-CSP-wind-thermal storage and PV-CSP-wind-battery systems have storage capacities of 0.340 TWhth and 0.109 TWhe, respectively. This work revealed that the integration of thermal storage to renewable power generation systems in Jordan is not only feasible and can cover 100% of the energy requirements at all times, but also can offset the huge need for the more common but perilous alternative (Li-ion batteries).