Decarbonizing the electricity sector using terawatt-scale interconnected photovoltaic power grids to meet the climate goals: A comprehensive review and a strategic roadmap

Abstract

High scalability and quick deployability of solar photovoltaic (PV) make it an ideal candidate for rapid decarbonization of electricity. The typical SPV generation profile and power grids designed for conventional power plants (PP) are the major obstacles to maximizing SPV utilization. While energy storage systems (ESS) are often deemed critical, scalable ESS are site-limited, highly dependent on rare-earth elements, and either have higher embodied energy and emissions or low round-trip efficiencies. This manuscript demonstrates that by strategically interconnecting SPV power plants longitudinally, PV can meet base load demands and extend availability beyond peak-solar hours, thereby reducing the need for ESS and replacing existing carbon-intensive electricity infrastructure. It is demonstrated by modelling two 12 GW longitudinally separated transmission lines interconnecting SPVPPs situated 40° (case-1) and 90° (case-2) apart can provide PV electricity beyond solar hours for 4.69 and 7.33 equivalent hours (daily average), respectively. For cases 1 and 2, the lithium battery-ESS route can result in 4.76 and 3.35 times more carbon emissions and cost 4.23 and 2.98 times more than the transmission route, respectively, for providing the same energy over the transmission line's 40-year lifespan. Technologies such as multi-terminal ultra-high-voltage-DC grids, hybrid superconductive cables, new semiconductor materials for PV and energy systems, etc. are explored for the globally interconnected solar grid. Findings suggest 90 TWp of PV capacity can supply a significant portion of world's energy demand by 2050. This study outlines a comprehensive approach to build a sustainable and interconnected global solar energy infrastructure that aligns with climate objectives.