Energy Return on Investment Trends of Solar PV in the Energy Transition

Solar photovoltaics (PV) is expected to play a central role in the global energy transition, yet its longterm energy requirements for its installations and operations are often underestimated. This study examines the evolution of energy return on investment (EROI) for solar PV systems between 2015 and 2050 across nine world regions. The analysis uses a dynamic modelling framework that combines life cycle assessment with cost-optimised system modelling, considering both utility-scale and prosumer-scale systems under five transition pathways. These include three rapid transition scenarios aiming for 100% renewable energy by 2035, 2040, and 2050, and two International Energy Agency scenarios that reflect more conservative policy projections. The findings show that under accelerated transitions, utility-scale PV achieves consistent improvements, with most regions converging to EROI values between 30 and 45 by mid-century. The highest outcomes are recorded in the Middle East and Africa, supported by large-scale adoption of single-axis tracking technologies. Prosumer-scale PV systems improve more gradually but still approach an EROI of 30 in most regions. By contrast, conservative scenarios deliver more uneven results, with strong performance in high-resource regions such as the Middle East but much weaker progress elsewhere. These findings highlight that the scale and configuration of solar PV deployment are decisive in shaping long-term energy returns.