Global Supply Chains Reduce the Cost of Achieving Paris Agreement Solar PV Targets by More Than Previously Estimated

Global supply chains (GSCs) reduce solar photovoltaic (PV) module costs and accelerate deployment for Paris Agreement targets. Using production, trade, price data, and learning curve modeling across regions, we estimate that GSCs could enable 4085 million tonnes of CO2 emission reductions from 2018-2030 through production scale-up. Relative to a counterfactual without GSCs, cost savings represent 15.85-17.95% of the cumulative module costs required for the 1.5 °C target. Validation against 2022-2025 data, however, reveals that these estimates are conservative: recalibrated learning rates and trade growth yield 77-99% higher savings by 2030. Stricter trade policies could erode savings by ∼8%, but learning gains far outweigh potential losses. Maintaining open supply chains is essential for capturing the full cost-reduction potential of solar PV.