The Net Fossil Energy Savings of Global Solar PV Supply Chains and Their Vulnerability to Tariff Barriers

Solar photovoltaics (PV) is a pivotal technology for achieving carbon neutrality, with its cost reduction deeply intertwined with the specialization of global supply chains. However, the spatial decoupling of production and usage has raised concerns about its net environmental benefits: while global supply chains facilitate PV deployment, do their own operations consume excessive fossil fuels? To address this question, this study develops an integrated framework combining a dynamic partial equilibrium model with life cycle assessment (LCA) based on counterfactual scenarios, aiming to quantify the net fossil energy savings of the global PV supply chain over its entire life cycle. The results demonstrate that although manufacturing and transportation increase consumption, the fossil energy displacement achieved during the deployment phase of PV systems supported by these supply chains is overwhelmingly dominant, with an energy payback ratio exceeding 5000. Nevertheless, trade protectionism severely undermines this net benefit: extreme tariff policies, by suppressing global PV deployment, could lead to a loss of up to 25% in net energy-saving potential. The study further reveals that trade openness is critical for the efficacy of climate policies; under high tariff barriers, the marginal gains of strengthened climate commitments diminish substantially. This research proves that maintaining open and efficient global supply chains is essential to realizing the full energy and environmental benefits of PV technology.