Domestic and overseas manufacturing scenarios of silicon-based photovoltaics: Life cycle energy and environmental comparative analysis

• Comparative life cycle study of silicon-based photovoltaic modules.
• Domestic and overseas manufacturing scenarios.
• Country-specific life cycle inventory database.
• Energy payback time, energy return on investment and greenhouse gas emission.
• Break-even carbon tariff model.

While life cycle assessment (LCA) has been recognized as an invaluable tool to assess the energy and environmental profiles of a photovoltaic (PV) system, current LCA studies are limited to Europe and North America. However, today most PV modules are outsourced to and manufactured in non-OECD countries (e.g., China), which have a substantially different degree of industrialization and environmental restriction. To investigate this issue, we perform a comparative LCA between domestic and overseas manufacturing scenarios illustrated by three kinds of silicon-based PV technologies, namely mono-crystalline silicon, multi-crystalline silicon and ribbon silicon. We take into account geographic diversity by utilizing localized inventory data for processes and materials. The energy payback time, energy return on investment and greenhouse gas (GHG) emissions for both scenarios are calculated and analyzed. Compared to the domestic manufacturing scenario, the energy use efficiency is generally 30% lower and the carbon footprint is almost doubled in the overseas manufacturing scenario. Moreover, based on the LCA results, we propose a break-even carbon tariff model for the international trade of silicon-based PV modules, indicating an appropriate carbon tariff in the range of €105–€129/ton CO2.