# Maximising environmental savings from silicon photovoltaics manufacturing to 2035

## TL;DR

This study compares the environmental impact of two solar cell technologies and shows that switching to a newer design can significantly reduce CO2 emissions by 2035.

## Contribution

The study provides a forecast of environmental savings from adopting tunnel oxide passivated contact solar cells and varying electricity mixes.

## Key findings

- Tunnel oxide passivated contact cells reduce CO2 emissions by 6.5% per watt peak compared to older technology.
- Switching to this new technology could save 8.2 gigatonnes of CO2 equivalent emissions by 2035.
- The carbon intensity of the electricity mix is a critical factor in the environmental impact of solar cell manufacturing.

## Abstract

The silicon photovoltaics market is transitioning from the incumbent passivated emitter rear cell to the higher efficiency tunnel oxide passivated contact technology and it is crucial to understand the environmental impact of this change. Here, we conduct life cycle assessment to compare both technologies quantitatively and identify environmental savings in 15 of 16 environmental impact categories for tunnel oxide passivated contact. This includes a 6.5% reduction in carbon dioxide equivalent emissions, per watt peak at the expense of 15.2% increase in metal resource use, for photovoltaic modules manufactured in China and transported to central Europe. A critical factor in photovoltaics manufacturing is the carbon intensity of the electricity mix. We model the impact of photovoltaics production across different global regions, incorporating future electricity mix scenarios and a projection for photovoltaics deployment. Our model provides a forecast of the environmental impact of global photovoltaics manufacturing and identifies a potential reduction of 8.2 gigatonnes of carbon dioxide equivalent emissions by 2035, depending on manufacturing location.

This study quantifies the environmental impact associated with photovoltaics manufacturing and demonstrates significant CO2 emissions savings, depending on solar cell technology and the composition of the electricity mix in the region of manufacture.