Manufacturing the next generation of solar panels could reduce global CO2 emissions by as much as 8.2 billion tonnes by 2035, according to a new international study led by researchers at the University of Warwick with colleagues from the Universities of Northumbria, Birmingham and Oxford. The team explored how the rapid scale-up of advanced photovoltaic technologies can both support global decarbonization and reduce the footprint of solar energy production itself.
Solar panels, scientifically known as solar photovoltaics, convert sunlight directly into electricity and are already central to climate mitigation strategies worldwide. As countries deploy solar energy at multi-terawatt scales over the next decade, policymakers and industry are paying increasing attention to the emissions and resource demands inherent in the production of these devices.
At the same time, the solar energy sector is undergoing a major technology transition. The long-dominant passivated emitter back cell, or PERC, architecture is being replaced by a newer, higher efficiency design called tunnel oxide passivated contact, or TOPCon, solar photovoltaics. Until now, the full environmental implications of switching production lines from PERC to TOPCon on a very large scale had not been comprehensively assessed.
In research published in Nature Communications, the team conducted a full life cycle assessment comparing the entire production chain of PERC and TOPCon technologies. They evaluated the impacts associated with material extraction, cell and module manufacturing, and upstream energy consumption to determine whether TOPCon can reduce the overall environmental burden of PV production as deployment accelerates.
Lead author Dr. Nicholas Grant, associate professor at the University of Warwick, said multi-terawatt scale photovoltaic production requires a sharper focus on its full carbon footprint. “Our paper shows how targeted supply chain improvements can deliver sustainable manufacturing at terawatt scale, avoiding twenty-five gigatons of production-related CO2 emissions if installed in 2035, while supporting rapid global deployment.”
The life cycle analysis showed that the production of TOPCon panels in fifteen of the sixteen categories has a lower impact on the environment than existing PERC technology. The analysis indicates a 6.5 percent reduction in climate change emissions per unit of installed electricity capacity for TOPCon, with the only significant trade-off being higher silver consumption, which puts additional pressure on critical mineral reserves.
The study underlines how the carbon intensity of local electricity grids determines the footprint of solar energy production. Producing solar photovoltaic energy using low-carbon electricity, such as in regions where grids rely heavily on renewable energy sources or nuclear energy, can significantly reduce production emissions compared to production on systems dependent on fossil fuels. This makes the establishment of new PV factories an important lever in reducing the overall climate impact of the solar supply chain.
By combining the widespread adoption of TOPCon technology with process improvements and the gradual decarbonization of electricity grids, the researchers estimate that cumulative emissions from solar energy production could fall by as much as 8.2 gigatonnes of CO2 equivalent by 2035. That figure is on the order of 14 percent of current global annual emissions, highlighting the potential climate benefit embedded in the technology choices made by PV manufacturers and policy makers today.
At the same time, solar photovoltaic research projects installed between 2023 and 2035 will help prevent more than 25 gigatons of CO2 emissions by replacing electricity generation from fossil fuels. This reinforces solar energy’s role as a cornerstone of global climate mitigation, even if the environmental costs of production are fully taken into account in system assessments.
Senior author Professor Neil Beattie from Northumbria University said solar photovoltaics is a crucial technology that can now be used globally to reduce greenhouse gas emissions and strengthen energy security. He noted that this role will become even more important as electricity demand surges over the next decade, driven by electric transport, low-carbon heating and the expansion of digital infrastructure for applications such as artificial intelligence.
“Even taking into account the impact on production, solar photovoltaics remains one of the least impactful and most sustainable electricity generation technologies available throughout its life cycle and we must now focus on its adoption at scale,” Professor Beattie added. The authors argue that aligning technology roadmaps, manufacturing locations and grid decarbonization strategies can maximize emissions savings from this rapid solar rollout.
Co-author Professor John Murphy, Chair of Electronic Materials at the University of Birmingham, said silicon-based photovoltaic technologies are immediately relevant to Britain and are already playing an important role in efforts to achieve net zero emissions. He described the work as a product of a new collaboration between four leading UK university research groups, which aims to investigate sustainability in the solar photovoltaic supply chain, from raw materials to end-of-life management.
Sebastian Bonilla, associate professor of materials science at the University of Oxford and co-author, said the world is at a critical juncture as solar energy is set to provide a substantial portion of global electricity generation. He said the study uniquely identifies the environmental impacts of the ongoing transition to solar energy and can inform decisions about materials, technologies and manufacturing sites that minimize damage while maximizing the benefits of green electricity at the terawatt scale.
Research report: Maximizing environmental savings in silicon photovoltaic solar energy production until 2035
