Next-Gen Solar Panels Could Avoid 8.2 Billion Tonnes of CO2 by 2035

Solar panels are already among the lowest-carbon electricity sources available over their full operating lifetime. But manufacturing them still has an environmental cost, and as global deployment pushes toward multi-terawatt scale, even modest reductions in the manufacturing footprint compound into enormous absolute numbers. A study published in Nature Communications by researchers from Warwick, Northumbria, Birmingham, and Oxford Universities quantifies exactly how large those numbers could be - and identifies which levers matter most.

The analysis compared the complete manufacturing lifecycle of two solar cell architectures: passivated emitter rear cell (PERC), currently the dominant commercial standard, and tunnel oxide passivated contact (TOPCon), a newer design with higher conversion efficiency that is rapidly gaining market share. Using life-cycle assessment methodology across 16 environmental impact categories, the team found TOPCon superior in 15 of them.

The 6.5% Advantage - and the One Drawback

Per unit of electricity generation capacity installed, TOPCon manufacturing produces 6.5% fewer climate-changing emissions than PERC. That percentage sounds modest, but it scales dramatically when applied to billions of panels. The one area where TOPCon performs worse is silver consumption: the newer architecture requires more silver per panel for its metal contacts, depleting a mineral already under pressure from multiple industries including electronics and electric vehicles.

Whether that silver tradeoff is acceptable depends on the scale of silver supply constraints and whether the industry can reduce silver content through metallization improvements - an active area of panel engineering. The researchers note the issue but do not treat it as disqualifying given the 15-to-1 advantage across other environmental metrics.

Where the Panels Are Made Matters as Much as How They Are Made

The location of manufacturing emerged as a critical variable. Solar panel production in regions powered by low-carbon electricity - the study specifically highlights European manufacturing scenarios - generates substantially fewer emissions than production reliant on coal- and gas-dominated grids. Today, most global solar manufacturing is concentrated in China, where coal remains a significant share of the electricity mix.

This creates a policy tension: the cheapest panels tend to come from regions with the least expensive labor and energy, which currently means higher-carbon grids. Paying a premium for panels manufactured under cleaner electricity could be offset by the lower lifecycle carbon cost - but that calculation requires accurate carbon accounting across supply chains, which remains imperfect.

"Multi terawatt-scale photovoltaic manufacturing demands a sharper focus on its full environmental footprint," said Dr. Nicholas Grant, Associate Professor at the University of Warwick. "Our paper shows how targeted improvements across the supply chain can deliver sustainable manufacturing at the terawatt-scale, avoiding twenty-five gigatonnes of manufacturing-related CO2 emissions if installed by 2035, while supporting rapid global deployment."

The 8.2 Billion Tonne Figure

Combining three factors - TOPCon adoption, targeted manufacturing improvements, and grid decarbonisation in manufacturing regions - the study projects potential reductions of up to 8.2 gigatonnes of CO2-equivalent in solar manufacturing emissions by 2035. That figure represents approximately 14% of current annual global greenhouse gas emissions. It is a ceiling, not a guaranteed outcome: achieving it would require coordinated industry shifts that depend on policy support, investment decisions, and grid decarbonisation timelines that are not guaranteed.

The broader displacement benefit is larger still. Solar panels installed between 2023 and 2035 are projected to avoid more than 25 gigatonnes of carbon emissions by replacing fossil fuel electricity generation over their operational lives. The 8.2 billion tonne figure captures only the manufacturing side - the avoided emissions from clean electricity generation dwarf it.

"Solar photovoltaics is a critical technology that can be used globally now to significantly reduce greenhouse gas emissions and create energy security," said senior author Professor Neil Beattie of Northumbria University. "Even when manufacturing impacts are considered, solar photovoltaics remains one of the lowest-impact and most sustainable electricity generation technologies available over its whole life cycle."

Model Assumptions and Their Limits

Life-cycle assessments are only as good as the data inputs and boundary assumptions that underlie them. The study's projections for 2035 depend on assumptions about how quickly TOPCon adoption will displace PERC, how rapidly manufacturing grids will decarbonize, and what manufacturing improvements will be achievable in the next decade. Each of those trajectories carries uncertainty. The 8.2 gigatonne figure should be understood as an upper bound achievable if favorable trends accelerate, not as a forecast of what will happen under current policies.

Silver supply constraints could also emerge as a binding limitation if TOPCon adoption scales faster than silver supply can accommodate, or if demand from other sectors restricts availability. Silver recycling and reduced-silver metallization techniques are potential mitigations but are not yet at production scale.

The study does not address end-of-life panel recycling, which is an increasingly important part of the solar lifecycle as first-generation panels begin reaching retirement. Future analyses that incorporate recycling infrastructure and material recovery rates will be needed to complete the full lifecycle picture.