How to assess the carbon footprint of 1 kWh from photovoltaic systems
A new standardized method for calculating the carbon footprint of solar panels is set to guide the industry toward more sustainable production. The tool, developed by the Joint Research Centre (JRC) of the European Commission, plays a key role in shaping ecodesign policies and meeting the EU’s climate goals for 2030 and 2050.
New EU method to measure the carbon footprint of solar panels
The European Union has taken another step toward more sustainable solar energy production. With the release of its report, “Harmonised rules for the calculation of the carbon footprint of photovoltaic modules“, the JRC outlines a consistent approach for evaluating the carbon footprint of photovoltaic (PV) panels.
The goal is twofold: provide a scientific foundation for future mandatory ecodesign requirements by standardizing calculations, and support the competitiveness of low-impact technologies across the solar value chain.
A harmonized regulatory approach
While solar-generated electricity is emissions-free, the lifecycle of solar panels is not. Like all products, PV modules carry a carbon cost.
The JRC methodology builds on the European Commission’s Environmental Footprint method (Recommendation 2279/2021) and the Product Environmental Footprint Category Rules (PEFCR) specific to PV modules.
It introduces scientific criteria to quantify lifecycle emissions, from raw material extraction to final distribution.
The key metric is grams of CO₂ equivalent per kilowatt-hour generated (gCO₂eq/kWh), allowing environmental efficiency to be measured in relation to panel lifespan. Compared to the original PEFCRs, the study has been expanded to include emerging and innovative photovoltaic technologies now gaining market share.
Data and scenarios for the carbon footprint of solar panels
The report shows that carbon footprints vary widely based on the energy mix used during manufacturing, materials, and the expected lifespan of the modules.
Estimates range from 10.8 gCO₂eq/kWh under favorable conditions to 44 gCO₂eq/kWh in more carbon-intensive cases.
Key contributors to the carbon footprint of mono- and multi-crystalline silicon panels include:
- Electricity used in silicon production: this varies depending on the carbon intensity of the local electricity grid.
- Silicon content: this has a strong impact on carbon footprint per kilowatt-hour. A higher silicon content can increase the footprint by up to 80%. This is influenced by wafer thickness and material losses during cutting, both of which are declining. Today, wafer thickness averages 150 µm, with less than 0.5 kg of silicon per square meter.
- Glass content
- Aluminum content
Panel lifetime is also critical. A longer lifespan allows initial emissions to be spread across more energy output. For example, reducing the lifespan from 30 to 25 years raises the carbon footprint by 20%. A drop to 20 years results in a 50% increase.
Ecodesign and REPowerEU
The carbon footprint of solar panels ties into broader regulatory goals.
The JRC’s proposed rules are designed to support the Ecodesign Directive (2009/125/EC), which sets minimum environmental performance standards for energy-related products.
Meanwhile, the EU’s REPowerEU plan aims to accelerate the green transition and reach 600 GW of installed solar capacity by 2030.
To ensure that this growth is sustainable, the European Commission wants to steer the market toward lower-impact solar products.
Mandatory carbon footprint criteria could help rebalance a market currently dominated by low-cost, high-emissions imports. In the long term, traceable environmental impact could become a competitive asset for European companies.
Technologies covered and future developments
The new methodology applies to several technologies, including mono- and multi-crystalline silicon panels, cadmium telluride (CdTe) modules, and potentially to future tandem perovskite-silicon technologies. CIGS and microcrystalline silicon, still marginal in the European market, are not included.
The methodology may later be expanded to assess other environmental impacts, such as resource depletion or particulate emissions.
Additionally, the JRC has developed a digital tool to support carbon footprint calculations, helping both manufacturers and institutions conduct evaluations more efficiently.