Full Carbon Lifecycle Analysis

What is the carbon footprint of solar panels?

Full lifecycle carbon analysis of UK solar panels: MANUFACTURING CARBON: Silicon purification, cell manufacturing, module assembly, and transportation emit approximately 400-500 kg CO₂ per kW of panel capacity (source: IEA PVPS Task 12, Fraunhofer ISE). For a 4kW system: 1,600-2,000 kg total manufacturing CO₂. ANNUAL CARBON SAVING: Each kWh from solar displaces UK grid electricity at approximately 180g CO₂/kWh (source: BEIS Greenhouse Gas Conversion Factors 2025, gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors). A 4kW system generating 3,800 kWh/yr saves: 684 kg CO₂/year. CARBON PAYBACK: 1,800 kg manufacturing ÷ 684 kg/yr saving = 2.6 years. After 2.6 years, every kWh is genuinely zero-carbon. LIFETIME SAVING (25 years): 17,100 kg = 17.1 tonnes CO₂ (net of manufacturing). Over 30 years: 20,500 kg = 20.5 tonnes. INCLUDING BALANCE OF SYSTEM (inverter, mounting, cables): total lifecycle CO₂ rises to approximately 2,500 kg. Carbon payback: 3.7 years. Still within the first 15% of panel lifespan. COMPARISON: Gas boiler (20 years): 25-35 tonnes CO₂. Petrol car (20 years): 30-40 tonnes CO₂. Solar panels (25 years): -17 tonnes CO₂ (net saving). Sources: IEA PVPS Task 12 Life Cycle Assessment (iea-pvps.org), Fraunhofer ISE Photovoltaics Report (ise.fraunhofer.de), BEIS GHG Conversion Factors 2025 (gov.uk), IPCC AR6 (ipcc.ch).