Nuclear power plants produce relatively low lifecycle emissions of carbon dioxide equivalent compared with fossil-fuel electricity. The Intergovernmental Panel on Climate Change assessment overseen by Ottmar Edenhofer at the Potsdam Institute for Climate Impact Research reported a median lifecycle footprint of about 12 grams CO2-equivalent per kilowatt-hour for nuclear electricity. This figure places nuclear in the same low-emission category as wind and solar when lifecycle analysis is harmonized across studies. Benjamin K. Sovacool University of Sussex reviewed many lifecycle studies and concluded that most modern analyses likewise find emissions in the low tens of grams CO2-equivalent per kilowatt-hour, although published values vary by study design and assumptions.
Causes of lifecycle emissions
Lifecycle emissions arise across the full chain: uranium mining and milling, enrichment, fuel fabrication, construction of concrete and steel-intensive reactors, operation, and later decommissioning and radioactive waste management. Mining energy intensity depends on ore grade and extraction method, and enrichment technology such as gas centrifuge reduces process emissions compared with older diffusion technologies. Construction emissions are driven by concrete and steel production, which are carbon-intensive industries. Operational emissions are very low relative to construction and fuel stages because reactors do not burn carbon, but long facility lifetimes and high capacity factors help spread up-front embodied emissions over large amounts of low-carbon electricity.
Consequences and relevance
The practical consequence is that nuclear power can deliver reliable, low-carbon baseload electricity and therefore plays a meaningful role in decarbonization portfolios that aim to reduce greenhouse gas emissions from electricity systems. However, the exact lifecycle footprint depends heavily on local and technology choices, including uranium source, enrichment pathway, construction practices, and assumed plant lifetime. There are also human and territorial dimensions: uranium mining has historically and currently affected Indigenous lands and local communities, with social and environmental impacts beyond greenhouse gases. Waste management and the long-term stewardship of spent fuel raise cultural and territorial stewardship questions that extend well beyond carbon accounting. Environmentally, nuclear plants use substantial water resources and require careful siting to avoid fragile ecosystems.
Taken together, peer-reviewed summaries and international assessments indicate nuclear is among the lowest lifecycle greenhouse gas options for large-scale, continuous power generation, while non-carbon impacts and local social consequences remain crucial considerations in energy planning.