Toward Low-Carbon Power Systems: Reviewing Life Cycle Carbon Footprints of Diverse Generation Pathways

Electricity generation is the largest contributor to anthropogenic greenhouse gas (GHG) emissions. This review synthesizes life cycle assessment (LCA) evidence for major power generation technologies published from 2015 to 2025. Using a structured screening approach, it identifies consistent cross-technology patterns and the methodological factors driving variation in reported results. Unabated coal and oil show the highest life cycle intensities; natural gas varies widely with methane management; and nuclear, geothermal, hydropower, wind, and solar power generally fall one to two orders of magnitude lower. Differences arise mainly from upstream processes, siting conditions, and system boundary definitions. Key mitigation levers include plant efficiency improvements, methane abatement, carbon capture and storage (CCS), and low-carbon manufacturing. The review also highlights how emerging policies—including the EU Carbon Border Adjustment Mechanism (CBAM) and China’s carbon-footprint standards—are integrating life cycle and Scope-2 accounting. Standardized, AR6-aligned LCA practices and transparent upstream data remain essential for credible, comparable electricity-sector decarbonization.