Hourly Attributional Prospective Life Cycle Assessment of the Italian Electricity Grid

This study presents a prospective attributional Life Cycle Assessment of the Italian na-tional electricity grid for 2024–2040, aligned with the integrated national climate and en-ergy plan and the country's decarbonization pathway. The main goal was to calculate, analyze, and apply hourly emission factors for electricity and compare them with annual average factors for the same consumption profile to assess temporal effects on environmental outcomes. Hourly factors were derived from a cost-optimization energy model simulating Italy's evolving generation mix. The model projects a sharp decline in fossil-based generation and a significant expansion of solar photovoltaics and wind, which together exceed half of national production by 2040. Natural gas remains essential for system balancing, while electricity imports stabilize the grid when renewable output is low. 16 impact categories were evaluated, revealing decreasing trends in climate change (255 to 141 g CO2-eq/kWhe), acidification, and others, and rising temporal variability in mineral/ metal resource depletion and land use due to renewable intermittency. Applying the method to a positive energy district in Bologna shows that time-resolved factors offer clearer insights than annual averages, especially for season-dependent impacts, and demonstrate substantial reductions in impact by 2040, alongside notable differences between consuming and exporting electricity.