Carbon footprint (Scope 2) and energy intensity per activity in intermediate-complexity hospitals in the Community of Madrid : panel analysis (2016-2024)

Resumen

Hospital buildings account for 60-80% of healthcare sector electricity consumption, yet robust causal evidence on the relationship between building energy efficiency and emissions per unit of clinical activity remains scarce. This study applies within-group fixed effects estimation to an unbalanced panel of 12 intermediate-complexity hospitals in Madrid, Spain (2016-2024; N = 107 hospital-year observations), controlling for activity volume and exogenous shocks. Cluster-robust standard errors and Wild Cluster Bootstrap inference address the limited number of cross-sectional units (N = 12). We propose a methodological correction for the artificial 74.6% discontinuity in Spain's electricity emission factor (2020-2021) caused by regulatory change. The within-hospital building energy use intensity (EUIe) coefficient is beta = 0.646 (p < 0.001), remarkably stable across six robustness specifications (range: 0.599-0.648; 8.2% variation). Wild Cluster Bootstrap confirms statistical significance despite 75% larger standard errors. A 20 kWh/m(2)& centerdot;year EUIe reduction achievable through Heating, Ventilation and Air Conditioning (HVAC) retrofit in 1980s-era buildings translates into 13 kWh/stay savings, equivalent to 216 tCO(2)/year for median-sized facilities (8.2% reduction). Within R-2 exceeds 0.97 across all specifications. Building envelope and HVAC retrofit constitute the dominant structural intervention for hospital Scope 2 emissions reduction. Facilities with EUIe > 150 kWh/m(2)& centerdot;year should be prioritized for energy efficiency interventions using NextGenerationEU funds.