Province-level estimation of sustainable agricultural biomass energy potential in Spain: A three-tier framework with cultivated-area stability and seasonal availability analysis

This study presents a province-level assessment of sustainable agricultural biomass energy potential in Spain, covering eighteen crop systems across the country's fifty-two provinces from 2013 to 2023. Building on established frameworks, the methodology applies a three-tier framework that distinguishes theoretical, technically recoverable, and sustainable biomass potential, incorporates province-specific sustainability parameters derived from livestock and land-use data, uses an area-based approach to estimate pruning residues from permanent crops to reduce bias associated with low-yield years, and employs a monthly availability model based on national harvest calendars. Results establish the national sustainable bioenergy potential at 158.8 PJ yr −1 (95% confidence interval: 124.7-193.0 PJ yr −1 ), representing 32.8% of the theoretical potential. Biomass is also highly concentrated geographically, with Jaén, Sevilla, and Córdoba sustainably and collectively contributing more than 28 PJ yr −1 . Olive residues constitute the largest provincial resource but are subject to considerable uncertainty due to variability in pruning yields. A yield-volatility analysis shows that rain-fed crops, including almond, rapeseed, olive, rye, and oats, exhibit greater variability in Mediterranean regions than in humid Atlantic provinces. A seasonal analysis indicates strong temporal concentration, with June contributing 21.0% of the annual potential. The current study demonstrates that feedstock timing and regional diversification are critical factors in planning and optimizing future bioenergy facilities.