Probabilistic assessment of Spain's 2030 electricity system via Monte Carlo analysis

As Spain accelerates its transition toward a renewable-based electricity system, the reliability of policy targets set by the National Energy and Climate Plan (PNIEC 2023–2030) must be tested against the reality of generation variability, mainly due to weather condition variability and demand uncertainty. This study presents a comprehensive and probabilistic assessment of Spain's 2030 electricity system, utilizing Monte Carlo Analysis (MCA) in conjunction with the EnergyPLAN simulation tool. Moving beyond traditional deterministic models, 93 synthetic years of hourly demand and energy generation profiles were obtained through a blockbootstrapping technique informed by historical data from 2016 to 2024. Simulation results highlight substantial variability in system behavior. Surplus energy often exceeds 100 TWh annually, with concentrated excesses during spring and summer. Moreover, the increasing reliance on variable renewable sources gives rise to periods of very low generation, known as Dunkelflauten, and steep evening ramps, highlighting the emergence of pronounced "duck" or "canyon" curves. While Dunkelflauten events are less frequent in Spain than in other parts of Europe, they remain significant during the autumn and winter seasons. In this context, P2G emerges as a technically and strategically relevant option, utilizing hydrogen, which can serve as seasonal storage or facilitate the decarbonization of hard-to-electrify sectors.