Cross-seasonal robust optimization of a rural electricity–heat–ammonia–agriculture energy synergy system

Rural multi-energy systems in northern China face seasonal renewable variability, limited energy coupling, and mismatches between renewable-ammonia availability and fertilizer-production opportunities. This study develops a two-stage robust scheduling framework for an integrated electricity–heat–ammonia–agriculture system. A season-conditioned convex-polyhedral uncertainty set derived from minimum-volume enclosing ellipsoids represents seasonal mean drift and wind–photovoltaic forecast-error correlation, while inter-seasonal ammonia-inventory continuity enables long-duration energy shifting. For the selected demonstration-year dataset, the proposed uncertainty-set case lowers the annual-equivalent system cost by 19.2% relative to the annual-static case. Under flexible power-to-ammonia operation, wind–photovoltaic curtailment decreases from 32.40% to 19.88%. Renewable-derived ammonia routed to fertilizer production reaches 24.55 t/year, corresponding to 59.17 t CO 2 -eq/year of avoided conventional coal-based-ammonia production emissions. The results show that coordinated seasonal uncertainty modeling and ammonia routing improve economy, renewable-energy utilization, and cross-season energy–agriculture integration.