Carbon‑removal opportunities and constraints of bioenergy crops on marginal croplands in China

Bioenergy crops present a promising solution for climate mitigation and clean energy, yet national-scale deployment is constrained by land availability, crop suitability, water resources, carbon capture and storage, and competing environmental priorities. Here, we combine satellite-based land-cover data with spatially-explicit yield model to assess the leverages, constraints and land–energy–carbon nexus of bioenergy deployment on 36 million hectares marginal croplands in China. This strategy could supply 1.88–2.09 EJ yr⁻¹ biofuel and deliver 192–298 million tonnes CO₂ yr⁻¹ net carbon removal—up to 76% over natural regrowth alone—with minimal risks to water scarcity or biodiversity. It could offset 8–12% of agri-food emissions and meet 15–17% of transport-energy demand. Nearly half of marginal cropland overlaps with biodiversity-priority areas, posing critical constraints on deployment, where natural regrowth serves as a preferable alternative. Optimizing crop selection, and carbon capture and storage consideration are more critical for enhancing outcomes than irrigation alone. Bioenergy crops on China’s marginal croplands could increase net carbon removal by up to 76% beyond natural regrowth alone with limited water and biodiversity impacts, based on satellite land-cover data and spatially explicit yield modeling.