Does Compliance Certainty Deliver Decarbonization? Comparing Mandate and Incentive Governance for Sustainable Aviation Fuel

Does governance design determine whether aviation decarbonization advances or stalls? This article introduces compliance certainty—the degree to which policy compels actors to secure supply, contract forward, and reconfigure operations—as the pivotal mechanism distinguishing directed from adaptive transition pathways. Comparing EU blending mandates under ReFuelEU Aviation with US production tax credits under the Inflation Reduction Act, the study uses theory-testing process tracing (2019–2025) and 49 causal process observations drawn from legal texts, regulatory guidance, and audited corporate filings. Evidence indicates that EU mandates generate strong compliance certainty: airlines explicitly cite binding quotas as drivers of offtake contracts and supply-chain investment. US credits narrow cost gaps but, absent purchase obligations, produce weaker compliance certainty and voluntary, price-contingent uptake. However, compliance certainty alone is insufficient. Both pathways confront acute planning constraints: waste feedstocks can support only ~10% of 2050 demand, and synthetic e-fuels require final investment decisions by 2026 to meet EU sub-targets while facing costs 3–5× above conventional SAF. The article contributes a replicable process-tracing design for hard-to-abate sectors and concludes that effective decarbonization governance must pair compliance certainty with feasibility planning.治理设计是否决定航空脱碳进程的推进与停滞？本文将合规确定性（compliance certainty）——即政策促使相关主体保障供应、签订远期合约并重构运营模式的程度——作为区分指令型与适配型转型路径的关键机制。本研究对比了《欧盟航空燃料掺混强制要求》（ReFuelEU Aviation）框架下的欧盟掺混指令与《通胀削减法案》（Inflation Reduction Act）下的美国生产税收抵免政策，采用2019—2025年的理论检验式过程追踪法，并基于法律文本、监管指南与经审计的公司备案文件，收集了49组因果过程观测数据。 研究证据显示，欧盟相关指令可催生较强的合规确定性：航空公司明确将具有约束力的配额列为其采购合约签订与供应链投资的核心驱动因素。美国的生产税收抵免虽能缩小成本差距，但由于缺乏强制采购义务，仅能产生较弱的合规确定性，且仅存在自愿性、随价格波动的采购行为。然而，仅依靠合规确定性并不足以推动脱碳进程。两类转型路径均面临严峻的规划约束：废弃原料仅能满足2050年约10%的航空燃料需求，而合成电子燃料需在2026年前完成最终投资决策，方能达成欧盟的脱碳子目标，但其成本较传统可持续航空燃料（SAF，sustainable aviation fuel）高出3至5倍。 本文为难脱碳行业提供了一套可复制的过程追踪研究设计，并得出结论：行之有效的航空脱碳治理必须将合规确定性与可行性规划相结合。