Ammonia is increasingly recognized as an important, sustainable fuel for global use in the future. Applications of ammonia in heavy transport, power generation, and distributed energy storage are being actively developed. Produced at scale, ammonia could replace a substantial fraction of current-day liquid fuel consumption. This ammonia-based economy will emerge through multiple generations of technology development and scale-up. The pathways forward in regard to current-day technology (generation 1) and immediate future approaches (generation 2) that rely on Haber-Bosch process are discussed. Generation 3 technology breaks this nexus with the Haber-Bosch process and enables direct reduction of dinitrogen to ammonia electrochemically. However, the roadmap toward scale in this technology has become obscured by recent research missteps. Nevertheless, alternative generation 3 approaches are becoming viable. We conclude with perspectives on the broader scale sustainability of an ammonia economy and the need for further understanding of the planetary nitrogen cycles of which ammonia is an important part.

氨越来越被公认为是未来全球使用的重要，可持续的燃料。氨在重型运输，发电和分布式储能中的应用正在积极开发中。规模化生产的氨可以替代当今液体燃料消耗的很大一部分。这种以氨为基础的经济将通过多代技术开发和规模扩大而出现。讨论了依赖Haber-Bosch过程的有关当前技术（第1代）和近期方法（第2代）的前进途径。第三代技术通过哈伯-博世（Haber-Bosch）工艺打破了这种联系，并使电化学将二氮直接还原为氨。但是，由于最近的研究失误，该技术的规模化路线图已变得模糊不清。不过，第三代替代方法正在变得可行。我们以对氨经济更广泛的可持续性以及需要进一步了解行星氮循环（其中氨是重要组成部分）的观点得出结论。