Green hydrogen, i.e., produced from renewable resources, is attracting attention as an alternative fuel for the future of heavy road transport and long-distance driving. However, the benefits linked to zero pollution at the usage stage can be overturned when considering the upstream processes linked to the raw materials and energy requirements. To better understand the global environmental implications of fuelling heavy transport with hydrogen, we quantified the environmental impacts over the full life cycle of hydrogen use in the context of the Planetary Boundaries (PBs). The scenarios assessed cover hydrogen from biomass gasification (with and without carbon capture and storage [CCS]) and electrolysis powered by wind, solar, bioenergy with CCS, nuclear, and grid electricity. Our results show that the current diesel-based-heavy transport sector is unsustainable due to the transgression of the climate change-related PBs (exceeding standalone by two times the global climate-change budget). Hydrogen-fuelled heavy transport would reduce the global pressure on the climate change-related PBs helping the transport sector to stay within the safe operating space (i.e., below one-third of the global ecological budget in all the scenarios analysed). However, the best scenarios in terms of climate change, which are biomass-based, would shift burdens to the biosphere integrity and nitrogen flow PBs. In contrast, burden shifting in the electrolytic scenarios would be negligible, with hydrogen from wind electricity emerging as an appealing technology despite attaining higher carbon emissions than the biomass routes.

中文翻译：

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氢在重运输中的作用在行星边界内运行

绿色氢，即由可再生资源制成，作为未来重型公路运输和长途驾驶的替代燃料正在引起人们的注意。然而，在考虑与原材料和能源需求相关的上游工艺时，在使用阶段与零污染相关的好处可能会被推翻。为了更好地了解用氢气为重型运输提供燃料对全球环境的影响，我们在行星边界 (PB) 的背景下量化了氢气使用整个生命周期的环境影响。评估的情景涵盖了来自生物质气化（有和没有碳捕获和储存 [CCS]）的氢气和由风能、太阳能、带有 CCS 的生物能源、核电和电网供电的电解。我们的结果表明，由于违反了与气候变化相关的 PB（独立超过全球气候变化预算的两倍），当前以柴油为基础的重型运输部门是不可持续的。氢燃料重型运输将减少全球对气候变化相关 PB 的压力，帮助运输部门保持在安全的运营空间内（即，在所有分析的情景中都低于全球生态预算的三分之一）。然而，就气候变化而言，基于生物量的最佳情景会将负担转移到生物圈完整性和氮流 PB 上。相比之下，电解方案中的负担转移将可以忽略不计，尽管风电制氢的碳排放量高​​于生物质路线，但其成为一项有吸引力的技术。