能源、气候与材料2021onlinelibrary.wiley.com
蓝氢到底有多绿？
How green is blue hydrogen?
入门 · 约 45 分钟读完前置知识：氢能基础概念、碳捕集与封存、甲烷温室效应
导读
这篇论文评估“蓝氢”（由天然气制氢并配合碳捕集）的温室气体足迹，结论是其碳排放反而比直接燃烧天然气取暖高 20% 以上、比柴油高约 60%，主要原因是制氢过程和上游甲烷泄漏的排放。论文质疑蓝氢作为清洁能源的定位。
HN 关注点：氢能在脱碳中的真实作用，讨论焦点是蓝氢是否只是给化石燃料“漂绿”，以及氢能整体的技术经济性。
HN 评论精选
这几条评论里：支持 1 质疑 1 补充 2
补充除绿氢外都是维持化石体系，氢应仅用于难以电气化的工业场景
除了绿氢以外的氢都只是维持化石燃料现状的复杂手段。虽然可能对全球变暖有一点好处（本文没发现），但会占用有限的碳捕集空间。我认为甲烷泄漏的捕集还有很大改进空间，是容易摘的果子。另外，即使是绿氢，用于供暖和交通的效率也远低于热泵和电池/直接用电——在可再生能源能量回收期还很高的早期阶段尤其如此。我们不需要用氢来供暖、交通或储能（除非清洁电力超过 95% 后的季节性储能可能是例外）。氢燃料卡车更贵且续航未必更长。不过工业上氨的生产和美国所有新建的铁矿石还原厂（DRI/HBI）都在用氢（通常是天然气制的合成气，但几乎可以完全用氢制造），所以过剩可再生能源制氢不会没有用武之地。
Robotbeat查看英文原文
Yeah, anything but green hydrogen is just a complicated way of keeping the status quo, fossil fuel oriented system in place. There might be a small benefit to global warming (not found in this paper), but it’s using up a finite amount of capture space. I do think we can probably get a lot better at capturing methane leaks, though. It’s low hanging fruit. …and even green hydrogen is much less efficient for heating and propulsion than heat pumps and battery/direct-electric. Especially in the early days when we are still working to increase the energy payback of renewables, this is not helpful! We need high efficiency usage of electricity. Making hydrogen is something you shouldn’t do unless there aren’t alternatives. We don’t need hydrogen for heat, for transport, or for storage (possible exception being seasonal storage once you’ve surpassed 95% clean electricity… no point in hydrogen storage if you’re still only a 50% clean grid). Hydrogen trucks are more expensive (to buy and ESPECIALLY a to operate) and not necessarily any more range (possible exception if you use liquid hydrogen). We do use hydrogen industrially for all ammonia production and (believe it or not) all new iron ore reduction plants (DRI/HBI plants) in the US (they use syngas usually, a mix of hydrogen and CO, usually made from natural gas but it could be made almost entirely with hydrogen), so it’s not like we won’t find a use for the hydrogen we might produce from excess renewable power.
支持氢能储存难、效率低，本质是糟糕的电池，主要作用是漂绿
氢是一种愚蠢的燃料。它难以储存、会泄漏、体积能量密度低（大量能量花在压缩上，体积能量密度只有锂电池的 3 倍），往返效率很差——水→电解→燃料电池只有 50%，本质上就是个糟糕的电池。它唯一的卖点就是给化石燃料漂绿。
dTal查看英文原文
Hydrogen is a stupid fuel. There, I said it. It's hard to store. It leaks away. It has poor energy density by volume (and much of the energy simply goes to compress the damn stuff) - only 3x li-ion, for your trouble. It has a crappy round-trip efficiency - only 50% for water -> electrolysis -> fuel cell. It's just a shitty battery. The only thing it's got going for it is that it's a way of greenwashing fossil fuels.
补充只有用清洁电力电解水制氢才合理
我原本希望燃料所需的氢能通过太阳能/风能/核能电解水来生产，其他方式都有些荒谬。
vondur查看英文原文
I would have hoped that the hydrogen needed for fuel would be produced by the electrolysis of water using solar/wind/nuclear. Anything else is kinda silly.
质疑论文的对比不公平，氢应与内燃机而非高效供暖方式比较
论文说蓝氢的温室气体足迹比烧天然气或煤取暖高 20% 多、比柴油高 60%——这完全是拿苹果比橘子。按每瓦特算，供暖本来就永远比发电高效，因为省去了压缩机和涡轮机的损耗。应该拿氢去和它要替代的东西比——也就是效率极低的内燃机。
elil17查看英文原文
> [The GHG footprint of blue hydrogen is] more than 20% greater than burning natural gas or coal for heat and some 60% greater than burning diesel oil for heat Totally apples to oranges comparison - heating is and always will be way more energy efficient than electricity generation on a per-watt basis because you eliminate the inefficiencies inherent in the compressors and turbines. You have to compare hydrogen to what it’s being used to replace - internal combustion engines, which are wildly inefficient.
历次讨论
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