Readers of a certain age are now permitted to roll their eyes. At least twice in the past 50 years—in the 1970s, after the oil crisis,

某个年龄层的读者会表示不相信。在过去50年里——在20世纪70年代，石油危机之后
and in the 1990s, when climate change started to acquire political salience—
以及在20世纪90年代，当气候变化开始获得政治关注的时候——
there has been excited talk of replacing hydrocarbons with hydrogen. It didn't happen.
至少出现了两次用氢取代碳氢化合物的令人兴奋的讨论。它没能成真。
There were several reasons for this. For a start, ripping up and replacing the world's fossil-fuel infrastructure is a huge job.
对此有几种原因。首先，取消并替换世界上的化石燃料基础设施是一项大工程。
And even were that an easy thing to accomplish, hydrogen itself has drawbacks.
即便这是件很容易完成的事情，氢本身也有缺点。
Though better than batteries, it stores less energy in a given volume than fossil fuels can manage.
虽然它比电池更好，但在一定体积内，它所储存的能量比化石燃料要少。
More important, it is not a primary fuel. You have to make it from something else.
更重要的是，它不是初级燃料。你需要从其他物质中获取它。
This can be done by a chemical reaction called steam reforming but, besides steam,
通过一种被称为蒸气重组的化学反应可以得到它，但除了蒸气，
the other ingredient of that process is a hydrocarbon of some sort, which rather defeats the object of the exercise.
这一过程中的其他原料是某种碳氢化合物，它与这个过程的目的相抵。
Or it can be done by the electrolysis of water.
也可以通过电解水来实现。
This has appropriate green credentials as long as the electricity is either from renewable sources or a nuclear-power plant.
只要电力来自可再生能源或核电站，这就具有适当的绿色资质。
But the laws of thermodynamics mean that the energy content of the hydrogen
但热力学定律意味着
which comes out of the process is less than the electricity that went in.
从这个过程中产生的氢的内能比进入的电流要少。
This inbuilt inefficiency raises the question "why not simply power the end-use electrically, rather than using hydrogen as an intermediary?"
这种固有的低效率引发了一个问题，“为什么不直接用电来驱动最终用途，而是要将氢作为一种媒介呢？”
To counter these arguments those who believe that things hydrogen-related really are different this time around can point to two things in their favour.
要反驳这些争论，那些认为和氢有关的事物这次真的会有不同的人可以指出对他们有利的两个点。
Several of the relevant technologies, notably electrolytic equipment,
一些相关技术，尤其是电解加速设备，
are now at a stage where it is possible to believe they might soon become cheap enough to do the job.
目前正处于一个可以相信它们很快就会变得足够便宜的阶段。
And the idea that economies need to be decarbonised fully in order to curb climate change is gathering speed.
经济需要完全脱碳化以遏制气候变化的想法正在逐渐加速。
Until 2019, for instance, Britain had planned to cut carbon emissions by 80% from their levels in 1990 by 2050.
例如，直到2019年，英国计划，在2050年前，将碳排放量在1990年的水平上减少80%。
It then, however, upped the ante to become the first big economic power to commit itself to a 100% cut. This has implications for hydrogen.
但英国提高要求，要成为首个承诺100%减排的经济大国。此举对氢能有影响。
Electrification using renewable sources such as wind and solar power would probably have got the country to 80%,
David Joffe观察称，使用风能和太阳能等可再生能源的电气化可能会让英国减排率到达80%，
observes David Joffe, a member of the Committee on Climate Change (CCC),
他是英国气候变化委员会（CCC）的成员，
an organisation that advises Britain's government on how to bring the transformation about.
该组织为英国政府提供如何实现转型的建议。
But full decarbonisation, he says, is a much bigger task, and one for which hydrogen may prove necessary.
但全面脱碳化，他说，是一项更艰巨的任务，并且可能会需要氢。

来源：经济学人