TED演讲:从大气中移除二氧化碳的新方法(3)
And now once you’ve captured the CO2,
在二氧化碳被捕获之后，
you have to be able to recycle that material that you used to capture it, over and over again.
我们还需要能够循环使用用来捕获它的材料，持续不断进行捕获。
The scale of carbon capture is so enormous that the capture process must be sustainable,
毕竟，当碳捕获具备了庞大的规模，其捕获方法必须能够满足长远需求
and you can’t use a material just once.
并能重复利用材料。
And so recycling the material requires an enormous amount of heat, because think about it:
另外，重复利用材料的过程需要消耗大量的热量，试想一下：
CO2 is so dilute in the air, that material is binding it really strong,
二氧化碳在空气中是如此稀薄，材料对它的约束力就会非常大，
and so you need a lot of heat in order to recycle the material.
你需要消耗很多热量才能回收这个材料。
And to recycle the material with that heat,
所以你消耗热量回收材料时，
what happens is that concentrated CO2 that you got from dilute CO2 in the air is now released, and you produce high-purity CO2.
从空气中收集的浓缩二氧化碳将被释放出来，你将得到高纯度的二氧化碳。
And that’s really important, because high-purity CO2 is easier to liquify, easier to transport,
这一点很重要，因为高纯度的二氧化碳更容易液化，都比气态二氧化碳更容易运输，
whether it’s in a pipeline or a truck, or even easier to use directly, say, as a fuel or a chemical.
无论是利用管道还是卡车，甚至更容易被直接使用，比如作为燃料或者化学品。
So I want to talk a little bit more about that energy.
关于能量，我想再多讲一些。
The heat required to regenerate or recycle these materials absolutely dictates the energy and the subsequent cost of doing this.
再生或者回收那些材料的热量需求决定了这个过程需要的能量和附随的成本。
So I ask a question: How much energy do you think it takes to remove a million tons of CO2 from the air in a given year?
我想问一个问题：你觉得在一年内从空气中移除一百万吨的二氧化碳需要多少能量？
The answer is: a power plant. It takes a power plant to capture CO2 directly from the air.
答案是：一个发电厂。需要一个发电厂来提供从空气中捕获二氧化碳所需要的能量。
Depending on which approach you choose, the power plant could be on the order of 300 to 500 megawatts.
发电厂的发电量，取决于选择的方法，可能在300到500兆瓦之间。
And you have to be careful about what kind of power plant you choose.
还要谨慎选择发电厂的燃料类别。
If you choose coal, you end up emitting more CO2 than you capture.
如果选择的是煤，产生的二氧化碳会比捕获的还多。
我们的地球有一个关于“碳”的问题——如果我们不开始从大气中移除二氧化碳，气温将很快变得越来越高。化学工程师珍妮佛·威尔考克斯介绍了可直接从空气中减少碳含量的前沿科技，使用化学反应捕获和再次使用二氧化碳，跟树木吸收二氧化碳的原理类似，但是规模更大。这个演讲详细地探讨了人类除碳的愿景和所需要面对的困难。