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I used to be a coal miner, but now I'm a full grown coal adult!
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Hey there dirty dozens, Jules here for Dnews!
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At the second presidential debate, Donald Trump brought up clean coal.
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Now, we saw some tweets from you guys wondering what clean coal actually is!
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But before we can explain clean coal, you kind of have to understand why we use coal
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in the first place.
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Coal is incredibly important.
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It's cheap -- one of the cheapest sources of energy available.
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It is amazingly efficient for making electricity, and it's one of the most abundant energy
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sources in the world, even more so than oil.
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But it has one huge drawback.
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It is so dirty that people regularly die from its pollution.
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When coal is burned it releases chemicals like sulphur dioxide, nitrogen oxides, a little
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mercury, and carbon dioxide, not to mention a bunch of various particulates.
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These leak into the air and water and result in smog, soot, acid rain, global warming,
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and toxic air emissions.
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Those can cause asthma, lung cancer, various heart diseases, and other health problems.
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Not good.
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So, in an effort to placate people worried about dying just to get a little electricity,
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the coal industry heavily invested in clean coal.
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But Clean Coal is still coal.
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It's not a different kind of coal.
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It's just handled differently in the process of turning it into energy.
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The term Clean Coal is actually shorthand for Clean Coal technologies, which are designed
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to lessen the number of pollutants released in the production of energy.
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One such method is called carbon capture and storage, which is exactly what it sounds like.
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Carbon dioxide is separated from the air before it leaves a power plant or other production
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plant using a process called “absorption” or carbon scrubbing.
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This is where chemicals called amines are used to bind to the carbon dioxide and pull
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it out of the air.
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This gas is then piped underground, or “sequestered” so that it can't leak into the atmosphere.
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It can even be used to help depleted oil fields coax their last bits of oil to the surface.
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We have a whole video about CO2 scrubbing if you want to know more.
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Another popular method to end the infamous acid rain scares of the 70s and 80s was to
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wash all the sulfur out of coal before it made its way into a plant.
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And when I say wash, I mean literally, they would break it down into chunks and run it
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through a water tank which could include minerals like magnetite to increase the density of
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the liquid.
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The coal floats, because it is less dense, while the sulfur and other impurities sinks.
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A third clean coal technology is called “oxy-fuel combustion”.
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When coal is burned at a power plant, the exhaust, also called “flue gas”, is usually
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just pumped into the atmosphere.
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But oxy-fuel combustion actually reroutes this flue gas back into the plant, where it
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is paired with pure oxygen and reused to burn more coal.
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The reason they do this is because the normal air we breathe air has a ton of nitrogen in
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it, and when it's heated with the coal, it reduces its efficiency and creates more
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nitrogen byproducts.
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But when we reuse flue gas and combine it with pure oxygen, this solves both of these
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problems and allows for hotter temperatures and more energy extraction.
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There are a number of other methods, but despite these efforts, environmental activists call
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“clean coal” an oxymoron, since it's not quite the anti-pollution miracle that
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coal companies make it out to be.
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The problem is that these methods are incredibly expensive and energy intensive, and that money
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and energy has to come from somewhere.
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Some estimate that the addition of capture carbon and storage to a coal fire plant increases
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coal use by 25% while keeping electricity output the same.
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Another huge problem is that these byproducts aren't so much being eliminated as they
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are being moved elsewhere, which is more of a storage solution than an environmental one.
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And on top of all that, for those reasons, clean coal technologies are not particularly
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widespread, at least not enough to make a significant difference for the time being.
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In the end, clean coal helps stem pollution at the source, but it seems to help coal companies
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maintain their image more than it helps the environment maintain itself.
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If you've been a subscriber of DNews for a while, you might've seen some of our recent
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VR videos.
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It's a completely new way to tell stories, learn and experience the world, and we just
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launched a brand new channel called Seeker VR.
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You can view the videos in 360 from your phone or computer.
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Click now to watch, or visit the first link in the description.
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And make sure you subscribe to Seeker VR.
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So, coal burning can contribute to acid rain.
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But we don't really hear about acid rain anymore.
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We used to a lot in the 70s and 80s.
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Is it still a big deal?
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What ever happened to acid rain?
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You can find out in this video here.
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What other science issues have come up in this election that you wanna know more about?
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Let us know down below in the comments and don't forget to like and subscribe to DNews
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for more video every day.