How to create cleaner coal - Emma Bryce
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0:07 - 0:10What lights up the screen
that you're looking at right now? -
0:10 - 0:13Trace back
the battery chargers and power cords -
0:13 - 0:15and you'll end up at an electrical outlet,
-
0:15 - 0:19providing easy, safe access
to reliable electricity. -
0:19 - 0:22But beyond that outlet,
the picture gets messier. -
0:22 - 0:24It takes a lot of fuel to heat our homes,
-
0:24 - 0:26preserve our food,
-
0:26 - 0:28and our power our gadgets
around the clock. -
0:28 - 0:32And for 40% of the world,
that fuel is cheap, plentiful, -
0:32 - 0:34and it's called coal.
-
0:34 - 0:37But coal also releases
pollutants into the air, -
0:37 - 0:39like sulfur dioxide,
-
0:39 - 0:40nitrogen oxides,
-
0:40 - 0:41soot,
-
0:41 - 0:44and toxic metals, like mercury.
-
0:44 - 0:47These cause environmental damage,
like acid rain, -
0:47 - 0:48and serious health problems.
-
0:48 - 0:53In fact, in 1952, coal burning
caused such heavy smog in London -
0:53 - 0:56that pedestrians
couldn't even see their feet, -
0:56 - 1:00and thousands of people died
from ill health. -
1:00 - 1:02Since then, many countries
have deployed technology -
1:02 - 1:05to remove most of these pollutants
before they reach the air. -
1:05 - 1:09But now we have a new
air pollution problem on our hands, -
1:09 - 1:11one that doesn't show up
in a cloud of dark smog, -
1:11 - 1:13but in rising seas,
-
1:13 - 1:14floods,
-
1:14 - 1:15and heat waves.
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1:15 - 1:17It's global climate change,
-
1:17 - 1:20and again, the main culprit is coal.
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1:20 - 1:24It's responsible for 44%
of global carbon dioxide emissions, -
1:24 - 1:27which trap the sun's heat
in the Earth's atmosphere, -
1:27 - 1:29instead of letting it escape.
-
1:29 - 1:33So now the question is
how do we remove that bad stuff as well? -
1:33 - 1:36That's the idea behind cleaner coal.
-
1:36 - 1:40Creating cleaner coal is really about
trying to contain its ill effects -
1:40 - 1:45with the help of special technologies
that make the end product more acceptable. -
1:45 - 1:47Just like the most intriguing superheroes
-
1:47 - 1:50often have their own dark powers
to overcome, -
1:50 - 1:54so we can try and keep
coal's negative forces in check. -
1:54 - 1:56But why don't we just exterminate coal
-
1:56 - 1:59if it takes that much effort
to clean it up? -
1:59 - 2:03Simply, coal is extremely valuable to us,
and it's easy to come by. -
2:03 - 2:05Compressed underground for ages,
-
2:05 - 2:08coal holds chemical energy from plants
-
2:08 - 2:11that were fed from by the sun
hundreds of millions of years ago, -
2:11 - 2:13long before humans evolved.
-
2:13 - 2:18That makes coal energy dense,
meaning it can be burned 'round the clock. -
2:18 - 2:22It's also cheap,
if you ignore the pollution costs, -
2:22 - 2:25and should last us
through the end of the 21st century. -
2:25 - 2:29We've already got all the infrastructure
in place for harnessing its power, -
2:29 - 2:30and globally,
-
2:30 - 2:32although countries are making a move
-
2:32 - 2:35towards energy from
cleaner and more renewable sources, -
2:35 - 2:39there's no sign yet
that coal use is slowing down. -
2:39 - 2:41In fact, as of 2012,
-
2:41 - 2:44over 1000 new coal plants
have been proposed, -
2:44 - 2:46mostly in China and India.
-
2:46 - 2:49Since for the time being
coal is here to stay, -
2:49 - 2:53experts say that if we want to reduce
its emissions' impact on the atmosphere, -
2:53 - 2:55and slow down climate change,
-
2:55 - 3:00we'll have to think of creative ways
of reducing coal's destructive power. -
3:00 - 3:03To do that, we need
to strip it of its foul forces, -
3:03 - 3:08all that toxic carbon dioxide
that causes havoc in the atmosphere. -
3:08 - 3:11Then, we need to store
the CO2 somewhere else. -
3:11 - 3:14This mission is called
carbon capture and sequestration, -
3:14 - 3:16or CCS.
-
3:16 - 3:21And as if carbon dioxide were some
evil genie we didn't want to escape, -
3:21 - 3:23once it has been separated from coal,
-
3:23 - 3:26we've devised ways
to banish it underground. -
3:26 - 3:29We can do this by injecting it
deep into the Earth, -
3:29 - 3:32or by placing it deep
under the ocean's surface. -
3:32 - 3:36Stripping away coal's negative elements
can happen in three ways. -
3:36 - 3:38First, and most commonly,
-
3:38 - 3:39as coal burns,
-
3:39 - 3:44the exhaust gas can be mixed
with a compound called monoethanolamine. -
3:44 - 3:49Like a forceful power-stripping magnet,
this compound bonds to the CO2, -
3:49 - 3:51yanking it out of the gas stream
-
3:51 - 3:54so it can be stored
separately underground. -
3:54 - 3:57Another method is
to relieve coal of its CO2 -
3:57 - 4:01before it even has a chance
to be released as exhaust. -
4:01 - 4:05In this process, steam and oxygen
swoop in to the rescue -
4:05 - 4:09to convert coal into a special
product called syngas, -
4:09 - 4:13made up of carbon monoxide and hydrogen
and some CO2. -
4:13 - 4:15Zap that with some water vapor,
-
4:15 - 4:19and the carbon monoxide
gets converted into carbon dioxide, -
4:19 - 4:21which can be isolated.
-
4:21 - 4:25The leftover hydrogen gas is then
used as energy to generate electricity, -
4:25 - 4:27so there's an added bonus.
-
4:27 - 4:31A third technique
exposes coal to pure oxygen, -
4:31 - 4:33instead of burning it in air.
-
4:33 - 4:37This creates exhaust gas with higher
concentrations of carbon dioxide, -
4:37 - 4:41which makes it easy to isolate
and to banish to the chasms below. -
4:41 - 4:46All this can reduce emissions
at a power plant by up to 90%, -
4:46 - 4:49but as with any superhero
struggling with their destructive powers, -
4:49 - 4:52it takes a lot of effort
to switch over from the dark side. -
4:52 - 4:55So these positive
pollution-busting forces, -
4:55 - 4:56although they're available,
-
4:56 - 4:59have barely been used
in commercial power plants -
4:59 - 5:01because they cost a lot.
-
5:01 - 5:05But ultimately, the bigger problem
is that in most parts of the world, -
5:05 - 5:11it's still too easy and much cheaper
to keep emitting carbon dioxide, -
5:11 - 5:15and that makes it tempting
to completely ignore coal's dark side. -
5:15 - 5:19In this case, the most powerful
force for good is regulation, -
5:19 - 5:22the rules that can restrict
the amount of carbon dioxide -
5:22 - 5:24emitted from power plants,
-
5:24 - 5:26and make energy companies
around the world -
5:26 - 5:28wary of what they put into the air.
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5:28 - 5:30Until then,
-
5:30 - 5:32every time you turn on a screen
or flick a light switch, -
5:32 - 5:35coal is lurking in the background,
-
5:35 - 5:38carrying its dark powers with it
wherever it goes.
- Title:
- How to create cleaner coal - Emma Bryce
- Description:
-
View full lesson here: http://ed.ted.com/lessons/how-to-create-cleaner-coal-emma-bryce
It takes a lot of fuel to heat our homes, preserve our food, and power our gadgets. And for 40 percent of the world, cheap, plentiful coal gets the job done. But coal also releases pollutants into the air, causing environmental damage like acid rain and serious health problems. Can we create a cleaner version of coal? Emma Bryce details the three ways we might strip coal of its foul forces.
Lesson by Emma Bryce, animation by Artrake Studio.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 05:54
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