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In this video Paul Andersen explains how energy can be harnessed was water moves through a turbine. Three types of systems are discussed in the video; run-of-the-water, impoundment, and tidal. Several advantages and disadvantages of dams are discussed.
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Transcript Provided by YouTube:
00:04
Hi. It’s Mr. Andersen and this is AP environmental sciences video 26. It is on hydroelectric
00:09
power, which is power created by the movement of water. If we look back in 1980 at the world
00:14
lead in the hydroelectric power, it was the United States followed quickly by Canada.
00:19
Nearly 300 billion kilowatt hours being produced mostly by dams. If we look at what has happened
00:25
over the last 35 years however we see a new country emerge. China. And the reason why
00:30
is the Three Gorges Dam. It is the largest dam on our planet. And they hope to produce
00:35
up to 10 percent of their electricity needs from this one dam alone. And what is hydroelectric
00:40
power? It is power through the movement of water. And we call it renewable. And the reason
00:45
why is it is really the sun. The sun is evaporating the water. It is moving up and as it falls
00:50
down again we can move that water through a turbine in most of the systems and we can
00:54
generate some electricity. The major types we will talk about are the run of the river
00:59
systems. Instead of having a dam they simply have a turbine on the river itself. So as
01:03
the water flows they can generate electricity. We have tidal systems. And we are starting
01:07
to bring on wave systems. And so as the water moves back and forth we can generate energy.
01:13
And then finally we have the most famous type, the water impoundment system or the dam. So
01:17
we essentially take a river, we build a wall on it and we can trap the water behind it.
01:21
Now we can regulate when we let the water out and when we let the water flow through
01:25
the turbines to generate electricity. And so what are some of the advantages of these
01:30
hydroelectric systems? We can reduce the amount of carbon dioxide into the atmosphere. Now
01:35
a lot of it is going to be produced as we are producing the dam, but once it is going
01:39
it is really cheap to maintain. If we look at flood control we can also regulate how
01:43
much water is moving down, especially in an impoundment system. And then you are creating
01:47
a lake so you can create a recreation system that can be used. What are some of the disadvantages?
01:54
Well these things fill in over time. So as the water flows into the impoundment system
01:58
it drops the silt and that is going to fill it up with solid material. So we either have
02:03
to remove that material or remove the dam. They are also limited. So if we look in the
02:07
US we pretty much used all of the viable places to have dams in our country. And since it
02:12
is disrupting flow it is disrupting natural flow of the river and anything that moves
02:17
in the river. For example spawning fish. And so how does this work? Well if you are familiar
02:22
with the water cycle you really know what is going on. We have evaporation, condensation,
02:27
precipitation and runoff. And as the water is running off we are capturing that energy
02:32
of the flowing water. We could also have tidal systems. So as the moon pulls on the water
02:38
on our planet and moves the water back and forth we can generate a little bit of energy
02:42
there as well. First type I want to talk about is the run-of-the-river system. Now this is
02:46
not a dam. It looks like a dam, it is just a very wide river. And so as the water runs
02:51
through it, it is generating electricity. What are some of the nice things about this?
02:55
We are not going to have that siltation problem. But the problem is that is only going to be
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generating electricity when the water is actually flowing. In an impoundment system what we
03:03
have is a dam. We have a huge wall and then we just have a reservoir behind it. So we
03:08
have a bunch of water behind it. As the water is let through we can generate electricity
03:12
as it moves down to the river. And so you can see we have a huge amount of potential
03:16
energy on that side. And if you look at the size of that Three Gorges Dam you can just
03:20
start to imagine how much electricity can actually be generated. We also have tidal
03:25
systems. So in a tidal system the water is moving back and forth as the tides come in
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and out. And so if we lower this down we can generate electricity. We also have a turbine
03:34
in there as well. What are the advantages? Well if we look at the Grand Coulee Dam, which
03:38
is the largest concrete structure that has ever been made on our planet. It is in Washington
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state. Some of the advantages? It is a renewable form of energy. So the sun is actually generating
03:48
the lifting of that water and as it flows down we can tap some of that energy. We can
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then use the water to irrigate crops in the nearby areas. This is an area that was actually
03:58
plagued by floods in the past. And so one of the reasons they put the Grand Coulee dam
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there was for flood control. Did not really work so they had to work with other dams in
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Canada to actually do that. We have created a giant reservoir behind here, a recreation
04:11
area that can be used. And then finally these are not carbon dioxide producers. We can reduce
04:18
our carbon dioxide emissions by running more hydroelectric power. What are some disadvantages?
04:23
Like everything, incredibly expensive to build and maintain. They destroy everything that
04:30
was there before. So this used to be a river that flowed up here. And so you are displacing
04:34
humans. You are covering up a lot of the Native American tribal areas as well. Siltation is
04:40
a problem. Silt is going to fill it in. Eventually it becomes useless. Fish can not move up.
04:45
So they can put fish ladders but they are not super effective. And then it is limited.
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So there are limited places on our planet where we can actually use hydroelectric power.
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And so did you learn the following? Could you pause the video at this point and fill-in
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all of the blanks? Let me do that for you. It is a renewable form where water flows through
05:01
a turbine in these systems. That could be run-of-the-river, impoundment or tidal systems.
05:06
Some of the advantages, lowers carbon dioxide emissions, increases recreation and also decreases
05:12
floods. Disadvantages, siltation disrupts the flow, it is limited. And the big thing
05:17
is it is breaking down the natural flow of the river. And so spawning fish, for example,
05:22
like salmon can not make their way up. That is hydroelectric power. And I hope that was helpful.
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This post was previously published on YouTube.