The Atmosphere, the Ocean, and Environmental Change

GG 140 - Lecture 33 - Energy Resources, Renewable Energy

Chapter 1: Energy [00:00:00]

Professor Ron Smith: Well, we’re going to finish up the course by talking about energy. It’s one of the primary–our need for energy is one of the primary ways that we interact with the environment, both draw resources from it, but also influence the environment. So I think it’s a fitting way to end up the course.

Today I’ll probably just get through these two. Although, so I’ve put hydropower down here and renewable for the future. But it’s a big player today. So I’ll probably talk about hydropower today. But the rest will be discussed mostly on Wednesday. Now, over here, then, is the cartoon that will kind of remind us where everything fits in this picture of energy resources.

Hydroelectric comes from rain falling on high ground, so it has potential energy. If it falls at sea level, you can’t get any hydro energy from it. But if it falls at a high altitude, you’ve got that potential energy to draw from.

The sun, through photosynthesis, will allow plants to grow. And then you can use that biomass in several different ways. Direct conversion of solar to, say, electricity. The differential heating from the sun, as you know, can create the winds. And the winds can turn a wind turbine. The winds also produce waves on the ocean. And those waves can be used to generate electricity. The heat from the sun also creates a temperature difference within the oceans. If the thermocline is there, you’ve got warm water above and cold water below. And that temperature difference can be used to derive a kind of renewable energy. The moon and the sun, their gravitational pull on the earth, produce tides. And that can be tapped for energy.

Everything else comes from down within the interior of the earth. Oil and gas in the ocean bottom comes mostly from algae that grew, or phytoplankton that grew in the ocean millions of years ago and then fell to the bottom and got covered over. Coal, oil, and natural gas on the continents came from ancient biomass that got covered over. Geothermal comes from the fact that the interior of the earth is hot. And sometimes those hot rocks or hot lava can come up pretty close to the surface. And then that temperature gradient can be used for renewable energy.

There is also uranium in the crust. In fact, some of this geothermal heat comes from the natural decay of uranium. But we can also dig up that uranium and use it in a nuclear power plant. What have I left out? Is there anything, any renewables you can think of that I don’t have on there, or any form of energy not included there?

OK, let’s start to go through this then. So first of all, we have to remind ourselves about units. You guys are good at this by now, so I won’t spend much time on it. But the SI system of unit of energy is the Joule. The unit of powers is the watt. Energy is power times the time over which you are using it. So a watt second is a Joule. And inversely, power is energy per unit time. So a Joule per second is a watt.

However, when we’re talking about electricity, there is a non-SI unit that is quite standard. And that’s the kilowatt hour. So the watt is an SI system of unit. And we’re used to putting a prefix on it–kilo meeting 1,000. But then the time unit is an hour instead of a second. So that kind of messes up the SI system a little bit. But it’s easy to go back and forth, because as you know, there are 3,600 seconds in an hour, 60 times 60. And therefore, one kilowatt hour is 3.6 megaJoules. And you don’t have to memorize that. Just remember how many seconds there are in an hour. You can just work that out, that correspondence, anytime you need it.

But it’s odd, because it’s an energy unit. It has a power times a time. So it’s a little like this, except we end up not with Joules, but kilowatt hours. And if you’re an economist and you want to have something to remember about this unit kilowatt hour, well, it’s about $0.10 per kilowatt hour when I pay my electric bill at home. It varies by a factor of two or three across the country however, so that’s not a fixed value. Any questions there?

Now, it is convenient to break up our use of energy into three general categories. I think you’ll appreciate this as we go through the material. Although it seems a little bit odd in the beginning to break it up in this particular way. We use energy for heating, heating your home, for example, just to raise the temperature. It’s a very kind of low-tech way of using energy. In fact, it’s the lowest form of energy when you’re just using heat to raise the temperature of something.

Transportation, moving goods or people. You can use gas in your car for that, or diesel fuel. And then electricity, which is a very broad category. It includes electric motors, lighting, electronics. But you can also use electronics for heating and for transportation. So electricity is a very broad category. But it’s a much higher form of energy in a sense that I’ll be describing later than just raising the temperature by adding heat. So we’ll see how well that three-part categorization works for us as we go through.

And then, of course, there’s all these energy resources. These are the ones that I put on the cartoon over there. I’ll just run over them briefly here and make a few additional comments. And we’ll be going through most of these in some detail today and tomorrow. Coal. There’s lots of it. It is rather heavily polluting, puts a lot of CO₂ in the atmosphere by burning coal, oxidizing it to form CO₂.

Oil and natural gas. There’s less of it than coal. It’s less polluting, both in terms of local air pollution–that is to say, less sulfur, less mercury, generally less ash–also, at about 20%–it’s about 20% less CO₂ emissions per Joule of energy than is coal. So it’s better in almost every respect than coal, except there’s less of it.

Nuclear–plentiful, mostly non-polluting. Certainly, it puts no CO₂ in the atmosphere. Waste storage is a problem, and public resistance because of a danger factor with nuclear plants.

Hydroelectric falls into the renewable category. Clean, it’s limited, and you lose natural rivers and ecosystems when you dam up large valley systems. There is a technology, though, called run-of-the-river hydroelectric, where you don’t dam it. You just take the flow that’s there on any particular day to put through your hydroelectric plant. That avoids the big dam, the big reservoir, and avoids a lot of the loss of natural rivers and ecosystems. So you can do hydroelectric without damming up. But it’s not usually done.

Wind is renewable, moderate cost. A lot of people don’t like to look at windmills. So there’s public resistance to it. Also, sometimes there can be noise and issues about bird kill.

Solar–renewable, high cost. Also, some people don’t like to see the landscape covered with solar panels.

Ocean waves and tides haven’t made very much progress. It’s renewable. It’s very high cost to build something that’s going to sit in the ocean and move around and draw energy from the waves and tides. The engineering really isn’t there yet.

And biomass. Renewable, polluting if you burn it, but no net CO₂ because you’re drawing in CO₂ from the atmosphere to make the biomass. And then when you burn it, you put the CO₂ back. If you’re only putting the CO₂ back, it wouldn’t be too bad. But you’re also putting in ash, probably some mercury, other things along with that burning of the biomass. Any questions there? All right. So that’s our starting point.

Now, this diagram takes a bit of getting used to. It’ll be in the, of course, in the lecture you’ll have on the server. But I’ll go through it. It’s from the year 2006. And it’s US per capita energy. And the units are in watts. So it’s the rate at which we’re using energy for a variety of different purposes. And I’ll run through some of it, but I won’t go through every detail.

So here’s oil, biomass, coal, natural gas. Obviously, oil, coal, and natural gas are the bigger inputs here. There’s geothermal, wind, hydro, nuclear, and solar up at the top as well.

Now, they’ve got a separate branch at the top for electricity production. Everything that’s going to be used by first making electricity goes up to this top area here. And we see that a little bit of oil is used for that, but a lot of coal. In fact, almost all the coal that’s used in this country is used for making electricity. A lot of natural gas, some geothermal, wind, hydro. All the hydro is used for electricity. All the nuclear is used for electricity. All the solar is used for electricity.

Of the 4,400 watts per capita that’s used for electricity production, 3,000 is lost as waste, energy waste, usually in the form of heat. And about 1,400 is used for residential, commercial, industrial, and even a tiny bit for transportation. So you see how the diagram works.

And then over at the right-hand side, it has brought together all the waste from the different energy streams and put them up here, and then brought together all the useful energy and has categorized them here in the green. So you can read this by sources, by use, and by this last category of waste or useful work. Questions there? Yeah?

Student: Is the wasted energy wasted in the process of getting the energy, or is it wasted like when you leave a light on in a room, and you’re not there?

Professor Ron Smith: Mostly, I think this diagram is meant to include all of that. For example, it includes transmission loss. If you have a power plant where you’re making electricity, and then you have to send it over power lines to get it to the consumer, there’s going to be loss in that. And then there’s going to be some–if you’ve got a motor running, but some of that energy goes into heat instead of turning the shaft of the motor, that would be lost. But I think it would also include your category, which is lost in the generation of the electricity. Yeah, good point.

So we’ll be going back to look at this dominance in fossil fuels. We can see it here. But we’ll look at it again in other ways in just a moment. So electricity consumption per capita, remember this was USA.

To put that in a somewhat broader context, let’s look at that quantity for various countries. So this is per capita consumption of electrical energy. And United States is here. I’ve put the arrow there to show it. It’s about 1,300 or 1,400 watts–well, no, this is kilowatt hours, sorry–kilowatt hours of energy used per year, yearly. And we are a high user. But there are higher users. Why would Iceland, Norway, Finland, and Canada use more than we?

Student: Heating?

Professor Ron Smith: Sorry?

Student: Electric heating?

Professor Ron Smith: Electric heat, yes. They do a lot of electrical heating. First of all, they’ve got a lot of electricity from hydro in those countries. So the electricity cost is pretty low. Generally, heating with electricity’s kind of a waste of a high form of energy. But in those countries where you have a lot of electricity, you can heat your house with it. And they do. And that gives them a very high per capita use of electricity.

Now, we heat our homes, too. But we do it more from natural gas, from oil. And so the heating we do would show up in a different category. It wouldn’t show up in the electricity consumption. And compared to other countries, however, we are pretty high in our electricity use. Questions on that?

And of course, these things have been growing over time. So we’ve got a green band, a red band, and a brown band–renewables, nuclear, and fossil since 1980. And this is annual electricity generation worldwide. It’s not per capita. So the unit is large. It’s a terawatt hour per year. A terawatt hour per year. Remember, it goes kilo-, mega-, giga-, tera-, in powers of three. Terawatt hour.

So nuclear has grown. But is steady the last 15, 20 years, renewable here is almost all hydro. Almost all the other renewables we’ll be talking about in this course, at the moment, are pretty tiny. And so the only one that really shows up on a graph like this is hydroelectricity.

Chapter 2: Coal [00:17:46]

And then the fossil fuel has been growing, unfortunately. And that’s the big CO₂ producer. So let’s start with coal and see where that is and how we use it. There are the global coal deposits. I’ll stick–I’ll keep my comments to the northern hemisphere. China has quite a lot. Russia has the largest of any country. Europe has quite a bit.

And the United States has quite a bit of coal. Zooming into the US, you see that there are coal beds along the Appalachian Mountains, some in the Midwest, and some in the Rocky Mountain West. They’ve sub-categorized it here in terms of different quality of coal. But I’m not going to go through that. I’m just going to show you generally where the coal is located.

So if you want to generate energy and you live in this part of the world, you’re probably going to find coal is the cheap way to do it. But maybe if you’re over here, you’ll find a different method because you’re pretty far from the coal beds.

How do you use coal? It’s very simple. You burn it, you generate steam, you put the steam through a rotating turbine. The rotating turbine’s hooked up to a generator. The generator makes electricity. You’ve got to cool that water off on the downside of the turbine, so it doesn’t give back pressure. And putting gas back in the wrong direction, you’ve got to have cooling as well. Very simple idea. You just make steam and put it through a turbine.

However, when you burn, of course, you’re going to generate–you’re oxidizing carbon. You’re going to generate CO₂. There’s some sulfur in the coal. You’re going to generate SO₂. There’s some mercury. You’re going to generate HgO and NO_X. Where does that come from? Well, remember, you’re burning this coal in the presence of air. Air has N₂ and O₂. If your flame is hot enough, you’ll dissociate N₂ and dissociate O₂, and they’ll recombine–NO. And then you’ve got a pollutant.

So these are coming from the fuel. The carbon was in the fuel, the sulfur was in the fuel, the mercury was in the fuel. This is not coming from the fuel. This is coming from air that you’re using to oxidize the coal. You’re basically dissociating air and forming NO_X. And then the particles are coming off the smoke. Remember that, because some other ways for generating heat will generate NO_X even if there’s no pollutant in the fuel itself.

So when you see a power plant like this, those are the smokestacks. That’s where the combustion products are going to be leaving. And that’s the cooling tower, where you’re cooling that steam on the backside of the turbine. So that is not smoke. That’s just water vapor condensing to form a cloud there. And they have enough scrubbers on the stack that you’re not seeing much of a smoke plume. But there is some coming off of the smokestacks there. So know what you’re looking at when you see this.

You know what you’re looking at here. Long trains full with boxcars with coal transport the coal from the mines to the power plant. And you see the big piles of coal ready to be put into the burners.

Now, there’s this useful quantity called the emission coefficient, which is how much CO₂ do you put in the atmosphere for every Joule of energy that you create electricity. And so the units here are CO₂ emission coefficient in units of kilograms per gigaJoule. Kilograms of carbon dioxide per gigaJoule of electrical energy produced. And different types of fuel is given here. The coals are generally in this region. And they are high, generally, about 95 kilograms of carbon dioxide for every gigaJoule that is produced.

The oils, burning fuel oil, is about 20% lower. And some of the natural gases are even 20% lower than that. So they’re still putting CO₂ in the atmosphere, but at a rate that’s maybe 30 or 40% less than coal does. So coal, in this measure, is the worst. And of course, in the local air pollution, it’s also the worst of all of these options.

And what is the future of coal? So here’s a timeline, 1950 up to 2100, 90 years from now. The units are megatons of coal. And it’s broken down by different parts of the economic world, North America, Europe, the Pacific countries, China, South Asian countries, and the former Soviet Union. Look at some of these characteristics. So North America has peaked and is going to be flat according to these projections. Europe peaked long ago and is now down to a fraction of what it was using 30 or 40 years ago.

China is rapidly increasing at the moment. Of course, these are projections. We don’t know exactly what they’re going to do. But it looks like they’re going to dominate coal use. They do already. It looks like they will continue to do that for 20 or 30 years. And then they’ll probably run out of coal.

The former Soviet Union, which–remember that big blob up in the right-hand side of that earlier diagram? We’re talking about that. And they’re not using much of it yet. But that’s probably all of this. So 50, 60 years from now, they will probably be the dominant user of coal. Any questions on that? Yeah?

Student: So the decrease over time for all of these regions, is that because of a change in energy use, or is it because they’ve run out of coal?

Professor Ron Smith: I think it’s mostly running out of coal. I don’t think these projections that are put forward put much stock in the fact that we’re going to purposely leave that stuff in the ground. Yeah.

There’s this term you hear on television all the time–“clean coal.” I can’t tell you how many times I’ve seen this commercial. Maybe I listen to the wrong channels or something. But “clean coal” is a marketing term used to indicate coal burning without local air pollution. And to some extent, that is feasible today with the appropriate scrubbers on the smokestacks, but also with carbon capture and sequestration. The term “clean coal” usually infers both of these.

But this second technology is not developed yet. So it’s talking about something really far into the future. So there is no such thing as “clean coal” if, by that term, they mean both of these characteristics. So watch out for this term “clean coal.” It’s a little bit of a figment of the ad agency’s imagination.

Chapter 3: Oil [00:26:32]

So then we’ll talk briefly about oil. Where is the oil? Well, I hope you can read that in the back. But most of it’s in the Middle East–Saudi Arabia, Kuwait, Iran, Iraq, and the Emirates. And so that’s just what we know about from the newspapers, right? That’s the cause of all of our headaches. The oil comes from the Middle East. But there is quite a bit in the USSR, Venezuela. The United States doesn’t have much left. A few other countries have it. This is as of this moment.

And what does it look like into the future? This goes to 2050 and starts in the year 1930. And it’s in units–strange units, billions of barrels per year. GB/A, gigabarrels per annum, is the unit on that thing.

And this brings us to this concept called “peak oil.” The concept of peak oil is that oil use will, at some point, reach a maximum and then begin to decrease slowly. And it’ll do that—it’ll peak at different times in different countries for different reservoirs. For example, the US has probably passed its peak oil. It probably did it 10 or 20 years ago. Other countries, for example, the Middle East, won’t reach their peak oil–or maybe they’re just about reaching it–these are all projections, though, so they can’t be trusted.

But eventually, they will all taper off because you’re using up the resource–not because you’ve decided to keep it in the ground, but because you’re using up the resource. So by the time we get to 2050, we’ll be already halfway down from the peak. And of course, the price at that point will be climbing even much more steeply than we see today. Remember, the coal curves went further than that. That plot went out to 2100, of course, just in the former Soviet Union.

You should know that New Haven is a big oil port for New England. Here’s a Google picture of the port in New Haven. And all these white circles here, of course–and there are dozens of them–are oil tanks. So when you drive across the Q Bridge and look around, you’ll see these things all over the place. And of course, that’s because the oil tankers come in there, off-load their oil into these tanks, and then they are transported by truck to the rest of New England, used for a variety of purposes. Some of it’s gasoline, some of it’s crude oil. Among other uses is that it’s used to drive the Harbor power plant, which is here, I guess, which gives us most of our electricity in New Haven.

There’s the power plant. It’s called the Harbor Generating Station. Last year, it emitted almost 600,000 tons of CO₂ into the atmosphere, while producing about 600,000 megawatt hours of electrical energy. Yale produces a little bit of its own. But this is the main generator plant for New Haven. This information and a lot more comes from a nice website called carma.org that tracks fossil fuel burning plants around the world. And you can get information on how much they burn, how much CO₂ they put in the atmosphere, and so on, from that interesting website, carma.org. Questions here?

Chapter 4: Natural Gas [00:30:46]

Natural gas has suddenly become very important. These are the areas where we are currently getting natural gas or we’ll soon be getting large amounts of natural gas. And they use this curious word “play” in the natural gas industry to indicate an area targeted for gas development. So if you run across that word, don’t be confused. It has that particular term in that field of study.

And it’s a very exciting field right now, because they’ve learned how to get–suddenly they’ve learned how to get natural gas out of shale, using this method called fracting. So when you look at the timeline, this is similar to the ones I’ve shown you for coal and oil, except it’s for natural gas and just for the US. And the timeline is a shorter one, 1990 to 2035. They’ve got these various categories–tight gas, onshore conventional, offshore, coal bed methane. But look at this new one, shale gas. It was almost nothing. And then just a couple years ago, they discovered this method for getting natural gas out of shales. And suddenly, that’s become the biggest one. And it’s growing.

So this is a big surprise. It humbles us in terms of our ability to predict the future of energy resources, because we didn’t see this one coming. And temporarily, this is going to really shake the markets and is shaking the markets, and is, to some extent, slowing down the development of renewables, because now we’ve got a cheap new source of natural gas, which, as they say, is cleaner than coal. However, it’s still a fossil fuel, still putting CO₂ in the atmosphere. Questions on this?

Chapter 5: Nuclear Power [00:32:59]

OK, we’ll move on to nuclear. That’s what a typical nuclear plant looks like. These are cooling towers. You don’t see any smokestacks. You’re not burning anything. You’ve got the reactor core. You produce steam from that. And the rest you know. Once you get the steam, you put it through a turbine, turbine runs a generator to make electricity. You’ve got to cool down the back side with cooling water. That’s what the cooling tower is for. And then you can recycle the water.

Now, remember, this is nuclear fission. This is taking large nuclei and splitting them apart to get energy. This is a book you’d find, in an introductory textbook in nuclear physics. It’s the binding energy per nucleon as the function of the mass number of the element that you’re talking about. It has a peak roughly where iron sits, and decreases to the right and the left of that.

This means that if you split apart heavy nuclei, you can get energy out, or if you combine like nuclei, you get energy out. That’s called fusion. This is the way the sun makes its energy, by taking hydrogen and hydrogen and making helium. And this is the way we make energy in a conventional nuclear plant, by taking uranium 235 and splitting it apart into lighter nuclei and getting energy out that way.

We’re still working on a way to do this synthetically. That’s one of the great unsolved problems in nuclear physics, is how to make a fusion reactor that’ll generate electricity for us. We’ve been trying for 50 years, still haven’t been able to do it. So all the nuclear plants we’re talking about here use fission to generate electricity. Questions on that?

These are the countries that do it, ranked by the percent of their total electricity generation that is done by nuclear. Lithuania and France lead the way with 75%. The United States is over here with 22% percent, and so on. So we are not a leader in this by any means. But we do some.

And here’s where the uranium is located. The big purple box for each country just gives you a measure of how much uranium is believed to be stored in the earth’s crust within the national borders of each of these countries. So we have a lot. Canada has a lot. Kazakhstan has a lot. Russia has some. Australia has a whole lot.

What about Connecticut? Yes, we get some of ours from Connecticut. There’s a nuclear plant in the southeast corner of the state called Millstone 2 and Millstone 3. That’s what it looks like from the air. And it generates about 2,000 megawatts of energy.

But it has a sad history in a way. The install capacity, in terms of gigawatts, is given here. And the number of reactors is given here, 100, 200, 300. And you see that it grew rapidly during the ’70s. But then because of these two famous incidents–Three Mile Island in eastern Pennsylvania and Chernobyl in the Ukraine–suddenly, people got spooked about the use of nuclear plants. And really, nothing much has been built for the last 20 years, even 25 years, in terms of new power plants. So that is a large build-out. But it’s pretty much flat for the last couple of decades.

And what to do with the nuclear waste? So I mentioned that there was a plant–there’s a nuclear plant in southeast Connecticut. There used to be one up on the river, up on the Connecticut River, in the center part of the state. That’s called the Connecticut Yankee Plant. That was shut down about 15 years ago. And not only did they have nowhere to ship the waste, the nuclear waste when that plant was active, but when they stopped the plant and decommissioned it, they still had no place to put the waste. So it’s still sitting there. 15 years after the plant was shut down, you still have all the nuclear waste below ground in these big tubes, because we don’t know yet in this country how to get rid of nuclear waste. So that’s a real problem. Questions on that?

Chapter 6: Hydroelectric Power [00:38:32]

I think we can get through hydro then. The basic idea is a simple one. For hydroelectric power, as I said before, you need to get the water falling on high terrain. Now, that’s likely to happen anyway, because when the air comes along and lifts up over a mountain, you cool the air adiabatically, generate clouds and precipitation. So you’ve got this process called orographic precipitation, mountain-induced precipitation, that automatically gives you a lot of rain on high terrain. So it’s kind of perfect in a way.

The potential energy, then, you’ve produced is the product–this is right out of your physics textbook–potential energy is the product of mass, gravity, and height. It’s simply Mgh. And that would have units of, well, Joules. Now, your job is not done. You’ve got to get this into your hydroelectric plant, get it through a turbine, and make electricity from it. But at least the energy is there from the rain falling on high ground. And as I mentioned before, it can be either a dammed up lake, or there are these new run-of-the-river designs, where you don’t have to dam, you just take the water. But then you’re subject to whatever the river flow happens to be at the moment. You don’t have any way to store and use it during dry periods.

So there’s a typical dam system. This is from Hydro-Quebec up in northern Quebec. A large dammed lake goes down through a power plant, generates electricity, off you go. Here are some examples. I’ll show you some of these in just a minute. The James Bay Project, up in northern Quebec, generates 16,000 megawatts when it’s operating at full capacity. The famous Grand Coulee Dam, about 7,000 megawatts. These are all the most famous dams in this country. Hoover Dam’s 2,000. Glen Canyon’s 1,300. And the Three Gorges dam, the new one that opened up in China about 10 years ago, is the largest of all. That’s about 20,000 megawatts.

Let’s take a look at these. So the James Bay Project is here. Do you know where you are? So here’s Labrador. Connecticut’s down here somewhere. And Hudson Bay is here, and James Bay is there. So they dammed up some of these rivers on their way into James Bay and Hudson Bay.

A word about the seasonality of hydroelectric. And I’ll use Hydro-Quebec as an example in my discussion of seasonality. As you know from this course, rainfall normally comes heavier in some seasons of the year than in other seasons of the year. Well, in Canada, for reasons we’ve already touched on, the maximum demand is in winter because of electrical heating. And yet, in winter, most of the precipitation falls as snow. So it doesn’t go right into the rivers. So the maximum natural river flow is in the spring and early summer from snow melt.

So how do you solve that problem? Your demand is in winter. Your natural river flow is in spring and early summer. Well, there are two ways to solve it. One is the obvious way. The reservoirs can store that water for six months until you need it. And the other thing is to sell it to a place that has a different demand curve. In other words, they sell a lot of energy to us down here in New England, because a lot of our maximum demand is in summer for air conditioning. So using those two methods, they solve this incompatibility between their demand and their natural river flow.

So as you go around the world, not only for hydro, but for the other renewables, you want to look at this issue. When is the demand? When is the source available? And find out some way to solve that problem. That applies to almost every renewable energy source. The timing isn’t what you would want. Questions on that?

Another famous one is the Columbia River and the Snake River that feeds into it. So here is Washington and Oregon. The biggest–there are a lot of big dams along there. I think the biggest is a Grand Coulee Dam, which is there. And that’s the one I gave you the production numbers for.

Another big area in this country is the Colorado River system. And the two most famous parts there are the Glen Canyon Dam with Lake Powell backed up behind it and Hoover Dam with Lake Mead backed up behind it. But on the scale of things, those are relatively small. Those are those numbers there. I mean, they look majestic to see them. But they’re not as large a some of the other big, new hydroelectric plants we have around the world.

And then the Three Gorges Dam in China, you see it here, backed up a huge lake. And that has that huge number of 20,000 megawatts of energy at full capacity. How does it work? Well, you’ve got your reservoir with a certain height of water. Hydrostatically, that generates high pressure at the bottom, which pushes water down through this smooth tube called the penstock, smooth to avoid turbulence and losses. And then it goes right into the turbine. And then the rest of the story you know. You turn the turbine, the turbine turns a generator, which makes electricity. And off you go. And the water then goes on down the river.

There’s the Grand Coulee Dam. And I want to show you this. There’s a couple of people standing there for scale. There is the turbine, one of the turbines for the Grand Coulee Dam. These are really massive turbines that generate a lot of electricity.

Chapter 7: Three State Comparison of Energy Production [00:45:46]

Yeah, so let me just wrap up with this then. I pulled off this data from the DOE a few years ago, comparing three states–Connecticut, Ohio, and Oregon. Now, Connecticut, as we’ve seen, has some petroleum and gas being used to generate electricity. But it also has a big nuclear component. In fact, that’s the largest single component. 44% of our electricity in Connecticut comes from nuclear. And our CO₂ emissions, on average, are pretty low because of that.

Ohio doesn’t have too much coal of its own. But West Virginia lies just east of it. It shares a long border with West Virginia, which is a strong coal-producing state. And so they ship the coal over the border, burn it. And 86, 87% of the electricity in Ohio is generated by coal burning.

Oregon, on the other hand, being on the West Coast, mountainous, heavy rainfall, 81% is hydroelectric. So here, within the same country, within the US of A, because of the way these states are located in different provinces, you’ve got three completely different dominant electrical energy sources–hydroelectric, coal, and nuclear. So there is a lot of variability out there. And it depends on what’s available nearby, basically. Any questions on this?

That was a lot. Let’s finish it for today. And on Wednesday, we’ll do the renewables.

[end of transcript]

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