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Introduction to Hydroelectric Power Plant Engineering

teacher avatar SaVRee 3D, Where engineers go to learn.

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Topics include illustration, design, photography, and more

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Taught by industry leaders & working professionals
Topics include illustration, design, photography, and more

Lessons in This Class

35 Lessons (2h 16m)
    • 1. Hydroelectric Power Plants Course Overview

    • 2. Welcome to the Course

    • 3. Hydroelectricity Introduction

    • 4. Short History Lesson

    • 5. Potential to Electrical Energy

    • 6. The Hydro Power Engineering Industry

    • 7. Hydroelectric Power Plant Terminology

    • 8. Impoundment and Diversion

    • 9. Headwater, Tailwater, Head, Pondage

    • 10. Upper and Lower Reservoirs

    • 11. Hydro Power Plant Components

    • 12. Prior Preparation and Planning

    • 13. Trash Racks

    • 14. Gates

    • 15. Spillway

    • 16. Penstock

    • 17. Turbine Runners

    • 18. Draft Tube

    • 19. Powerhouse

    • 20. Generator and Power Distribution

    • 21. Hydroelectric Turbines

    • 22. Reaction and Impulse Turbines

    • 23. Axial Radial and Mixed Flow

    • 24. Kaplan Turbines

    • 25. Variable Pitch Blades and Control Pitch Propellers

    • 26. Francis Turbines

    • 27. Pelton Turbines Part 1

    • 28. Pelton Turbines Part 2

    • 29. Types of Hydroelectric Power Plants

    • 30. How Hydroelectric Dam Power Plants Work

    • 31. How Run of the River Power Plants Work

    • 32. How Tidal Power Plants Work

    • 33. How Tidal Stream Power Plants Work

    • 34. How Pumped Storage Power Plants Work

    • 35. Final Thoughts

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About This Class

Humans have been harnessing the power of water for thousands of years. The potential energy of water has been used to drive mills, pumps and for numerous other applications. Converting the potential and kinetic energy of water to electrical energy however, is a relatively new concept. Modern hydroelectric power plants represent the pinnacle of hydropower engineering, but how do they work? How efficient are they? Are they really 'green'? In this course we are going to answer all of these questions and many more!

You will learn:

  • What role hydroelectricity plays in today's power engineering market.
  • What the common hydro power plant components are (penstock, gates, spillway, turbines etc.).
  • Hydro power plant terminology (headwater, tail race, etc.).
  • How different hydro power plants work (dam, run of the river, tidal, pumped storage etc.).
  • The differences between several hydro turbines and their typical applications (Kaplan, Pelton, Francis).
  • And a lot lot more!

The course is designed to take you from zero to hero concerning hydroelectric power plant engineering knowledge. Even if you already have some background power plant engineering knowledge, this course will serve as an efficient refresher. Whatever your level of understanding, or engineering background (electrical engineering, automobile engineering, power engineering, oil and gas, chemical engineering, mechanical engineering etc.), we guarantee you will have never taken an engineering course like this one (unless you have taken one of our other courses!).

Interactive 3D models are used to show you each type of hydroelectric power plant, their main components and each type of hydroelectric turbine. 

Hope to see you on the course!

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SaVRee 3D Where engineers go to learn.


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If you are a professional engineer, or a student preparing for entry into the exciting world of engineering, we guarantee you will find our courses of great benefit.

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1. Hydroelectric Power Plants Course Overview: in this course, we're going to learn about hydraulic power plants. We're going to have a look at some of the historical aspects that have shaped the hydro electric industry on. We'll look at the state of the hydro electric industry today. We'll cover all of the hydro electric power plant components such as trash racks, spillways, pen stocks, turbine runners, draft tubes, generators and electrical transformers. Well, look a hydro electric turbines in great detail. This includes reaction and impulse type turbines. Axel Mixed radio type turbines on the three most common types of turbine used in the hydro electric industry, the Kaplan Francis Pelton turbines. Finally, we'll have a look at different types of hydroelectric power plant, and you'll learn how each type of power plan works as well as the advantages and disadvantages associated with each plant will look a hydro electric dams run of the river plants, tidal barrage plants. Tidal stream plants have finally pumped storage plants. By the end of this course, you'll know exactly how hydro electric power plants work, and you'll have a very good understanding off turbine theory. You can use the knowledge gained from this course to understand the words and concepts behind combustion turbines and steam turbines. So if you want to learn about hydro electric power plants, how they work the terminology and the components involved, then you should definitely check out this course. 2. Welcome to the Course: welcome to this course on hydro electric power plants. In this course, we're gonna look at how we convert the potential and kinetic energy off water into electricity. We're gonna discuss a lot of hydro electric power plant terminology such as impoundment diversion, headwater tail, water and upper and lower reservoirs. We're going to look at all common hydro electric power plant components. This includes things like the trash racks, gates, spillway, pen, stock, toe by generator, toe by runners, draft tube powerhouse, etcetera. We're then gonna look in great detail at hydro electric turbines. We're gonna discuss things like reaction impulse turbines of what defines each will look Axel mixed radial flow turbines. And then we'll look at the three most common types of hydroelectric turbine you're likely to encounter, such as the Kaplow, Francis and Pelton. And finally to round it all off. I'm gonna explain to you exactly how each common type of hydro electric power plant works. By the end of the course, you'll know how hydro electric dam works. You'll know how a run of the river plant works. You also know how tidal power works. Tidal stream on pumped storage. This course is very visual. There are a lot of three D models. There are a lot of animations. There are a lot of pictures. I really do hope that you're gonna take away a lot from this course, and you can learn a lot. So I'm now going to get out off the way and let you get on with this fun, exciting and very educational course. 3. Hydroelectricity Introduction: in this section will do a short history lesson just to recap on how the harder electric power industry became the way it is today. We'll look at the fundamental operating principles off how hydro electric power plants work , and then we'll look at the state of the industry today and we'll see just how much power is generated using hydroelectric power plants compared to all other types of power plan. 4. Short History Lesson: a short history lesson. Humans have been harnessing the power of water for several 1000 years. Now we've been using it for mills and pumps and other operations. However, using water to generate electricity is relatively new. I'd say it's been around for approximately 140 years. Most of the earliest hydropower plants were built either in the States or Europe, and they were spurred on by the Industrial Revolution. Over time, the hydropower plant industry has expanded and the installed capacity in megawatts has gradually increased. In the 19 seventies, there was a sudden increase in the amount of power generated by renewables on this was due to the oil crash, all the or crisis of the 19 seventies. A lot of countries wanted to reduce their reliance upon fossil fuels, especially fossil fuels delivered by other countries far away. In order to do this, they actually started building up their renewable megawatt capacity as quickly as possible . One of the most efficient and reliable means of generating electricity is by using hydropower plants, and that was the reason that so many hydropower plants were built up quickly in the 19 seventies. Since then, Europe's been quite saturated with hydropower plants, there's not much room to install more capacity. The U. S and Canada continue to improve their hydropower plant capacity, sometimes increasing and sometimes just renewing their plants to increase the efficiency. But the main focus of the current industries. Asia with China building many many hydropower plants over the past 20 or 30 years, and I think it's safe to say the most famous is the Three Gorges Dam, which I believe at the moment is the largest hydropower plant on the planet. So that's the current state off the industry and how things have been developing over the past 140 years or so. Let's not go have a look at the fundamental principle behind hydro electric power plants. 5. Potential to Electrical Energy: the principle behind hydro electric power plants is simply that they want to convert potential energy to electrical energy. Now the potential energy is actually within the water. You could say on this potential Energy represents itself sometimes as dammed water may be restored. Water somewhere on this water is at a higher elevation on the inlet side of the power plan compared to the outlet side of the power plan. So this gives us potential energy, the movement of water due to the difference in elevation. When we have this difference in elevation and we have a movement of water, then the water will flow from one place to another. If it flows through a power plan, then we can get it to rotate a turbine on many generator, which is going to generate electricity. So the common thing for all hydropower plants is simply that they require water, usually lots off it, especially in the industrial plant. Onda difference in elevation in order that the water will move or flow from one place to another. If you have elevation and a lot of water, then you can install ah hydropower plant and generate electricity. In the next lesson will look at just how much electricity we can generate from hydropower 6. The Hydro Power Engineering Industry: Let's now take a look at the state of the hydro electric power industry on the power industry in general, I'm on a website called Aida Warg International Energy Agency. And if you go to the website, you can actually access a lot off data for free. What we're looking at now is a graph off electricity generation by fuel. We've got the fuel indicated on the bottom. This is the fuel used to generate the electricity or the source, I should say of how we generate the electricity on the way axes. We've got gigawatt hours. That's the vertical axis here and on the X axis. We've got the time period as the horizontal axis, and it's from 1990 to 2000 and 16. What I'll do is I'll remove some of these fuels because some of them are not so interesting . And it just makes it a little bit easier to see some of the trends. So we can now see the cold is being used to generate electricity. And the general trend is that it's going up on its sort of tailed off a bit between 2014 and 2016. If we compare that to for example, wind, we can see that wind contributes comparatively little compared to coal. However, wind is also trending upwards. And if we didn't compare it to hydro, we can see that hydro is actually contributing quite a lot, considering it's a form off renewable energy. So let's remove all of the fossil fuels and what we'll do, We'll add the ones that we class as renewable. I feel solar PV on going to say solar thermal. These are the ones with class as renewable. Some people actually argue about what is renewable and what is not. But I'm gonna go these options because they look pretty safe and we can see that hydropower . He's not only trending upwards over time, but it is a huge contributor in terms of renewable energy and how much it contributes to the grid. If we look at things down here such as wind, we've also got solar PV. We can see that there are also increasing now quite a lot. The cost of solar panels has actually come down considerably in the past 20 years on. That's made them a lot more affordable, and a lot of people have been stalling the Mont opera houses or in fields will pretty much anywhere else where they can have enough space to generate a little bit of electricity. Wind power is also now becoming a big factor. And if I simplify the graph a little bit, what we should actually see is the big free. I would say for the Big Four they're going to be hydro, wind, geothermal and solar. Most places are classified the Big Three as being hydro, wind and solar. So here's that big free in terms of renewable energy, and we can see there are all trending up over time. But hydropower is by far the largest contributor to the group, so there is a lot of power available from hydro electric power plants. It's not brightness down into apply a graph. We can have a look at it more closely can see again. Hydro's here 16.7% of all the world's electricity is provided for by hydropower. Coal is a big contributor, but this is non renewable gas as well. A little sliver of geothermal on nuclear power is also quite a large contributor, generally as a rough approximation. 15 to 20% of all electricity is generated by renewable sources I say is a very rough approximation because I want to show you the difference between two different countries have different available resources. So let's go and have a look at, for example, India. So India is burning a lot off coal, their second largest contributor looks like it's hydro and the third is guess India has a lot of people. So the fact that they're burning a lot of coal to supply those people with electricity is perhaps seen a slightly negative. Hopefully there. In the future, these renewable sections will become bigger and groups like hydro, solar and wind will become larger. On this, coal will gradually be phased out or credit reduced, I should say, compared to how it is now is free. Quarters of electrical power generated in India is generated by coal. Let's go, never looked at another country and this country is Norway, and Norway's blessed in a way because they've got oil have got gas. Hardly anyone lives there. Andi, they've got the ability to generate a lot of hydropower. We can see that here. 96.4% of all the electricity generated in Norway comes from hydro power. We look at another country such as Iceland, we can see again. They're heavily reliance upon hydro and geothermal. We look at Kenya. There are also blessed with hydro resources and geothermal. So there are many countries, including some in Central America such as Costa Rica. And we can see again that they also have hydro resources. Wind, biofuels, geothermal, solar on only a little bit off oil for those countries Norway, Kenya, Costa Rica, Iceland, they all have access to renewable energy sources. But these countries are more the exception than the general rule. If we look at where I'm from, which is the United Kingdom, we can see here that the UK uses a lot of gas for electrical generation. On a lot of nuclear. On the third biggest provider seems to be wind. So it's a very diverse set up if we don't have a look at somewhere like France, if that we can look at United States because they're also quite a large consumer of electricity and we can see coal, gas, nuclear. Those are the three big providers for the United States. However, in fourth place is a renewable energy source, a nice hydropower, So the importance of hydropower does very depending upon the country in which you live. However, as a renewable energy source, it's generally largest contributor to the grid. We can see the overtime power generated from wind turbines is increasing. Power generation from solar PV cells is increasing. Hydro electric power generation seems to be relatively static. But this is all for the US. If we switch to the world, we can see that increasing same for solar PV, same for wind. And if we look at waste and bio fuels, we can see those increasing as well. So this trend that we're getting more power from renewable energy sources is increasing, and it's mostly based on the fact that the oil and the gas at some point is going to run out, and we need to shift on to renewable energy sources. Not only that, but economics come into play when something becomes scarce, then its value increases on the same things going to happen with a lot of resources, such as coal and oil. At some point, it's no longer cost effective to have a coal fired power station or a power station that burns gas because the fuel itself simply costs too much money by, irrespective of how we looked at these graphs, we can see the hydropower plays a very important part in the power generation industry, and that is not going to change any time soon. 7. Hydroelectric Power Plant Terminology: in this section. We look at the concepts off, impoundment on diversion. We'll look ahead. Water, tail, water, head in, pond each on. We'll also look at upper and lower reservoirs. The idea of this section is simply to introduce some common hydro electric power plant terminology so that the terms become familiar to you before use them later in the course. 8. Impoundment and Diversion: Let's discuss now the concept of impoundment on diversion can see here we've got a hydro electric dam also referred to as a hydro down. We've got water on the left side of them. Well, Zuman, over here on water on the right side of them. Over here, the concept off impoundment and you'll sometimes hear of power plants being impounding type of diversion type is that impoundment stops water flow on. We can regulate the water flow by allowing in through the down or through the powerhouse or by shutting off completely. So remain. Always have a damn. Maybe we'll have a powerhouse that's used for tidal power generation on the powerhouse itself. Might should be the damn. But the concept of empowerment is simply that we can either stop the flow or start the flow on demand, and I'll show you how this compares now to a diversion type hydropower plant. So here we have a different type of hydro electric power plan. This one is called a run of the River plan. Let's go to the top. Look another quick look. This is a diversion type off hydropower plant. The reason it's diversion is because we are diverting some of the water to the power plan, and some is not going to the power plan. The diversion to the plan is through this hole here. This intake and the rest of the water is allowed to flow onwards, and we can see it goes over this lip here. Sometimes it may be possible to vary the height so we can change the amount of water that is required in order to flow over the top off the barrier. Here we can see it flows over the top, and that means any wildlife that may be swimming in the water. If it does want to continue swimming downstream, it can swim further downstream. This is a diversion type off hydropower plan. If we blocked this section here, then we would effectively dam the river on soon enough. The area behind the concrete structure would actually overflow, and that's why you see a large amount of flooding associated with hydro dams compared to run of the river plants. Once you stop the river flowing, you need a large space upstream of the down which could be flooded because that's exactly what's going to occur. So this is a diversion type of plan, and the other type is an impoundment type of plant 9. Headwater, Tailwater, Head, Pondage: let's now discuss the concepts off Upper reservoir, lower reservoir bondage, headwater and tail water. So with this type of hydropower plan, we can see that a large body of water is stored on the left on. We allow the water to flow through these small in. Let's in a damn structure goes down to the powerhouse on, then is released on the opposite side. The body of water on the left is known as the headwater on the body of water. On the right is known as the tail water. The difference in elevation between the headwater on detail water that is the top of the head water in the top of the tail water he's known as the head. Remember that in order to have a hydropower plant, you need two things and that is a difference in elevation on a large amount of water. If we don't have a look at a run of the river, power station is slightly different. So here we are again, looking out of one of the river power station. We can see that although there is some headwater here on, there is some tail water, which is actually this area here immediately downstream of the power plan. We may also have an area referred to as Pond Egx. Let's just imagine for a moment this area was a lot larger. Let's imagine that the trees in the hill we're not here. We flooded this entire space where my mouse is. We would then refer to that area. Has pond egx. What he actually is is a small amount of water that's held in reserve in order to deal with water flow fluctuations on and also so that we can perhaps put another turbine on load on. We can use up some of the water reserve in the pond area. Hopefully, the bondage water will be replaced quite quickly. But this isn't always the case because the water flow depends upon environmental conditions . If it's spring time, then we're gonna have a lot of water melting from the mountains. Maybe, and that's gonna flow downstream and it's gonna refill our bondage area very quickly. However, in summer and autumn we're not gonna have such a high flow, and that means that the water in the bondage area is going to be replaced a lot more slowly . But essentially, it's just a reserve capacity for the hydropower plant. No all run of the roof plants have upon DJ area. I've surveyed about 30 run of the river hydropower plants, and I would say I've seen it a few times, but it's not always the case. A lot of these plants are simply run of the river with no reserve war to supply. What you've also got remember is a lot of these one of the group of plants, Aaron Siri's. That means that you're gonna have one plan on, then maybe another five kilometers further down river and then another five kilometers further down river. And that means that although you may have a bit of reserve capacity at one of the plants, if you're using that reserve capacity or if you're using more than your allowance, then you always have to think out. That's gonna affect the other plants downstream in the same manner as if you were to close off your plan and reduce the flow. How would that affect all the other plants downstream on? Normally, they'll actually measure the height off the water or the elevation of the water at various points between the plants in order that they can counter or allow for these change in flow fluctuations. Let's not go and have a look at number type plan where we use an upper and a lower reservoir. 10. Upper and Lower Reservoirs: we are now looking at a pump. Stories type plans once again. Don't worry too much about the actual design. The plan. We're gonna go through each one individually later in the course. However, what you can actually see is that we haven't upper Reservoir located here. And then we have a lower reservoir, which actually just joins directly onto a river so you can see there are different terms used for different types of plan. A lot of the time, these terms are used interchangeably with each other, although strictly speaking, the terms upper and lower reservoir are usually used for pump storage type plants only headwater and tear water you can use for all types off plant. It's simply indicating the body of water upstream of the plant, which is ahead water on the body of water, which is downstream of the plant, which is the tail water 11. Hydro Power Plant Components: in this section, we're going to look at all of the common components that make up a hydroelectric power plan . Well, look at things like trash racks, gates, spillway, pen stocks, toe by runners, The turbine generator Draft two. Powerhouse on the electoral transformer. No, All of these components are going to be used for all types of plant. It's always good, though, to get an overview of exactly what the components are and how they fit into the system in general, and that's what this section is all about. 12. Prior Preparation and Planning: So before we go too much further in the course, let's just have a quick look at this three d model here on. I want to explain the importance off preparation. Now, My brother was in the military and he used to say that there are six piece that always essential on that is prior preparation and planning prevents poor performance. He actually told me seven piece, but I'm not gonna mention the other one. So here we are. We can see a little bit off preparation. In effect, this water intake system is actually taken from a sewage treatment plant. But if we spend around, we can see that the water is flowing in from the left on its passing through. This first item here on then is flowing along, passing through another item here on. Then it will continue to the plant. So why am I showing you this? Well, the reason I'm showing you this is because there are certain things you need to do before you can start sending water to your hydraulic power plant. We'll do it like she just pours the animation for a moment. And I'll explain to you exactly what's happening on this three D model, So the first thing we have is a trash rack. This is the trash rack. We can see that it's got these metal bars or come from the direction of the water. I've got metal bars here. He's a quiet, thin, and these were used to capture bits off rubbish. Or, as our American friends call it, trash. What will happen is plastic bags on other bits of debris that may be floating in the water . They're going to be swept along the water inlet. And if we didn't have this great his trash rack, then they would be allowed to pass directly to plant. Now I plant maybe a reversals. Most of plan. It may be a hydroelectric power plants it maybe any other process or plan that uses a large volume of water. But we don't want plastic bags and other bits of debris getting something Teoh pumps and turbines etcetera. So we'll have a trash rack that means large bits of wood. Maybe plastic bags and other bits will get stuck on this trash rack on. We were used, then the scraper. That's this item here on the scrape is going to go up and down, and it's going to scrape off the contents. And when it scrapes off the content, what it thinking to do is dump the contents into a container. Conceive the container here, it's this bucket shaped here on. Then we will remove the container, maybe daily or weekly on. We can take away the rubbish and put an empty container there again, let's just see that in operation so we'll go down. We can actually just follow it. Find the right angle so you can see what is actually doing. They would go. It's going up, scrapes the rubbish, goes across, dumps it into the container, sometimes skip and then back down again, pivots slightly, and then it will scratch the rubbish. Or scrape the rubbish off and dump it into the container. So that is a trash rack. Let's now have a look. At the next stage, we can see the next stage involves a rotating or a movable great zoom, and we can see that the iron bars that we had on the trash rack are no longer present. Instead, we have quite a fine great we can see here. There's only small holes for which the water can pass through, but foreign bodies and foreign objects cannot. So we may have already taken out the bits off wood and plastic bags, except for here on may be at this stage what we're going to do. We will take out the leaves on off a smaller foreign bodies. How are we going to do that? While we can see if I push play, it's constantly rotating on. The reason that we actually want to turn this into a moving great is because leaves and other items that stick to it, they will tend to clog. These very fine greats quite quickly sculpted a top of moment. So now at the top and we can see that the screen, the movable screen, has actually just dumped its contents into this channel. Here, this little canal. We're going to allow water to flow through here continuously, and it's actually going to just gradually wash away the leaves on it will take it to a holding tank where will drain the water off on. We can keep the leaves on. We'll probably send those off to be disposed off. Sometimes they'll actually be burnt as well, but anyway, that's what's gonna happen if I go inside? Maybe we can actually see little bit. We can see the screen is coming down on. We can actually see. We look at these spray nozzles here. The's spray nozzles blast jets of water out onto the movable screen on. They're going to spray those leaves off on the leaves. That ain't gonna just land into the channel here. Water that's flowing along in that direction will take the leaves away, so that is a continuous process. Where is for the trash rack? Although erection seen this going up and down continuously, If we see it here, this might not always be the case. Generally, trash racks are used every now and again, maybe once a day, just to clean off the trash rack. And we'll actually use the crane just every one or two days, maybe once a week, to clean off the trash rack. Whereas the movie screen is gonna be used continuously. It all depends on how dirty the environment is, so that's how we prepare water before it's taken into on industrial process. This type of installation is slightly different to a normal hydropower plan. A normal hydropower plan will definitely have a trash rack, but you are not going to have a moving screen like the one we're seeing here. 13. Trash Racks: in the previous lesson. We talked about preparing the water before it gets into the plant. Now I want to talk about exclusively is the trash rack, and we use the same freedom model again just to discuss very quickly some important points about the trash rack. As explained previously, the trash rack is going to stop bits off rubbish and foreign bodies entering the plant. One of the most important things about the trash rack is actually the size off the greats. That is the gap between the metal bars on also the amount of vibration that the trash rack is likely to encounter. The trash rack is the first point of contact for the water as enters the plant so it will flow through the trash rack on. Then later it will flow through a gate, which is used to close off the water inlet and then down the water inland. Trash racks are going to be usually vertically installed, and we can make the trash racks so they're either fixed, such as the one we're looking at now or so that their movable. That means we can either pull the trash rack up and clean it or we can just fix it in place as shown here, so they're different designs of variations. The frequency of cleaning depends strictly upon how dirty is, and you may have an automatic cleaning crane, such as this one here, which schedules cleaning perhaps for once a day, once a week. And it's fully automated, which is always good. Or you may have a mobile crane, so different set ups. But the most important thing to realize here is that although the trash rack is very simple item, it's also crucial. The last thing we need is a whole or large gaps in the trash rack that allow bits of rubbish to enter into the water Inlet and damage are very expensive turbine if the trash rack becomes cloaked. If there is a lot of rubbish that has accumulated on the trash rack, we're going to restrict flow on this reduction in flow may lead to very unusual flow paths for the water Entering into the water inlet on this again may cause vibration on the trash rack itself. Vibration is a very big consideration for track tracks, so simple construction, simple design, very similar in a way to a strainer that you'll use before a pump or a filter that using a system. The idea is simply that you want to protect all of the expensive equipment downstream by removing the foreign bodies that you don't want flowing further down through the system. Let's now have a look of the next item that the water will encounter as it enters the hydropower plan that is Thean licking. 14. Gates: So let's now have a look at the inlet gate on gates in general. So we gotta have run of the river Power station again. Well, come around. If we can zoom in just a little bit more, we have to show you the gate. Now, gates are used to start stop on regulate flow, so very similar in a way to valves. We can see that this gate has a long spindle and if we zoom in, might even be able to see the hand wheel that is used to open and close the gate. Now this type of gate is quite small, and that's why you can manually actuate it. Generally, Gates are going to be mechanically actuated, that is to say, by hand, electrically actuated, using a three phase motor normally or perhaps a single phase motor relying on D C power in an emergency or hydraulically actuated on will use hydraulic oil pressure and I draw like cylinder to loan raised the gate normal operation. You can use things like 80 motors onda, also hydraulic pistons and stuff like that. In an emergency, you are going to either open and close the gates manually, which is quite difficult if you have a very large gate, or perhaps you'll use power from batteries and send it for an inverter to power the A C motors And maybe even in some cases, you have an emergency generator withdrew. We hooked up to the control system for the gate in order that you can operate all the machinery required in order to open and close the gate. The reason that you have a normal operation on emergency operation of all of the gates you simply the gates are very, very important. If you cannot close this gate in an emergency, all of the water that is above the plan is gonna be allowed to flow down to the turbines. If we look on the other side, there is the pipe coming down to the power station is known as a pen stock. On the only gate between the inlet on the powerhouse is the one at the top. There is, however, additional valves further down. We can see we have a full valve zerman on this ball valves used to start stopping regulate flow as well. Ball valves typically and not used to regulate flow. Actually just on and off valves. The reason being is when you open a ball valve halfway, you have a lot of turbulent flow on the degree to which open the valve is not proportional to the amount of flow through the valve, So this is very much an open and closed valve. We can see also that this is hydraulically actuated. It's not going to be new radical actuated because the valve is too big. That cylinder is too small to use. Compressed there. It will actually use hydraulic fluid. But all of these items are installed to stop starting regulate flow in order that we can control what is happening in the process. We go further down. We should actually see another gate on the outside. We can see there. It's mechanically actuated on that would just close off the draft tube or the outlet off the powerhouse. So very, very, very important. You don't just want to close these often emergency. You'll also need to close them off to perform maintenance. When you're performing maintenance on the turbines, you close off the valves on the inlet, an outlet size off the turbine, and you close off the gates as well. You can nd water, and that means to pump the water out off those spaces. We just zoom in for a moment. We can see the bottom of the turbine. He's along this pipe here. So if we closed off the gate and we closed off the ball valve that we saw earlier on maybe the other gate atop, then we could pump the water out of this space and then we'll be able to inspect a turbine , which we are looking at. Here is a vertically orientated turbine, and we're actually looking at an item called the Runner and when we pump out the water it that is the time to inspect all of these areas. If the gates or the valves are leaking, then you'll need to fix those leaks in order that you can work in the area safely. A little bit of leakages, OK, but obviously you need to be able to work in the area for maintenance on. It's never a good feeling if you're working in there and the space is gradually flooding. So that's the reason we have gates and valves on all of the water conductors. The water conductors themselves are any items that bring water to the plant or away from the plants. In the example here, we've actually got a penny stock. That is his point. And we've got a draft tube, which is the outlet side off the powerhouse. Zoom in here. This item here would be a draft tube, so all of those things are called water conductors. 15. Spillway: Let's now have a look at an item that we call the spillway. Here is a model of a hydro dam again and we can see it has a pipe over here on this exit pipe. Here. This discharge pipe is actually for a spillway. What is this doing? It's allowing for overflow. What we want to avoid is the headwater becoming so high that it overflows over the top of the dam. This puts very large stresses on the dam. And not only that, we don't really want the water overflowing and landing on a powerhouse. So in order to stop this occurring or hopefully prevented occurring, we use a spillway spillway. It could be thought off as an overflow device. Sometimes what you'll actually see is that the dam itself has a notch or rich, and it will be approximately this height here. And that means that when the water comes up to that high, it will overflow and it will go down A dedicated passage, a dedicated spillway, Andi. Then it will go to the tail water. The one we've got here has a very similar concept. When the headwater water level becomes quite high, it's going to overflow and go down this pipe Here, this water conductor, we can see that it's actually a lower level than the top of the dam, so the water will begin to overflow down that water conductor before it starts overflowing over the top off. Damn! Where is it going to? Well, I'll try to go through the pipe and perhaps we can have a bit of a look. Conceive. That pipe takes a few turns. I think what I'll actually do is I'll go outside of the pipe in a moment. Perhaps we can see a little bit more. It's going through the rock. It takes another turn. We're actually inside the rock now, and we can see these going along along. And then out of that spillway that we saw earlier, we'll zoom now. Now we can see the spillway on. Do all of that water that's overflowing is essentially going down through the water conductor here into the rock along here, Andi, then back out off the spillway. So that's the function off the spillway is to allow for overflow. Obviously, there's only a certain amount of flow that spillway can allow. Four. If we exceed the maximum flow capacity of the spillway, Then the dam will overflow. There's nothing we can do about that, unfortunately, but normally calculations have been made, and only in extreme cases where we have extreme high rainfall and flooding should the dam overflow. This has happened a few times in the past and cause dam collapse. So this is not totally unheard off, and large plants will have not only a spillway but also an emergency spillway. We should give you an indication of how important the spillways are. If, for example, this spillway was broken, perhaps the concrete have fractured and some of the spillway was blocked. Then we re send the water instead, if possible, to our emergency spillway. Spillway collapse is also not totally unheard off. I believe the last spillway collapse that was on the news was in 2018 in America, and they actually did open up the emergency spillway in order to prevent an overflow situation. So it's always very, very important precautionary measure, but definitely something that every large dam will have other plants. They may not have spillways as such, but what they will have is a means off controlling the flow during an overflow situation. This may be simply if we have a run of the river plan that well, oral of the gates on the river is allowed to simply flow at its natural pace. That being said, even in extreme cases, off bad weather, where we have very high rainfall, there is little that a run of the river plan conduce you to prevent an overflow situation once the river is more or less free to flow at its own pace. If the amount of water keeps increasing anyway, then all you'll find is that the powerhouse is sitting in the middle of a river, these gradually overflowing. For this reason, powerhouses and run of the river plants are designed to withstand 500 year floods. 100 year floods, etcetera, actually busy one run of the river plant where water was actually flowing over the top off the powerhouse on That happened about three years before I visited to plan. The plant was still in service, and they did have some downtime. But it just goes to show you how resilient these structures can be. If they're designed well, 16. Penstock: So let's talk briefly now about the pen stock. The pain in stock is quite important part of every hydropower plant. The pen stock is a pressurized water conductor, so we can see the pen stop here. It's coming from the headwater down to the turbine, which is located in the powerhouse. There are three main types of Penn stocks. Hence, stocks themselves may be supported. Their supported a intervals on concrete or steel saddles like what we're seeing now. Well, sometimes to be partly or fully embedded in the soil. And sometimes they might even used fully enclosed steel liners. So different variations off pen stock. This particular pen stock is used to drive one turbine. It comes down and connects onto one individual turbine. This is ideal because we can close off the pain in stock, and then we can also hydraulic be isolate the turbine. Unfortunately, sometimes this is no always the case for every hydropower plant. If we have one pen stock per turbine, it's actually cost quite a lot of money. If we can reduce the number of Penn stocks Onda, we can use one pen stock to distribute to, say two turbines. Then we're saving on materials and cost. Unfortunately, one pen stopped for two turbines means if we close off one pen stock, we isolate two turbines instead of one, so there's less redundancy in the system. Large power stations using medium to high head to pressure will almost always have one pain stock per turbine. Smaller power stations with a smaller head well, sometimes have one pen stock for multiple turbines, so different variations. But ideally, especially from much larger plants, you should have one penny stock feeding one turbine. Occasionally you will need to D ward to the pen stock on a larger plants. You'll actually send people down the pen stock. They'll be able to walk down the penny stock and inspect all of the internal surfaces. This type of plant is slightly smaller, so perhaps you'll send a pic down there or another. The voice, which can go down through the pain in stock on inspecting internal surfaces. Some of the most important things to look out for would be thinning off the pen stop walls . If that occurs, any cracks or leaks on defusing a pen stock that has been concrete lined, then you'll need to inspect the internal surface on also any coatings that may have been placed on it 17. Turbine Runners: in this lesson. What? Have a quick look at where a turbine is installed within the system. We've got a whole section dedicated to turbines later in the course. What I'll try and do is to show you exactly where the turbine is installed and we can actually see. This is a scroll case Scroll case allows us to distribute water evenly to the turbine. Let's go inside. In fact, before we go side, let's just quickly back up a moment. We can see the water's coming in here. It's fed into the scroll case. That's quite unique shape school case, Andi. Then the water is gonna be allowed to run off down through the draft tube golf down that way. Resuming now we'll have a look at the actual turbine. Now I've been calling it a turbine, but the item that we're actually looking at now is specifically known as the runner or the turbine runner. The reason we differentiate between the runner on the generator is because it makes it easier to locate the parts. If we talk about the turbine. We're actually talking about the runner on the generator in the shaft and everything in between. If we talk about the runner, then we're just talking about this item here. This item looks a little bit like a propeller on a ship. It's actually known as a Kaplan turbine, and as the water flows in from the left, it's going to be distributed evenly. So they flows down through this pipe and causes the Kaplan runner to rotate due to the pressure differential it creates as it flows across the blades. See if I can get a slightly better angle here, although we might not be able to. So we can see there. There is a pointed shape where the water will exit, so it's gonna go down and then out through the bottom off the draft do so. That is where the turbine runner fits into the system. The turbine runner will actually change, depending on the flow characteristics of the plan. On also the pressure head. Regardless of the type of running used, the run is going to be connected onto a generator. Now this is actually our generator. I'll go down again to the structure we can see there is a turbine within this spiral case will go straight up. It's connected on a common shaft to the generator. So as the turbine runner rotates, it causes a rotor within the generator to rotate on. We generate electricity, so we've now seen exactly where the runner fits into the system. On also where the generator fits into the system, the actual speed of rotation is going to be quite slow compared to other prime movers used for power generation. When I talk about prime movers, I'm talking about things such as these Lane Jin's combustion turbines, steam turbines, etcetera, prime movers, writers used to harness energy and convert it into mechanical energy. Once we have the mechanical energy than we converted into electrical energy using the generator, we will look at different designs of variations. When we look, each individual plant will actually come back to this one a little bit later, because we can talk about what happens after the generator on how we get the power into the grid. 18. Draft Tube: Let's now talk about the final piece in our hydraulic circuit. We've already seen that we have trash racks, Andi Inlet Gates. They would be located around here. Then we have a pen stock. Then we have a turbine. And after the turbine, we have a draft tube. Draft tubes are located directly after the turbine runner. We can see that this is the draft tube discharge. I'll try and get a side view from another angle now, Although you can't see very well here, the draft tube would actually connect onto a cylinder shape, usually perhaps within this concrete structure. And it will change the round cylindrical shape off the water conductor at the start of the draft tube to this rectangular shape that we can see on the discharge side of the draft to the draft. Tube itself connects to tail races if the draft tube is quite long on. The idea with this unique shape off the draft tube is that we can recover some of the kinetic energy from the water on Turn this into pressure if we turn into pressure than we have a larger pressure differential across the turbine runner, and that leads to a greater overall turbine efficiency. Noel Hydropower plants require a draft chew draft tubes and not used for impulse type turbines, which again will cover later. In the course, we're gonna look at impulse on reaction type turbines. 19. Powerhouse: Let's have a quick chat now about the powerhouse. The powerhouse is this whole section. Here it houses the turbine runner, the generators. Sometimes it will house the control equipment associated with the generation the turbine. And it will also house some of the water conductors on the scroll case associated with the turbine runner. So there's quite a lot of items within the powerhouse itself. Notice, however, that this powerhouse does not form part off the structure, which restricts the water flow. The water flow here is seen is just flowing over this lip and then going down stream until it flows past a powerhouse. So this is quite a small power plant. Sometimes, though, you'll actually see that the powerhouses used to block the river for run of the river plants. This lonely occur when you have relatively small heads up to about 40 meters maximum, and that is an extreme head for a run of the river plant. Once you start getting quite large heads for medium to large heads of pressure, then you'll no longer use the powerhouse to restrict the river flow on. Definitely not to dam the river so the powerhouse will be located away from the river itself. If we have a diversion power plant like we're looking at now, or it will be located on the opposite side of the dam at the toe of the dam, that is to say, the base of the dam on the tail waterside where it is protected and does not after handle some of the large pressures and stresses involved with holding back so much water on the head. Wards aside, powerhouses can also be either surface powerhouses like the woman we're looking at now. Or they could be on the ground powerhouses, the pump storage stations. They'll often be underground. Sometimes they'll actually be built into a mountain or a rock side. Now this is beneficial for a couple of reasons. But the biggest benefit is simply that people can't complain when the entire powerhouse is underground. Getting planning permission sometimes for power plants is very difficult, even if you're installing renewable energy power plants. However, if you say the powerhouse is gonna be located within a mountain, there's not really too much people can say against that. The downside with installing a powerhouse within a mountain is that the ventilation system associated with the powerhouse can often be quite extensive on also quite expensive. Other equipment that may need to be located in the mountain itself may include a transformer. Transformers are these items here? They could be quite large. They're also very expensive, and you've gotta have places doing stories within the mounting. Sometimes you can install them outside, but generally they'll be installed as close to the generator is possible. Let's go and have a look. Now what happens after we generate power using our generator? 20. Generator and Power Distribution: So in this lesson will look at what happens after we've generated electricity using our generator, I assume in so we can have a look at the generator itself. We can actually follow the cables out of the generator because that's how we connected the model. So it's not an easy to understand. So here we are. We've got free cables coming out. I shoot knows will be free phases X Y set. And if ever look here, we can see that we've got a electrical cabinet on this electrical cabinet is actually known as switchgear. These type of switchgear is a medium voltage type of switchgear. Think of it as a circuit breaker similar to what you have in your house. It actually protects the generator and ensures that if there's any over voltage or over current or anything like that, it will actually trip on. We will disconnect the generator from the grid that protects the generator, and it may also protect the transformer. Not only that, but it allows us to completely electrically isolate the generator, which is very important if you performing maintenance on the generator. I know from experience that this is a medium voltage switchgear by looking at it, and generally you'll find that they're fully enclosed units on. It's quite difficult to get access to the internal Bart's and they should have a key or the associated equipment. This is good, though, because inside this cabinet we're gonna have around 10,000 volts, maybe, or 10,500 volts, maybe even 20,000 volts. So that's 20 K V. And that's the reason we don't want people to have unrestricted access to the switchgear. Switchgear itself is located within. A room on the room will be locked again because we don't want people going in there and tampering with switchgear. Once we pass current through, the switchgear is going to go to a transformer again. We can see our three phases coming here will connect them onto the three separate areas off the transformer. The's Christmas tree like structures are actually called bushings. So this is we're pushing here on another bush in here on these air electrical insulators. Essentially, what we want to do is stop the voltage from touching the casing on raising the voltage potential off the transformer casing. And that's what we have Bushings. The Transformers job is to increase the voltage, so we may have 10,000 or 20,000 volts coming into the transformer, but we're then going to step it up to perhaps 220,000 volts or 380,000 volts. For this reason, we call this type of transformer a step up transformer or a GS you also known as a generator Step up transformer. Once we increase the volt each, we can then transfer along here through some conductors on, then into the national grid. The reason we increase the voltage is because we want to reduce our power losses. Power is represented by I squared. Are if we can actually reduce the current, then will reduce. Our loss is once we get the power into national grid. Now, as we raise the voltage, we're reducing the current. And that means we're reducing our transmission losses. Even when stepping the voltage up to maybe 380,000 volts, etcetera, we're still gonna get losses in the range of between 4 to 8% depending upon how far the hydro plan is from the point of use. Hydro plants can be very, very far away from the point of use. That means the transmission losses need to be reduced as much as possible. When we look at different types of hydropower plan, the set up is always going to be the same generator Switchgear Transformer, National group Even if you're looking at coal fired power stations or other fossil fuel power stations, the set up from the generator onward is almost always totally the same generator switchgear , transformer, national Groot or perhaps generator switchgear, transformer switchgear, national grid. Or perhaps you won't have switchgear here, but you will. On the opposite side, that would be slightly unusual. Although I've seen that installed in a few plants, The downside here is that if the generator has a problem to do with over voltage or over current, then we're gonna pass that problem. Oneto transformer on both these items the generator and the transformer are high value assets. They cost a lot of money, so wherever possible, it makes sense to install some switchgear and protect the items from each other. Not only can you get problems from the generator itself being passed on to the transformer , but because we have a national grid and it's prone to get lightning strikes and other things like that. We may also get a surge of current coming back the other way, and for this reason we have Serge arrest er's on other items installed in the open air switchyard to protect the transformer. Everything within this fenced area is known as an open air sweet shot on every medium and large hydro plan is going to have an open air switchyard. The only time you're not going to see an open air switchyard is if you have a transformer installed on, then the cables go to ground and they disappear into the ground. But this only works if the point of use is very close because she can't run underground cables always from a hydropower plan all the way to the point of use. It simply cost too much money. And that's the reason why you have an open air switchyard and you'll send the power above ground, which is far cheaper, especially over a longer distance. So in the next section we can go and have a look at turbine runners on. We'll have a look at the different I've used on where you're likely to see them 21. Hydroelectric Turbines: so let's not have a look at hydro turbines. This is a particularly relevant part. Of course, if you are interested in power engineering in general because what you're gonna learn in this section is very relevant to steam turbines as well. A lot of the underlying principles behind different turbines can also be applied to steam turbines or combustion turbines. Not only that, but it's actually really interesting to see the different variations of turbines used for out the power engineering industry. Now I'm gonna cover all of these turbines in greater detail in this part off the course. So don't get too stressed If it seems like I'm skipping across stuff very quickly because everything I cover in this lesson is gonna be covered in this section generally in a lot more detail. So let's start by getting an overview of what hydro turbines are and why we have so many different designs. So he would got a graph concedes called hydro turbine design on the left axis. We've got head of pressure on the lower axes. We've got flow. The head is measured in meters. You can think of that as being a difference in elevation from the headwater to the tail. Water on the flow is measured in meters Q per second. You can also see that we've put a few different types off turbine runners onto this graph. It's gonna look each type. Here we have a horizontal Kaplan runner. The next one is a vertically orientated Kaplan runner. We're now looking at a Francis Runner and if we go up to left here, we can see we have a Hilton Runner. Also referred to his a pelton wheel on the Y axes. That is to say, the vertical axis you start off with head off five. So five meters on ahead is gradually increasing until we get up to about 2000 meters and that is a significant head. We go down and C we've got outflow on that ranges from about 0.5 meters coming across gradually increasing until we get to 1000 meters cute per second. That again is quite a significant amount float. Notice that each one of these turbine runners has been allocated a section on the graph. This horizontal Kaplan runner operates within this section of the graph here where my analysis going so everything that is green up until the green dotted line as well. What that means is the horizontal Catalan runner can operate efficiently within this range , so it's gonna operate up to about 25 meters or 30 meters of head all the way down to five meters of head. It's also gonna operate quite comfortably within a range of about 200 meters Q per second on the flow, going all the way down to almost two meters Q per second on the flow, but 2.5 free. So that is its operating range, where operates very efficiently. If we made the Kaplan Rana vertically or incited instead of horizontal, we can see that it's operating range changes as well. This time we've got an upper operating limit on the head of about 80 meters on. That's gonna go all the way down to five meters on. We can deal with flows anywhere up to 1000. It is cute but a second all the way down to less than two meters. Q per second and again, that is, it's typical operating range notice so that other turbine runners are not happy operating on the lower end off the graph This particular turbine. The Pelton turbine does not want to be operating with a low head. It simply does no work. Pelton runners operate with low flow and high heads. Francis runners operate over a very wide range, although typically they're not used for extremely high heads. But they are. However, the most versatile off turbine runners you can see operates in a huge area, and it can do so very effectively. As you gonna learn later in the course is, well, this type of runner, the Francis Runner can actually pump water, so it connectors both a pump and a turbine. Kaplan runners operate down here. They typically operate with medium to high flows, but they're quite happy operating with also very low heads. That's what makes him quite unique. Run of the river plants, tidal stream generators, title Barrows, generators, anything like that. Anything that has a low head is going to utilize a cap plan runner. You're never going to see Pelton Wheel used for anything related to run of the river or for title generation or anything like that, simply because they use a very high head. You're going to see Pelton runners in places like Switzerland, whether terrain is very mountainous on their sudden drops in elevation in a small area, the pelting runner itself has a very unique shape. You can see here as a series of buckets mounted on the outside periphery of the wheel, and we'll look at that in the next few lessons. The Francis Runner. Generally, it will have this shape, although the actual geometry off the runner depends upon the speed and the pressures in which it operates. The Kaplan Runner is very much like a normal propeller, except the blaze can be varied in their angle of pitch can be changed. That means these blades can be adjusted and they will rotate over to the right or to the left. And that is a variable pitch propeller or a control bitch propeller. And you'll see that in action, and we'll talk about it once again just to refresh your memory. When we look at tidal power generation, let's now go have a look each of these turbine runners in a bit more detail. We'll look at the pros and cons off each, and then we'll discuss where you're likely to see each of these types of runners on what sort of geographical features you need in order to use one of these runners within your power station. 22. Reaction and Impulse Turbines: I want to do a quick note here to talk about reaction on involves turbines. I didn't talk about it in the previous Lessing's I don't want to overwhelm you with too much information. There are two main types off turbine. These are classified as either reaction or impulse reaction type. Turbines are pressure turbines. Impulse type turbines are pressure lists. Turbines reaction turbines allow water were a fluid to flow across the blades of a turbine runner, and assets occurs will get a pressure differential across the blades. And this causes of rotation off the turbine runner. That is a reaction to life turbine. Impulse type turbines don't have that, because their pressure lis What they rely on instead is kinetic energy or impulse energy. Now the best way. Think about imports energies. Imagine a baseball player getting ready to throw a ball. Now the ball itself doesn't have any velocity, has no speed. We've got to give it the speed. Will do that by drawing our arm back, holding the ball in her hand and then throwing the ball as quickly as possible forward and at the point that it leaves our hand when we let go. The ball with applied an impulse. We've given it the Connecticut energy to fly through the air. That's what a baseball player is doing. He draws his arm back. He holds the ball. He pushes on forward as quickly as you can. T let's go the ball and the ball shoots off. That is why one refers to his impulse energy or by strictly speaking, we can just call it impulse. Francis and Kaplan type turbine runners are reaction turbines. Their pressure turbines. We have a full column of water on both the suction and pressure side off the runner. Pelton Turbine runners do not have a full column of water on the suction on pressure side off the turbine because their pressure lists Instead, what we're gonna do is apply an impulse tow water on. We're gonna change pressure energy to kinetic energy, and we're actually going to shoot a jet of water at very high velocity at the Hilton Runner . On this causes of built and run it to rotate. The concept of reaction impulse type turbines is also applied to steam turbines and combustion turbines. Let's now go and have a look at each off the different main types of hydro turbine. These are Kaplan, Francis and Pelton, 23. Axial Radial and Mixed Flow: Let's just clarify here some different terms relating to turbines. You'll often hear turbines classified as being axel mixed or radio flow. Axel flow simply means that the flow of water across the runner is parallel. Put simply, if we had a propeller, then the water would flow from the left hand side off the propeller to the right hand side in a straight line. But his actual flow now mix flow is where we have radio entry or discharge on also Axel entry or discharge. Francis Runner is a good example. We allow the water to enter the Francis Runner radio. Early on. We discharge the water, actually, so these type of runners classed as a mixed flow runner. There are other types off turbines that rely on radio flow. Only that is where water is fed into the runner. Radio Lee from the outside to inside, and then the water float out off the runner from the inside to the outside. Again, strictly radio floater lines are not very common. The ones that we're going to look at more in this course of the common types on these are actual flow and mixed flow. Just keep in mind that. Although we're talking about Kaplan turbines, Francis Turbines and Pelton turbines, there are many other different types that just Noah's popular. That areas turbine is one. The cross flow turbine is another, but there are numerous other variations. Let's go have a look now at the main three types off Hydro turbine on. We'll see in a real world situation how axle and mixed flow occurs across these turbine runners. 24. Kaplan Turbines: So here we have our first turbine runner. Let's do a little spin for my moon. We can see that this particular turbine has been sliced in half and we've taken a cross section so we can see the interior. But the end we've got a propeller on these type of turbine is actually a derivative off a propeller type turbine propellor turbines have variations on. One of those variations is actually a Kaplan turbine. This stock turbine is a bowl turbine because of its bold like shape. We go over here like she see that this shape is known as a bowl, and it allows liquid to flow across the bulb whilst encountering very little resistance. So if the water flows from the direction where we are now and goes forward, it's gonna flow across the bulb on. There's not gonna be too much turbulent flow. The bowl turbine is quite unique because the generator and the rotor on all of the machinery that we need to generate electrical power is within this space. Bowl turbines are a relatively new development, and they used for things like tidal power generation. Let's have a quick look at some of the components, then we'll look another model so we can see it working. So we've got a propeller that is on the end here, then got on Main Drive shaft that is your sites in here that connects to a rotor on the generator rotor, which is actually this entire piece. We'll rotate when the propeller rotates as well. So as water passes over the propeller is going to create lift across the propeller blades that's going to impart a force onto the propeller hub. And then this talk he's going to cause the generator rotor to rotate. So we're taking the potential energy of the water. We're using the propeller to change that potential energy to mechanical energy on. Then we're using the generator to convert the mechanical energy to electrical energy. We're going to see that a lot over the next few videos, and I'm gonna keep mentioned it so you can really understand exactly what's occurring now. As I mentioned previously, this type off turbine, the bowl turbine, belongs to the propeller turbine family. The type of turbine that we're actually interested in in this video is known as a cap plan turbine. But what's the difference? Kaplan turbines don't typically have above shape, but what they're consist off is a propeller on a May drive shaft that I need the ball shape because a lot of the time only the runner is sitting under the water and you have a main shaft, and then you'll have a seal. Once it passes for you to see a little connects straight onto a generator rotor. The difference between a normal propeller runner, Onda Kaplan Runner, is simply that the blades pivot in the mountains. Now I've read, If you ever books recently about hydro turbines and absolute, it's slightly confusing. Trying to nail down the exact definition off a Kaplan turbine, I recently read, The Kaplan turbines are propel its turbines that have variable peach blades. However, I also read another power engineering handbook that said that Kaplan runners may have fixed blades or variable pitch blades. Not only that, these type of turbine is an axle flow turbine. The flow off the water comes from the left passes over. The runner on goes away to the rights of read. Several books that define a Kaplan turbine is being a variable pitch play propeller where the water is inlet Radio Lee but allowed to flow across the blades. Actually, now we see here the water is no inlet radio lease actually just allowed to flow in. Actually, there are so many different sources relating to Kaplan turbines, and there are very different definitions. I'm gonna go with the safe one here and just say that a Kaplan turbine is a propeller type turbine with variable pitch blades. And I'm also going to say it's an axle flow type turbine, as I say that when you do go into a lot of the literature, it becomes very complicated very quickly. But most sources agree that Kaplan Turbine is simply one with variable pitch blades, and it's going to be axel flow. Let's go have a look now at variable pitch blades and we can actually see a Kaplan turbine operation. 25. Variable Pitch Blades and Control Pitch Propellers: So here we have a title power plant. You can see that we've got a bulb turbine and it's been mounted down here. So this is effectively out powerhouse on the ball Turbine sits in this water passage, which may be the pen stockholder draft to depend on which way the water is flowing. One of the items that we didn't discuss in the previous video is this item here looks a little bit like a fan and that's called the wicket gate. Gonna show you what the wicket gate does. I'll play the animation and we should see over time that the wicket gate changes position, so the wicket gate is now open. As soon as the wicket gate opens, the flow of water is allowed to pass through the space between the wicket gate, and it's then going to allow the water to flow over the propeller. Andi, as it does so the propeller is going to rotate, and that's going to rotate the Rosa generator. Now there's only one other thing I want to show you in this video because we're going to go into death about how we're generating electricity using title power in the next section. The one thing that I want to draw your attention to are the blades. Keep your eye on the blades. As the war to begins to flow across the propeller, I noticed that the angle off the blades has remained constant. The blades have not changed angle at all. The reason the blazes sitting in that position is because we want the place to slice through the water at the optimum angle in order to generate power. We actually called this angle the angle off attack by very in the angle of attack on the blades, we can vary the amount of lift that is imparted onto the blades. So we're very in your mouth force that is imparted onto the blaze and used to create talk. Now imagine for a moment that the blaze was just sitting more or less horizontal. Well, then the water is just gonna flow over the blaze on. We're not going to convert much off that potential energy into mechanical energy. However, when we change the angle, the water flows across in such a way. In order to ensure that we get a high pressure differential across the blades on, we convert as much off that potential energy as possible into mechanical energy. What's interesting know about Kaplan Runner is that the blades are variable on. By varying these blades and the angle of attack, we can vary the speed of the runner on. We can vary the amount of energy that is converted into mechanical energy. Let's see that in operation when we allow the water to float back in the opposite direction . So you should have noticed. There the blades completely pivoted. Let's go back and have a look again. I'll do it from this angle over here this time so noticed that the blade here he's pointing off as it goes down to lower left hand side. And now the blades of pivoting the angle of attack has changed. And that's because we want to extract the energy from the water flowing this way from right to left rather than as before. From left to right, that's what we call a control pitch propeller, variable pitch propeller. You'll see this design also used on aircraft. Sometimes propeller planes use it to actually reverse or go forward on. They can also vary the speed other by slowing down the engine or increasing the engine, rotational speed or by changing the angle of attack off the blades. So that's one example of a cap plan turbine. Although, strictly speaking, this is a bowl turbine that uses the Catalan runner. We're going to cover it. Exactly how Title Power Generation works in an exception, And I'm gonna go over all of the components again, and we're gonna discuss everything that you're seeing on this screen and how it all works. If you could remember nothing else from this lesson, just remember that Kaplan runners are used for medium toe high flow applications where we have low to medium heads down to as low as two meters. 26. Francis Turbines: What we're looking at now is a Francis Runner. See that the water comes in from the right hand side and it's delivered to the runner. Radio Lee, the Francis start runner is actually a mixed flow turbine. The water is allowed to enter Radio League because it comes in from the sides, is drawn into the center and then drops out off the bottom. So compared to an access later. But I was quite not happening. If this was an actual flow turbine, it would just float him from the top, go straight through the runner and drop out the bottom. Not so here. We're using radio entry where we have flowing to the center of the runner and then we are dropping out off the bottom in an axle manner. So that's why we call it mixed flow radio entry, an axle discharge. Notice that we have quite a unique shape. The scroll case itself, sometimes called a spiral case, gets narrower as we loot back around to where the water enters the scroll case. The reason it does this is because we want to distribute the water to all areas of the runner in uneven manner. We can see The diameter of the water inlet here is very large diameter off the water in there on this side gets gradually narrower as it comes around. See that if we zoom out, see gradually narrower. But this ensures that all of the water is delivered evenly to the runner. So we're not getting a huge influx of water that just flows into the run on one side. That would causing imbalance potentially vibration which may even damage the runner. Not only that, but the run is gonna operate inefficiently. We use a wicket gate to feed the water into the runner. These are wicked gave. You can see that They're sort of plates that are mounted between the water suction side on the runner itself. The wicket gate is controlled hydraulically. See, we've got to hydraulic cylinders here. If one of the hydraulic cylinders to imagine for a moment this one where analyses Now, if that was fully extended and usually the other one on the lower side of screen where my mouse is, will retract when they do this actually going to turn this entire assembly here and that is going to rotate the position of all of the we kicked gate paddles. So all of these pieces here are going to rotate anywhere between 0 to 90 degrees if the wicket gates fully opened and the water's allows simply just to flow through and go directly to the runner. If the work it gates fully closed, then non off the water is going to be allowed to flow through and get to the runner. We can use the wicket gate in an emergency to shut off the water flow. Although it's more generally used for flow control, the wicket gate also allows us to angle the water as it enters the runner on. This increases the runners overall efficiency. The upper side off the Francis Runner is noticed the crown, and that's where the run of veins connect to the top off the runner. The lowest side off the Francis Runner is known as the band, and that's where the veins connected on the lower side. So let's discuss exactly what's happening here. Water is flowing in from the right and is gradually being distributed to the Francis Runner as it passes through the wicket gate as it flows into the runner. We're going to get a pressure differential created across the blades. Remember, this is a reaction type turbine. So the entire area is flooded and this is a pressure turbine. I'm gonna flow into the runner. Now you can see you are now in the middle of the runner. If I was water, I would now drop out the middle of the runner. I know I would enter the draft tube. Today is the path off the water is relatively simple. Radial entry axel discharge. As with all reaction, turbines were taking the potential energy off the water and we are converting it into mechanical energy. Francis Turbines Air used for a wide range off applications because they're suitable for many different heads on many different pressures. This mixed flow turbine runner can pump water as well as actors. A turbine so is essentially a hydraulic pump and a hydraulic turbine. Pumped storage plants used Francis type runners. Now that we've looked at Kaplan Turbines and Francis turbines, let's go and have a look at the final type of turbine, which is an impulse type turbine known as a Pelton turbine 27. Pelton Turbines Part 1: in this lesson. We're going to cover the Pelton turbine. What we're looking at now is the Pelton Runner. This type of runner is actually my favorite type of turbine runner. It is incredibly unique in shape. The geometry is just very interesting. And I'm gonna tell you exactly how this whole contraption works. We can see that we've got a central disc in the middle and on the outer periphery off this disc, we've actually got some buckets. These are the buckets here. These buckets also known as impulse blades because this is an impulse turbine. So where is before? We had reaction runners such as the Catalan and Francis type runners. Now we're looking at an impulse type runner on. The difference is actually quite colossal. For one, this type of runner does not sit in water. It's not totally submerged. It rotates on the Andean air conditions. Despite this, it is still a hydro turbine. Let's see what it looks like when actually starts to rotate. Can see there that is now rotating from the forest direction going backwards. And that's how it normally looks when it's operating. It's ever looked at some of the components in a bit more detail, and then we're gonna have a look at a working model. So the buckets amounted on the outer periphery. We can see the buckets have a very unique shape. What actually happens is a water jet will be shot at the buckets so that it impacts directly with this line here. Fact, if I go around the other side, it's just big animation. We can try and figure out where the water jet would come from it actually becoming from this side, so the water jet would be shot at the buckets, and it's going to impact on this line. On this line is known as a splitter. It's a high reach that splits the two sections off the bucket. The water then divides onto both sides off the bucket, and as it does so, it's going to fill up the bucket. It's going to spray around in this direction with the mouse is going on. Then it's going to be discharged on the lower side off the bucket because this is an impulse type turbine, relying on impulse, energy or impulse. The water itself has no pressure energy. It only has kinetic energy that kinetic energy is given up as the water jet approaches to split up impact with the bucket and then gradually does 180 degrees turn inside the bucket . And then he's discharged on the lower side of the bucket. As the water is turning within the bucket, it's giving up its kinetic energy. And we're converting that to mechanical energy in order that we can get the runner to rotate. Let's go. Never look at another model. Now we can see how that works. 28. Pelton Turbines Part 2: So here we are. We can see our Hilton Runner has now being mounted inside a casing, and that's typically how it would look when it's mounted inside a casing on a horizontal axis. Chef. Sometimes you may have more than one Hilton wheel that's mounted onto one shaft, but a lot of the times you'll only have one built of runner on one chef belt on runners could be either vertically or horizontally installed. Large plants tend to favor vertical orientation, while smaller plants favor horizontal orientation. It's gonna look now exactly how the Hilton Runner works. Water comes from a pen stock. The pain in stock is this manifold here on the head of pressure behind this pen. Stock is typically going to be greater than 400 meters. That means your head water is going to be 400 meters higher than the point at which the pen stock ends, which is where we have a spray nozzle. So let's go through here. We're going through the pen stock. Conceived as a shaft in the middle of the pen stock. This shaft actually leads to a nozzle so we can see the water comes down from the pen stock on actually reaches the end off the shaft, and currently the nozzle is actually only slightly open, so we could see that on this side, just gonna poise the animation for a moments otherwise is bit too much happening. So the water comes down from the pen stock through the nozzle Paston item called the Needle that is this pointy bit. Here, the needle is used for flow control. We conniver fully extend the needle to block off the nozzle and stop the flow. Or we can retract need or backwards, and that allows flow through the nozzle on onto the Pelton Runner. What's interesting here is that when the jet of water leaves and nozzle, it may be travelling at several 100 meters per second. The nozzle is turning the potential energy of the water into kinetic energy. The nozzle sprays a jet of water at very high velocity into the buckets, as it does so, the buckets convert this kinetic energy into mechanical energy. Now, this is quite interesting, because before we were using potential energy directly and maybe with a bit of kinetic energy, But now we're using kinetic energy only. Remember, this is a pressure lis space. This is entirely filled with air on a little bit of water that's being sprayed out of the nozzle. So this is kinetic energy only, which is driving this turbine runner. Now it's essentially are Pelton Turbines work a very simple design in a way, because we're simply using a large head of pressure converted map to a high velocity jet and then blasting it at the runner buckets, also known as the impulse blades. What's interesting here, though, is the fact that impulse turbines have been around for a very long time. Mr Pilsen when he invented this type of turbine, it's not amazing that he invented an impulse turbine because that already existed. What's amazing is the buckets that he invented. These buckets is shaped in such a way as to convert as much off that kinetic energy is possible into mechanical energy. That's why they have such unique shapes. So we've got the splitter, which splits the flow. We've got the notch, which allows the water jet to get to the next bucket on optimum angle, and then we've got the curve shape of the bucket, which is a little bit like a spoon which converts as much kinetic energy as possible into mechanical energy. So that is truly amazing that all of that happens just because of the unique shape off the buckets. Pelton runners are used for high pressure heads only typically great and 400 meters. But they only require low flow because the nozzoli shaped to only allow low flow. That may be a lot of head water, and it may be sitting very high up the mountain. But at this stage, we only need a small amount of flow in order to drive this pill to run up. So let's see it going again. Fact, if we go over, we can actually have a look at a larger model. We can see what happens to the waters impacts with the buckets. Now, you gotta imagine that this is a continuous water stream, not just a blast of water every few seconds. It's a water jet that is continuous. And if we push pause right about here, you can see we were spraying this bucket in the back. And as the runner comes down, we're going to begin spraying the next bucket at an optimum angle again. There, there. If we had a round shape here, then you just simply wouldn't work. We'd lose contact with this bucket before we got contact with the next bucket. Now we can still push this bucket a little bit further using that jet of water, and that's exactly what the notch allows us to do. So we're pushing that as far as we can possibly get it away from the water jet before we then cut to the next bucket on. We continue the process again. I find these types off turbine runners very, very interesting. The design is fantastic. They look really interesting, especially compared to some other types of turbine runners. The actual diameter off these particular runners, maybe in excess of four meters. And they can generate alone just one pelt of well over 400 megawatts of electricity. That is a truly huge amount off electricity, especially when you consider we're generating this only from water, which has been stored it off the mountain. The largest one in the world is in Switzerland, and that's with good reason is because Switzerland is very mountainous, so it's an ideal place to have a power plant that uses Pelton turbines. If you remember nothing else. From this lesson, simply remember the high heads, low flow, ideal conditions for building turbines. Remember, also, this is a pressure lists type turbine. It relies on converting kinetic energy into mechanical energy, not pressure energy into mechanical energy. 29. Types of Hydroelectric Power Plants: in this section, we're going to look at types off hydro electric power plan. We'll discuss the terms of empowerment on diversion. Will also have a look at how hydro electric dams work, running the river plants, tidal barrage plants, died of stream plants. And finally, how pumped storage plants work as we're going through. Have a look at the runners of these type of plan and try and use some of the information that we got in the last section to make sense of how these plants of working on why the design the way they are. 30. How Hydroelectric Dam Power Plants Work: So we've covered a lot off the terminology associated with hydropower plants such as headwater tail, water, upper reservoir, Lower reservoir, etcetera. We've also covered the components associated with hydropower plants. Penn Stock draft to gates, trash rack, etcetera. And now we're going to look at all of the different types of hydropower plans out there on exactly how they work. The first type of hydropower plant is what we call a conventional hydropower plan, which is actually a damn. So we're looking at a hydroelectric dam. This is an empowerment type off power plant. This is not a diversion type. We've essentially blocked the flow of the river completely on. We flooded the entire area behind the dam in order that we can get ahead water because we flooded the entire area. We then have a difference in elevation between the headwater and the tail water on. We can use this difference in head in order to generate electricity. A lot of people associate hydro electric dams simply with large concrete structures similar to that which we're seeing now. But there are different types off damn structure. You can have a gravity dam. Nrcc Dan Arch dam buttress down Earth dam on rockfield down. So although hydro dams are associated with concrete structures, and that's what makes him so I catching and so famous in a way, the most common type of hydro electric dam you're likely to encounter is actually an Earth down, which is not as spectacular by a long way. Earth dams are essentially piles of earth that have been pushed together in order to create a space where the head water can accumulate, although they're not very spectacular to look out, there is quite a lot of engineering that goes into unearth damn especially to ensure that no water seeps through the dam. So let's now run through the entire process off how we generate electricity with this type of power plant, we can see that we've got our water in. Let's we've actually got three of those, although they may be more. We've got an intake gate, which can be slid down in order to close off the penny stock. And if we're going to decide now, we can actually see how the water flows down through the penny stock into the powerhouse so we'll follow it down along the pain in stock and it will go down into a scroll case which houses after by runner from the turbine runner. We have a generator connected on a common shaft. That's this shaft here on the generator. Runner will rotate and will generate electricity. The water will then flow out of the scroll case and it will flow down through a draft tube . On it will reach the tail water, which is a space where I'm currently in now. And that is essentially how a hydro dam works. It's not a particularly complicated way of generating electricity compared to a thermal power station, for example, a coal fired power station. This entire process is incredibly simple. With the thermal type power station, you're gonna need a very large water tube boiler. You're gonna need a lot of water treatment. Chemicals may be different machinery such as feed water pumps, the air raters. You're also gonna have to clean the flue gas for the exhaust gas. That also requires a lot of equipment which can be quite expensive on the process is actually very complicated. Not so here. The water runs down through the pain in stock passes over a turbine runner on, then is discharged through the draft tube. Incredibly simple, incredibly green to use a common term and also incredibly efficient. You can expect the mechanical efficiency associate it with this turbine runner here to be in excess of 0.9 or, in other words, greater than 90%. So that's how a hydro electric down works. But there are some disadvantages associate it with this type of power plant. The largest disadvantage with this type of power plan is simply that we need to have a huge space up river of the dam where we can store the headwater. This means we're going to have to flood a lot of the area upstream of the dam. This is not particularly friendly to the wildlife that may be living in that area. Not only that, there may be people living in the area, and they're gonna have to move. So although we have this abundance of energy that we can harness and turn to electrical energy, it comes at a pretty high cost. Sometimes I'm actually a fan of renewable energy. I think it's a really good thing. We're definitely moving in the right direction compared to how we were maybe 100 years ago . But to give you an idea of the damage that these dams can sometimes cause the wildlife, you have to look at things such as the Three Gorges Power Plan in China. It is a huge, colossal hydro electric dam. But unfortunately, in order to build that huge, colossal structure, they had to flood a very large area upstream off the dam. And unfortunately, there are a lot of people living in that area who had to be moved. Perhaps even more unfortunate was the fact that one of the world's only freshwater dolphin species, I was living in the river that was about to get damned. The Three Gorges Dam itself may not have led directly to the extinction off this freshwater dolphin, however, it probably didn't help. So although hydro electric dams create clean green electricity for very prolonged periods of time, there are disadvantages associated with hydro electric dams in order that you can put them into operation. One of them is the environmental factor. On the other. Big disadvantage is that they cost a lot to construct. If you can earn your money back from a hydro electric dam within 10 years, then you've actually done quite well. This is what we referred to as a payback period. So if we were to build a hydro electric down today, it would pay for itself in perhaps 15 years. And some people would consider that a good deal. And other people would consider that not such a good deal the Three Gorges Dam was set up so they can pay for itself within 10 years. 31. How Run of the River Power Plants Work: So here we are again looking at a run of the river power Station. Let's go to the top when we can follow the process and will discuss exactly how this type of power plant works. So we're diverting some of the flow of the river towards our power station, and we'll do it by taking the water through this water inlet, which then leads to the pain in stock, which goes down to a turbine runner. Let's follow the pen stock down. There's are supported pen stock again. We'll zoom out slightly. Teams began lost in the trees. It passes through the ball valve. And if we go down below our openness, which yard? We can actually see here. A scroll case that this girl case is going to deliver the water evenly to Turbine Runner, which in this case is a vertical reinstated Kaplan runner. The water passes over the runner, which causes around to turn on the runners connected on a common shaft to a generator, which is directly above the runner. Once that's being done, the war is going to drop out of the scroll case on. It's going to go along the draft tube on be discharged to the tail water. So again, another very clean, simple way of generating electricity. However, there are some disadvantages with this type off power plan the advantages of the same as for other types of hydropower plants. Simply that we can harness the power of water to generate electricity. And there are no byproducts such as exhaust gas, so it's very green and it's very reliable. Not only that, but this started power plant is very efficient compared to other types of power plants, such as coal fired power plants. The big disadvantage with this type of power plan is simply that used reliant upon the flow of water in the river, the amount of water that is flowing in the river is variable. In the spring time, we're gonna have a large flow of water. In the winter, the river might freeze. If the river is completely frozen, then we're not gonna be able to generate any electricity. For this reason, maintenance on one of the roof power stations will often be conducted in winter. There is literally not much else you could do because there's no flow in water in some of acclimates. The temperatures will not be sub zero, so it may be that this type of plant can remain in service all year round. If you're in Brazil, for example, there may just be an abundance of water all year round, which means you can always keep your run of the vote of power station in service in Europe , especially places like Switzerland or Germany, France, anywhere near the Alps, sub zero temperatures and winter a perfectly normal. And there's a massive reduction in river water flow. So depending where you're based, this type of power plan can be seasonal dependent. That is the largest disadvantage associated with this type of power plant. Another disadvantage is the environmental impact that it may have on the local area. There are many people for this type of power plan, but there are also people against this type of power plan. In order to try and satisfy the people against building this type of power plan, they'll often install what's called the fish ladder. Fish ladders allow fishes to swim upstream and downstream without having to pass through the hydropower plant itself, where fish ladders have not been installed. Sometimes you're here off fish friendly turbine runners now no entirely sure how fish friendly these turbines runners are. I can't imagine that fish do want to swim through turbine runners when they're rotating, irrespective of how fish friendly they may be. But it's definitely a move in the right direction that people are thinking a lot more about the environment rather than just creating an environment that suits the plant in Europe. At the moment, it's more or less a requirement that you have to build a fish ladder if you're building a run of the river plant. Not only that, but when you're de watering part of the plan, you actually have to get the fish out alive and put them back into the river. This actually takes considerable mouth time sometimes because you have to catch the fish as you're reducing the area that's being de watered, and then you have to move the fish back into the river. Sometimes they'll actually tagged them as well, so that they can see how big the fishes are on what type of fish is growing in the river. But more and more now, the environment is becoming a deciding factor in designing on building and operating hydropower plants 32. How Tidal Power Plants Work: in this video, we're going to look at eight title power plant. We're going to look at how we can generate electricity using only the movement of water created by the tights. So here we have a title power plant. You can see that it's quite a large structure we can actually see that has a road on the top. So this is acting more or less as a bridge. You'll see these types of structures used to block off entire s trees in areas that have tired of several meters or more. Let's have a look at some of the compartments you can see. We've got a load off in Let's and discharges on this side. We've got a trash rack which were used for picking up bits of rubbish and trees, except for anything that might want to go through here and into the pen. Stock and damage turbine runner higher up. We've got something that they call a slew escape. The sluice gate can be used to start stopping regulate flow, although it's very ill suited to regulate inflow. If you know anything about valves, you'll know that gate valves and ball valves are very ill suited for regulating flow. And that's because they generate a lot of turbulent flow, which creates a lot of vibration. So this sluice cape will actually be used more for starting and stopping flow. Only if we go down, we can actually see a turbine. This particular turbine is a bulb turbine. It's a derivative off a propeller type turbine. We can see that it's been kind of half so we can see the internals. We'll have a look at this turbine in a bit more detail later in the video. The most important thing with this turbine no, especially concerning the animation that are about see, is this item here, which is known as a wicket gate. You can see it looks a little bit like a fan that's currently closed will return to that in a moment as well. We then go a propeller on some propeller blades on the opposite side. We've got much the same set up. We have a sluice gate, and we have another trash wrecked. After that, we go toe in little discharge, which will be either a pen stock or a draft tube, depend on which way the water is flowing. So let's now talk about how all of this is working. Let's talk about how we generate electricity from the movement of water caused by the tides . So played animation and we could see already that the water level on the left hand side of the screen is gradually increasing. It's increasing because the tide is coming in. The reason that the water level is not increasing on the right hand side is because the wicket gate was closed. If we zoom in, we can have a look at that. See, now that it's slightly open and that was why on the right hand side the screen, the water level on the right side to increase. If you go back a little bit in the animation, we'll see if I can back it up slightly. The wicket gate now is completely closed. There is no flow past the wicket gate from the left hand side to the right hand side. Now the tide on the left was increasing its board because we stopped the animation. But if I play the animation again, the type will increase even more on the left and you'll see what happens to the wicket gate , the wicket gate now opens on it is fully open noticed. As the wicket gate opens, water begins to flow immediately due to the height difference between the water on the left on the water on the rights. Now you'll need at least a couple of meters in height difference in order to get a relatively decent amount off flow. Once the water is flowing dough and the wicket gate is open, it comes along here and it will flow across at Turbine Runner. Now that's Irvine. Runner consists of a Siri's off blades, much like the propeller on a ship. And as the water flows across these blades would create a pressure difference across the plaids. On this pressure difference exerts a force on this force causes the propeller to rotate. We actually called the force applied talk. The propeller is connected on a common shaft to rotor. As the propeller rates hates, it rotates the generator rotor that is this component here on as a generator, Rosa rotates in juice ease current in the generator strata, and when we induce current in the generator stater, we get current flow on. At this point, we are generating electricity. I'll play the animation. We can see that the propeller is now turning because water is flowing down the pen stock across the propeller blades. As it does so, the generator rotor spins we induce current in the state are on. At this stage. We are generating electricity. Of course, the animation. Let's go see what's happened to the water level and why, exactly? The water flow has stopped. The reason the water flow has stopped is because the water on the left is it the same height as the water on the right. If the war levels are at the same quite on both the left and the right, then there will be no float. There has to be a difference in elevation between the left and right size in order that we can have flow now. The tide came in from the left, which was the ocean, and it filled up our bay on the rights you can think of. The bay is being a very, very, very large bathtub. When the tide came in, it filled the bay up on. Now what's going to happen is we're going to empty the bay out in order to generate electricity again. So we'll play the animation and you can see on the left hand side that the water level is starting to decrease. Once we have a sufficient difference between the elevation on the left on the rights, we're going to get flow. We can see now that we've got flow. The wicket gate is open. The propeller is turning on that is, rotating the generator rotor, which is connected on the common shaft. So that is the basic concept of how we generate electricity using title power. 33. How Tidal Stream Power Plants Work: So now let's take a look at a tidal stream generator. This figure is gonna be a little bit sure because title stream generators are no really a huge part off the power engineering industry. They don't contribute a lot in terms of Major what capacity. Despite that, they have huge potential. And I think it's worth talking about them a little bit just to get an idea of how they work . So you can see here. We've got a title stream generator. He looks very similar to a wind turbine. If we took the base away here where these three legs are, then we defective. You have a wind turbine. So we got the vertical tower coming up and on top of the tower is mounted the turbine body , which Rex trickled in the cell on the end of the Miss cell. We have a rotor hub that's this section here and then we have some rotors. In that case, we actually three of them. So then the cell is the entire body, and you can see that it's actually quite aerodynamically shaped except underwater. Obviously, instead of having aired that flows past are actually having water. The reason this type of power generation is quite exciting is because when we have high and low tides and a movement off water, the actual amount of water that is moved by the tides is huge. And not only that, it's very reliable. We know that we have to tides per day. So we have water flowing from the left to the rights and then back again from the right to left and then left to the right, Right to left. We're gonna have to generate electricity from the movement of water. We'll explain how we do that in a moment. Let's been around here. What else have we got? Who got the feet now? These three feet are designed like that so that there is less vibration when the title stream generator is in operation. So how does this title stream generator work? Well, we're gonna get water passing over from the left hand side as the water passes over from the left to the right is going to pass over the rotor hub over the rotors over them, A cell on a way to right hand side of the screen. The rotors themselves have a very unique shape. You can see here that the road a blazer slightly twisted there also fat at one end. Andi thing on the other. As the water flows over the rotor blades, Max gonna create a pressure differential that's going to create a force which we call lift . And the lift is going to apply a talk on the road to hope on a shaft. And then we're going to use this rotor emotion to drive the rotor inside a generator and generates electricity. So let's see how that works. Could see now that it is rotating. And that means that we've got water flowing from the left inside the screen to the right. Let me just pause it, because I can show you what's gonna happen next. We more or less took this model from a wind turbine. We changed the design in the exterior appearance a little bit, but the interior we just left the same you can see. We've got a central shaft that comes from the rotor hub, assuming slightly here, so there is ah, shaft that's connected to the writer hub. When the rotor have rotates, the shaft rotates. This is called a primary shaft because it's connected directly to the rotor hub. We then passed through a bearing, and we could see the chef comes through a little bit further. It then goes to a break. Use the hydraulic brake to stop the rotation off the runner in an emergency. See the hydraulic brake here that would just clamp onto this round disk on. When it does so, then the entire rotation will be stopped. So it's also useful to put in place if ever before we maintenance on the internal parts off the title stream. Generator Primer Chef comes along here and then goes into a gearbox. We'll use the gearbox to increase the speed of rotation we didn't have. A secondary chef that comes out on the secondary shaft goes into a generator. The reason that we increase the speed of rotation on the secondary shaft is because this type of turbine actually rotates quite slowly on will actually increase the speed using the gearbox before we connected directly to a generator. Once we've connected the secondary shaft of the generator, the generator rotor will rotate. It will cut through the magnetic field. It will induce a current in the generate state of wine ings on, we will generate electricity. So that's how tidal stream generators work. If you look at wind turbine, it is pretty much the same other than the rotor blades. Longer a mass because we're trying to extract MAWR energy from the air, the air is less dense, so it makes more sense to have road ablaze. A very long with the title stream generator. The water is much more dense, 100 times more dense, so we can have shorter blades and still generate a reasonable amount of power. So let's imagine for a moment that the tide is coming in, so we're gonna flow past the title stream generator. Just imagine where a bit of water coming in. And then when we reach high tide, what's actually gonna happen is we are going to turn around and then we're gonna have to flow back the other way. Unfortunately, the turbine, it's actually facing the wrong way, so it's not gonna be able to generate as much power as if it was facing the other way. So there is a solution. We simply turn it around when we turned it around, we can do the same thing again on this time we will flow. Pass a turbine over the blaze rather than through them on the turbine can generate more electricity. So quite a simple design. We can adjust the blades in the same manner as we saw for title stream generators. These blades are variable bitch or control pitch on. If we rotate these blades, we can actually vary the amount of lift that we're generating across the blades, which varies the amount of talk that we apply to rotor Hub and that varies how much electrical power we are generating. So that is how it started. Stream generates his work. The big benefit with title stream generators and with tidal power in general is that he's quite reliable. We know exactly when the tide is coming and going. People have been predicting the tides for a very long time, so we know we're gonna get a huge body of water moving one way and the huge body of water moving back the other twice a day. So this much more reliable than, say, wind power or solar, which is know, as reliable by a long way because the wind major stop and then we're not generating any electricity and obviously, if clouds come, we're not going to generate any electricity from solar power or very little. We don't have that problem. No, we title stream generators Because the tires are constant on Reliable, the fish mortality rate as well is proven to be less than 5%. That's for both tidal barrage systems and for title stream generators, so that's really quite exciting. A lot of these new plants have not been 50 jet with fish friendly turbines was really skeptical. In the past, I have to say when people say fish friendly But when I started reading warm or about title barrage installations and the fact that they're getting the fish mortality rate down to below 5% this is actually quite encouraging. I believe the largest tidal barriers plan, currently online is one in South Korea, and I think it's around 240 megawatts, and for a renewable energy source, that is a considerable amount of power. So it's a very exciting field, very interesting, and it could become in the future, a significant provider of megawatt capacity. But there are definitely some hurdles to overcome before we get there. However, like a savoury exciting very interesting and I definitely recommend it. If you're interested in issues, check out wind turbines because the technology is more or less the same, and you can apply it to title stream generators in the same manner as wind turbines. 34. How Pumped Storage Power Plants Work: So in this lesson, we're going to have a look at a special type of hydropower plant known as a pumped storage power plan. We've already looked at how various types of hydropower plant work on this type is not much different from some of the others we've seen. However, it's got quite a unique operating characteristic, which I'm going to discuss with you in a moment so we can see we've got our water inlet, and that is on the opposite side of this reservoir wall. It's been around so we can actually go down. Another look at the inlet there is Inlet because he we've also got a gate so we can close off the water inlet to depend stock. We then got a pen. Stock comes down, comes all the way down the hill, the sexual quite a large head of pressure or large head to have with this type of power plan. Now, having a large two medium head is a characteristic off a pumped storage power plant. What's unusual here is that the pen stock is split into two and feeds to separate turbines . Remember, you don't normally see that on power plants where you have a medium to large head. Normally, one pen stock will supply one turbine. Now I'm gonna go and have a look at the turbines and generators from the outside because I did actually try and look earlier from inside, and it's quite cramped. We can see that we've got a turbine runner which is housed within this casing on the water itself comes from the pain in stock. You can see it coming in here. It's fed to the turbine runner and then it is discharged and it will go out through the draft tube Andi into the river to see if we can find the draft tube. And this is it. Here on the opposite side, we also have another draft tube. So this is very similar in a way to some of the other hydro plants that we looked at. It's just that the head is much larger if we've got a larger head, and that means we can have either a Pelton type turbine or a Francis type turbine. We're not going to have a Kaplan type turbine because the head is simply too large. Pumped. Storage power plants, though, only utilize a Francis type turbine they do not use Pelton type turbines or cap plan. And there's a very simple reason for this. Francis type turbines could be used to pump water back up the mountain. That means we can generate electricity when water flows down the mountain, and then we can pump the water back up again to the upper reservoir in order to refill the upper reservoir. But why would we do this? Why would we pump war to back up and then let water back down again later? Well, they pumped storage Hydropower plan is very similar to a battery, except we're not storing chemical energy or actions during the potential energy of the water at a higher elevation. Let's imagine for a moment that it's a very sunny, windy day, and that means that we're generating a lot of electricity from wind turbines and solar power. This also means the electricity is cheap. It's in abundance. So imagine we're paying one cent per kilowatt hour just to keep things simple. Now it might be that the people operates in this pump storage plan. Think that one cent per kilowatt hour is very cheap and now by the electricity in order that they can power the Francis turbines and pumped the water from the lower reservoir. In this case of river up to the up the reservoir. And they'll do this all day because it's been sunny all day on. There's also been a lot of wind. So we've got a lot of cheap electricity when the up of reservoirs full and this may take 8 to 10 hours, maybe more, maybe less will hold on to all of this stored potential energy and what we'll do. We'll wait until it's dark and all of a sudden all of the abundant electrical supply that was provided by the sun from solar power and maybe the wind dies down as well. All of that abundant electrical power will disappear. You'll no longer be available in the national grid now, because we have a free market. Whenever we have something in abundance, it's not very valuable. Whenever something becomes scarce, its value increases. Now this is same with electricity, so there's no longer an abundance of electricity in the national grid, and it may be that the grid operator is willing to pay two or three cents per kilowatt hour that we sell to the grid. So if we opened the valves and the gates and everything else and we allow the water to flow down to a turbine runner, we can then begin to generate electricity on because we pump so much water into the upper reservoir. We may have to do this for several hours or longer as the water flows down and we generate electricity were making money. We're making the difference between what it costs to pump the water up the mountain, which was one cent per kilowatt hour on the price that we're getting now, which maybe two or three cents per kilowatt hour in the past, the actual operation off a pump storage plan would be very regular because coal fired power stations and other thermal plants often stay online day and night on do not cycle on and off because they're not capable of that, especially not on a daily basis. There was an abundance of power available at nights on these pumps stories. Plants would come online at night time and they would use some of this abundant electrical power to pump water up to the upper reservoir. And that was how things stayed for about 30 years in the morning when people started waking up in the electrical demand was very high. We reduced pumped storage plants to deal with these peaks in electrical power consumption. Member pumped storage plants can come online very, very quickly, typically less than a minute. So any large peaks that we have in our grid, we can cover those using pumped storage power plants. Now. This set up continued for about 30 years on. Then we started getting renewable energy sources coming more and more onto the market, and I'm talking here mostly about wind turbines and solar power generation, typically PVS, or photo voltaic aches. When renewables came online, the whole industry changed. The reason the industry changed is because suddenly there was an influx of power available during the day. If we had a very sunny day, then there would be a lot of power generated by all of these solar panels. If it was very windy, would be a lot of power generated by all of these wind turbines, and all of a sudden, instead of having to wait until night when the power demand dropped on, pumped storage plants could actually purchase the electricity at a better price. They were able to purchase electricity at a cheaper price during the daytime and at night. So the dynamic in the power industry slightly changed. So at the moment, it's a very good time to own a pumped storage power plant. There is a lot more opportunity to make a profit than they used to be in the past. I'm actually a big fan off this type of power plan. They give the grid operator good flexibility concerning frequency regulation and voltage regulation off the grid, and they have a high level of dispatch ability. Remember, we can have the entire plant online in less than a minute, and that is very, very fast compared to a coal fired power station, which may take a day or two days to come fully online. They're a very unique and interesting type of hydropower plan. Perhaps one of the most interesting aspects off this type of power plan is that we can store the energy. Remember, we can have an upper reservoir like the one we're looking at now, and we can store all of that potential energy and turn it into electrical energy on demand . That is a very unique feature for this type of plants, and it's a very unique feature in the power plant industry. Generally, the only problem with this type of plan is that you need very unique geological features. In orderto have this type of plant, we need a difference in elevation that is quite large, and you can see that here because the penny stock is running all the way up the side off the mountain. Sometimes you'll actually see these types of plants where the powerhouse will actually be built into the mountain. That's not unusual on the Penn stocks themselves will also be built into the mountain. So I would be very little of the power plant you can actually see other than the upper reservoir at the top on the open air sweet shot, which will be down at the bottom because you need an abundance of water on. You also need these geological features that allow you to bring the body of water from the upper reservoir to lower reservoir with quite a large head between the upper and lower reservoir. You're very restricted on way. You can actually have these types of plan somewhere like Norway is ideal because they're they have very rocky and rugged to reign with a lot of water. A place like Switzerland is also ideal. They have hard rock, they have deep valleys. They have a lot of opportunity to capture water, are higher elevation on, then to allow it to run down to river and pump it up and down on demand. Somewhere like the middle of Germany is less ideo. The change in elevation per square mile is rather low. You're more likely to get hills or plains than you are likely to get these large mountains with sudden drops in elevation. Most of Europe has already exploited its pumped storage capacity, and it's becoming more and more difficult to build this type of plan for the same reasons. As with other types of planets, there are environmental factors to consider. If you want to build a pumped storage hydro electric plant in central Europe, you're gonna find it quite difficult because often these plants will be located in remote areas. Sometimes they may even be located in areas that have protected. Building enough of reservoir like the one we're seeing now is very, very difficult to get planning permission for. There are a lot of environmental agencies that will be against building this type of installation within a wildlife area, especially if the area is protected. Not only that, there were other factors that you need to consider for Go down to the bottom off this freely model and spin around. You can see here we've got things like electrical transformers and open air switch charts and generators and turbines. These items of machinery require maintenance, which means you need to build a road out to the plant again. This may be difficult to get permission for all of the machinery Associate with this plan may also need to be environmentally friendly. What I mean here is that the electrical transformer is often for off oil. This is an insulate ER, and it's a requirement for very large transformers. Now it's possible to get biodegradable oils and filled the transformer up with these, but they're incredibly expensive. This is another factor that you have to factor in When you wanting to build one of these power stations. Is the power station going to be within an environmentally protected area? And if it is, what does that mean for all of the equipment and machinery that is gonna be operating in this area. If, for example, we were using oils and greases to seal the turbine Reiner space between the runner on the generator. What happens if some of this oil and grease leaks into the water here and then starts going downstream again? You need to have biodegradable, environmentally friendly. All in Greece is he's also cost more money. So there are little things that need to be taken into account with every type off hydropower plan. There are always good, large vantage ease on there, always some disadvantages. But as I say, a very unique type of plan, one of the very few that allows us to store and release energy on demand but also one that requires very unique geological features. In order it can be put in service. 35. Final Thoughts: so welcome to the final lesson off this course. I really do hope you enjoy the course and that you got a lot from it. In this course, we've talked about how we can convert potential on kinetic energy to electrical energy. We've looked at the state of the hydropower industry. We've talked about terms such as empowerment and diversion headwater tail, water, head on bondage. We've looked at all of the common hydro electric power plant components such as trash racks , gates, spillway, pen stock turbine runners, the turbine generator, a draft tube on the electrical transformer. We've looked at hydro electric turbines. You now know what every action to my knees and an impulse turbine. You also understand concepts such as Axl mixed radial flow turbines. And we've looked a great detail at the Kaplan, Francis and Pelton type turbines. By now, you should have a level of understanding that allows you to know roughly when each type off turbine will be used for which type of power plant. And you also understand how the various types of hydropower plant work, such as hydro dams along the river and pump storage. I hope you've got a lot from the course and that you learn a lot. I hope it was fun and the pace was good for you. If you got any comments or feedback, please do send them to me. You can find me on Savary dot com. I'm more than happy to take any feedback you're willing to give. These courses are not static. They're very dynamic. We're constantly improving them. I get feedback from students trying, then reiterate the courses so that we can have always better and better course. That really does help people learn once again. I do hope you enjoyed the course and that you've got a lot from it. Hopes eu another course soon life, you know.