Como funciona uma USINA HIDRELÉTRICA? Quais são os tipos de USINAS HIDRELÉTRICAS?

Today I'm going to talk about something you've never been told about hydroelectric plants. What's up engineering lovers, my name is Igor Felipe and today I'm here to talk about hydroelectric plants, and more than that, I'll tell you that there are more than 1 type of hydroelectric plant that we are used to seeing. So first of all, you need to like the video to help us get our content to more people.

This theme was asked by Gabriel Maximus in our video about substations, and then we thought, dammit, what would be nice to tell about hydroelectric plants? So what if I tell you that there are more than one type of hydroelectric plant. Yes, if you thought there was only one type, I'm here to extend your knowledge about it.

Calm down, before I tell you about these guys, let's tell you what a hydroelectric dam is and how it works. The energy in a hydroelectric plant is basically generated by transforming the potential force of water into electrical energy. The most famous hydroelectric plant we know is the Itaipu hydroelectric plant, which is located on the Paraná River, on the border between Brazil and Paraguay.

And in summary, this type of hydroelectric is formed by 3 types of structures: the dam, the dam, and the power plant. The dam is the water reservoir. When we talk about hydroelectric dams, we think of big lakes, and that's exactly what we want.

This dam is used to accumulate water as if it were a giant water tank. The dam is the structure that bars and contains the water from the reservoir, and in the case of hydroelectric plants, they are usually made of concrete. In other words, the dam is nothing more than a wall used to hold water.

Looking at the dam, we say that the side of the water reservoir is upstream of the dam, while the side that does not have the reservoir is known as downstream of the dam or spillway. This is the part where the water that has passed through the dam is returned to the river's course. And the last structure is the plant, where the potential energy stored in the reservoir is converted into electricity itself.

Now that we know the 3 structures of a hydroelectric plant, how does it produce energy? Hydroelectric plants use the concept of potential energy difference of a body of water and the concept of kinetic energy. It works like this.

Once we dam water in a reservoir, we accumulate potential energy. What we want then is to transform this potential energy into kinetic energy, and for that we install a pipe that connects the reservoir upstream to the downstream of the dam, creating a gap between these two points. In other words, we are taking the water from a higher point and taking it to a lower point, and this causes this potential energy to be transformed into kinetic energy, that is, the water starts to move and gains speed.

Now that we have a flow of water moving with speed, we've installed a turbine inside this pipeline. Once the water with all its kinetic energy hits this turbine, it spins. When this turbine turns, we transform the kinetic energy of water into mechanical energy.

This rotating turbine, filled with mechanical energy, is then coupled to a generator, which is installed on the shaft of this turbine. And it is exactly in this generator that there is the conversion between the mechanical energy of the turbine into electrical energy that we use. And why do we adopt this hydroelectric system?

Well, first because Brazil is a country rich in water resources. Second, because this generation method is very efficient. A hydroelectric plant can yield between 90 to 95% of production.

In other words, it manages to use between 90 and 95% of the potential energy of water. But calm down, the energy doesn't come straight from this generator straight to our homes. As we've already talked about in our videos about substations, transmission lines and transformers, the energy generated by the generator goes to a substation.

In this first substation, we raise the voltage level of this energy so that we can transmit this energy without much loss. After we have an extremely high voltage, it travels through the transmission lines to the place where we want to distribute and use this energy. Once it arrives at the place we want, it has to go through another substation, where the voltage level is reduced and it distributes energy through the poles in our cities.

Then it arrives at a transformer near our streets and from it comes the energy to our homes. Seriously, if you haven't watched these 3 videos I said, I'll leave it in the description of the video and it's really worth watching, because then you'll be able to understand this whole process and what each step does. Well, so far I've explained what a hydropower plant is and how it goes to bring energy to your home, but how come there are more than one type of hydropower plant?

Yes, oddly enough, there is not only one type of hydroelectric plant, but 3 types of plants. In the end, the 3 types of hydroelectric power plants use the same concept I've already said, which is to transform potential energy into electrical energy. But these 3 types have differences in their usage.

So here we go, the three types of hydroelectric plants are: run-of-river plants, reservoir plants and reversible plants. Run-of-river plants are adapted in places where it is not possible to build a large reservoir or even no reservoir at all. Imagine that you live near a river course and are wanting to produce your own energy.

You can use the flow of this river itself to capture the kinetic energy of this flow, concentrate it in a turbine, and from there you already know, right, from the turbine it goes to a generator and you can convert this flow into electrical energy. These plants can even have a continuous operation, but as we do not have control over the flow of water in the river, the energy produced varies. A nice example of where it is used is in those whirlpool micro-plants.

In it, it is possible to concentrate all possible kinetic energy of the water flow in the form of a vortex, and from there, electrical energy is produced. The second type of plant is the plant with reservoirs, and I think it needs no explanation, because this type is what I used to explain about hydroelectric plants and it is the most common type we know. Now the third type of hydropower plant may be the concept of “infinite” energy production, and it is the reversible type of plant.

Lately, we have had problems with a water crisis when it doesn't rain enough to fill the reservoirs of the dams. And it looks like this problem could end up becoming more and more common with the climate change we're going through. So how can we supply these reservoirs from the dams we have?

And that's where reversible power plants come in. And for you to understand better, let's go back to that explanation I made about a hydroelectric plant. This whole set basically takes the water upstream and drains the water downstream, and this water follows the natural course of the river.

What if we could dump this water that would leave the spillway, back into the upstream reservoir? And that's exactly what reversible power plants do. On the same shaft that connects the turbine to the generator, a hydraulic pump is also connected.

This hydraulic pump captures the water that drains downstream and returns with it to the upstream reservoir. Wait Igor, do you mean that we create an infinite production of energy? We dam the water, we produce energy, and the water that would be thrown forward ends up returning to the reservoir and then we create an infinite cycle and infinite energy.

It would be great if that actually happened, but no, it doesn't because of the law of energy conservation. As I had said, the yield of the systems of a hydroelectric power plant ranges from 90 to 95% of efficiency, that is, we cannot extract 100% of the energy from the system, as we have factors such as water friction, the head losses of the system, and several other factors. And by including a pump in this system, the plant's efficiency can drop a little more, because you end up using part of the mechanical energy to also turn a water pump.

That is, even if you pump the water back upstream, there will always be losses in the system. If there is no river feeding the reservoir as well, the tendency is that the energy level in the system would tend to zero over time. What this reversible plant does is simply decrease the size of the upstream reservoir due to pumping water and consequently it needs less water supply from a river.

But even so, it is necessary to supply water from a river. This type of hydroelectric plant could be a solution for the drought periods we are living in, making it possible to maintain energy production even with a low water flow. I'm going to leave a very interesting article in the description of the video about the use of reversible plants in Brazil and in the world.

Check it out Hey, you liked knowing about these 3 types of hydroelectric plants, so leave here in the comments what you think. Remember the videos I mentioned in the video, they are here on the side and in the description of the video for you to check out, so don't miss it. You still have time to give your like and if you are not subscribed, close with us and subscribe to the channel.

That's it my friends, that hug and I'll see you in the next video.