With the largest hydroelectric dam in the world, China is the leading producer of hydroelectricity. The Yangtze River is held by the Three Gorges Dam in China. It is 7,660 feet (2,333 meters) long and its height is about 607 feet (185 meters). Huge right? Its generators produce enough power that they can supply 22,500 megawatts of power easily. Coming to think of this, some of you might wonder what hydroelectricity is. Well, along with this why not get to know about the advantages and disadvantages of hydroelectric energy? Of course, it is a smart catch.
What is Hydroelectricity? Is Hydropower Renewable?
The electricity generated by harnessing the power of the moving water is known as hydroelectricity. You also know it by other names like hydroelectric power or hydroelectric energy. It is a form of energy that is derived from water through a wheel or other similar mechanisms to carry out different actions. For example, in Ancient Greece, flowing water was used to turn the wheel of the mill that ground wheat into flour.
Of course, it is renewable because electricity generation depends on water flow which can be adjusted. Also, there is hardly any wastage of the resource, that is, water, which means there is the least requirement for renewing the resource. After understanding what is hydroelectricity and is hydropower renewable, you have enough basic knowledge to start learning about the advantages and disadvantages of hydroelectric energy.
5 Advantages and Disadvantages of Hydroelectric Energy
This is the most commonly used form of renewable source of electricity. Almost 71% of total renewable electricity generation on Earth is through hydropower. With China being the largest producer, other countries in the list of hydropower producers are Brazil, Canada, India, Russia, and the United States. However, just like every resource, this one also has its advantages and disadvantages.
What Are the Advantages of Hydroelectric Energy?
1. Adjustable
The flow of water is easily adjusted by the energy plant. The adjustments are possible because the flow of water is increased when more energy is required. On the other hand, water flow is decreased to the extent that only enough electricity is produced. This type of adjustment is only possible with hydroelectric power.
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2. Land Development
With the development of hydroelectric plants at specific locations there is a good chance for the land development of nearby locations, cities, and towns. This is because of the new opportunities created while building the dam like the construction of roads that connect the rural areas with urban regions.
3. Pollution Free
Another advantage of hydroelectricity is that there is no emission into the atmosphere. Hydroelectric energy does not create air, water, or land pollution.
4. Lakes
With dam construction often lakes are formed that are also a type of tourist attraction. With flooding tourists, the economic conditions of the nearby town or village are. Lake Mead in the states of Arizona and Nevada was created as a result of the Hoover Dam is an example of this.
5. Reliable and Renewable
Water flowing constantly makes it a reliable source of energy. Other sources like the sun or wind are not so reliable because on cloudy days you cannot rely on the sun to generate good amounts of energy. Similarly, on days when the wind is not at a certain speed, it cannot turn the turbines to generate electricity. Hydropower is a renewable resource for energy generation. Therefore, hydro plants are built with the same consideration.
What Are the Disadvantages of Hydroelectric Energy?
1. Emissions
Here comes the first disadvantage from the list of advantages and disadvantages of hydroelectric energy. There are generally no emissions during electricity generation. Reservoirs are created in the process to hold water. Plants present at the bottom of the reservoir begin to decompose over time. The decomposing plants release large amounts of methane and carbon that are harmful to marine life.
2. Expensive
Building any power plant needs heavy investments. But building a dam to stop the running water is an additional structure required in hydroelectric plants. Thus, the construction of a hydroelectric plant is costly in comparison to other power plants of the same size.
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3. Floods and Droughts
Dams are built at high elevations, but this is dangerous during heavy rainstorms and typhoons. A dam poses a flood threat to the nearby town that is below it. Though it hardly happens, a dam breaking and releasing all the water may result in flooding.
A one-program approach as discussed in past retreats should be implemented. The plants need water to generate electricity and if there is insufficient water the performance of the plant is affected. Also, with climate changes the situation may become more common.
4. Impact on Marine life
Dams are built on running water sources, this becomes a barrier between fishes and their breeding ground. Also, when other fish are not reaching this side there can be a shortage of food for other fishes. Not only this, access to water for animals becomes difficult.
5. Limited Locations
Places for hydropower plant construction are limited. A dam cannot be built in any random place with flowing rivers. Also, the selected places where these plants are constructed are far from major cities. Thus, the energy produced could not be utilized by the cities.
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How Is Hydroelectricity Produced Step by Step?
Hydroelectricity is an ample source of energy that is also a fundamental vehicle for the development of new and old communities. This can be counted as an advantage among the advantages and disadvantages of hydroelectric energy. But if you are wondering how is hydroelectricity produced step by step? Here it is mentioned below.
Step 1: A large dam is built to stop the course of the moving water source and use that force to generate electricity. Some of these power plants are located near rivers, streams, and canals but still, dams are built to provide a reliable water supply.
Step 2: Large amounts of water are filled in the reservoirs. It is also termed the head. The purpose is to release the stored water as and when power generates.
Step 3: A generator or generators are placed at the lower elevation of the dam that is connected with a turbine. It is placed at a certain length within the water.
Step 4: Water is released from the reservoir at a higher elevation, and it rushes downwards at high speed. This moving water moves through pipes and hits the turbines like wind touches the blades of a windmill. As the wire coils sweep past the stator (stationary coil) of the generator, electricity is produced. It happens when the magnets within the copper coils rotate at a specific speed for a defined time period.
Step 5: With a vast network of transmission lines and facilities, electricity is transferred to residential and commercial areas. Electricity from power plants first passes through the transformer that raises the voltage so that it can travel through power lines for long distances.
Step 6: Local substations transformers reduce the voltage, and then it is divided and directed throughout the area.
Step 7: Pole transformers reduce the power to the right voltage that is required to run the home appliances.
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How Does Hydroelectric Energy Work?
After learning about the advantages and disadvantages of hydroelectric energy, it would be interesting to know how does hydroelectric energy works. Gravity and the water cycle are advantageous together in producing hydroelectricity. Hydroelectric energy works by generating kilowatts of electricity per second. As per a rough assumption, one gallon of water falling from 100 feet is capable of generating 1 kilowatt of electricity.
Four major components of a hydroelectric plant are
1. Dam: Built at higher altitudes to allow water to fall with great force.
2. Turbine: This enables the conversion of the kinetic energy of falling water into mechanical energy. Different types of turbines are used, but it depends on the number of hydraulic heads at the plant. It is the vertical distance between the turbine and the dam.
3. Generator: It is connected to turbines with shafts and gears that enable the spinning of coils in the generator. Then mechanical energy is converted into electrical energy.
4. Transmission lines: Electricity generated in the power plants is conducted to residential and commercial areas.
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How Hydroelectric Energy is Used?
Now that you have learned about how does hydroelectric energy works, let’s also see how hydroelectric energy is used. The kinetic energy of hydroelectric energy is used to power hydropower plants. With hydroelectric plants, it is possible to generate immediate power for the grid. Such power serves as a great backup during electricity shortages and outages. Hydroelectric energy is also used for supplying power to residential and commercial areas. Additionally, it is used as a green and renewable source of energy to reduce negative impacts on the environment.
Run-of-the-River
This is another way in which hydroelectric energy works to generate electricity. But in this method, dams are not built to raise the volume and speed of the water. Instead, a run-of-river project freely turns the turbine blades by using the energy of moving river water. This system is not time bound and lacks the ability to control the time and amount of electricity to be generated.
What are Different Types of Hydroelectric Energy Plants?
These are the basic types of hydroelectric power plants that use different methods to generate electricity. The advantages and disadvantages of hydroelectric energy may be defined by the type of energy plants too.
1) Diversion facility: In this system, a series of canals are used to channel the flow of moving rivers. The water is moved towards the turbines. They move to power the generator. This facility is considered unique because it does not use the traditional method of the dam.
2) Impoundment facility: This one is the commonest type of hydroelectric energy plant, and it uses the traditional method of the dam. Through this water flow is controlled and stored in a reservoir of a pool. Water is released from here in the desired quantity when more power generation is required. When the water is released, it flows down through the turbine blades to power the generator.
3) Pumped storage facility: This facility stores energy produced from solar, water, and wind along with that generated by nuclear power. Energy is stored by pumping water uphill into a reservoir from the pool. The reservoir is at a high elevation and the pool is at a lower location. Energy is generated when water is released from the reservoir, at high pressure, turning the turbines and thus powering the generator.
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What Are Different Types of Turbines?
The most commonly used turbines are Francis, Pelton, and Kaplan wheel designs. The reaction and impulse wheel designs use the water pressure along with the kinetic energy of moving water to generate electricity.
1. Francis Turbine: This has a runner with 9 or more fixed wanes. The water is directed by the runner into an axial flow. The turbine can be around 800 MW in size.
2. Pelton Turbine: It has specially designed buckets mounted towards the outside of the circular disk. It looks similar to a water wheel. This turbine is usually used in high hydraulic head sites, and it is as large as 200 MW.
3. Kaplan Turbine: It is similar to the boat turbine with 3–6 blades. The size of a Kaplan turbine is 400 MW. By changing the pitch of the blades, the performance of a Kaplan turbine can be improved.
Well, after learning about the advantages and disadvantages of hydroelectric energy, it looks like every good thing has a bad impact somewhere. Though it has disadvantages, looking at the bright side of how advantageous and beneficial it is, hydropower has a bright future ahead. Also, the way hydroelectric energy is used through its reliable water resource and its popularity is ever-increasing.
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