GENERAL CONCEPT [4×2=8, 2×5=10]
2.1 Diesel power plant and hydropower plant
.1.1 General concept
2.1.2 Classification
2.1.3 Advantages and disadvantages
Diesel power plants generate electricity by converting the chemical energy of diesel. In other terms, a diesel power plant is a power generation facility that uses a diesel engine as the primary mover to generate electrical energy. NEA NOTE:
Schematic Diagram and Working of Diesel Power Plant
The schematic arrangement of a typical diesel power plant is shown in the figure given below.
In a diesel power plant, the diesel engine is used as the prime mover to drive an alternator. The diesel (fuel oil) burns inside the engine and the products of this combustion acts as the working agent to produce mechanical energy. The diesel engine drives an electric generator which converts the mechanical energy into electrical energy.
Due to high cost of diesel, the diesel power plants are only used to produce small power. The diesel power plants are used at such places where demand of power is less and sufficient quantity of coal and water is not available. The diesel power plants are also used as standby sets for supplying power to important points such as hospitals, cinema halls, telephone exchanges, etc.
Advantages of Diesel Power Plant
The key advantages of a diesel power plant are as follows:
A diesel power plant has a relatively straightforward layout.
A diesel power plant takes up less area due to the limited number and size of its auxiliary equipment.
A diesel power plant is quick to start and can handle a large load.
A diesel power plant uses less water for cooling.
A diesel power plant has a substantially lower overall cost per unit capacity than a thermal power station.
A diesel power plant has a better thermal efficiency than a thermal power plant of the same capacity.
A diesel power plant requires less staff to operate.
A diesel power plant can be installed in any location.
A diesel power plant has no standby losses.
Disadvantages of Diesel Power Plants (NEA NOTE)
Below are some downsides of a diesel power plant:
As diesel (fuel oil) is expensive, the diesel power plant has a high operating cost.
The diesel power plant can create only a tiny amount of power.
Lubrication costs for a diesel engine are often significant.
For extended periods of time, the diesel power plant fails to function satisfactorily under overload conditions.
Conventional energy sources are those that are found naturally in the environment. They are in limited supply over the world and will eventually disappear if not used sustainably. Conventional energy sources include natural gas, coal, oil, thermal power plants, hydroelectricity, and hydropower plants. Hydroelectricity is regarded as a clean and efficient long-term energy source.
The most major downside of traditional sources of energy is their tendency to harm the environment. They are also extremely limited in terms of the amount of extractable material. The sole exception is hydroelectricity. Nepal has a large potential for hydroelectric power generation. Just 15% of the total open source is being used right now. Therefore, you need to get a proper grasp on what is hydroelectricity and on what is hydropower plant.
Hydroelectricity
Let’s start by defining hydroelectricity. Hydroelectricity refers to the generation of electrical current from the kinetic energy of flowing water. It might be a water turbine-driven electric generator in a dam, a generator powered by a water wheel in a stream, or even an air-driven electric generator that is compressed by ocean waves.
Advantages of Hydroelectricity:
It is a clean, non-polluting source of energy.
No fuel is required. Water is a source of energy and does not consume water.
Dams are built near rivers. As the water level rises, the kinetic energy of water converts to potential energy.
Disadvantages of Hydroelectricity
Very costly.
Large portions of human settlement and agricultural land are inundated.
Dams can be built in limited locations.
Applications of Hydroelectricity:
To develop and provide renewable energy.
Hydroelectricity is stored during periods of low demand and then used when demand grows.
Hydropower Plant
Let us try to grasp what a hydroelectric plant is. When water is at a height, it contains potential energy. When this water runs down, its potential energy is converted to kinetic energy, which is then turned to mechanical energy using turbines. A generator converts mechanical energy into electrical energy. Hydropower is only as important as thermal power. Hydropower plants account for almost 20% of total global electric generation. NEA NOTE:
Advantages of Hydropower Plants:
Rainwater is kept in the dam. Thus, it is regarded as a renewable source of energy.
Dam development benefits local farmers by providing irrigation and regulating floods.
This method of electricity generation does not produce any pollution.
Their operational cost is very low.
The Disadvantage of Hydropower Plants:
Hydropower projects need significant capital and have a low rate of return.
Dams can only be built in specified sites.
A large region of agricultural is inundated in water.
Uses for Hydropower Plants:
Hydropower plants, which generate electricity quickly, can supply critical backup power during catastrophic power outages.
Hydropower is used to manage floods, irrigation, and water supply.
Hydropower plays a significant role in lowering greenhouse gas emissions.
Working Principle of Hydropower Plant
Now that you have a solid grasp of what is hydroelectricity and what is a hydropower plant, we will look at how hydroelectricity is generated in the plants. We use the gravitational force of water to generate power.
The first thing we need is a high-rise dam that will stop the flow of water and collect it in one location. When all of the water is collected, a lot of potential energy is stored in the water. The sluice gates are then opened, allowing the water to flow under high pressure. When water moves, potential energy is transferred to kinetic energy. When moving water strikes the blades of a turbine, its kinetic energy is converted to mechanical energy. This turbine is attached to a generator. The generator in the powerhouse produces electricity while the turbine rapidly turns. The used water will be released into the river, lowering the dam’s water level. This level will rise again with the help of natural rains. As a result, it is an infinitely renewable natural resource.
World Distribution of Hydropower
The most important and extensively used renewable energy source is hydroelectricity, which is generated in hydropower facilities. Hydropower plants account for only 20% of total global electric generation. China is the world’s largest generator of hydroelectricity, followed by the United States, Brazil, and Canada. Approximately 66% of the economically possible hydropower has yet to be utilized. Untapped resources still exist in Central Africa, China, India, and Latin America.
Hydropower remains the leading source of electricity in North and Central America.
South America had the second-fastest growth rate, adding 4,855 MW of installed hydropower capacity in 2018.
Hydropower is increasingly recognized in Europe for its flexible services in maintaining secure, economical, and ecological electricity supply.
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