There are various sorts of hydro power plants based on the types of hydropower producing facilities. These hydroelectric plants will be discussed. The construction of big hydropower plants is a practical and economically viable concept since the project’s capital expenses can be decreased.
The demand for peak load capacity of hydropower facilities has grown in tandem with the growth of power systems. The ratio of power needs between peak and off-peak periods has also increased in several power plant systems. One way for meeting the increased demand for cost-effective peak electricity is to deploy reversible pump turbines.
Bulb turbines, sometimes known as pump turbines, have helped to reduce the cost of developing low-head river and tidal power facilities.
Pumped Storage Hydropower Plants:
Hydropower plants must have installed capacity of high loads to serve peak loads, with the capacity remaining idle during off-peak hours. The more variable power supply needs increase, the more it becomes vital to create a method for achieving the most cost-effective loading of the power plant by levelling up the load curve. Some of the methods are as follows:
(a) Commercial Method: Charge a greater rate for electric current during peak hours than during off-peak hours.
(b) Technical method: The two ways are as follows: (i) By erecting specialised peak-load power plants. (ii) By storing energy generated during non-peak times. Pumped Storage Plants are a type of system like this.
Purpose of Pumped Storage Hydropower Plants:
When these facilities are integrated with steam power stations, power load changes are kept to a minimum. In certain circumstances, the storage plant is simply a pump and motor without any turbines. The motor enhances the power factor in the electric supply network while the pump increases the head in the feeder reservoir of a separate hydro-electric plant.It can handle daily peak loads and seasonal water changes when combined with hydroelectric power units.
Types of Pumped Storage Plants:
Plants for daily, weekly, or seasonal storage Plants with a high, medium, or low head The type of turbine utilised in the plant determines the price. Hydropower plants with pure or mixed storage Storage plants that are horizontal or vertical
Reversible Turbine Hydro Power Plants:
Francis turbines, which are just a reverse of centrifugal pumps, act in one direction as a motor-driven pump and in the other way as a turbine in this sort of hydropower plant.
Pumping and producing operations have been determined to be more than 65 percent efficient. Because the particular speed of a pump is higher than that of a geometrically equivalent turbine, the two machines must rotate at two distinct speeds to achieve the best efficiency in each direction of rotation. The same speed might be achieved only at the expense of efficiency.
Underground Hydropower Plants:
The underground hydropower plants are built below the water’s surface. These are plants with a small head. This sort of installation comprises of a weir over a river that will be harnessed, as well as the power plants that will be housed within the weir. The tubular or bulb turbines operate in a straight passage that connects the head and tail races. A horizontal or inclined shaft connects the turbine to the generator, depending on convenience. The following are some of the benefits of underground hydropower plants: They are safe against enemy or terrorist attacks, rock and earth tremors, and snow avalanches. Throughout the year, air conditioning is available. They have a larger number of operational heads.Because the excavation is done in rocks, there are significant cost reductions in the power plant.
Tidal Power Plants:
Hydropower plants do not include tidal power plants. Due to the tide, the discharge and head are made available. This is due to the earth’s rotation. Tides inundate large areas and elevate the sea level along the seashores by a few millimetres to several metres. This process stores a large quantity of energy in the earth. The force exerted by tides causes the earth’s rotation to slow down.(Photo courtesy of technology student.com Artificial arrangements can increase tidal energy, such as: The tidal wave rapidly raises the basin level if the gates linking the tidal basin and the sea are suddenly opened during high tide. The filling wave returns to its original position after reflection.
Impoundment, diversion, and pumped storage are the three types of hydroelectric facilities. Dams are used in some hydroelectric facilities, although they are not used in others. Despite the fact that not all dams were built for hydropower, they have shown to be effective in delivering large amounts of renewable energy to the grid. There are more than 90,000 dams in the United States, but only about 2,300 produce electricity as of 2020. The dams used for recreation, stock/farm ponds, flood control, water supply, and irrigation are among the others. Hydropower plants come in a variety of sizes, from tiny systems for a single home or community to big projects that provide electricity for utilities. Find out more about hydropower plant sizes.
IMPOUNDMENT An impoundment facility is the most prevalent type of hydroelectric power plant. A dam is used to store river water in a reservoir at an impoundment plant, which is usually a big hydroelectric system. Water released from the reservoir spins a turbine, which then activates a generator, which generates power. The water might be released to satisfy changing electrical needs, as well as other purposes including flood control, recreation, fish passage, and other environmental and water quality concerns.An impoundment hydrodam is depicted in this illustration. DIVERSIONA diversion, often known as a “run-of-river” facility, directs a section of a river through a canal and/or a penstock to generate energy by utilising the natural drop in river bed height. A penstock is a closed conduit that transports electricity.
SIZES OF HYDROELECTRIC POWER PLANTS
Hydropower plants range in size from huge power plants that produce electricity to a large number of people to small and even “micro” plants that are run by individuals for their own energy needs or to sell power to utilities. Large-scale hydroelectricity Although definitions differ, the Department of Energy classifies major hydropower plants as those with a capacity of more than 30 megawatts (MW).Small-scale hydroelectricity Small hydropower facilities, according to the DOE, are projects that generate between 100 kilowatts and 10 megawatts. Micro hydropower is a type of hydroelectric power thatA tiny hydropower plant can produce up to 100 kilowatts of electricity. A single home, farm, ranch, or community can get enough electricity with a small or micro hydroelectric power system.
Hydroelectric power plants
Hydropower projects can be divided into four categories. These technologies frequently collide. Storage projects, for example, may include some pumping to supplement the water that naturally flows into the reservoir, and run-of-river projects may give some storage capabilities. A system that conducts flowing water from a river through a canal or penstock to spin a turbine is known as run-of-river hydropower. A run-of-river project often has little or no storage capacity. Run-of-river provides a constant supply of energy (base load), as well as some flexibility in operation for daily fluctuations in demand, thanks to the facility’s control of water flow.A huge system that employs a dam to store water in a reservoir is known as storage hydropower. Water is used to generate electricity.
Hydropower is perhaps the first kind of automated power generation that is not powered by humans or animals. Initially, milling was accomplished by moving a grind stone, which evolved into the operation of an electrical generator. It was, for a long time, the primary source of electricity, alongside steam. Its continuous availability (unlike wind and solar electricity) does not necessitate any power storage. The majority of the hardware is mechanical. This makes it relatively simple to comprehend as well as repair/maintain. Its environmental impact is negligible in smaller units (see: environmental impact assessment and pros and cons of micro hydropower).
Flow & Head
Two factors are crucial in generating electricity from hydropower:Flow refers to the amount of water that is always accessible throughout the year.The difference in height between the head and the rest of the body These particulars.
Hydropower is divided into three categories based on its size. Although the power output is merely an approximate diversion between different classes, hydropower installations can be classified by their magnitude of power output. There is no international agreement on how to define the size difference between small and large hydropower plants.A total capacity of up to 10 MW is becoming the generally accepted norm for small hydropower facilities, according to the United Nations Industrial Development Organization (UNIDO), the European Small Hydropower Association (ESHA), and the International Association for Small Hydro (IASH) (SHP). Small can refer to capacities of up to 25 MW in China, up to 15 MW in India, and up to 1.5 MW in Sweden, while’small’ in Canada can refer to upper limit capacities of between 20 and 50 MW.
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