A Report On,Hydro PowerPlant Created By, Gaurav S. Maniar Karan S. Raithatha Electronics & Communication Department,Dasrshan Institute Of Engineering & Technology
CHAPTER 1: INTRODUCTION1.1 Introduction Energy is the most important thing in this world. All living plants, animals (organisms) on this earth require energy to perform any type of work. The capacity to do a work is energy. The energy may require in smaller amount or in larger amount depending upon the nature of work to be performed. The different things from which we get the energy are called as Energy Sources. This is the simplest meaning of energy sources. Hydropower, hydraulic power, hydrokinetic power or water power is power that is derived from the force or energy of moving water, which may be harnessed for useful purposes. Prior to the development of electric power, hydropower was used for irrigation, and operation of various machines, such as watermills, textile machines, sawmills, dock cranes, and domestic lifts. In hydrology, hydropower is manifested in the force of the water on the riverbed and banks of a river. It is particularly powerful when the river is in flood. The force of the water results in the removal of sediment and other materials from the riverbed and banks of the river, causing erosion and other alterations.1.2 Conventional OR Non-Renewable Energy Sources The energy sources, which we are using from long time and which are in danger of exhausting, are called as Conventional OR Non-Renewable Energy Sources. They are not renewed by Nature and they are perishable, are going to get exhausted one day. e. g. coal, petroleum products, nuclear fuels etc.1.3 Non-Conventional OR Renewable Energy Sources These are the energy sources whose utilization technology is not yet fully developed. These are the sources, which can be recovered and reused. i. e. they can be used again and again to generate energy because of the renewal of their energy. We are going to consider one of the ways of generation of energy from non- conventional energy namely hydroelectric energy. As name suggest, it is the energy obtained from water. The main principle used in this type is the kinetic energy of falling water is converted into electric energy using turbines. Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy.
1.4 History Fig 1. Irrigation Water Wheel A water wheel is a machine for converting the energy of free-flowing or falling water into useful forms of power. A water wheel consists of a large wooden or metal wheel, with a number of blades or buckets arranged on the outside rim forming the driving surface. Most commonly, the wheel is mounted vertically on a horizontal axle, but the tub or Norse wheel is mounted horizontally on a vertical shaft. Vertical wheels can transmit power either through the axle or via a ring gear and typically drive belts or gears; horizontal wheels usually directly drive their load.
CHAPTER 2: Hydro Energy Fig. 2 Hydrological Cycle The total amount of water on the earth and in its atmosphere does not change but the earth‟s water is always in movement. Oceans, rivers, clouds and rain, all of which contain water, are in a frequent state of change and the motion of rain and flowing rivers transfers water in a never-ending cycle. This circulation and conservation of earth‟s water as it circulates from the land to the sky and back again is called the „hydrological cycle‟ or „water cycle‟. The hydrologic cycle begins with the evaporation of water from the surface of the ocean. As moist air is lifted, it cools and water vapor condenses to form clouds. Moisture is transported around the globe until it returns to the surface as precipitation. Once the water reaches the ground, one of two processes may occur; 1) some of the water may evaporate back into the atmosphere or 2) the water may penetrate the surface and become groundwater. Groundwater either seeps its way to into the oceans, rivers, and streams, or is released back into the atmosphere through transpiration. The balance of water that remains on the earths surface is runoff, which empties into lakes, rivers and streams and is carried back to the oceans, where the cycle begins again.
CHAPTER 3: Power Plants There are 5 different ways to generate electricity from hydro energy.3.1 Conventional Dam Most hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. The power extracted from the water depends on the volume and on the difference in height between the source and the waters outflow. This height difference is called the head. The amount of potential energy in water is proportional to the head. A large pipe delivers water to the turbine. Fig.3 Conventional Dam
3.2 Pumped Storage This method produces electricity to supply high peak demands by moving water between reservoirs at different elevations. At times of low electrical demand, excess generation capacity is used to pump water into the higher reservoir. When there is higher demand, water is released back into the lower reservoir through a turbine. Pumped-storage schemes currently provide the most commercially important means of large-scale grid energy storage and improve the daily capacity factor of the generation system. The method stores energy in the form of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost off-peak electric power is used to run the pumps. During periods of high electrical demand, the stored water is released through turbines to produce electric power. Although the losses of the pumping process makes the plant a net consumer of energy overall, the system increases revenue by selling more electricity during periods of peak demand, when electricity prices are highest. Pumped storage is the largest-capacity form of grid energy storage now available. Fig. 4 Pumped Storage Power Plant
This system may be economical because it flattens out load variations on the power grid, permitting thermal power stations such as coal-fired plants and nuclear power plants and renewable energy power plants that provide base-load electricity to continue operating at peak efficiency, while reducing the need for "peaking" power plants that use the same fuels as many base load thermal plants, gas and oil, but have been designed for flexibility rather than maximal thermal efficiency. However, capital costs for purpose-built hydro storage are relatively high. Along with energy management, pumped storage systems help control electrical network frequency and provide reserve generation. Thermal plants are much less able to respond to sudden changes in electrical demand, potentially causing frequency and voltage instability. Pumped storage plants, like other hydroelectric plants, can respond to load changes within seconds.3.3 Run Of The River Run-of-the-river hydroelectric stations are those with small or no reservoir capacity, so that the water coming from upstream must be used for generation at that moment, or must be allowed to bypass the dam. A dam – smaller than used for traditional hydro – is required to ensure there is enough water to enter the “penstock” pipes that lead to the lower-elevation turbines. Run-of-the-river hydroelectricity is ideal for streams or rivers with a minimum dry weather flow or those regulated by a much larger dam and reservoir upstream. A dam, smaller than that used for traditional hydro, is required to ensure that there is enough water to enter the "penstock" pipes that lead to the lower-elevation turbines. Projects with poundage, as opposed to those without poundage, can store water for peak load demand or continuously for base load, especially during wet seasons. In general, projects divert some or most of a river‟s flow through a pipe and/or tunnel leading to electricity-generating turbines, then return the water back to the river downstream.
Fig. 5 Run of the River ROR projects are dramatically different in design and appearance from conventional hydroelectric projects. Traditional hydro dams store enormous quantities of water in reservoirs, necessitating the flooding of large tracts of land. In contrast, most run-of- river projects do not require a large impoundment of water, which is a key reason why such projects are often referred to as environmentally-friendly, or "green power." The use of the term "run-of-the-river" for power projects varies around the world and is dependent on different definitions. Some may consider a project ROR if power is produced with no storage while a limited storage is considered by others. Developers may mislabel a project ROR to sooth public image about its environmental or social effects.
3.4 Tidal Power A tidal power plant makes use of the daily rise and fall of ocean water due to tides; such sources are highly predictable, and if conditions permit construction of reservoirs, can also be dispatchble to generate power during high demand periods. Less common types of hydro schemes use waters kinetic energy or undammed sources such as undershot waterwheels. Tidal power is extracted from the Earths oceanic tides; tidal forces are periodic variations in gravitational attraction exerted by celestial bodies. These forces create corresponding motions or currents in the worlds oceans. The magnitude and character of this motion reflects the changing positions of the Moon and Sun relative to the Earth, the effects of Earths rotation, and local geography of the sea floor and coastlines. Fig. 6 Working A tidal generator converts the energy of tidal flows into electricity. Greater tidal variation and higher tidal current velocities can dramatically increase the potential of a site for tidal electricity generation. Tidal stream generators make use of the kinetic energy of moving water to power turbines, in a similar way to wind turbines that use wind to power turbines. Tidal barrages make use of the potential energy in the difference in height between high and low tides. Barrages are essentially dams across the full width of a tidal estuary.
Fig. 7 Schematic3.5 Under Ground An underground power station makes use of a large natural height difference between two waterways, such as a waterfall or mountain lake. An underground tunnel is constructed to take water from the high reservoir to the generating hall built in an underground cavern near the lowest point of the water tunnel and a horizontal tailrace taking water away to the lower outlet waterway. Fig. 8 Working of Underground Plant
CHAPTER 4: Classification Of Turbines Flowing water is directed on to the blades of a turbine runner, creating a force on the blades. Since the runner is spinning, the force acts through a distance. In this way, energy is transferred from the water flow to the turbine. Water turbines are divided into two groups; reaction turbines and impulse turbines. The precise shape of water turbine blades is a function of the supply pressure of water, and the type of impeller selected. There are mainly two types of turbines used in hydro electric power plant to generate electricity. Classification of turbine is given below. Turbine Impulse Reaction Turbine Turbine WaterPelton Turgo Francis Tyson Kalpan Wheel 4.1 Impulse Turbine Impulse turbines change the velocity of a water jet. The jet pushes on the turbines curved blades which changes the direction of the flow. The resulting change in momentum causes a force on the turbine blades. Since the turbine is spinning, the force acts through a distance and the diverted water flow is left with diminished energy. Prior to hitting the turbine blades, the waters pressure is converted to kinetic energy by a nozzle and focused on the turbine. No pressure change occurs at the turbine blades, and the turbine doesnt require a housing for operation. Impulse turbines are most often used in very high head applications. Newtons second law describes the transfer of energy for impulse turbines.
4.2 Reaction Turbine Reaction turbines are acted on by water, which changes pressure as it moves through the turbine and gives up its energy. They must be encased to contain the water pressure (or suction), or they must be fully submerged in the water flow. Newtons third law describes the transfer of energy for reaction turbines. Most water turbines in use are reaction turbines and are used in low and medium head applications. In reaction turbine pressure drop occurs in both fixed and moving blades.
CHAPTER 5: Important Points5.1 Advantages Renewable source of energy thereby saves scares fuel reserves. Economical source of power. Non-polluting and hence environment friendly. Reliable energy source with approximately 90% availability. Low generation cost compared with other energy sources. Indigenous, inexhaustible, perpetual and renewable energy source. Low operation and maintenance cost. Possible to build power plant of high capacity. Plant equipment is simple. Socio-economic benefits being located usually remote areas. Higher efficiency, 95%to98%. Fuel is not burned so there is minimal pollution. Water to run the power plant is provided free by nature. Its renewable - rainfall renews the water in the reservoir, so the fuel is almost always there.5.2 Disadvantages Susceptible to vagaries of nature such as draught. Longer construction period and high initial cost. Loss of large land due to reservoir. Non-availability of suitable sites for the construction of dam. Displacement of large population from reservoir area and rehabilitation. Environmental aspect reservoirs verses river ecology. High cost of transmission system for remote sites. They use up valuable and limited natural resources They can produce a lot of pollution. Companies have to dig up the Earth or drill wells to get the coal, oil, and gas. For nuclear power plants there are waste-disposal problems.
CHAPTER 6: References Domkundwal Maps Of India Wikipedia Google Images Indian Energy Portal International Energy Association Data