Slide 1: HYDRO ELECTRICITY PRESENTED BY : PRESENTED BY ROHITH NAIR CONTENTS : CONTENTS What is hydro electricity ?
History of hydro electricity
Methods to generate hydro electricity
How to calculate the amount of available power
Advantages and Disadvantages of hydro electricity
World Hydro electric capacity What is Hydro electricity : What is Hydro electricity Hydro electricity is the term referring to electricity generated by hydro power ; 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. Once a hydroelectric complex is constructed, the project produces no direct waste, and has a considerably lower output level of the carbon dioxide (CO2) than fossil fuel powered energy plants. History of hydro electricity : History of hydro electricity Hydro power has been used since ancient times to grind flour and perform others tasks. In the mid-1770s, a French engineer Bernard Forest de Belabor published Architecture Hydraulique which described vertical- and horizontal-axis hydraulic machines. In the late 1800s, the electrical generator was developed and could now be coupled with hydraulics. The growing demand for the Industrial Revolution would drive development as well. In 1878, the world's first house to be powered with hydroelectricity was Cragside in Norththumberland England. The old Schoelkopf power station No 1 near Niagara falls in the U.S. side began to produce electricity in 1881. Methods to generate Hydro electricity : Methods to generate Hydro electricity There are four methods to generate Hydro electricity :-
Conventional Conventional method : Most hydroelectric power comes from the potential energy of dam water driving 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 water's outflow. The amount of potential energy in water is proportional to the head. To deliver water to a turbine while maintaining pressure arising from the head, a large pipe called a penstock may be used . Conventional method Pumped storage method : Pumped storage method 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. Tide method : Tide method A tidal power plant makes use of the daily rise and fall of water due to tides; such sources are highly predictable, and if conditions permit construction of reservoirs, can also be dispatched to generate power during high demand periods. Less common types of hydro schemes use water's kinetic energy or undammed sources such as undershot waterwheels. How to calculate the amount of available power : How to calculate the amount of available power A simple formula for approximating electric power production at a hydroelectric plant is :-
P= ρhrgk where
P is Power in watts,
ρ is the density of water (~1000 kg/m3),
h is height in meters,
r is flow rate in cubic meters per second,
g is acceleration due to gravity of 9.8 m/s2
k is a coefficient of efficiency ranging from 0 to 1. Efficiency is often higher (that is, closer to 1) with larger and more modern turbines. Advantages : The major advantage of hydroelectricity is elimination of the cost of fuel. The cost of operating a hydroelectric plant is nearly immune to increases in the cost of fossil fuels such as oil , natural gas or coal and no imports are needed.
Since hydroelectric dams do not burn fossil fuels, they do not directly produce carbon dioxide.
A hydroelectric plant may be added with relatively low construction cost, providing a useful revenue stream to offset the costs of dam operation. Advantages Disadvantages : Disadvantages Hydroelectric power stations that uses dams would submerge large areas of land due to the requirement of a reservoir.
Changes in the amount of river flow will correlate with the amount of energy produced by a dam.
Generation of hydroelectric power changes the downstream river environment.
Large reservoirs required for the operation of hydroelectric power stations result in submersion of extensive areas upstream of the dams, destroying biologically rich and productive lowland and valley forests, marshland and grasslands. World hydro electric capacity : World hydro electric capacity World renewable energy share as at 2008, with hydroelectricity more than 50% of all renewable energy sources. : World renewable energy potential.
The ranking of hydro-electric capacity is either by actual annual energy production or by installed capacity power rating. A hydro-electric plant rarely operates at its full power rating over a full year; the ratio between annual average power and installed capacity rating is the capacity factor Ten of the largest hydroelectric producers as at 2009 : Ten of the largest hydroelectric producers as at 2009 Slide 16: Thank you