•Hydroelectricity is a form of hydropower.•It is form of renewable energy.•It produces no waste and carbon dioxide(CO2), which contributes to greenhouse gases.•Hydroelectricity now supplies about 715,000MW or 19% of world electricity, accounting forover 63% of the total electricity from renewablein 2005.
Hows ? Water in a high reservoir has potential energy. The water is allowed to fall under gravity. The water gains kinetic energy. The kinetic energy drives the turbines. The turbines drives the generators. The kinetic energy of the shafts of the generators is converted into electrical energy.
Gravitational Mechanical Electrical
The two basic types of hydroelectric systems are those based on falling water and natural river current. First system , water accumulates in reservoirs created by the use of dams. Second system, called a run-of-the-river system Another kind of hydroelectric power generation is the pumped storage hydroelectric system.
This system, called a run-of-the-river system. The force of the river current (rather than falling water) applies pressure to the turbine blades to produce electricity. Since run-of-the-river systems do not usually have reservoirs and cannot store substantial quantities of water. Power production from this type of system depends on segeonal changes and stream flow. These conventional hydroelectric generating units range in size from less than 1 megawatt to 700 megawatts. Because of their ability to start quickly and make rapid changes in power output.
Another kind is pumped storagehydroelectric system. Pumped storage hydroelectric plantsuse the same principle for generationof power as the conventional.Hydroelectric operations based onfalling water and river current. However, in a pumped storageoperation, low-cost off-peak energy isused to pump water to an upperreservoir.Where it is stored as potential energy. The water is then released to flowback down through the turbinegenerator to produce electricity .
The La Grande Complex in Quebec, Canada, is the worlds largest hydroelectric generating system. The eight generating stations of the complex have a total generating capacity of 16,021 MW. The Robert Bourassa station alone has a capacity of 5,616 MW. A ninth station (Eastmain-1) is currently under construction and will add 480 MW to the total. Construction on an additional project on the Rupert River was started on January 11, 2007. It will add two stations with a combined capacity of 888 MW.
1. Cragside, Rothbury, England completed 1870.2. Appleton, Wisconsin, USA completed 1882, A waterwheel on the Fox river supplied the first commercial hydroelectric power for lighting to two paper mills and a house, two years after Thomas Edison demonstrated incandescent lighting to the public.3. Duck Reach, Launceston, Tasmania. Completed 1895. The first publicly owned hydro-electric plant in the Southern Hemisphere. Supplied power to the city of Launceston for street lighting.
Can convert as much as 90% of the available energy into electricity. Best fossil fuel plant is only about 50% efficient. The use of hydropower prevents the burning of 22 billion gallons of oil or 120 million tons of coal each year. The carbon emissions avoided is equivalent to 67 million cars on the road.
1) They use up valuable and limited natural resources.2) They can produce a lot of pollution.3) Companies have to dig up the earth or drill wells to get coal, oil, or gas.4) For nuclear power plants, there are waste disposal problems.
No pollution and no consumption of resources. Hydrogen is produced from water and oxidized back into water. There are no byproducts, toxic or otherwise, produced by the process. Safety. Hydrogen systems have an enviable safety record; in many cases, hydrogen is safer than the fossil fuel it replaces. In addition to dissipating quickly into the upper atmosphere if it leaks, hydrogen is completely non-toxic, unlike fossil fuels. High Efficiency. Fuel cells convert chemical energy directly into electricity with greater efficiency than any other current power system. Long life and minimal maintenance. Though fuel cells have not been in use long enough to give a definite lifespan, fuel cells may have significantly longer lifetimes than the machines they replace.
You have to flood a valley to build a big dam there is a big impact on the environment possible loss of habitat for some species initial costs are high