Hydro power systems convert potential energy stored in water held at height to kinetic energy (or the energy used in movement) to turn a turbine to produce electricity. Energy available in a body of water depends on the water’s flow rate and the height (or head) from which the water falls. These are divided into low head, medium head and high head, where the height drop is greater. Hydro power is mainly used in remote areas where there is plenty of natural water supply.
Mini-Micro Hydro Power Plants are those hydroelectric power installation units that generate less than 100kw of power.
Why should I be aware of this?
- The source of power is naturally replenished as water travels through the water cycle and provides rivers with water on a continuous basis. There is never a time when water is not flowing because there is never a full interruption of the water cycle.
- Hydroelectricity is also a nonpolluting source of electricity. There are no emissions released by the burning of fuels. According to estimates, using hydropower instead of burning fossil fuels to create electricity reduces the amount of carbon dioxide released into the atmosphere by about 77 million metric tons. This amount is equivalent to the amount of exhaust from 62.2 million cars being driven for a year, which is about half the cars in the United States.
Hydropower and environment
Hydropower has come under criticism because it does change the environment by affecting natural habitats. The series of dams constructed to generated hydrapower gets in their way of fish which must swim upstream to their spawning grounds to reproduce Different approaches to fixing this problem have been used, including the construction of "fish ladders" which help the salmon "step up" the dam to the spawning grounds upstream.
All about hydropower
Hydropower is a nonpolluting source of energy as it does not require steam to be released into the atmosphere like several other forms of energy production. Steam can alter weather patterns and requires large quantities of water from the surrounding environment. Production of hydroelectricity also does not require the use of chemicals that need to be disposed of in the environment. Since most dams are located in remote areas, there is no noise pollution.
Provides one-fifth of the world's electricity
Hydroelectric power provides almost one-fifth of the world's electricity. China, Canada, Brazil, the United States, and Russia were the five largest producers of hydropower in 2004. One of the world's largest hydro plants is at Three Gorges on China's Yangtze River. The reservoir for this facility started filling in 2003, but the plant is not expected to be fully operational until 2009. The dam is 1.4 miles (2.3 kilometers) wide and 607 feet (185 meters) high. 
The biggest hydro plant in the United States is located at the Grand Coulee Dam on the Columbia River in northern Washington. More than 70 percent of the electricity made in Washington State is produced by hydroelectric facilities.
As each hydroelectric power plant is built according to the requirement of its location, construction cost varies accordingly. Once such a plant is built, however, the cost to maintain and operate it is fairly minimal in comparison to the income a dam provides the power company. A dam rarely needs to be shut down for maintenance nor does it suffer breakdowns. The life expectancy of any given dam tends to be two to ten times that of a coal or nuclear power plant, which can last up to fifty years.
There are many social and ecological impacts of setting up hydroelectricity plants. Hydroelectricity requires water to be dammed in a reservoir, which is often very large in size. This requires relocating people living in the area. As a result many lives are interrupted and forced in new directions.
Another ecological impact of hydroelectricity involves the movement of sediments down the river. Sediments are small particles of soil that are rich in minerals and nutrients. It is made up of decaying plants and animals as well as worn-away bits of rock. The health of animals that live in and along the river depends upon sediment and its minerals.
Usually sediment flows from a mountaintop to the ocean down the course of a river. When a river is dammed, however, the reservoir that is created can act as a large trap for sediment, stopping its downstream progress. Sediment does not go through the dam, and the plants and animals in and along the river downstream from the dam do not get to benefit from the nutrients it provides. At the same time, the animals that live in and along the reservoir get too much of the built-up sediment. It can clog the gills and breathing ways of the aquatic life. The sediment can also slowly poison the animals and plants living in the water. When there is too much sediment in the water, aquatic animals and plants become sick and often die.
The growth of hydroelectricity globally is impressive. Most developing countries are exploring major rivers to bring more power to their countries. With such developments it is felt hydroelectricity will become the most established form of renewable energy throughout the world in the decades to come.
- Hydropower is the force of energy of moving water.
- Hydropower is clean renewable energy source that doesn't pollute environment.
- Hydropower uses the Earth's water cycle to generate electricity because movement of water as it flows downstream creates kinetic energy that can be then converted into electricity.
- Construction and work of the dams can affect natural water systems and also affect wildlife and fish population.
- Hydropower's air emissions are negligible because there are no fuels burned.
- Hydropower can't be used in all areas because it needs fast flowing water throughout whole year.
- Hydropower is very efficient energy source because some turbines can achieve efficiency of 95 % and more.
- Hydropower is renewable energy source that doesn't cause global warming because it doesn't releases dangerous greenhouse gases.
- Hydropower produce no air pollutants that cause acid rain and smog.
In the late 19th century, hydropower became a source for generating electricity. The first hydroelectric power plant was built at Niagara Falls in 1879. In 1881, street lamps in the city of Niagara Falls were powered by hydropower. In 1882 the world’s first hydroelectric power plant began operating in the United States in Appleton, Wisconsin. 
- Hydro Power