Hydroelectric Energy

Man has been using water as a source of power for centuries, from the early water wheel to the advanced versions of this ancient technology in use today.
Hydroelectric energy is a renewable energy source dependent upon the hydrologic cycle of water, which involves evaporation, precipitation and the flow of water due to gravity.

Electricity produced from generators driven by water turbines that convert the energy in falling or fast-flowing water to mechanical energy. Water at a higher elevation flows downward through large pipes or tunnels (penstocks). The falling water rotates turbines, which drive the generators, which convert the turbines’ mechanical energy into electricity. The advantages of hydroelectric power over such other sources as fossil fuels and nuclear fission are that it is continually renewable and produces no pollution.

Myth:
Using hydropower means building new dams.

Reality:
Only 2,400 of 80,000 dams are online and used for hydroelectric energy generation.

Did You Know?

-In the United States, hydropower produces enough electricity to serve the needs of 28 million residential customers. That is equivalent to all the homes in Wisconsin, Michigan, Minnesota, Indiana, Iowa, Ohio, Missouri, Nebraska, North Dakota, South Dakota, Kentucky, and Tennessee.

-Hydropower can come “on-line” quickly to meet rapid increases in electric demand and respond to emergency energy needs.

-Hydropower does not produce greenhouse gases or other air pollution, and it leaves behind no waste.

Hydropower

What is Hydropower?

Hydropower is the force or energy of moving water captured for some useful purpose.

Though types of water power include waterwheels (used to power mills and machinery for hundreds of years), damless hydro (captures the kinetic energy in rivers, streams and oceans), tidal power (captures energy from the tides in horizontal direction), tidal stream power (tidal power vertically) and wave power (uses the energy in waves), the most common is hydroelectric power (in hydroelectric dams or run-of-the-river setups).

How long have we used Hydropower?

Before commercial electric power was widely available, hydropower was used for irrigation and operating watermills, textile machines, and sawmills. The energy of moving water has been used since before the Roman Empire. At the height of the canal-building era in the 1830’s, hydropower was used to transport barge traffic up and down steep hills using inclined plane railroads.

How much Hydropower is available?

Hydroelectric power now supplies about 715,000 megawatts (MWe) or 19% of world electricity. In the United States, only about 10% of the total energy production comes from hydropower and only 20 percent of the nation’s hydropower potential has been developed.

The amount of electricity which can be generated by a hydroelectric plant is dependent upon the vertical distance through which the water falls (the “head”), and the flow rate measured as volume per unit time. The electricity produced is proportional to the product of the head and rate of flow.

Power (kW) = 5.9 x (Flow) x (Head)
In this equation, Flow is measured in cubic meters per second and Head is measured in meters.

How does Hydropower work?

Electricity is produced by spinning electromagnets within a generator’s wire coil that creates a flow of electrons. To keep the electromagnets spinning, hydroelectric stations use falling water. Hydroelectric power plants convert the kinetic energy contained in falling water into electricity.

The energy in flowing water is ultimately derived from the sun, and is therefore constantly being renewed. Energy contained in sunlight evaporates water from the oceans and deposits it on land in the form of rain. Differences in land elevation result in rainfall runoff, allowing some of the original solar energy to be captured as hydroelectric power.

Most hydroelectric stations use either the natural drop of the river or build a dam across the river to raise the water level and provide the drop needed to create a driving force. Water at the higher level (the forebay) goes through the intake into a pipe, called a penstock, which carries it down to the turbine. The turbine is a type of water wheel that converts the water’s energy into mechanical power. The turbine is connected to a generator, and when the turbine is set in motion it causes the generator to rotate, producing electricity. The falling water, having served its purpose, exits the generating station through the draft tube and the tailrace where it rejoins the river.

Hydroelectric Energy

Hydroelectricity is the renewable energy source that is used most often to generate electricity by dams. It accounted for over 7 percent of total U.S. electricity and 73 percent renewable energy in 2005. Hydroelectric Energy is one of the oldest sources of energy, and it was used thousands of years ago to turn a paddle wheel for grinding grain. The United States' first industrial use of hydroelectricity was in to generate electricity occurred in 1880, when 16 lamps were powered using a water turbine in Grand Rapids, Michigan. The first United States hydroelectric power plant opened on the Fox River near Appleton, Wisconsin, on September 30, 1882. Until that time, coal was the only fuel used to produce electricity thus polluted the air greatly. Because the source of hydroelectric power is water, hydroelectric power plants must be located on a water source (e.g. a river). Therefore, it was not until the transition of electricity over long distances was developed that hydroelectric power became widely used.

The energy is derived by directing channeling moving water. The amount of available energy in moving water is determined by its incline and speed of the water (also known as flow). Large rivers, like the Columbia River along the border between Oregon and Washington, carries a great deal of energy in its flow. Another example of high flow is show in Niagara Falls in New York where the water descends very rapidly. In either instance, the water flows through a pipe in a damn, then it pushes against and the blades of a turbine to spin a generator to produce electricity. Meanwhile, the dam creases a large reservoir or a lake. This can be used for recreational purposes like boating, fishing, and even swimming. On the other hand, the rivers beyond the dam provide excellent opportunities for whitewater rafting, kayaking, and other boating trips. A great example of this situation is the Hoover Dam that tames the wild Colorado River between Arizona and Nevada. People can relax in Lake Mead (the reservoir), or enjoy other water sports in a one hundred and ten mile recreational area. The magnificent thing is that this all happens in a desert setting.

Many people regard hydroelectric power as an ideal fuel for electricity generation because, unlike its nonrenewable fuels counterparts, hydroelectric energy cost barley anything. Another great advantage is that there are no waste products, and hydroelectric power does not pollute the water or the air. Despite its great advantages, hydroelectric power receives criticism because it creates an artificial lake thus changing the environment and affects the natural habitats. This is a great problem for salmon because they must swim upstream to their spawning grounds to reproduce, but numerous dams gets in their way. Although the construction of fish ladders has solved this problem, the natural way the salmon get to their breeding grounds is lost. Despite the fact that dams obstruct the nature, hydroelectric power is still a great option to go due to the fact that it costs very little and reliable because it has been used since ages. If you want, a cleaner planet with virtually no cost hydroelectric power is for you.