What is water energy?
Water energy is energy derived from the power of water, most often its motion. Energy sources using water have been around for thousands of years in the form of water clocks and waterwheels. A more recent innovation has been hydroelectricity, or the electricity produced by the flow of water over dams. In the twenty-first century scientists are developing water-based applications ranging from tidal power to thermal power.
Kind of water energy?
1.Wave power captures energy from waves on the surface of the ocean using a special buoy or other floating device.
2.A hydroelectric dam captures energy from the movement of a river. Dam operators control the flow of water and the amount of electricity produced. Dams create reservoirs (large bodies of calm water) behind them, which can be used for recreation, wildlife sanctuaries, and sources of drinking water.
3.Tidal power captures the energy of flowing waters with the help of turbines as tides rush in and out of coastal areas.
Wave energy converters (WECs) capture the energy contained in ocean waves to generate electricity.
There is a wide range of wave energy technologies. Each technology uses different solutions to absorb energy from waves, and can be applied depending on the water depth and on the location (shoreline, near shore, off shore). Although there is a wide range in technologies that signals that the sector has not yet reached convergence, it also shows the many different alternatives to harness wave power under different conditions and emplacements. Future evolution of the sector will aim for an initial deployment of demonstrating WECs in small arrays of 10 MW, close to shore or on specific testing emplacements. Making the jump to the full commercial phase requires some research on the basic components to reduce costs and increase the performance.
This brief forms part of a set by the International Renewable Energy Agency (IRENA) covering four main types of ocean energy technologies: Ocean Thermal, Tidal, Wave and Salinity Gradient energy.
Successive technology briefs have highlighted a wide range of renewable energy solutions. Each brief outlines technical aspects, costs, market potential and barriers, combined with insights for policy makers on how to accelerate the transition to renewables.
Tidal power or tidal energy is harnessed by converting energy from tides into useful forms of power, mainly electricity using various methods.
Although not yet widely used, tidal energy has the potential for future electricity generation. Tides are more predictable than the wind and the sun. Among sources of renewable energy, tidal energy has traditionally suffered from relatively high cost and limited availability of sites with sufficiently high tidal ranges or flow velocities, thus constricting its total availability. However many recent technological developments and improvements, both in design (e.g. dynamic tidal power, tidal lagoons) and turbine technology (e.g. new axial turbines, cross flow turbines), indicate that the total availability of tidal power may be much higher than previously assumed and that economic and environmental costs may be brought down to competitive levels.
Historically, tide mills have been used both in Europe and on the Atlantic coast of North America. The incoming water was contained in large storage ponds, and as the tide goes out, it turns waterwheels that use the mechanical power to mill grain. The earliest occurrences date from the Middle Ages, or even from Roman times. The process of using falling water and spinning turbines to create electricity was introduced in the U.S. and Europe in the 19th century.
Electricity generation from marine technologies increased an estimated 16% in 2018, and an estimated 13% in 2019. Policies promoting R&D are needed to achieve further cost reductions and large-scale development. The world's first large-scale tidal power plant was France's Rance Tidal Power Station, which became operational in 1966. It was the largest tidal power station in terms of output until Sihwa Lake Tidal Power Station opened in South Korea in August 2011. The Sihwa station uses sea wall defense barriers complete with 10 turbines generating 254 MW.
A hydroelectric dam is one of the major components of a hydroelectric facility. A dam is a large, man-made structure built to contain some body of water. In addition to construction for the purpose of producing hydroelectric power, dams are created to control river flow and regulate flooding. In some rivers, small scale dams known as weirs are built to control and measure water flow.
Dams are a type of retaining structure, which are structures built to create large standing bodies of water known as reservoirs. These reservoirs can be used for irrigation, electrical generation, or water supply. These structures are built on top of riverbeds and hold back water, raising the water level. Dikes can be built along with the dam to increase the dams effectiveness by preventing water from leaving the reservoir through secondary routes.
Dams can range from relatively small to extremely large structures. The highest dam in the United states is located near Oroville, California and stands at 230 meters tall and 1.6 kilometers across. The largest dam in the world is the Jinping dam on the Yalong river in China, standing at 305 meters tall. In Canada, there are more than 10 000 dams, with 933 categorized as being large dams. The tallest dam in Canada is the Mica dam, on the Columbia river, standing at 243 meters tall. Another notable Canadian dam is the W.A.C Bennett dam on the Peace river, notable for its large reservoir volume of 7.4 x 109 cubic meters and height of 190.5 meters.
