What Is Hydropower?

Providing a substantial portion of the electricity generated worldwide, and with potential for more in the future, hydropower is a major component of meeting the globe's electrical demands. Furthermore, hydropower sources are renewable and create no greenhouse gas emissions, making them very desirable in meeting the requirements of the energy industry.

Identification

Hydropower refers to a broad group of machines that derive energy from harnessing the kinetic energy of moving water. It is most commonly identified with hydroelectric dams, but this is not the sole means of using hydropower.

Types

There are three broad categories of hydropower: waterwheels, hydroelectricity (including both dam and damless hydroelectric designs), and tidal and wave hydropower.

Features

A waterwheel works by capturing the kinetic energy of moving water, such as can be found in a river or waterfall, and converting it to mechanical energy. This is then used to power machines like mills or lathes through the use of gears. A similar concept is employed in hydroelectric power, where the mechanical energy runs an electrical generator by means of a turbine, producing electricity. Another similar process is tidal power, which harnesses the moving water of the tides to produce electricity. This has been done in France, Russia and Canada. Wave motion power is currently being experimented with.

Significance

The most important source of hydropower is hydroelectric, which produces 19 percent of the world's energy. Based on moving water, hydropower is a renewable source of energy that does not produce greenhouse emissions. It is also very convenient to use, as the dam can be easily stopped and started to meet peak demands for electricity.

Misconceptions

Hydroelectric dams are not completely environmentally friendly. While they do not pollute, the diversion of rivers and creation of reservoirs that comes with any dam does have the potential to inflict great harm on an area's environment. A famous example are species of fish like salmon that must swim up river to lay eggs for future generations of fish. Building a dam can disrupt their entire reproductive cycle. There are also social costs as well, since dam reservoirs often flood local riverfront communities behind, resulting in population displacement. The largest scale displacement of people from the erection of a dam was tied to China's Three Gorges Dam, the largest dam in the world.