GC: n

CT: Hydropower is considered a renewable energy resource because it uses the Earth’s water cycle to generate electricity. Water evaporates from the Earth’s surface, forms clouds, precipitates back to earth, and flows toward the ocean.
The movement of water as it flows downstream creates kinetic energy that can be converted into electricity. A hydroelectric power plant converts this energy into electricity by forcing water, often held at a dam, through a hydraulic turbine that is connected to a generator. The water exits the turbine and is returned to a stream or riverbed below the dam.
Hydropower is mostly dependent upon precipitation and elevation changes; high precipitation levels and large elevation changes are necessary to generate significant quantities of electricity. Therefore, an area such as the mountainous Pacific Northwest has more productive hydropower plants than an area such as the Gulf Coast, which might have large amounts of precipitation but is comparatively flat.

S: EPA – http://www.epa.gov/cleanenergy/energy-and-you/affect/hydro.html (last access: 12 December 2014)

N: 1. hydraulic (adj): c.1600, from Greek hydraulikos organon “water organ,” from hydr-, stem of hydor “water” + aulos “musical instrument, hollow tube”. Extended by the Romans to other kinds of water engines.
turbine (n): 1838, from French turbine (19c.), from Latin turbinem (nominative turbo) “spinning top, eddy, whirlwind, that which whirls,” related to turba “turmoil, crowd” (see turbid). Originally applied to a wheel spinning on a vertical axis driven by falling water. Turbo in reference to gas turbine engines is attested from 1904.
2. A hydraulic turbine is a prime mover (a machine which uses the raw energy of a substance and converts it into mechanical energy) that uses the energy of flowing water and converts it into mechanical energy (in the form of rotation of the runner). This mechanical energy is used in running an electric generator which is directly coupled to the shaft of the hydraulic turbine; from this electric generator, we obtain electric power which can be transmitted over long distances by means of transmission lines and transmission towers. The hydraulic turbines are also known as ‘water turbines’ since the fluid medium used in them is water.

S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=hydraulic&searchmode=none (last access: 12 December 2014)
http://www.etymonline.com/index.php?allowed_in_frame=0&search=turbine&searchmode=none (last access: 12 December 2014)
2. https://docs.google.com/document/d/1zsY70sFOExMnjSOcM0gMqUDi8AiSW7IFzuGXWIWiWEU/edit (last access: 12 December 2014)

SYN: water turbine

S: USED – http://energy.gov/eere/water/history-hydropower (last access: 12th December 2014)

CR: cavitation, dam, hydroelectric power, hydroelectric power plant, water hammer, [water power].