[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:06.69,0:00:21.24,Default,,0000,0000,0000,,♪ [Soothing music] ♪
Dialogue: 0,0:00:21.29,0:00:24.67,Default,,0000,0000,0000,,The use of water\Nto produce electrical energy
Dialogue: 0,0:00:24.73,0:00:26.45,Default,,0000,0000,0000,,is an extraordinary invention
Dialogue: 0,0:00:26.45,0:00:28.80,Default,,0000,0000,0000,,made possible by\Ngravity power plants.
Dialogue: 0,0:00:29.91,0:00:32.25,Default,,0000,0000,0000,,A hydroelectric plant\Non the water
Dialogue: 0,0:00:32.25,0:00:36.14,Default,,0000,0000,0000,,produces renewable energy\Nfrom a river current.
Dialogue: 0,0:00:37.52,0:00:40.47,Default,,0000,0000,0000,,The hydroelectric plant\Nincludes a dam,
Dialogue: 0,0:00:40.62,0:00:45.38,Default,,0000,0000,0000,,which allows water to accumulate\Ninto a quasi-reservoir.
Dialogue: 0,0:00:45.40,0:00:51.12,Default,,0000,0000,0000,,♪ [Soothing music] ♪
Dialogue: 0,0:00:51.18,0:00:54.52,Default,,0000,0000,0000,,The more the distance between\Nretained and open water is raised,
Dialogue: 0,0:00:54.79,0:00:57.81,Default,,0000,0000,0000,,the greater the potential energy.
Dialogue: 0,0:00:58.84,0:01:01.31,Default,,0000,0000,0000,,Retained water flows through\Nunderground pipes,
Dialogue: 0,0:01:01.39,0:01:03.83,Default,,0000,0000,0000,,to be deposited on\Nthe other side of the dam.
Dialogue: 0,0:01:07.21,0:01:08.28,Default,,0000,0000,0000,,A turbine,
Dialogue: 0,0:01:08.28,0:01:12.43,Default,,0000,0000,0000,,for instance a Kaplan turbine,\Nis integrated into the pipeline.
Dialogue: 0,0:01:13.88,0:01:17.86,Default,,0000,0000,0000,,It is fitted with a propeller wheel,\Nsimilar to a ship's propeller.
Dialogue: 0,0:01:21.16,0:01:23.57,Default,,0000,0000,0000,,The steering wheel has\Norientating blades,
Dialogue: 0,0:01:23.57,0:01:26.78,Default,,0000,0000,0000,,which direct the water flow\Ntowards the moving wheel blades,
Dialogue: 0,0:01:26.78,0:01:28.07,Default,,0000,0000,0000,,in an effective manner.
Dialogue: 0,0:01:29.35,0:01:33.13,Default,,0000,0000,0000,,The electric motor \Nchanges the blades' direction.
Dialogue: 0,0:01:34.40,0:01:35.78,Default,,0000,0000,0000,,Once set in motion,
Dialogue: 0,0:01:35.78,0:01:39.76,Default,,0000,0000,0000,,the turbine drives an electric\Ngenerator, which produces electricity.
Dialogue: 0,0:01:43.62,0:01:46.09,Default,,0000,0000,0000,,The change of the blades'\Ndirection
Dialogue: 0,0:01:46.09,0:01:48.45,Default,,0000,0000,0000,,strives to achieve\Na high degree of efficiency,
Dialogue: 0,0:01:48.45,0:01:52.60,Default,,0000,0000,0000,,avoiding the inconvenience\Nof fluctuating river water levels.
Dialogue: 0,0:01:54.95,0:01:57.29,Default,,0000,0000,0000,,The spiral cover accelerates\Nthe water...
Dialogue: 0,0:01:57.63,0:02:01.77,Default,,0000,0000,0000,,then, the steering wheel blades\Ndirect it toward the moving blades.
Dialogue: 0,0:02:02.05,0:02:05.54,Default,,0000,0000,0000,,As the water hits the blades,\Nthe moving wheel drives the generator
Dialogue: 0,0:02:05.54,0:02:08.53,Default,,0000,0000,0000,,which transforms mechanical energy\Ninto electrical energy.
Dialogue: 0,0:02:09.60,0:02:12.88,Default,,0000,0000,0000,,Here are the components of\Na hydroelectric power plant
Dialogue: 0,0:02:12.88,0:02:14.74,Default,,0000,0000,0000,,to better explain\Nthe operation.
Dialogue: 0,0:02:14.98,0:02:18.65,Default,,0000,0000,0000,,Several installations, and the generator,\Nare in the machine building.
Dialogue: 0,0:02:19.13,0:02:20.80,Default,,0000,0000,0000,,With some exceptions,
Dialogue: 0,0:02:20.80,0:02:23.58,Default,,0000,0000,0000,,a transformer raises the voltage\Nof the current produced,
Dialogue: 0,0:02:23.59,0:02:27.57,Default,,0000,0000,0000,,so it can be transported easier\Nthrough high voltage lines.
Dialogue: 0,0:02:29.98,0:02:34.44,Default,,0000,0000,0000,,In 1913, engineer Victor Kaplan\Ninvented the Kaplan turbine
Dialogue: 0,0:02:34.44,0:02:37.37,Default,,0000,0000,0000,,which perfected the concept\Nof the Francis turbine.
Dialogue: 0,0:02:39.15,0:02:43.95,Default,,0000,0000,0000,,The efficiency of a Kaplan turbine\Nvaries generally between 90 and 95 %.
Dialogue: 0,0:02:44.62,0:02:48.51,Default,,0000,0000,0000,,The cavitation phenomenon has been\Na major problem, persisting to this day.
Dialogue: 0,0:02:48.70,0:02:52.42,Default,,0000,0000,0000,,However, today there are several solutions\Nagainst cavitation,
Dialogue: 0,0:02:52.54,0:02:54.78,Default,,0000,0000,0000,,to protect the blades\Nof the Kaplan turbines.