English script :
0:02 Hydropower, or hydroelectricity refers to the conversion of energy from flowing water into electricity. 0:09
0:10 It is considered a renewable energy source because the water cycle is constantly renewed by the sun. 0:15
0:15 One of the first uses of hydro-energy was for mechanical milling, such as grinding grains. 0:20
0:20 But today, modern hydro plants produce electricity using turbines and generators. 0:25
0:26 The mechanical energy created by moving water spins rotors on a turbine. 0:30
PartieA : 83 mots
0:31 This turbine is connected to an electromagnetic generator which produces electricity when the turbine spins. 0:36
0:37 There are two main types of hydroelectricity production. : dams and run of river. 0:42
0:43 Hydro dams utilize the potential energy from damned water to produce electricity. 0:48
0:49 A dam is a large barrier constructed to raise the level of water and control its flow. 0:53
0:54 The elevation created by the dam creates gravitational force for turning the turbine when water is released. 0:59
PartieB : 79 mots
1:00 Some dams also contain an additional reservoir at their base where water is stored to be pumped to the higher reservoir for release when electricity is in demand. 1:09
1:10 This is referred to aspumped storage hydro. 1:12
1:12 The second form of hydroelectricity production is run of river hydro. 1:16
1:16 Run of river still uses turbines and generators but relies on natural water flow rates of rivers, diverting just a portion of the water through turbines. 1:25
1:26 Because run of river hydro is subject to natural water variability, it is more intermittent than dammed hydro. 1:32
1:32 There are various sizes of hydro plants that produce electricity. 1:36
1:36 Large hydro, greater than 30 megawatts, small hydro, 100 kilowatts to 30 megawatts. 1:43
1:43 And micro hydro, less than 100 kilowatts. 1:46
1:46 The Hoover Dam in the United States is a whopping 2074 megawatts, which is enough to serve 1.3 million people. 1:54
PartieC : 82 mots
1:54 Of all renewable energy sources, hydropower holdsthe largestshare of worldwide electricity production. 2:00
Hydropower has several benefits. It is thecost competitive form of electricity. Even though the initial building cost can be high. 2:08
2:09 It is quitereliable compared to other renewable options and pairs well with other sources as it can be used as base load power. 2:16
2:16 In some cases, dammed reservoirs can also help with floodcontrol and be a reliable water supply for communities. 2:22
2:22 There are also some concerns with hydropower, especially when it comes to large dams. 2:27
PartieD : 81 mots
2:28 Damming a river has a major impact on the local environment, changing wildlife habitats, blocking fish passage and often forcing people in riverside communities to move out of their homes. 2:37
2:38 In addition, dam failures can be catastrophic claiming the lives of those living downstream. 2:44
2:44 Hydro plants are also not completely free of greenhouse gas emissions. 2:48
2:48 As with most form of energy carbon dioxide emissions happen during construction, particularly due to the large quantity of cement used. 2:56
2:56 And plant matter in the flooded areas makes methane another greenhouse gas, as it decays underwater. 3:02 That’s hydropower. 3:04