TPE : L'Hydroélectricité

Dialogue de la saynète en anglais, TPE :

Mickaël:
For our series about renewable energies, we’ll deal, today, with hydroelectric energy, and especially, the amazing Chinese project of Three Gorges dam. It was launched in 1993 and should be completed in 2009. This work aroused violent and conflicting reactions throughout the world.
Asking questions to Mr Bertrand who is a scientific pressman specialized in renewable energies, we’ll try to understand the interests at stake for such a project.

Enzo:
Hello, Mr Bertrand.

Adrien:
Hello, Mr Calleri.

Mickaël:
You closely followed the building of the Three Gorges dam on the Yangtze River in China. Could you explain to us the use of an hydroelectric dam ?

Adrien:
A dam uses water’s potential energy to produce electricity. It’s a renewable energy such as the sun, the wind and geo-thermal heat. But the most important is that it does not emit greenhouse gases.

Enzo:
Tell us how a dam works.

Adrien:
A dam is a thick wall across a river. It controls the water-flow and creates a reservoir.
The power-plant uses the water-flow to activate the turbine-driven generators which produce electricity.

Mickaël:
The Three Gorges dam, in the Chinese province of Hubei, is the largest dam in the world: 2.3 km wide and 175 meters high. The 26 turbo-generators will produce 1800 MW of electricity. What pushed China to launch such a tremendous project?

Adrien:
China needs more and more energy for its development and the question is to avoid additional electric production from coal. As you know, when burning, coal emits carbon dioxide and other greenhouse gases that are responsible for global warming and damaging to the environment.

Enzo:
Do you mean that, in China, coal power-plants could be completely replaced by this dam?

Adrien:
No. This dam will never replace the use of coal. But one of the greater purposes of this dam is to reduce air pollution. The hydro-powered generators will produce 10% of the Chinese electric consumption saving 50 MT of coal per year.
In addition, the navigation of big cargo boats will be easier. That will contribute to the limitation of carbon dioxide emission by trucks.

Mickaël:
If this dam is so beneficial, why did so many people raise a strong protest against its building?

Adrien:
Of course, this dam has various harmful effects. For example, owing to the creation of the reservoir, thousands of homes have been flooded and more than a million people will have to be relocated.

Enzo:
The consequences are huge ! We can expect the flood of 19 cities, 140 small towns and about 400 villages. A large part of the fertile land and historical heritage will disappear too.

Adrien:
It’s true. But every year, the Yangtze River has some devastating and sometimes murderous floods. These floods are also an ecological disaster. The dam will enable them to control the floods, to irrigate the crops, and to supply water to the North provinces of China.

Mickaël:
Some people fear an important pollution of the reservoir water due to its stagnancy. Is this fear justified ?

Adrien:
Yes but, the Yangtze River has been polluted for many years. For example, the town of Chongqing, situated above the reservoir, dumps a huge quantity of hydrocarbons and quick-silver. But the Chinese government has taken anti-pollution measures such as the building of water-treatment facilities.

Enzo:
One of the main problems brought about by the dam is the attack on bio-diversity. Many animal and vegetable species could disappear.

Adrien:
Indeed, the disappearance of several fish, animal and medicinal herbs species owing to the dam is a cause of concern. We can think of the currently endangered Baiji dolphin. Moreover, the slowing down of the water-flow will induce a decrease of food supplies which will affect the whole food chain.

Mickaël:
Is the Chinese government taking measures to fight this problem ?

Adrien:
Yes. A natural reserve should be created in the Three Gorges area where the bio-diversity is very rich and vast stretches of the reservoir, which is 700 km long, will be used as an aquaculture farm for the production of shrimps and fish.

Enzo:
So, the Chinese government seems anxious to limit the environment destructions due to the dam ?

Adrien:
Of course, and remember that the most part of the Chinese people are very proud of the dam because the advantages are higher than the drawbacks. It will prevent the devastating floods and will also produce a green energy contributing to the decrease of the greenhouse effect worldwide.

Mickaël:
Do you think that in the world hydroelectricity will be able to substitute oil, coal and gas for the production of electricity ?

Adrien:
Hydroelectricity can’t replace the fossil energy alone because dams need a suitable location. In Europe, 90% of the suitable sites are already used. However, vast areas are still available in Asia, Africa and South America. And we shouldn’t forget "small" hydroelectricity that produces a power less than 10 MW. It has a lower impact on the environment than that of a big dam.

Enzo:
So, hydroelectricity has a great future in the years to come ?

Adrien:
Certainly and it’s a chance for the planet.

Mickaël:
Well, thank you, Mr Bertrand, for all your information about hydroelectricity and especially about the Three Gorges dam.
Our audience can now understand the pros and the cons of such a great project.