«Much of our energy supply comes from coal, oil, natural gas, or radioactive elements. They are considered non-renewable because once they are removed from the ground and used, they are not immediately replaced. Renewable energy is usually available in a never-ending supply. Renewable energy comes from the natural flow of sunlight, wind, or water around the Earth. With the help of special collectors, we can capture some of this energy and put it to use in our homes and businesses. As long as sunlight, water and wind continue to flow and trees and other plants continue to grow, we have access to a ready of supply of energy. When fossil fuels are burned, they release carbon dioxide. This gas acts like an invisible blanket, trapping more of the sun's energy in the atmosphere, causing the Earth to warm up little by little. Carbon dioxide is building up in the atmosphere as more and more fossil fuels are used in homes, factories, and automobiles. If this continues, most scientists think our planet is likely to become significantly warmer, which could cause many serious problems around the world.»
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QUESTIONS
1/ Translate the words and the following sentence:
- Coal, supply of energy, blanket, trapping
- “Renewable energy is usually available in a never-ending supply”
2/What are renewable energies?
3/Give examples of renewable energies and, for the main ones, explain how they can help produce electricity.
4/ What is the percentage of renewable energies in the world?
5/ In your opinion, will the share of renewable energies increase in the future? Are there barriers to their development?
1/ Translate the words and following sentence:
- Coal, supply of energy, blanket, trapping
- “Renewable energy is usually available in a never-ending supply”
Coal = charbon, blanket = couverture
2/What are renewable energies?
A renewable energy is an energy coming from a source that will not run out (they are continually replaced).Renewable energies come from natural resources.
3/Give examples of renewable energies and, for the main ones, explain how they can help produce electricity.
As renewable energies, we can mention:
- Sunlight (solar energy): Photovoltaic plants or farms. Solar radiation can be used to heat water or it can directly convert solar radiations into electricity (using solar cells). The photovoltaic effectis when photons of light knock electrons into a higher state of energy to create electricity.
- Wind: Airflows are used to run wind turbines. Notice that the power output of a turbine depends on the square cube of the wind speed, so as wind speed increases, power output increases dramatically. Modern wind turbines can produce around 2 or 3 MW.
- Rain: Hydroelectric plants. Production of electrical power through the use of the gravitational force of falling or flowing water (a stream of water is used to drive a turbine). The production of hydroelectric plants is highly variable: from a few kW (small hydroelectric power plants) or MW to 22500MW ( like the three Gorges Dam, in China).
- Tide/Marine current power (ocean energy)
- Geothermal heat…
4/ What is the poercentage of renewable energies in the world?
In the world, renewable energies represent about 18% of the total energy used.Notice that all the renewable energies are not used to generate electrical power (for instance, sun light can heat water directly).
5/ In your opinion, will the share of renewable energies increase in the future? Are there barriers to their development?
For our planet, the share of renewable energies must increase, that’s sure. However, the world’s population is increasing drastically, and we need more and more energy, and not only when the sun is shining, the wind is blowing, the rain is falling… That’s why non-renewable energies have also, in my opinion, abright future ahead of themselves.