Renewable energy sources-3
Activities
B. Read the text and answer the following questions.
Countries of the world rely heavily on petroleum, coal and natural gas for their energy sources. There are two major types of energy sources: renewable and non-renewable. Hydro-carbon or fossil fuels are non-renewable sources of energy. Reliance on them poses real big problems. First, fossil fuels such as oil, coal, gas etc, are finite energy resources and the world eventually will run out of them. Secondly, they will become too expensive in the coming decades and too damaging for the environment. Thirdly, fossil fuels have direct polluting impacts on earth's environment causing global warming. In contrast, renewable energy sources such as, wind and solar energy are constantly and naturally replenished and never run out.
Most renewable energy comes either directly or indirectly from the sun. Sunlight or solar energy can be used for heating and lighting homes, for generating electricity and for other commercial and industrial uses.
The sun's heat drives the wind and this wind energy can be captured with wind turbines to produce electricity. Then the wind and the sun's heat cause water to evaporate. When the water vapour turns into rain or snow and flows downhill into rivers or streams, its energy can be captured as hydroelectric energy.
Along with the rain and snow, sunlight causes plants to grow. Plants produce og biomass which again can be turned into fuels such as fire wood, alcohol, etc identified as bioenergy.
Scientists have identified Hydrogen as another form of renewable energy source. It is the most abundant element in nature. But it does not exist separately as a gas. It is always combined with other elements, such as with oxygen to make water. Hydrogen, separated from another element, can be burned as a fuel to produce electricity.
Our Earth's interior contains molten lava which gives off extreme heat. This heat inside the Earth produces steam and hot water which can be tapped as geothermal energy to produce electricity for heating homes, etc.
Ocean energy comes from several sources. Ocean's force of tide and wave can be used to produce energy. The surface of the ocean gets more heat from the sun than the ocean depths. This temperature difference can be used as energy source too. (Source: the Internet)
Questions
D. Read the dialogue between Raju, a student of class ten and his uncle, Mr Barua who works at Sangu Gas Field and answer the following questions.
Mr Barua : What are you reading, Raju?
Raju : English, Uncle. A chapter on renewable energy sources.
Mr Barua : I see. Do you know renewable energy is also called green energy?
Raju : Green energy?... No Uncle, I don't know. Nothing is there about green energy in the text either.
Mr Barua : Are you sure? Anyway, renewable energy sources provide us with energy which doesn't harm environment during its production or consumption. Say, solar energy. You see, there's no burning, no smoke, no emission of gases. It's a sort of clean technology and clean energy source.
Raju : Oh exactly. That's what our teacher said, I remember.
Mr Barua : On the other hand, burning fossil fuels, say oil or coal, emits greenhouse gases that harm the environment.
Raju : 0... I see. Yes, I've got the clue, Uncle. Thanks a lot. I now understand the relation between the two pictures in section A. Green energy sources make a green globe. Excellent!
Questions
F. Now write dialogues on hydroelectricity, ocean energy, geothermal energy, hydrogen energy, using the model in E above.
Solution file on processing
G. Both South and North Dhaka City Corporation are installing solar panels in place of conventional electricity connections to illuminate roads in many areas. Write a letter to the editor of a daily newspaper appreciating this initiative and saying why this should be followed by other city authorities too.
Solution file on processing
H. Complete the following table with the name of the renewable energy sources and how they are produced as mentioned in the passage. One is done for you.
| Name of energy source | Process of production |
|---|---|
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1. Solar energy |
1. From sunlight |
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2. Wind energy |
2. |
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3. |
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4. |
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5. |
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7. |
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