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.

MCQ: 39

Practice

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