Energy Sources Flashcards
What are fossil fuels formed from?
The remains of dead plants and animals buried millions of years ago.
What are fossil fuels also called, and why so?
They are also called non-renewable energy sources, since they take a very long time to replenish.
Coal is (1) directly used as fuel. It is used mainly in (2) to (3). Today, about (4) of the world’s electricity supply still comes from (5).
1) usually
2) power stations
3) generate electricity
4) 40%
5) the burning of coal in power stations
Crude oil is (1) directly used as fuel. It is (2) to produce (3), such as (4).
1) seldom
2) produce several types of fuels
3) petrol, liquefied petroleum gas and diesel oil
Natural gas is (1) directly used as fuel. In some countries, natural gas is used for (2). In Hong Kong, natural gas is used mainly for (3).
1) usually
2) cooking and as fuel in cars
3) generating electricity and to produce town gas
The burning of fossil fuels in (1) releases many (2) such as (3), and also produces (4).
1) power stations, factories and vehicles
2) harmful substances
3) nitrogen oxides, sulphur dioxide, lead and carbon monoxide
4) a large amount of carbon dioxide
What are the three main problems of fossil fuels?
1) Air pollution, when harmful substances are released into the air. They can cause many health problems, like irritation of eyes and throat, dizziness and headaches, and respiratory diseases such as bronchitis and asthma when breathed in for a long time.
2) Global warming, which is caused by the increased amount of greenhouse gases such as carbon dioxide and nitrogen oxides. They trap heat in the atmosphere and the average temperature of the Earth then increases. This speeds up the melting of ice at the North and South Poles, leading to a rise of sea level and high risk of flooding for low-lying coastal areas.
3) Acid rain, which is formed by sulphur dioxide and nitrogen oxides dissolved in rainwater. When it falls into rivers and lakes, it makes the water acidic and this causes harm to fish and other aquatic life. Acid rain also damages trees, plants and buildings made of metals or stone.
