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Exercises
Energy in the
Future
by Terry Bell
Great sources of energy are needed if governments want to develop
industry and make life more comfortable. However, fuels which are used to produce
energy at the moment will soon run out. It seems certain that people will have
to depend on nuclear power as the source of energy. But a lot of people do not
want this form of energy; they think it is dangerous and so would like some
other source of power. Many suggestions have been made; some of them are not
very practical but others could be used successfully.
People who are against nuclear
power would rather use the forces of nature, for example the wind, the sea,
the rivers and the sun. It is strange to think that these sources of energy
were used long ago for windmills or for watermills but then were almost forgotten.
Hydro-electricity is probably the most used form of energy supplied by nature.
Yet only a small part of the water energy which could be used is indeed used.
In countries such as Britain, America, Canada and Russia, there are great possibilities
for developing hydro-electricity but only a small number of generators have
been built.
Hydro-electricity cannot be developed in certain countries, however, because
mountains or hills are needed to give the necessary force to the water as it
falls. More than three-quarters of the earth is covered by the sea, which is
always moving. The movement of the water depends on the moon which pulls at
the earth. The sea moves first in one direction and then back again; this movement
backwards and forwards is called the "tide". In some parts of the
world the tide is very strong and water moves very quickly. It is possible to
produce electricity by using the forces of tides to turn the blades of a turbine.
This source of power is called "tidal energy". It is surprising to
find that only one country in the world produces energy in this way: France.
The sea can provide energy in other ways. The movement of waves is quite different
from the movement of tides. Waves are caused by winds and storms. Each wave
moves across the surface of the ocean with an up and down motion. Think of the
sea on a stormy day. You can see the energy of the waves.
One way of using the movement of waves as source of energy is to build a Cockerell
raft. This is actually a series of rafts. They move up and down on the waves.
This movement is made into pressure, which is used to produce electricity. There
are several other ways of using wave power. But they are still in the early
stages. There are no
commercial schemes yet.
Another way we can get energy from the sea is to use the power from under the
oceans. Sunshine and its energy is absorbed by the oceans, and stored in them.
Scientists are now looking for ways to use this energy.
One possibility is to use the difference in temperature between the warm surface
of the sea and the colder layers of water underneath. This can be used to generate
electricity. Underwater cables then can carry the electricity to the land.
Power plants like this are called Ocean Thermal Electric Conversion plants (OTEC).
The best seas for this sort of
energy are the Caribbean and the Pacific. There, the temperature difference
between the surface of the water and the colder layers can be as much as 4.4°C.
Another natural source of energy is wind power. Wind is produced by the heating
and cooling of the earth; some countries have more wind than others because
of great changes in the heat. Britain is a good example of a country with strong
winds for many months of the year. Some parts of Britain are especially windy
and in these places energy from the wind could be generated most easily. In
the north of Scotland, for example, plans were made to build a large number
of windmills. Each windmill would be 24 metres high with three blades, each
7 metres long. With enough windmills it would be possible to generate power
for the whole of Scotland. However, the number of windmills which would have
to be built and the high cost of the plan means that this is not very practical.
Probably a cheaper source, such as nuclear energy, will be used. But wind power
has not been forgotten completely. Work is going on in France, the USA and Russia
to try to develop a low-cost windmill.
In some parts of the world, large amounts of hot water and steam come out of
the ground at great speed. This is because there are lakes of water deep down
inside the earth. It is very hot indeed deep down in the earth and so the water
is heated; steam is produced which forces its way to the earth's surface. The
hot water and steam which shoot into the air are called geysers and can be found
in America, New Zealand and Iceland. In New Zealand and Iceland the energy produced
by the steam is used for power stations. Geothermal energy, as it is called,
is a cheap source of energy. After the power stations have been built there
are no further costs for the electricity supply.
Only
a few countries have geysers but it is also possible to produce energy of this
sort by drilling holes deep into the ground and pouring water down the pipes
so that it becomes so hot as to produce steam.
The sun is the most powerful source of energy known on the earth. More energy
is produced by the sun than the world could ever use. If the energy from the
sun could be caught and used to make electricity, then the energy crisis would
disappear and there would be a cheap, never-ending source of energy without
any danger to human life. During the last few years, solar energy has been used
to heat water and make steam to drive a turbine for electricity. This is done
by using mirrors to make the sunlight very strong. This system works very well
in some countries with a lot of sunshine. In Europe, where the sun is not always
very strong, the cost of making electricity from solar energy is not practical
for the amount of electricity produced. But it is possible to heat enough water
for a family to use each day for washing, by building metal plates into the
roof of the house. Even the sunlight in Britain is strong enough to heat water
in pipes behind the metal plates. This warm water then flows from the water
taps in the house. In this way other forms of fuel can be saved. During the
next few years a lot of new designs for solar energy will be invented and introduced
into people's homes.
This form of solar energy and a fuller development of wind energy together with
more hydro-electric power are ways in which the fuel problems could be solved.
At the moment, however, most countries seem happy to develop plans for nuclear
power stations. But one question which some people are asking is this: is it
right to continue living as people do now, developing industry, wasting fuels
and building everything bigger and more powerful than before, without thinking
of the possible dangers? Or is it better to change ideas about industrial progress?
At the moment people waste very much of what they have or of what they produce.
They waste their fuel supplies by burning up energy carelessly; they waste materials
which are produced and throw them away; they buy more products which are then
also thrown away. However, a few scientists in Britain have decided to save
energy by doing something about all these waste products. They have found a
way to make good oil from waste products, especially from waste plastic. At
the moment they are still testing the oil but there is hope that the new oil
will be suitable for driving engines and for heating.
( 1,380 words )
(From Energy,by Terry Bell, Cassell Ltd.)
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