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Electrical Engineering and Technology |Электротехника и электротехнологии

LESSON 3

Read the text:                    INDIRECT USE OF SOLAR ENERGY

The above examples illustrate the direct harnessing of the sun's radiant energy to produce heat and electricity. But the sun's energy can also be harnessed via other forms of energy that are indirect manifestations of its power. Principally, these are bioenergy and hydropower, already discussed  above, together with wind energy and wave power.

Wind energy

When solar radiation enters the earth's atmosphere, because of the curvature of the earth it warms different regions of the atmosphere to differing extents – most at the equator and least at the poles. Since air tends to flow from warmer to cooler regions, this causes what we call winds, and it is these air flows that are harnessed in windmills and wind turbines to produce power.

Wind power, in the form of traditional windmills used for grinding corn or pumping water, has been in use for centuries. But in the second half of the twentieth century, and particularly in the past few decades, the use of modern wind turbines for electricity generation has been growing very rapidly. Installed wind generating capacity has doubled every two and a half years since 1991, and at the end of 2001 the world total was over 23,000 MW. (Windpower Monthly, 2002) Denmark derives more than 15% of its electricity from wind, and in other countries such as Germany, Spain and the United States of America turbines have in recent years been installed at a rate of more than a thousand megawatts per year.

At present, most of these turbines have been installed on land. But several countries have ambitious plans to install thousands of wind turbines offshore. Denmark, for example, has three offshore wind farms and plans many more, as part of its aim of deriving 30 per cent of its electricity from wind by 2020 – though these plans are subject to future political approval.

The UK, too, has ambitious offshore wind power proposals. Britain's first two offshore wind turbines were installed off Blyth harbour in Northumberland in 2000, and sites have been identified for 13 offshore wind farms that could be built in the coming decade. These would have a total installed capacity of 1600 MW.

 

1. Match the left part with the right:

 

1. Indirect manifestations of sun’s power are

a) installed on land.

2. Air-flows from cooler to warmer regions are

b)bioenergy, hydropower, wind energy and wave power

3. Most of wind turbines have been

c) growing very rapidly.

4. The use of wind turbines for electricity generation has been

d)harnessed by windmills and wind turbines to produce power.

 

2. Complete the sentences with the suggested words:

been   has   of   use

 

Wind power, in the form (1)_____ traditional windmills used for grinding corn or pumping water, has (2)_____ in use for centuries. But in the second half of the twentieth century, and particularly in the past few decades, the (3)_____ of modern wind turbines for electricity generation (4)_____ been growing very rapidly.