Global Warming

Energy from theSun 299

Wind power on Fair Isle

A good example^46 of a site where wind power has been put to good ef-

fect is Fair Isle, an isolated island in the North Sea north of the Scottish

mainland. Until recently, the population of seventy depended on coal

and oil for heat, petrol for vehicles and diesel for electricity generation.

A 50-kW wind generator was installed in 1982 to generate electricity

from the persistent strong winds of average speed over 8 ms−^1 (29 kmh−^1

or 18 mph). The electricity is available for a wide variety of purposes;

at a relatively high price for lightingand electronic devices and ata

lower price controlled amounts are available (wind permitting) for com-

fort heat and water heating. At the frequent periods of excessive wind

further heat is available for heating glasshouses and a small swimming

pool. Electronic control coupled with rapid switching enables loads to

be matched to the available supply. An electric vehicle has been charged

from the system to illustrate a further use for the energy.

With the installation of the wind generator, which now supplies over

ninety per cent of the island’s electricity, electricity consumption has

risen about fourfold and the average electricity costs have fallen from

13 pkWh−^1 to 4 pkWh−^1. A second wind turbine of 100 kW capacity

was installed in 1996/7 to meet increasing demand and to improve wind

capture.

has to be provided as well. The installation on Fair Isle (see box) is a
good example of an efficient and versatile system. Small wind turbines
also provide an ideal means for charging batteries in isolated locations;
for instance, about 100 000 are in use by Mongolian herdsmen. Wind
energy is often also an ideal source for water pumps – one million small
wind turbines are used for this purpose worldwide.^47
In the longer term it can be envisaged that wind generation could
expand into areas remote from direct electricalconnection providing an
effective means for energy storage (for instance, using hydrogen; more
of that possibility later in the chapter) is developed.

Energy from the Sun

The simplest way of making use of energy from the Sun is to turn it into
heat. A black surface directly facing full sunlight can absorb about 1 kW
for each square metre of surface. In countries with a high incidence of
sunshine it is an effective and cheap means of providing domestic hot
water, which is extensively employed in countries such as Australia,
Israel, Japan and the southern states of the USA (see box above).