304 Energy andtransport for thefuture
Figure 11.14A simple ’solar home system’ now being marketed in many
countries in Africa, Asia and South America for a cost of a few hundred US$. An
array of thirty-six solar cells, covering an area of 60 cm×60 cm, provides
around 40 W of peak power. This is sufficient to charge a car battery that can
power up to three 9-W fluorescent lights and three hours of radio and one hour
of television per day. With more restricted use of these devices or with a larger
solar array, a small refrigerator can be added to the system.20 000 water pumps are now powered by solar PV and thousands
of communities receive drinking water from solar-PV-powered puri-
fiers/pumps. The potential for further growth and development of so-
lar systems is clearly very large. For instance, mini-electrical grids
powered by a combination of solar PV, wind, biomass and diesel are
beginning to emerge especially in the remoter parts of China and
India.^55
The total installed world capacity of PV grew from about 500 MW
peak in 1998 to about 1500 MW peak in 2002, an increase of about
thirty per cent per year. With that rate of continued growth it should be
possible to more than meet the projected contribution by PV solar cells
to world energy supply in WEC scenario C of at least 150 GW^56 by
the year 2020 (Table 11.5). In the short term, increased development of
local installations is likely to have priority; later, with the expectation of
a significant cost reduction (Figure 11.13), penetration into large-scale
electricity generation will become more possible. Eventually, because of
its simplicity, convenienceand cleanliness, it is expected that electricity
from solar PV sources will become one of the largest – if not the largest –
of the world’s energy sources.