Environmental Engineering Reference
In-Depth Information
Even though solar PV still represents just a tiny portion of the energy mix (0.04 per
cent), far lower than hydroelectricity or even wind power, solar panels have become an
emblem of the transition to renewable energy. Perhaps the reason for this is their visibility.
There is every chance that suburban commuters will pass several roof-mounted solar plants
on their way to work, but it is less likely that they will see wind turbines or nuclear cooling
towers. Roofs are the ideal surface for solar PV for three reasons. First of all, by definition
the roof is the highest point of a building and therefore receives unobstructed sunlight.
Second, many roofs are already inclined, allowing maximum exposure to sunlight. Third,
roof mounting involves the least environmental impact because it does not usurp space
from other uses. On the ground greater compromises have to be made, since solar panels
require a lot of space per unit of energy generated (see
Table 4.4
).
Table 4.4.
Solar electricity that can be generated in various locations
City
Country
Solar
radiation
kWh/m
2
/year
Usable
energy
kWh/m
2
/year
Area of PV
panels
m
2
New York United
States
1,664
162
31
Buenos
Aires
Argentina 1,840
174
29
Beijing
China
1,778
172
29
Nairobi
Kenya
1,840
174
29
New Delhi India
2,197
197
25
Stockholm Sweden
1,088
103
48
Cairo
Egypt
2,066
191
26
Aswan
Egypt
2,489
227
22
