Solar energy represents our largest source of renewable energy supply. Effective solar irradiance reaching the earth’s surface ranges from about 0.06 kW/m2 at the highest latitudes to 0.25 kW/m2 at low latitudes. Fig. 1 compares the technically feasible potential of different renewable energy options using the present conver-
sion efficiencies of available technologies. Even when evaluated on a regional basis, the technical potential of solar energy in most regions of the world is many times greater than current total pri-
mary energy consumption in those regions [18].
Table 1 presents regional distribution of annual solar energy
potential along with total primary energy demand and total elec-
tricity demand in year 2007. As illustrated in the table, solar energy
supply is significantly greater than demand at the regional as well
as global level.
Kurokawa et al. [9] estimate that PV cells installed on 4% of the
surface area of the world’s deserts would produce enough elec-
tricity to meet the world’s current energy consumption. Similarly,
EPIA [8] estimates that just 0.71% of the European land mass, cov-
ered with current PV modules, will meet the continent’s entire
electricity consumption. In many regions of the world 1 km2 of land