Environmental Engineering Reference
In-Depth Information
7
7
Solar Power Plants - Even More
Energy from the Sun
When we think of power plants, we usually imagine large central complexes with
cooling towers and enormous chimneys emitting clouds of smoke. In terms of the
concept itself, a power plant is merely a technical installation that converts a par-
ticular energy supply into electricity. A solar power plant produces electric energy
from solar radiation. We have already learned about one type of solar power plant
- photovoltaic power plants. In principle, a small photovoltaic system sited on a
family home already constitutes a solar power plant. Because many people envisage
a power plant as something much larger than a few square metres of solar modules,
this chapter is devoted to really large-scale systems that generate electricity from
sunlight.
Even photovoltaic systems can reach a size that easily competes with conventional
power plants. Year after year new photovoltaic power plants have been exceeding
records for size. Photovoltaic systems with 5 megawatts of power and module areas
of around 40 000 m
2
have already been installed on the roofs of industrial buildings.
However, existing roofs are usually not appropriate for higher output levels. If 50,
100 or even 1000 megawatts are to be installed in one location, this can only be
done with open space systems mounted directly in the ground. Large photovoltaic
power plants are technically very similar to the small systems on single-family
houses, except that they are larger in scale. Thus this chapter only deals with large-
scale solar power plants.
Concentrators can be used to increase the intensity of solar radiation. Photovoltaic
cells with very high effi ciency then convert the concentrated sunlight into elec-
tricity, as this chapter will explain. In addition to photovoltaics, other technologies
for generating power from sunlight also exist. Solar thermal power plants convert
solar radiation fi rst into heat and then into electric energy. A number of different
interesting and very promising technologies are available and are particularly
suitable for the very sunny regions on earth because they need direct sunlight,
