Photovoltaic Power Generation - Renewable Energy: Technology, Economics and Environment - page 291

progress beyond the current state of technology. Operating costs and interest rate
have, by contrast, only a minor impact on photovoltaic power generation costs.
Solely the depreciation period still has certain effect on the specific production
costs of photovoltaic power generation.
The indicated figures reveal that the power production costs within the sun
belts of the earth (e.g. Southern Europe, North Africa), due to a solar radiation
doubled compared to Middle Europe, can be reduced significantly. Under such
favourable conditions costs of electricity production with small-scale photovoltaic
systems are already below 0.30 €/kWh. For photovoltaic power plants the produc-
tion costs can even be at 0.25 €/kWh and below.
6.3.2 Environmental analysis
Photovoltaic electricity provision is characterised by noiseless operation without
any release of toxic substances or particles by the actual conversion plant. Never-
theless, the following environmental effects may occur.
Construction. Environmental effects related to the manufacture of photovoltaic
plants especially occur during the production of the solar cells. In recent years
they have been discussed primarily in the context of consumption of scarce min-
eral resources and toxicity.
Mono-crystalline and multi-crystalline as well as amorphous silicon solar cells
are generally characterised by a low consumption of scarce resources, whereas
cadmium telluride (CdTe) and CIS cell technologies show medium mineral re-
source consumption. The application of germanium (Ge) appears to be particu-
larly problematic for amorphous silicon cell production; the same applies to in-
dium (In) with regard to CIS cells and tellurium for CdTe cells. According to
current knowledge only limited quantities of these elements are available on earth
/6-37/.
In terms of toxicity only low environmental effects are expected for crystalline
silicon technologies. However, CdTe and CIS cell technologies are considered
more problematic due to their high content of cadmium (Cd), selenium (Se), tellu-
rium (Te) and copper (Cu). In addition, during manufacture of CIS modules gase-
ous toxic substances (e.g. hydrogen selenide (H 2 Se)) may be produced which are
generally associated with a certain environmental hazard potential.
On the whole, the environmental effects related to solar cell manufacture are
equivalent to those of the overall semiconductor industry. However, the described
environmental effects are relatively low due to the challenging legal environ-
mental protection regulations. This is also true due to the required material purity
during solar cell manufacture. On the other hand there might exist a manufacture-
related hazard potential in case of malfunction.