Photovoltaic Power Generation - Renewable Energy: Technology, Economics and Environment - page 292

Normal operation. During the operation of roof-mounted photovoltaic modules
no noise is created and no substances are released. Only the inverters currently
available on the market are characterised by a low noise development to be mini-
mised with special design measures. This allows a priori for very environmental-
friendly power generation. Furthermore, photovoltaic modules are very similar to
roofs in terms of absorption and reflection properties. Thus, no major impacts on
the locale climate have to be expected. Yet, modules mounted on slanting and flat
roofs are in some cases visible from long distances. This might impact the appear-
ance of cities and villages. But on the other side, such an installation does not
require any additional (scarce) space.
Ground mounted photovoltaic generators (i.e. photovoltaic power plants in-
stalled on e.g. former agricultural areas or on land used formerly for opencast
mining) partly or entirely inhibit the use of the ground for other purposes. How-
ever, only a very small part of the ground is lost for other purposes (i.e. only
around the foundations of the support frames of the solar modules). The major
remaining part can still be greened or extensively be used for cultivation (e.g.
sheep pasture). In comparison to intensive plant cultivation ecological conditions
may even be improved, for instance by biotope creation /6-38/, /6-39/.
Due to the relatively large covered surfaces and the highly divergent absorption
and reflection conditions when compared to the agricultural cropland impacts on
the microclimate are possible. Yet, these kinds of environmental effects are only
relevant in case of intensive photovoltaic utilisation, which is very unlikely due to
economic reasons.
The operation of photovoltaic generators is also related to the transmittance of
electromagnetic radiation (aspect of electromagnetic compatibility). Unlike com-
mon power generation plants, photovoltaic plants are generally provided with
extensive direct current cabling and with regard to the solar generator a corres-
pondingly large radiating surface; furthermore, they are partly installed in the
vicinity of residential area /6-40/. However, during the installation of such plants
it is generally ensured that the wiring loops, acting as antennas, are kept as small
as possible. This is a protective measure against both irradiance and receipt of
electromagnetic radiation. The latter is particularly critical with regard to lightning
strikes in the vicinity of solar modules and could create excess voltages and ex-
cess currents in case of a too large receipt area. The destroying of electric compo-
nents could be a result. However, the low-frequency magnetic fields emitted by
photovoltaic components are not higher than those of household appliances; emis-
sions are considerably lower than those of e.g. television sets. The efforts of
manufacturers in terms of module design will further reduce emissions, so that no
major impacts have to be expected.
Malfunction. To prevent hazards to humans and the environment due to opera-
tional malfunctions of photovoltaic generators, generator failures and inadmissible
fault currents must be reliably identified and signalized. The inverter and photo-
voltaic plant design must allow for power disconnection detection and auto