Environmental Engineering Reference
In-Depth Information
According to this assumption, the coal-fired power plant shows power genera-
tion costs of approximately 0.038 €/kWh. Power generation by natural gas is com-
paratively more expensive. Power production costs amount to 0.047 €/kWh (Ta-
ble 1.5). For power generation by natural gas, the applied fuel accounts for the
major share of the annual costs, whereas for hard coal-fired power plants costs are
distributed relatively evenly among investments, fuels and further operation.
Environmental analysis. Besides the airborne emissions of harmful substances,
like SO 2 and NO x as well as greenhouse gas and dust emissions, additional pollut-
ants (such as heavy metals) are released during ordinary operation of the assessed
power plants. In addition, the provision of fossil fuels is associated with a series
of further environmental effects. In the following, some of these environmental
effects are discussed exemplarily.
For a long time, coal-fired power plants have been a considerable source of an-
thropogenic dust and SO 2 emissions in Europe. Only after more strict legal
emission regulations had been introduced, requiring the installation of exten-
sive flue-gas cleaning systems, these emissions have been considerably re-
duced.
Above ground mining of lignite greatly affects the scenery due to its space-
consuming measures and the transfer of large material quantities. However,
these effects can be partly compensated by re-cultivation measures once the
available lignite is extracted from the ground; in some cases, the establishment
of lakes can even enhance the recreational value of a particular site. Hard coal
underground mining may cause downfalls of the created hollow spaces and
thus lower the earth's surface. Due to this fact, the ground water layer may be
disturbed, buildings located on the surface may show fissures, small streams
may be diverted, and thus the use of the affected areas may be significantly
limited.
The residues remaining after coal combustion (i.e. ashes or dusts) may contain
heavy metals and radioactive elements. Depending on the coal composition,
especially the particulate matter, partly released with the flue gas into the at-
mosphere, may be charged with these harmful substances. Such contaminated
dusts must therefore be safely removed from the flue gas and securely evacu-
ated.
During the exploitation of natural gas reservoirs the ground (onshore) or the
ocean (offshore) may be polluted, for instance, due to chemical auxiliary and
operating materials (e.g. drilling fluid) released during drilling of wells and/or
production of gas.
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