Introduction and Structure - Renewable Energy: Technology, Economics and Environment - page 17

available wind or water supply). The achievable full load hours are thus depend-
ent on the energy availability of the respective site. Although such plants could
theoretically also be operated according to the given power demand within the
grid, they are for economic reasons optimised to such an extent so that they
maximise power generation. However, conventional power plants operated within
a conventional-renewable power plant system usually supply as much electrical
energy to cover the given demand according to their respective task within the
overall power plant system (provision of base, medium or peak load). Therefore,
the full load hours of conventional power plants are defined here on the basis of
the demand unlike systems based on renewables, where full load hours are deter-
mined by the availability of primary energy. Additionally, it has to be considered
that the energy provided by conversion plants based on renewable sources of en-
ergy, usually substitutes medium load.
To estimate the costs of power generation by fossil fuel energy, in the follow-
ing, variable and fixed costs as well as the specific power generation costs of the
reference plants outlined in Table 1.4 are discussed (Table 1.5).

Investments and operation costs. When compared to natural gas-fired gas and
steam turbine power plants, hard coal-fired power plants are characterised by con-
siderably higher investment and operation costs due to the higher expenditures for
e.g. coal preparation and flue-gas treatment (Table 1.5). The operation costs are
due to, for instance, personnel, maintenance, flue-gas cleaning, and disposal of
combustion residues (i.e. ashes) and insurance and, in particular, fuels. Due to the
specific lower fuel costs the assessed hard coal-fired power plant has lower ex-
penditures for fuels than the gas and steam turbine power plant.

T able 1.5 Costs of power generation from hard coal and natural gas (see Table 1.4)

Hard coal-fired
power plant

Natural gas-fired
power plant

Total investments in €/kW 1,100 500

Annual costs
Annual investments in Mio. €/a 40.5

22.3
52.0
114.8

20.2
8.8
111.7
140.8

Operation costs in Mio. €/a

Fuel costs in Mio. €/a

Total in Mio. €/a

Electricity generation costs in €/kWh 0.038 0.047

Electricity generation costs. According to the discussed boundary conditions,
power production costs at the power plant (Table 1.5) are calculated on the basis
of the indicated assumption (Table 1.4) and the assumed economic boundary con-
ditions (i.e. interest rate of 4.5 % assumed throughout the physical life of 30 or 25
years respectively).