Wind Power Generation - Renewable Energy: Technology, Economics and Environment - page 342

above ground. The smallest examined converter (converter of 1,500 kW, Table
7.2) thus results much more cost-effective than wind energy converters of lower
installed capacities; they have thus lost importance within the course of the last
decade.
Power generation costs are influenced by a multitude of parameters. To esti-
mate and assess their impact Fig. 7.26 shows variations of the main influencing
variables and related effects on resulting power generation costs. For this purpose
a site with 2,500 h/a and a 2.5 MW converter is analysed.

0.080

Interest rate
4.5 % = 100 %

0.075

Depreciation period
20 a = 100 %

0.070

Overall investment
2,599 k€ = 100 %

0.065

0.060

Yearly costs
151 k€/a = 100 %

0.055

Full load hours
2,500 h/a = 100 %

0.050

0.045

0.040

70 80 90 100 110 120 130

Fig. 7.26 Parameter variation of the main influencing variables on the power generation
costs

Parameter variation in %

Fig. 7.26 shows that the full-load hours - and thus the site-specific annual
mean wind speed - have the biggest impact on power generation costs. Due to the
increase in the mean wind speed at increased heights above ground there is a ten-
dency towards ever higher towers to allow for optimum exploitation of the avail-
able wind quantities at a potential site. Besides annual full-load hours, investment
costs represent the second deciding factor with regard to the specific power
generation costs. Operation costs, interest rate and amortisation period, by con-
trast, only have a slight impact on the power generation costs.

7.3.2 Environmental analysis

There are also environmental effects caused by wind energy converters. Such ef-
fects are discussed below with regard to manufacturing, normal operation, possi-
ble malfunctions and the end of operation.

Construction. Conventional industrial branches, such as classic mechanical and
electrical engineering, are involved in the manufacturing of wind energy con-
verters. Hence, wind energy converter manufacturing has the same environmental