Civil Engineering Reference
In-Depth Information
TABLE 15-2
Wind Power System Component Cost Contribution in Total
Capital Cost
Cost Item
Percent Contribution
Rotor assembly
25
Nacelle structure and auxiliary equipment
15
Electrical power equipment
15
Tower and foundation
10
Site preparation and roads
10
Ground equipment stations
8
Maintenance equipment and initial spares
5
Electrical interconnections
4
Other nonrecurring costs
3
Financing and legal
5
TOTAL
100
(Land cost is not included)
used for learning lessons and making improvements. In the wind power
industry, the failures, their causes and effects are recorded and periodically
published by ISET, the solar energy research unit of the University of Kassel
in Germany.
Figure 15-2
summarizes the ISET database.
The statistics show
that 67 percent of the time during the reported failure period, the plant is
nonoperational. Among the repairs needed to bring the plant back in oper-
ation, 20 percent are in the electrical power equipment and 19 percent are in
the electronic controls. The major causes of the failure have been 28 percent
in the control systems and 24 percent in the component defects. The failure
rates are declining from this level with the design improvements made since
then.
The overall availability of the plant is defined as the ratio of hours the
plant is operating to deliver full power over the total hours in the year. It is
impacted by downtimes due to repairs and routine maintenance. Significant
improvements in reliability and maintainability have pushed the availability
of modern renewable power plants up to 95 percent in recent years. The
availability factor, however, is reflected in the energy delivery factor EDF.
2
15.4
Energy Cost Estimates
The principal decision-making parameter of an electrical power plant is the
unit cost of energy (UCE) per kWh delivered to the paying consumers. It
takes into account all economy factors discussed above, and is given by the
following:
(
)
+
ICC
⋅
AMR
+
TIR
OMC
UCE
=
(15-4)
EDF kW
⋅
⋅
8760
