Introduction to Modern Wind Turbines - Wind Turbine Technology: Fundamental Concepts of Wind Turbine Engineering - page 84

Wind Turbine Economics

The economic igure-of-merit most often used as the basis for choosing the coniguration
of a wind power station -- including the type and size of turbines, number and location of units,
electrical collection and distribution system, and operation and maintenance strategies -- is the
unit cost of energy , or COE , delivered to the customer. The COE of a wind turbine system, like
that of a conventional power plant, contains the following three general elements: (1) Capital
cost, (2) operating and maintenance costs, and (3) energy output. The following simpliied
formula can be used for estimating COE:

COE = ICC ´ FCR + AOM
AF ´ AEO G

(2-26)

where

COE = unit cost of energy delivered to the customer ($/kWh)
ICC = total initial capital cost of the wind turbine system; includes complete cost
exposure for land, equipment, and start-up operations ($)
FCR = levelized ixed charge rate; includes return on capital, income and property
taxes, and insurance (1/y)
AOM = annual cost of operations and maintenance of the system ($/y)
AF = availability factor accounting for system downtime, partial or total
AEO G = gross annual energy output of the system; without downtime (kWh/y)

Initial Capital Cost

Items usually included in the initial capital cost of a wind power station are listed in
Table 2-3, together with an early estimate of their relative contributions to the total cost. The
hypothetical station in this study was composed of 60 large-scale HAWTs [Boeing 1988].
Land costs are not included because they are highly variable. In this early estimate, made
when only prototype utility-scale wind turbines were available, the cost of the turbine itself
is about 51 percent of the total installed cost.

Table 2-3.
Early Estimate of Relative Contributions to Initial Capital Cost (ICC) of Components
in a Wind Power Station with 60 Large-Scale HAWTs [Boeing 1988]

Initial Cost Item Contribution

Rotor Assemblies ............................................................23.2 %

Nacelle Structures and Auxiliary Equipment ..............................15.1 %
Power Train Equipment .....................................................13.0 % Turbine: 51.3%

Site Preparation and Roads ..................................................10.3 %
Towers and Foundations ...................................................... 8.9 %
Proit ........................................................................... 8.7 %
Ground Equipment Stations .................................................. 8.2 %
Maintenance Equipment and Initial Spares ................................. 5.0 %
Electrical Interconnections ................................................... 3.8 %
Transportation ................................................................. 2.5 %
Other Non-recurring Costs ................................................... 1.3 %
Initial Capital Cost of Wind Power Station ...........................100.0 %