Page 314 - Fluid Power Engineering

280 Chapter Thirteen

Scheduled maintenance charges are also easy to compute in the
warranty period. In 2009, most manufacturers provided warranty
for 2–5 years. One notable exception is Enercon of Germany with a
partner concept program that provides 12-year warranty for a yield-
(kilowatt-hour produced) based fee. As the wind industry matures,
manufacturers are increasingly providing warranties that include
95% availability and guaranteed performance for at least 5 years.
For newer wind plants, maintenance cost is becoming predictable
within the warranty period. In order to budget for unscheduled
maintenance costs postwarranty, most operators establish a reserve
or a sinking fund. A reserve fund contains money set aside each
year for the explicit purpose of funding repairs and replacements of
components.
Scheduled maintenance charges are in the range of $0.008 to
2
$0.012/kWh during the warranty period. LBL reports that the O&M
cost (including land lease payments) for a project installed since 2000
has been $8/MWh. Postwarranty, the scheduled maintenance charges
are difficult to predict given the limited experience with the new gen-
eration machines; however, $0.01 to $0.015/kWh would be a reason-
able assumption. Annual contributions to a reserve fund of 0.75 to 1%
of total installed cost is deemed appropriate to manage unscheduled
maintenance postwarranty.
6
NREL JEDI model provides a more detailed breakdown of the
O&M costs into components, See Table 13-2. The default costs in
the model are in terms of dollars per kilowatt, instead of dollars per
kilowatt-hours used above.
Rest of the recurring costs is even more locale-specific compared
to O&M costs, because these costs deal with insurance, taxes, land
lease, and other related costs. Following are approximate cost ranges
for US-based projects.

Insurance cost for property and business interruption are 0.1–

0.15% of the TIC
Administration and management of wind farm include

salaries of people employed in the wind farm onsite, admin-
istration, financial, and legal. This cost is in the range of 0.1 to
0.15%.
Transmission cost, if applicable, is negotiated with the trans-

mission provider; it may be in the range of $0.005/kWh.
Land lease payments are negotiated with landowners. The

cost is commonly negotiated as a percentage of revenue from
energy production. The range for land lease payment is 2–
5% of revenue. Another source of land lease payment data is
6
from NREL JEDI model, which uses $3,000 per megawatt as
a default for US-based projects.