POWER December 2014 - 43

Wind PoWer
mon goal should be that, if a generator has to
come down tower for repairs, it should only
happen once. Ensure that all the recommended
upgrades to the collector assembly, bearings,
and insulation systems are included.
Also, it is critical that the generator be
properly transported and stored before installation.
The unit should be carefully and
properly aligned during installation and a
base line set of test values established for
vibration and electrical condition trending.
Contracting for the installation of the remanufactured
generator by the service provider is
a good idea, as it resolves many conflicts if a
warranty claim does develop.
Be Prepared
The maintenance issues that need to be addressed
while developing a wind project
maintenance plan are really the same as for
any other large generating site or industrial
facility. Although there are many ways to
structure the risk, there is general agreement
on how reliability allows you to maximize
profitability for the project when the wind
is blowing.
According to a 2013 survey from the
National Renewable Energy Laboratory,
total average annual wind project O&M
costs are $45/kW. With an estimated 2% to
3% generator failure rate, that would represent
<5% of total cost-small, but still
significant. However, unplanned outages
could affect production at a much higher
cost. If, as has been estimated for some
designs, there will be a need to replace every
generator once in the 20-year design
life of the turbine, the cost becomes very
significant.
Realistically planning a maintenance
strategy as part of the project development
process can save a lot of angst in the long
run. Negotiating operation and reliability
data-sharing with the turbine manufacturer
during the contract phase is a critical step in
that process.
Understanding the performance expectations
of the equipment is good, of course, but
obtaining the maintenance records of what
has happened and the root cause failures
during the warranty period would be a boon
to maintenance planning for the future. The
generators and related electronics in most
wind turbines are manufactured by specialty
OEMs rather than the turbine manufacturers
themselves, so multiple warranties and
multiple opinions on what happened (and
therefore who is responsible) are unavoidable.
Agree on what post-warranty options
will be available, and develop a cost/return
analysis for each turbine design under consideration.
There is a general consensus that
average O&M costs will escalate as projects
mature, and some of the rationale behind
that opinion will be discussed in the DOE
Wind Vision update that is due out in the
spring of 2015.
Knowing your generator model and its
related service history-what will probably
break and why-is the key to developing the
maintenance plan for your specific turbine.
Both the turbine OEM and generator manufacturer
can help with that, but don't forget
to establish the service partnerships you will
need for ongoing support. ■
-Kevin Alewine (kalewine@shermco.
com), corporate director of marketing for
Shermco Industries, previously served
as director of the company's renewable
energy services and for 35 years has
focused on the manufacture and repair
of rotating machinery up to 15 kV. He is
active on several IEEE Dielectrics and
Electrical Insulation Society testing standards
working groups and is chair of the
American Wind Energy Association O&M
Working Group.
Air Handling
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Field Services
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POWER December 2014

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