www.PowerEngineeringInt.com 9 Power Engineering International June 2017
of green energy reached a record $30 billion
in 2016 according to Bloomberg New Energy
Further to these pledges, there are offshore
wind farm projects under construction in
European waters that equate to 27 GW in
capacity. This adds signifcantly to the global
wind power capacity of 433 GW logged in
Despite being one of the leading forms of
renewable energy, the design of wind turbines
– and the environments within which they
operate – pose a variety of different problems
from a maintenance perspective.
Corrosion of components and foundation
damage are among some of these
maintenance issues. However, it is recognized
that the single largest problem for the wind
power industry is leading edge damage.
Blade tips can revolve at up to 300 kmph
in widely-fuctuating temperatures, humidity
levels and rates of UV exposure. Coupled
with the damage from a variety of impact
and abrasion factors including rain, dust, ice,
insects, birds and lightning, this can cause
substantial erosion of the substrate.
Evidence suggests that damage to the
leading edge can lower annual energy
production (AEP) of a wind turbine, with
energy losses estimated at between 4 and
20 per cent if the erosion damage is severe.
This generates a reduction in aerodynamic
effciency, affecting the energy output as well
as exacerbating the damage to other turbine
components. Imbalance between the blades
can cause wear and damage in the shaft and
gearbox, in addition to putting further stresses
on the tower and base. Overall, this reduces
the tower’s operational life expectancy.
Alternative solutions for this problem
include fllers, binders and tapes, yet none of
these will provide extensive, long-term repair
and protection. In these scenarios, repairing
the damaged substrate can be easily
achieved with reconstructive composites and
Following sanding of the damaged area
and adequate surface preparation, an
epoxy-based repair composite can rebuild
the eroded blade to original specifcations,
adhering extremely well to FRP substrates.
As a protective layer, the moulded surface
can be overcoated with one of a range of
erosion- and corrosion-resistant epoxy systems.
Brush- and spray-applied, they offer a high
level of durability and fexibility versus the
threats of abrasion and impact.
Rather than simply a reactive option, these
solutions can be applied proactively at the
OEM stage, protecting the most threatened
areas before they enter service.
This approach was taken by an
industry-leading Japanese engineering
company, which specifed Belzona 1341
(Supermetalglide) as a protective coating
for the leading edges of turbine blades
during manufacture. Over an estimated ten
years since their original installation across
sites throughout the US, these blades have
withstood the effects of erosion beyond their
anticipated life expectancy.
It is not just leading edge damage which
can be rectifed to improve the output and
operation of wind turbines. Some of the other
major issues that befall these structures involve
the components in the nacelle.
Protecting brake drums, sealing cables,
as well as the repair of worn and damaged
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