Yukon Wind Energy
Wind Energy Research, Development
and Operation in Harsh Arctic
Environments
For:
International Wind-Diesel Workshop
March 8-11, 2011 Girdwood, Alaska
By John Maissan, P.Eng.
and
JP Pinard, PhD, P.Eng.
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Introduction
•
•
•
•
History of wind in Yukon
Wind in mountainous terrain
Icing and measurements
Wind turbine operations in Yukon
– The Bonus 150 kW
– The Vestas V47 660 kW
• Wind turbines in the north
2
History of Wind in Yukon
• First wind measurements were made in 1980’s,
results were negative.
• Serious research began in the early 1990’s
focused on mountaintops.
• 1993 the Bonus 150 kW was installed with blade
heating.
• Wind program expanded to cover almost every
community.
• The Vestas V47 660kW was installed in 2000
• The wind research is ongoing...
3
Short Lesson on Wind in Mountainous
Terrain
• Inversions are a mainstay affecting wind with
respect to height.
• Winds in valleys are different from winds on
mountaintops (geostrophic).
• Winds are commercially better on mtn tops,
however... icing
4
Northern Wind Climate:
Stratification
• The atmosphere is stability stratified
• Air tends to flow in layers
• Cold air sits at the valley bottom and is
difficult to push along by air above
• Air in valleys flow like rivers
5
Wind and Temperature profiles in a
Yukon Valley
Profiles from
Whitehorse weather
balloon station
Haeckel Hill
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JP Pinard photo
JP Pinard photo
JP Pinard photo
7
Northern Wind Climate: Seasonal
variation
• In winter larger temperature difference from
equator to North pole
• Means larger pressure difference -> windier.
• Winds on the mountaintops tend to increase in the
winter
• However, Winds in the valleys tend to decrease in
the winter: due to temperature inversion.
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2400 m ASL: above
the mountaintops
When observing
upper winds from
this direction only
900 m ASL: within
the valley
Valley winds
are like this
Inversion in
effect here
From Pinard, 2007
7.9 m/s mean
wind speed
from this sector
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Northern Wind Climate: wind
pattern changes with height
• Winds above mountaintops are typically geostrophic:
they follow the pressure contours, high pressure to
the right when facing downwind
• Winds at mountaintops can be controlled by
orography (mtn topography)
• Winds within valleys tend to follow the valley axis.
• Valley winds move from high pressure to low
pressure areas.
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LOW
HIGH
HIGH
2400 m ASL:
above the
mountaintops
LOW
LOW
HIGH
LOW
HIGH
From Pinard, 2007
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Northern Wind Climate:
Mountaintop icing
• Icing is caused by supercooled water droplets: liquid
water at 0 -> -20C temperatures.
• Super-cooled water solidifies onto a solid surface.
• Typically when there is a cloud at freezing
temperatures, there is icing.
• Mountaintops and coasts are prone to icing
• Icing is worst in fall when air temperature drops
below freezing and lakes still open.
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John Maissan photo
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Icing issues with measurements
•
•
•
•
Icing can destroy met masts/towers
Icing contaminates wind sensors
Icing has been difficult to prevent
Icing has been difficult to detect and measure
14
Icing on Towers
• Ice can weight down heavily on the guy lines of a tower
• Tower must support the added weight and vibration in
high winds
• Need tower tubes and guy wires of heavy gauge.
• Lattice towers have more surface for ice to cling to.
• Booms need to be sturdy
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JP Pinard photo
Yukon Energy photo
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Icing on Sensors
•
•
•
•
Ice contaminates sensors
Ice throw can be damaging
Plastic components of sensors can break
Perceived wind speed is reduced under light icing
and is hard to detect
• Heavy icing is more obvious in data
Yukon Energy photo
JP Pinard photo
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Anti-Icing on sensors
• Need full body ice prevention
• Heated portions of sensors can still be covered by icing
stemming from non-heated part of the body
• A variety of heated sensors with power requirements ranging
from 75 to 1500 watts have been tried.
• Power supply is a problem in remote locations: energy
efficiency and management is critical
• Need smaller sensor with less surface area to heat
• To save energy use ice detector to detect icing and then turn on
heated sensor. This causes problems with the sensor: eg.
bearing issues.
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Yukon Energy photo
Yukon Energy photo
Yukon Energy photo
Yukon Energy photo
Yukon Energy photo
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Detecting Ice
• Two heated anemometers: one is always on; the other is
intermittent and comes on when slows.
• Ice detector technology from aviation industry like the
Goodrich (formerly Rosemount) Ice Detectors: models
0871LH1 (available today) and 0872B12 (better but no longer
available) have been tested.
• Ice detector technology is still in need of improvement
• Need full body heating, however power is premium in remote
sites
• Need physically smaller instruments with less surface area, so
that less power is required to heat and operate.
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JP Pinard photo
Yukon Energy photo
Goodrich photo
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Wind Turbine Operations in Yukon:
The Bonus 150 kW installed in 1993
Special Features
– low-temperature-tolerant steels (to -30°C)
– synthetic lubricants
– six-inch wide heaters for the leading edges of the blades
– heating systems in the gearbox, generator and electronic
cabinets
– heated bearings for the wind vane and anemometer
– hinged 30-metre tower capable of installation without a
large crane
Yukon Energy photo
Yukon Energy photo
Wind Turbine Operations in Yukon:
The Bonus 150 kW installed in 1993
Challenges
– Blade icing behind the heaters in severe icing
conditions
– The heated-bearing anemometer iced up
– The two-section blades meant that the blade tip
heaters often didn’t work, leading to icing and
reduced output
– Turbine shutdown when discrepancy between
anemometer and power output
Yukon Energy photo
Yukon Energy photo
Wind Turbine Operations in Yukon:
The Bonus 150 kW installed in 1993
Solutions
– Wider heaters were installed on leading edge to
extend the ice free blade area
– A black-coloured fluorourethane (StaClean) coating
was applied to the blades to encourage ice shedding
after warranty
– Installation of fully heated anemometer and wind
vane eliminated rime icing problems with them
– Allow turbine to operate when power output below
anemometer suggested output – right to nil
Yukon Energy photo
Wind Turbine Operations in Yukon:
The Vestas V47 660kW, installed 2000
Features
– Operation rated to -30C (“Arctic” version)
– Pitch regulated
– StaClean coated black blades
– Twelve-inch heating strips for the blade leading edges
– heating systems in the gearbox, generator and
electronic cabinets
– Shorter tower (37m)
Yukon Energy photo
Wind Turbine Operations in Yukon:
The Vestas V47 660kW, installed 2000
Challenges
– Still icing downstream of surface heaters
– Turbine shutdown when power output below 75% of
what it should be
Solutions for Future
– Full surface blade heating
– Ice detector controlled blade heating
– Allow turbine to operate at reduced output as long as
no imbalance or vibration issues
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10
0
-10
-20
OutdoorTemp NRG
Icing
-30
1-Jan-01
31-Jan-01
2-Mar-01
1-Apr-01
1-May-01
31-May-01 30-Jun-01
30-Jul-01
29-Aug-01 28-Sep-01 28-Oct-01 27-Nov-01 27-Dec-01
Icing and WTG Operations
• Blade heating properly designed works – need
commercial availability
• Black surface works – assists in de-icing
• Ice-phobic / hydro-phobic coatings appear to work
• Rotor balance & vibration needs monitoring
• Ice throw not a big issue with rime ice and in remote
locations
WTG in larger northern locations
For northern industry or power grids
• Scale is somewhat smaller than mainstream grid-connected
systems.
• Cranes are very expensive to deploy to remote locations
• Wish list:
– Optional operation to -40°C
– Towers & nacelles that require reduced crane size
– More selection in 300kW to 1MW turbines
– Optional blade heating when required
– Expanded remote operational and maintenance
monitoring and control
WTG in small remote communities
• Scale is smaller than mainstream grid-connected systems
• Cranes are very expensive to deploy to remote communities
• Wish list:
– Optional operation to -40°C & blade heating
– Tilt up towers that require no crane
– More selection in 50 – 150 kW turbines
– Simple generator and blade designs
– Cookie cutter foundation and electrical integration designs to
reduce costs
– Expanded remote operational and maintenance monitoring and
control
Thank You!
This and other related publications can be found at
http://www.esc.gov.yk.ca/publications_yukon.html
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