Transcript Wind farms in regions exposed to tropical cyclones

Wind turbines in regions exposed
to tropical cyclones
Niels-Erik Clausen, Søren Ott and Per Nørgård, Risø National Laboratory
Niels-Jacob Tarp Johansen, DONG Energy
Anaflor Candelaria and Samuel Hernando, PNOC-EDC, Philippines
Søren Gjerding, Tripod
Outline
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Tropical cyclones
Tropical cyclones and wind turbines
Extreme wind from tropical cyclones
Impact on design and cost
Conclusions
Cat. 4 tropical cyclone IVAN 15 Sept 2004
at landfall near Luisiana, USA
(NASA/GSFC)
EWEC 2007 7-10 May Milan, session BW4
EU-ASEAN Wind project
Feasibility assessment and capacity building for wind
energy development in the Philippines, Vietnam and
Cambodia. Project period: Feb. 2005 – Dec. 2006
Risø National Laboratory (coordinator)
Denmark
Innovation Énergie Développement
France
Mercapto Consult
Denmark
PNOC Energy Development Corporation
Philippines
Institute of Energy
Vietnam
Ministry of Industry, Mines and Energy
Cambodia
The project is financially supported from the EC-ASEAN Energy facility through the
ASEAN Energy Centre in Jakarta. Contract 125-2004.
A tropical cyclone
Initially a rotating collection
of thunderstorms over a
warm sea water surface.
Tropical depression <17 m/s
Tropical storm
17-32 m/s
Tropical cyclone
>32 m/s
(hurricane, typhoon)
Average 48 TC per year
globally (20 - 35 years data)
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Geographical distribution of tropical cyclones
The Philippines
NW Pacific
average 17 TC
per year
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Sea water temperatures
T > 26.5 C
Sea water temperatures in May 2001.
Source: MODIS Ocean Group, NASA/ GSFC and Miami University)
Damaged wind farms
Gujarat, India 1998 (left and top)
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Japan: Miyakojima wind farm after
being hit by a typhoon Sept. 2003
(right)
NorthWind, Bangui Bay, Philippines
This wind farm have
survived two typhoons
but with damage
to cabling (flooding)
57 km 69 kV transmission line
to substation
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Power
back-up for yaw system
Photo by
EWEC 2007 7-10 May Milan, session
BW4
NorthWind
ASEAN wind case study
St. Ana
Dinagat Island
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Sta. Ana, Philippines
The mast is located 10 m asl
Measurement heights 10 and 27 m
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Tropical storm near Sta. Ana in 2005
SW
NE
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Analysis of typhoon best track data
1977-2005
2006
2005
Data
Japan
Meteol.
Agency
JMA
2004
Only12
parts of tracks with Vmax > 50 knots are shown
Estimation of U50
1. Choose a grid of observation points (e.g. 1x1)
2. For each typhoon track find the smallest distance
from the observation point to the track
3. Calculate the corresponding Vmax using a model
for dist. versus V (Holland’s model). Neglect Vmax
if below 50 knots
4. Find all the yearly maxima
5. Repeat for observation points in the grid covering
the NW Pacific
6. Find U50 from the 28 yearly maxima at each grid
point assuming a Gumbel distribution
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Extreme wind atlas for Western N Pacific
U50
10 min average
10 m above sea
based on JMA
typhoon tracks
1977-2005
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Comparison with Philippine Structural Code
3 sec gust
10 m height
land (3 cm)
10 min av
10 m height
over sea
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Cost impact from typhoon design
Assumptions for simple cost model
• Grid connection costs are disregarded
• The foundation contributes about 1/6 of the total costs
• The rotor, the nacelle, and the tower contribute each about
one 1/3 third of the remaining 5/6
• The rotor-nacelle-assembly is basically design-driven by
fatigue
• Approx. 1/2 of the tower and foundation costs are assumed
driven by extreme loads
• The extreme load driven costs are assumed proportional to
the load, which is proportional to the square of the mean
wind speed Vav and the load safety factor γf
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Estimated impact on wind turbine cost
In the standard IEC 61400-1 the partial safety factor is
1.35, and for wind turbine class IA Vref = 50 m/s
This is the reference
For typhoon area we estimate the partial safety factor of
1.7 leading to cost increases of:
50-year wind 60 m/s: 20%
50 year wind 70 m/s: 30%
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Sta. Ana 30 MW wind farm
U50 was found to 67 m/s
in 80 m height
Met mast
Wind farm
Conclusions
• U50 can be estimated from best track data
• Cost increase est. 20-30% for wind turbines
Next steps
• Improved knowledge of site design data
• Ground measurements of TC pass
• Assess impact on design (cost model)
• Design guidelines and application examples
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EWEC 2007 7-10 May Milan, session BW4
Thank you for your attention
More info at
www.aseanwind.eu
or at the Risø stand F012
Wednesday 9 May 15:30