Wind turbines in regions exposed to tropical cyclones

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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

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Outline

• 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)
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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 Philippine
  s
• 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.

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A tropical cyclone
Initially a rotating collection of thunderstorms
over a warm sea water surface. Tropical
depression lt17 m/s Tropical storm 17-32
m/s Tropical cyclone gt32 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 gt 26.5? C
Sea water temperatures in May 2001. Source MODIS
Ocean Group, NASA/ GSFC and Miami University)
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Damaged wind farms
Gujarat, India 1998 (left and top)
Japan Miyakojima wind farm after being hit by a
typhoon Sept. 2003 (right)
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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 Power back-up for yaw system
Photo by NorthWind
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ASEAN wind case study
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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

2006
1977-2005
2005
Data Japan Meteol. Agency JMA
2004
Only parts of tracks with Vmax gt 50 knots are
shown
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Estimation of U50

• Choose a grid of observation points (e.g. 1x1?)
• For each typhoon track find the smallest distance
  from the observation point to the track
• Calculate the corresponding Vmax using a model
  for dist. versus V (Hollands model). Neglect
  Vmax if below 50 knots
• Find all the yearly maxima
• Repeat for observation points in the grid
  covering the NW Pacific
• 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 ?f

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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
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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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Thank you for your attention

• More info at
• www.aseanwind.eu
• or at the Risø stand F012
• Wednesday 9 May 1530