Wind turbines in regions exposed to tropical cyclones Niels-Erik Clausen, Søren Ott and Per...

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

EWEC 2007 7-10 May Milan, session BW4

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)

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 EnergyCambodia

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)


Geographical distribution of tropical cyclones

The Philippines

NW Pacific average 17 TCper year

Sea water temperatures

Sea water temperatures in May 2001.

Source: MODIS Ocean Group, NASA/ GSFC and Miami University)

T > 26.5 C

7

Damaged wind farms

Japan: Miyakojima wind farm after being hit by a typhoon Sept. 2003 (right)

Gujarat, India 1998 (left and top)


NorthWind, Bangui Bay, Philippines

This wind farm have survived two typhoons but with damage to cabling (flooding)

Photo byNorthWind

57 km 69 kV transmission line to substationPower back-up for yaw system


ASEAN wind case study

St. Ana

Dinagat Island


Sta. Ana, Philippines

The mast is located 10 m asl

Measurement heights 10 and 27 m


Tropical storm near Sta. Ana in 2005

NE

SW

12

Analysis of typhoon best track data

Only parts of tracks with Vmax > 50 knots are shown

2004

1977-20052006

2005

DataJapanMeteol. AgencyJMA


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

14

Extreme wind atlas for Western N Pacific

U50

10 min average

10 m above sea

based on JMA

typhoon tracks

1977-2005

15

Comparison with Philippine Structural Code

3 sec gust10 m heightland (3 cm)

10 min av10 m heightover sea


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


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%

Met mastWind farm

Sta. Ana 30 MW wind farm U50 was found to 67 m/s in 80 m height


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

Thank you for your attention

More info at

www.aseanwind.eu

or at the Risø stand F012

Wednesday 9 May 15:30

Wind turbines in regions exposed to tropical cyclones Niels-Erik Clausen, Søren Ott and Per...

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