1. Siting of Offshore Wind Farm in Coastal Waters: Presentation of Progress OCE 495 Section 1 10/31/2008

2. Outline of Presentation Site Boundaries and Layout Wind Module – Wind Speeds – Power Production – What else is needed and how we plan on doing it Wave Module – STWave results – STWave Problems and how we plan on fixing them – Sea State Calculations GeoTech Module – Sub-bottom Profiles Constituent soils Depth to bedrock indications – Surficial Sediments – More Sub-bottom profiles to be analyzed. Structure and Foundation Module – What we’ve done Research – Where we are going Change of Design Order Fatigue Loading ANSYS Choosing Diameter and Thickness P-Y Curves – Precautions Depth to Bedrock

3. Site Boundaries and Turbines Detailed bathymetry to create better polygon – SAMP data or Taylor’s bathymetry grid being used in Stwave – Unable to create a attribute layer from Taylor’s grid thus far Determine predominant wind direction for turbine arrangement Layout turbines, omitting places where bedrock is known to be too shallow – Maintain organized pattern GPS coordinates for each turbine location – Need bathymetry grid of high resolution and maintain geo-referencing

4. Wind Modules Wind Module – Wind Speeds – Power Production – What else is needed and how we plan on doing it

6. Mean Wind Speeds (WIS 95, elevated to 80m) Winter (Jan through March)…10.47 m/sec Spring (April through June)…6.63 m/sec Summer(July through Sep)… 6.18 m/sec Fall (Oct. through Dec.)…10.20 m/sec Annual Average………8.37 m/sec

7. Wind Rose (WIS 95) This plot shows direction the wind is blowing from. (0o corresponds to wind blowing in from the North, and 90o corresponds to wind blowing in from the East.)

8. GE 3.6MW Turbine

10. Power Density The Preceding Power density graph assumed ~Air density = 1.25 kg/m 3 (ICAO standard) (0m altitude, 15 o C, 0% relative Humidity and 1 atm pressure) Air density changes in relation to -Humidity -Pressure -Temperature We need to obtain Metrological data for better monthly and seasonal estimations

11. Wind density with relation to temperature and humidity

12. Density vs Humidity vs Temperature

15. Power Output (for a single turbine, WIS 95 Model) Winter (Jan through March) 4.25x10 6 kW hours Spring (April through June) 2.03x10 6 kW hours Summer(July through Sep.) 1.75x10 6 kW hours Fall (Oct. through Dec.) 4.13x10 6 kW hours Annual Power12.7x10 6 kW hours (note: RIWinds predicted 13.9x10 6 kW hours Annually for speeds of 8.25 m/sec)

16. Wind Modules What We Need and How We are Going to Get it Wind Loading Estimation ~What we need: Down Stream Velocity ~How we are going to get it: Using Cp Diagram + know up stream velocity and solving down stream algebraically

17. Wind Modules What We Need and How We are Going to Get it Monthly Electrical Output ~We need: Meteorological data (Temp, Humid, Press) ( to calculate air density for wind density calculation ) ~How we are going to get it: Searching Websites (NOAA,… )

18. Wind Modules What We Need and How We are Going to Get it Extreme Wind Speed analysis ~What we need: Gumbel Probability Distribution for WIS 95 ~How we are going to get it Using wind rose to determine directions,calculating Gumbel distribution in those directions for a given wind speed and return period

19. Wave Module STWave Analysis – Results – Problems Encountered and how we plan on fixing them Sea States – Results

20. Wave Module: STWave Objectives: Find from the WIS Data from the Station 79. Calculate transformed wave heights to the selected site using linear wave theory. Obtain an understanding of STwave, so more in depth wave analysis can be calculated.

21. Wave Module: STWave Given Information: Storm Surge Bathymetry WIS Station Data

22. Wave Module: STWave How STwave Functions Four Input Files of Interest Bathymetry Model parameters Incident wave spectra Currents

23. Wave Module: STWave Progress in Creating STwave Input Files Bathymetry file obtained; must interpolate data points, so that spacing between each is decreased preferably 25-50 meters, current spacing is approximately 60.5 meters. Model Parameters are found and understood, file can easily be written. Currents are negligible due to orthogonal interaction with wave heights and do not induce wave infraction Currently working on obtaining correct wave spectra.

24. The graph on the left Correctly Portrays the frequency spectrum For a Hs of 4 Ts of 12 and an angle of incidence of 30 o The graph on the right is wrong. For an angle of incidence 30 o the direction should be centered on 30 o.

25. Wrong Energy Spectra Input Problems: Angle of incidence is wrong. The peak is too skinny and pointy.

26. Sea State Calculation In order to calculate the different sea states the structure will encounter; wave data from WIS Station 101 was used. http://frf.usace.army.mil/cgi-bin/wis/atl/atl_main.html

27. Sea State Calculation Use WIS Data to calculate how often certain sea states occur. Data has hindcast predictions for every hour over a whole year. WIS DATA DEFINITIONS ID Station number YEARYear using 4 digits MMMonth number (January is 1, October is 10) DDDay of the month HHHour of day (GMT) LONGLongitude of station (- indicates West Longitude) in degrees LATLatitude of station in degrees North DPTHDepth of station in meters HmoSignificant wave height in meters (includes high frequency parametric tail energy) DTpPeak spectral wave period in seconds using discrete frequencies in calculation AtpPeak spectral wave period in seconds using a parabolic fit in calculation tmeanMean wave period in seconds calculated using the inverse first moment wdvmnOverall vector mean wave direction in degrees using Meteorological (MET) convention wvVector mean wave direction at spectral peak frequency in degrees in MET convention wspWind speed in meters per second wdirWind direction in MET convention 101 1980 1 1 1 -71.66690 40.99976 42.0 0.16 1.55 3.33 1.55 270.0 270.0 6.3 350. 101 1980 1 1 2 -71.66690 40.99976 42.0 0.27 3.33 3.33 3.33 350.1 350.1 6.2 350. 101 1980 1 1 3 -71.66690 40.99976 42.0 0.35 3.33 3.33 3.35 354.5 354.5 6.2 355. 101 1980 1 1 4 -71.66690 40.99976 42.0 0.43 3.33 3.33 3.40 354.9 354.9 6.1 355. 101 1980 1 1 5 -71.66690 40.99976 42.0 0.50 3.33 3.33 3.45 357.7 357.6 6.0 359. 101 1980 1 1 6 -71.66690 40.99976 42.0 0.57 3.33 3.33 3.50 358.3 358.2 6.0 0. 101 1980 1 1 7 -71.66690 40.99976 42.0 0.65 3.33 3.33 3.59 0.1 1.0 5.9 4.

28. Sea State Calculation US Army Core of Engineers calculates the % occurrence of specified wave heights and periods on their site. Multiplying percentages by hours in a year will find how many hours in a year the specified sea state can be expected to occur. http://frf.usace.army.mil/cgi-bin/wis/atl/atl_main.html

29. Wave Period Tp (S)3 - 44 - 55 - 66 - 77 - 88 - 9 9 - 1010 - 1111 - 1414+ Wave Height Hmo (m) 0 - 0.5 300.47117.38125.27189.22190.09108.6256.0620.1525.40.88 0.5 - 1.0 1027.55456.4403.84444.13297.84163.8177.0940.342.926.13 1.0 - 1.5 47.31019.66271.56282.95310.98160.3183.2240.358.6912.26 1.5 - 2.0 0264.55279.44185.71186.59150.6765.728.9126.287.01 2.0 - 2.5 016.64154.18125.2794.61129.6556.9423.65 5.26 2.5 - 3.0 00.5317.5260.4456.0669.254.3122.7817.523.5 3.0 - 3.5 00013.1429.7832.4123.6519.2713.142.63 3.5 - 4.0 0001.7510.5115.77 6.138.761.75 4.0 - 4.5 00000.887.886.134.386.131.75 4.5 - 5.0 00000.531.756.131.753.50.88 5+ 00000.53 4.385.26 0.53 Table showing hours each sea state can be expected to occur in a single year. Tp is the Peak Period Hmo is Significant Wave Height based on spectrum Hmo=Hs if we assume the wave height follows the Rayleigh distribution.

30. Plot of Sea States

31. Geo-Tech Module Sub-bottom Profiles – Constituent soils – Depth to bedrock indications Surficial Sediments More Sub-bottom profiles to be analyzed

32. What Has Been Done

33. What’s Known Glacial Moraine Holocene Glaciolacustrine

34. Known Surficial Sediments Sandy Gravel ~ McMaster& Battelle

35. What’s Next Determine grain sizes of soils present in Area B – Glaciolacustrine – Holocene – Glacial Moraine Determine depth to bedrock Interpret seismic profiles from Needell & Lewis Report (Profiles 5,6,10,11)

36. Seismic Profiles

37. Foundation and Structure What we’ve done – Research Where we are going – Change of Design Order – Fatigue Loading – ANSYS – Choosing Diameter and Thickness – P-Y Curves Precautions – Depth to Bedrock

38. Research Wind Farms – Both offshore and onshore Standards and Regulations – No American Standards – API – DNV Effects on Foundation and Structure – Sediment – Waves – Wind – Cyclic Loading

39. Change of Design Order Currently working on foundation and working up Changing to “Top-Down” design – Design the structure above the transitional piece – Design the transitional piece – Design the foundation

40. Fatigue Loading Take sea states and their occurrences Calculate the damage done by each sea state Combine these two to discover the total damage done Create minimum diameter and thickness – Minimum values for our design structure life

41. All figures and equations on this slide are taken from: Fatigue Loading is Wind Turbine, 2007, M Ragheb

42. ANSYS Finite element analysis – Use parameters of our design site Discover the minimum thickness and diameter

43. Choosing Diameter and Thickness Compare the two design thicknesses and diameters – Choose the largest values of these two Apply factor of safety according to the section of the structure/foundation

44. P-Y Curves Simulate sediment using springs – Finds load deflections – Research needed to see if P-Y curves will work for large diameter monopiles Use our design thickness and diameter to find penetration depth

45. Precaution We do not have the estimated 30m of sediment needed – We are gong to design as if we did with the caveat that we will have to deal with bedrock – If we discover that bedrock creates an impossible state, we will have to deal with this at that time Move Site