Wind Resource assesment Anna University.pptx

Renewable Energy Technologies Notes Anna University Mech Sem V

1. Recent Trends in Wind Energy Technology D r.S.Rajakumar Assistant Professor Department of Mechanical Engineering Anna University: Tirunelveli Regional Centre

2. Wind Resource Assessment Wind Turbine Technology Performance of Wind turbine Research opportunities

3. WIND ENERGY PROGRAMME IN INDIA Potential Vs. Achievement Potential : 49,130 MW (Source: Indian wind Atlas) Achievement : 19,661 MW (as on Jan. 2013) (Source : "Indian Wind Energy and Economy" . Indianwindpower.com. Retrieved 2013-08-06 ) The worldwide installed capacity of Wind power  reached 197 GW. India is the Fifth largest wind power producer in the World after China(44,733MW), USA(40,180MW), Germany(27,215MW) & Spain(20,676MW).

4. It is estimated that 6,000 MW of additional wind power capacity will be installed in India by 2014 Wind Power generation in states Tamil Nadu (7158 MW) Gujarath(3768W) Maharashtra (2976 MW) Rajasthan (2355 MW) Madhya Pradesh (386 MW)

5. Indian Power Scenario India's total installed capacity as on August, 2013 227.35 GW (Source: Central Electricity Authority, Ministry of Power, Government of India. August 2013) Non Renewable Power Plants constitute 87.55% of the installed capacity, and Renewable Power Plants constitute the remaining 12.45% of total installed Capacity Source : CEA Technology Installed capacity (in MW) Wind 19661 Small Hydro 3496 Biomass 1248   Cogeneration 2239 Solar 1176

6. Advantages of Wind Energy No fuel cost Environment friendly and pollution free Potential exists to harness wind energy Cost of generation reduces over a period of time Low of O&M Costs Limited use of land Accommodation of other land uses Employment New market Local Infrastructure development

7. ‘Wind’ refers that Air in motion is called ‘ Wind’ It has a mass A mass in motion has a momentum Momentum is a form of energy that can be harvested Wind is the conversion of potential energy of the atmosphere into the kinetic energy due to pressure gradient.

8. Global creation of Winds Uneven heating of the earth's surface. When sun hits one part of the earth more directly, it warms that part up. The warm air rises and cooler air rushes in, creating wind.

9. Wind energy relies on sun. Wind is created by uneven heating of the earth’s surface . 11.02.2011

10. Uneven heating of the earth’s surface Earth’s rotation- Coriolis force Local influences – sea breezes, slope winds, channeling through valleys, etc.

11. WIND CLIMATOLOGY OF INDIA India is located in South of Asia continent and to the North of the Equator Characteristic features - global circulation (trade winds) and the regional wind systems (monsoons). With the Characteristic features of India get 4 different seasons Winter (Dec. - Feb.) Pre - Monsoon summer (Mar. – May) Monsoon (Jun. – Aug.) & Post – Monsoon Summer (Sep. – Nov.) General Wind Pattern : South West Monsoon (Summer) – Strong Winds (Western Ghats - Palghat gap, Shenkottai pass & Aralvaimozhi gap ) North East Monsoon (Winter)

12. Wind Resource Assessment Definition It is defined as the process of characterizing the wind resources, wind characteristics and the site‘s wind energy potential for that specific site or geographical area. Objective To identify potentially windy areas that also possess other desirable qualities for wind project development.

13. Large Areas Screening Field Visit Micrositing transfer of wind data to WT positions and hub heights Long term wind data (Good continuity) Annual Energy Yield Wind Resource Assessment Methods High quality Wind speed measurement

14. Wind Resource Assessment Methods Large-area screening includes review of existing wind resource maps & data meteorological information (pressure, temperature etc.) & analysis of the climatology of the region topographical maps (such as terrain form, land use and land cover, and other logistics like accessibility, grid availability etc.).

15. Site Visit To look for physical evidence to support the wind resource estimate developed based on the large-area screening To select a possible location for establishing wind monitoring station Potential sites are Gap, passes, and long valleys, high elevated plains and plateaus, exposed ridges and mountain summits. Wind Resource Assessment Methods

16. Wind Resource Assessment Methods

17. Wind measurement To estimate the energy production of a wind farm, developers must first measure the wind on site. Meteorological towers equipped with anemometers, wind vanes, temperature, pressure, and Solar radiation are installed. Data must be recorded for at least one year to calculate an annually representative wind speed frequency distribution. Wind Resource Assessment Methods

18. Wind Resource Assessment Methods Data Analysis Inspection of all the collected data for completeness and reasonableness and the elimination of erroneous values. This steps transforms raw data into validated data The validated data are then processed to produce summary reports for require analysis. Wind data analysis software assist to removing measurement errors from wind data sets and perform specialized statistical analysis. Popular applications are Windographer and WindRose

19. Micro- siting conducting surveys and monitoring at individual sites to quantify the small-scale variations in the wind resource over the area. In complex terrain, micrositing may involve numerous wind speed measurements combined with computer modeling to predict speeds in areas where no measurements are taken. The results of the micrositing survey are used to position the wind turbines in a wind power plant to maximize their energy output. Wind Resource Assessment Methods

20. Selection of site: Site can be in any orographical region – homogeneous or heterogeneous topography. Site should have open environment all around or at least to the sectors of prevailing wind direction. Site should not be in forest area with very high roughness that retards wind. Wind data , wind maps and publically available data base of historical climate data need to be analyzed. GUIDELINES

21. In case of sites being selected in non-flat terrain, sites needs to be located in probable locations which have the advantages of accelerated flow due to the complexity of the region. The probable locations - Ridges, Hills & Mountains GUIDELINES

22. Sites with enough area for commissioning of power projects of atleast 10MW capacity The area considered needs to be near a load Centre and have facility to evacuate power generated at a later stage with out much expense. The area considered should not be very close to habitation to avoid flying objects causing damages to life and property when wind farms come up. GUIDELINES

23. Tower Placement Two important guidelines should be followed when choosing an exact location for the monitoring tower: It should be as far away as possible from local obstructions of the wind. Select a Location that is representative of the majority of the site. As a thumb rule the tower should be located at a horizontal distance at least 20 times the height of the obstruction in the prevailing direction. Other issues Permitting Lease agreements GUIDELINES

24. TOWER/SENSOR INSTALLATION Tubular towers are preferred to minimize tower wakes. Tower should be structurally stable. Ground level components clearly marked to avoid collision hazards Should be - with lightning protection. - protected against corrosion. GUIDELINES

25. Sensor Support Hardware Masts (vertical extensions) and mounting booms (horizontal extensions) Both must position the sensor away from the support tower to minimize any influence on the measured parameter caused by the tower. structurally stable Properly oriented into prevailing wind. Protected against corrosion from environmental effects GUIDELINES

26. WIND MONITORING STATION A wind monitoring/measurement station consist of the following systems and subsystems: Tower (tubular / lattice) with accessories Sensors for multilevel measurements Data loggers with memory devices, Cables for sensor wiring Instrument support systems Grounding and Lightning protection systems All the instruments / equipment's are to be tested before the deployment to a site. Details of instruments at multilevel (make, serial no. calibration details & map) along with site details are to be documented.

27. WIND MONITORING STATION

28. Measured Parameters Unit Monitoring Heights Wind Speed m/s 10m, 30m, 50m & at tower height Wind Direction Degree 30m, 50m & at tower height Temperature ( C) 3m or close to tower height Pressure mb 3m or close to tower height Solar Radiation (optional parameter) W/m 2 3m MEASUREMENT PARAMETERS & INSTRUMENTATION The core of a WRA program is the collection of wind speed, wind direction, air temperature and pressure data at a location to evaluate the resource related wind energy feasibility issue.

29. 50m: The measurement at 50 m height is mandatory as the potential of a site is assessed based on the WPD at 50m level. 30m: This level approximates the minimum height reached by the blade tip portion of a rotating turbine rotor and will help define the wind regime encountered by a typical turbine rotor over its swept area. 10m: This is the universally standard meteorological measurement height. However, in locations where the interference of local vegetation (e.g., forest) at this height is unavoidable, an alternative low-level above the forest canopy may be used. WIND SPEED

30. WIND SPEED MEASUREMENTS Name of the sensor : cup anemometer Mounted on a meteorological mast on a sufficiently long boom to avoid wakes The cup rotation is linearly proportional to the wind speed and generate signals. The signals could be continuous or intermittent. Continuous signals - wind speed at any instant Intermittent signals - average wind speed during the specific interval.

31. SPECIFICATIONS FOR ANEMOMETER Specifications Anemometer Measurement range 0 to 50m/s Starting threshold < 1.0 m/s Operating temperature range - 40 o C to 60 o C Operating humidity Range 0% to 100% System error < 3% Recording resolution < 0.1 m/s

32. WIND DIRECTION MEASUREMENTS Name of the sensor : wind vane Mounted on a vertical axis on which it is free to turn. To identifying terrain shapes and orientations To optimizing the layout of wind turbines of the wind farm. Most wind vanes use a potentiometer type transducer that outputs an electrical signal relative to the position of the vane usually true north. Thus alignment of vane is important in data collection. The signals will be either indicating discrete direction or instantaneous directions.

33. Specifications Wind vane Measurement range 0 to 360 Starting threshold < 1.0m/s Operating temperature range -40 o C to 60 o C Operating humidity Range 0% to 100% System error < 5 o Recording resolution < 1 o SPECIFICATIONS FOR WIND VANE

34. TEMPERATURE Name of the sensor : Thermistor Composed of three parts the Transducer, an Interface device & a radiation shield An important descriptor of a wind farm’s operating environment. To calculate air density, a variable required to estimate the wind power density Alternatively temperature information from a nearby climatological station after necessary elevation correction also can be considered.

35. SPECIFICATIONS FOR TEMPERATURE Specifications Temperature Measurement range - 40 o C to 60 o C Operating temperature range - 40 o C to 60 o C Operating humidity Range 0 to 100% System error ≤0.1 o C Recording resolution < 0.01 o C

36. PRESSURE Name of the sensor : Barometer Most Barometer use a Piezoelectric transducer that provides a standard output to a Data logger. It require an external power source to operate properly. Pressure data from a nearby climatological station with correction for elevation can be used alternatively.

37. SPECIFICATIONS FOR PRESSURE Specifications Pressure Measurement range 94 to 106kPa (sea level equivalent) Operating temperature range - 40 o C to 60 o C Operating humidity Range 0 to 100% System error ≤ 1kPa Recording resolution < 0.2kPa

38.  SOLAR RADIATION Name of the sensor : Pyranometer Mounted on a horizontal axis to measure accurately. Most Pyranometer uses a Photodiode that generates a small voltage( millivolts ) across a fixed resistance proportional to the amount of solar radiation. An indicator of atmospheric stability and numerical wind flow modeling. Used to estimate the solar energy resources available at a location like wind.

39. SPECIFICATIONS FOR SOLAR RADIATION Specifications Solar Radiation Measurement range 0 to 1500 W/m 2 Operating temperature range - 40 o C to 60 o C Operating humidity Range 0 to 100% System error < 5% Recording resolution < 1 W/m 2

40. DATA LOGGER The instruments send low-voltage-electrical signals to a data recorder at the base of tower, where ten minutes averages of the speed and direction are recorded in memory. Mounted in a non-corrosive, water-tight, lockable electrical enclosure to protect peripheral equipment from the environment and vandalism. The logger has a fixed averaging interval of 10 minutes. Each of the 12 channels’ averages, standard deviations, minimum and maximum values are calculated from continuous 2 second data samples.

41. Data Storage device : EPROM, EEPROM & MMC Power requirement(capability to work with solar panel/1.5V Alkaline batteries) Storage capacity for at least one month or more without any attention. DATA LOGGER

42. DATA TRANSFER Manual data transfer Remove and replace current storage device or data card Transfer of data directly to the lap top Advantage – leading to visual on site inspection. Disadvantage - frequent site visits. Remote data transfer By direct wire cabling Phone modem Cellular modem Satellite communication Internet connection Advantage - Retrieve and inspect data more frequently and allows promptly to identify and resolve problems . Disadvantage – Cost

43.     ANEMOMETER WIND VANE THERMISTOR BAROMETER PYRANOMETER 50m WS (m/s) 50m DIR ( o ) Temperature ( o C ) Pressure ( mb ) Solar Radiation (W/m 2 ) Date & Time Stamp AVG SD MAX MIN AVG SD MAX MIN AVG SD MAX MIN AVG SD MAX MIN AVG SD MAX MIN 01-05-2013 15:00 5.9 0.3 6.4 4.9 257 3 255 32 0.1 32.4 31.5 1015.2 1015.4 1015.4 841.3 5.9 853.9 826.6 01-05-2013 15:10 5.4 0.4 6.4 4.9 256 3 255 31.8 32.1 31.5 1015.2 1016.4 1015.4 819.9 6.4 833.3 811.1 01-05-2013 15:20 4.9 0.3 5.7 4.1 255 3 261 31.6 0.1 32.1 31.5 1014.9 1015.4 1015.4 794.8 7.6 811.1 783 01-05-2013 15:30 5.1 0.2 5.7 4.5 257 2 256 32.1 32.4 31.8 1014.9 1015.4 1014.4 770.4 7.6 785.1 755.9 01-05-2013 15:40 5.2 0.2 5.7 4.5 257 2 260 32 0.2 32.4 31.5 1014.9 1015.4 1014.4 744.3 7.6 760 729.8 01-05-2013 15:50 5 0.3 6 4.5 256 3 273 31.9 32.4 31.5 1014.9 1015.4 1014.4 713.7 9.5 733.8 695.1 01-05-2013 16:00 4.8 0.2 5.3 4.1 256 3 255 31.8 0.1 32.1 31.5 1014.9 1015.4 1014.4 681.6 10.3 698.9 663.8 01-05-2013 16:10 4.4 0.2 4.9 3.8 257 2 258 31.8 32.1 31.5 1014.9 1015.4 1014.4 647.8 9.9 665.6 630.5 01-05-2013 16:20 4.6 0.2 4.9 4.1 255 3 253 31.7 0.1 32.1 31.5 1014.7 1015.4 1014.4 613.3 9.5 630.5 597.3 01-05-2013 16:30 4.6 0.2 5.3 4.1 259 2 257 31.7 31.8 31.5 1014.4 1015.4 1014.4 579.8 10.3 598.9 562.7 SAMPLE DATA

44. Turbulence Intensity Energy Pattern Factor Air Density Wind Power Density Power law Index Weibull Parameter (c & k) Wind Rose Diagram Percentage frequency distribution of wind speed and joint frequency wind speed and direction DATA ANALYSIS – DERIVED PARAMETERS

45. TURBULENCE INTENSITY (TI) An important site characteristic, because high turbulence levels may decrease power output and cause extreme loading on wind turbine components. As per IEC standard TI is considered at 15m/s TI ≤ 0.10 - low level. up to 0.25 - moderate level > 0.25 - high level

46.   MEAN WIND SPEED & STANDARD DEVIATION

47. Example Calculate the mean and standard deviation for the given wind speed values of 2,4,7,8, and 9 m/s.     

48. Example: Calculate TI with mean wind speed 15m/s and standard deviation 4.5m/s. Solution: TI = 4.5 m/s 15 m/s TI =0.3

49. ENERGY PATTERN FACTOR calculating the available energy in the wind from the values of mean annual or monthly wind speed Range 1.50 to 2.50

50. Example Calculate EPF for a given mean wind speed 6 m/s for a month of January in a 10 minute interval and Solution: = 1594001 4464x(6) 3 EPF = 1.65 = 1594001 (m 3 /s 3 )

51. AIR DENSITY Varies with pressure and temperature and also vary 10% to 15% seasonally. Site pressure is known the hourly air density values with respect to air temperature can be calculated from the following equation

52. The site pressure is not available, air density can be estimated as a function of site elevation (z) and temperature (T) as follows:  = ( P O / RT) exp (- g.z /RT) (Kg/m 3 )  = (353.05/T ) exp – 0.034 (Z/T) (Kg/m 3 ) Where P O = the standard sea level atmospheric pressure (101,325 Pa), or the actual sea level adjusted pressure reading from a local airport. g = the gravitational constant (9.8 m/s 2 ) z = the site elevation above sea level (m) The thumb rule for obtaining air density at higher elevation is to allow a decrease of 1 % for every increase elevation by 100m. The Standard Air density value is 1.225 kg/m 3 AIR DENSITY

53. Example Calculate Air density for the given Pressure 994.7 mb and Temperature 20.55 C Solution:    = P/RT Kg/m 3   P = 994.7 mb T = 20.55 + 273 = 293.55 Kelvin    = 1.180 Kg /m 3

54. WIND POWER DENSITY WPD is defined as the wind power available per unit area swept by the turbine blades. Real indication of a site’s wind energy potential than wind speed .

55. Wind Power Class Wind Speed (m/s) Wind Power Density at 50m AGL (W/m 2 ) Description 1 0-5.6 0-200 Poor 2 5.6-6.4 200-300 Marginal 3 6.4-7.0 300-400 Fair 4 7.0-7.5 400-500 Good 5 7.5-8.0 500-600 Excellent 6 8.0-8.8 600-800 Outstanding 7 8.8-11.9 800-2000 Superb Wind class definition at 50m height * * Ref: Wind Energy Resource Atlas of the United States

56. Example Calculate WPD for a given Air density is 1.180 kg/m 3 and for a month of January in 10 minute interval. = 1594001 (m 3 /s 3 )

57.   WIND SHEAR / PROFILE Wind shear is defined as the change in horizontal wind speed with change in height.

58. POWER LAW PROFILE α is the power law exponent (wind shear exponent) The equation of power law is given by The Power Law Exponent (  ) should be determined for each site, because its magnitude is influenced by site-specific characteristics, with a value of 0.14 for most of the homogeneous site.

59. Weibull distribution is a mathematical approximation of real distribution of wind speed frequencies, which gives the shape of the distribution.   WEIBULL DISTRIBUTION

60. Distribution is represented by two-parameters known as shape parameter (k) and scale parameter (c). The values of k vary widely from about 1.5 to 4.0 . Higher values of k imply a sharper maximum in the frequency distribution curve and consequently a lower wind power density.   WEIBULL PARAMETERS

61.        WEIBULL DISTRIBUTION FOR VARIOUS VALUES OF K

62.  WIND ROSE The wind rose presented in circular format shows the frequency of winds blowing from particular directions. The wind rose is a method of graphically representing the occurrence of winds at a location, showing their strength, direction and frequency. It is a very useful representation as a large quantity of data has been summarised in a simple graphical plot

63. To estimate the annual energy production from a given machine at a site, power curve method can be used since this method gives most realistic results. The wind speed frequency distribution will be used to estimate the annual energy production of a wind turbine by multiplying the number of hours in each interval with the power output that the windmill generates at that wind speed interval. If the frequency distribution of wind speed at the hub height is not available, the wind speed at the hub height level is to be generated by the power law equation. ANNUAL ENERGY PRODUCTION

64.      P ercentage frequency distribution of wind speed Wind Turbine Power Curve Annual capacity factor = (Actual energy produced during year) / (capacity * 8760) ANNUAL ENERGY PRODUCTION

65.      Example – Annual Energy Production for 100 MW wind park Ideal energy yield: 867.8 GWh/yr Gross energy yield: 350 GWh/yr Production Losses: 10% Net energy yield: 315 GWh/yr Capacity Factor: 36% ANNUAL ENERGY PRODUCTION

66.      Correlations between long term reference stations and onsite meteorological towers 12 months of measured site data recommended Find appropriate long-term reference stations Determine correlation between site data and reference stations for a concurrent period using Least squares linear regressions method Determine long-term wind data set for site Predict long-term wind speed distribution at the site MEASURE – CORRELATE – PREDICT (MCP)

67.      LONG TERM OBSERVATION OF WIND SPEED

68.      WIND FLOW MODELLING To predict important characteristics of the wind resource at locations where measurements are not available using WAsP , (Wind Atlas Analysis Application Program) WAsP uses a potential flow model to predict how wind flows over the terrain at a site. WAsP is developed and distributed by the Department of Wind Energy at the  Technical Universityof Denmark ,  Denmark

69.      WIND FARM MODELLING Simulate the behavior of a proposed or existing wind farm, most importantly to calculate its energy production using Meteodyn WT, WindFarmer , WindPRO and WindSim .

70. WIND MONITORING STATIONS IN INDIA

71. WIND RESOURCE MAP OF INDIA Source : Indian Wind Atlas

72. Wind Monitoring Stations WIND MONITORING PROGRAMME Source : C-WET

73. Potential Stations WIND MONITORING PROGRAMME Source : C-WET