SOLA 5053: Assignment 1 2025

The Wind Resource

DUE: by 17th  March 5pm

Out of 75 (includes quality mark worth 5 marks – 70+5) worth 15%

Submit via Moodle. All work will go through Turnitin.

Understanding the wind resource

Weather and climate [12 marks]

Question 1

(a)    Figure 1a shows the location of the wind farm sites all the wind farms in the South and SE States.

Figure 1b is the associated MSLP chart, which corresponds to around Monday 10th  February 2025 (a snapshot at 11am). By looking at the synoptic map (Figure 1b), name all the features marked with blue arrows (4 in total), and in a short sentence explain their effect on the weather.           [4 marks]

Figure 1a. Location of the wind farms in the SE and Eastern states.

Figure 1b. MSLP chart associated with Fig. 1a.

(Hint: You may wish to refer to the following webpage on the Australian Bureau of Meteorology website which describes the motion of air in high and low pressure systems with animations, and provides a basic introduction to weather maps and isobars:www.bom.gov.au)

(b) The wind farm energy production by capacity is shown in Figure 1d for Tasmania, and one wind farm in Victoria. As you can see it is highly varied depending on location and weather. Looking at all Figures 1a. 1b and 1c, 1d, note down how the weather system will impact the wind farms in Tasmania, relate it back to the capacity data. What could have made Bald Hills wind farm so high? (Note you may need to go onto the website https://anero.id/energy/wind-energyto see the names of the farms)    [4 marks]

Figure 1c, zoomed in of 1a

Figure 1d. Capacity factor of wind generation from Tasmania and Bald Hill wind farm Vic.

(c) Looking at Figure 1a. Note down on a state wide level (NSW, VIC, SA and Tas) how each state performs overall in relation to the weather map (weather systems each state is experiencing) in Figure 1b. What can we conclude about grouping of wind farms based on your findings?               [4       marks]

https://anero.id/energy/wind-energy

Weather maps [12 marks]

Question 2

Figure 2 and 3. MSLP chart for Winter and Summer, retrieved from the BoM

http://www.bom.gov.au/australia/charts/synoptic_col.shtml.

a)    Produce a table stating the relative wind direction (using the meteorological convention) for each location, for each chart. Format your table in the same way as Table 1. Note (for relative wind speed strength choose between calm-gentle; moderate; strong)[9 marks]

b)   Discuss how the wind power production with the evolution of the weather pattern in winter (Fig.

2 - July) would change over the 3 locations. Refer to the current situation, and knowing how the pressure systems move from west to east explain how the States locations power production would change as the systems move across.           [3 marks]

The atmosphere [16 marks]

Question 3

The following information is for the questions below:

Location 1 – near Perth Airport WA

Annual average Surface temperature –  18.8 C

Annual average Mean sea-level pressure (MSLP) –  1015 hPa

Elevation – 20 m above sea-level

Surface profile – forest land

Scale height – 8000 m

Atmosphere – dry

Location 2 – near Mudgee, NSW

Annual average Surface temperature – 15.5 C

Annual average Mean sea-level pressure (MSLP) – 1019 hPa

Elevation – 471 m above sea-level

Surface profile – farmlands isolated trees and small buildings

Scale height –  8500 m

Atmosphere – wet

R= 286.9 [J/kg K]

Turbines with a hub height of 100 metres exist at locations 1 and 2.

[IMPORTANT NOTE: MSLP at a location refers to what the surface pressure would be at that location  if it were at sea-level, that is 0 m elevation. The actual pressure at the ground level will be different if it is elevated.]

For BOTH locations:

[NOTE: marks are total for both locations, under each answer first calculate Location 1 and then Location 2 – see Figure 5]

(a) Calculate the density of the air at hub height.                                                                           [6 marks]

(b)  Estimate  the gradient wind speed  using the  isobar  spacing  and  the  equation for geostrophic balance and the data provided for the gradient height in Figure 5. Clearly mark on the map the Δx selected to evaluate ΔP.                                                                                                                       [6 marks]

Figure 5. Locations for question 3, part b. Retrieved from BoM

Table 2. Gradient height data [1]

(c) Based on your answer to part b) and using the data provided for the roughness length scales in Table 2, estimate the wind speed at hub height. When selecting a roughness scale, pick a mid-point value.                                           [4 marks]

Characterising the wind resource [20 marks]

Question 4

a) Consider the data in the excel spreadsheet which represents recordings of wind speed taken at the Mudgee BoM station at 10m above ground level in km/hr. Using the hourly values determine the factors 'c' and 'k' for the year 2015. Show all relevant calculations (you can use excel/python to sort the data, and remember the units) .             [3 marks]

b)   In the same excel spreadsheet there is also data for the same latitude and longitude as the

Mudgee station, but from MERRA-2 reanalysis data (100m height) for the year 2015. Using the hourly values determine the factors 'c' and 'k' for the year 2015. Show all relevant calculations.   [2 marks]

c)     How do the values for ‘c’ and ‘k’ compare from the two different datasets? Comment on what could be a cause of any differences in values.                                            [3 marks]

d)  The  ``c''  and  ``k''  parameters  that  you  calculated  in  Q4-a  were  obtained  from  a  bureau  of meteorology (BoM) weather station closest to Location 2 (from Figure 5). The data was recorded at 10 metres elevation (above ground level) and the nearby terrain is farmland, with few trees and buildings. You are considering expanding the Crudine  Ridge Wind  Farm  (134  MW).  The area you propose is predominantly open grassland. The turbines you wish to install will have a hub-height of 100 metres.

(i) Determine the “c” and “k” parameters that are relevant for your prospective wind farm at the wind farm site (using the BoM data). Show all working (explain all working and include a  print screen of the excel/python sheet used to determine the factors).  [4 marks]

(ii) Translate the “c” parameter at hub height (100m) at the BoM station location, and calculate the ‘’c’’ and ‘’k’’ values for the MERRA2 data tab Crudine Ridge Wind farm. Using the three values of “c”(station, station translated wind farm and MERRA2 Crudine Ridge Wind farm), calculate the power potentials (wind power per unit area) at:

•    Hub height at the station location

•    Hub height at the wind farm location

•    Hub height using the MERRA data in the tab Crudine Ridge wind farm    [4 marks]

e) Comment on the implications of any differences for predicting the wind power potential. Give two reasons why wind data from a weather station should not be directly used when predicting the wind  resource for a nearby wind farm (justify your reasoning).           [3 marks]

f) How does the MERRA2 data at the site (tab named MERRA2 Crudine Ridge Wind farm) compare to your translated wind farm potential data?                                                                                      [1 mark]

Wind farm performance [10 marks]

Question 5

The following questions will use the Weibull parameters calculated in questions Q4-d (for the wind farm location at hub height and the MERRA2 wind farm location Crudine Ridge wind farm) and the wind turbine power curve in Table 4.

(a) Present the following graphs for both sets of Weibull parameters:

(i) Weibull PDF  (ii) Weibull CDF

Present results of both sets of Weibull parameters on a single set of axes and comment on the differences you see between the two values used.                                                         [3 marks]

For both sets of Weibull parameters for the following questions:

(b) (i) Present the velocity-duration curve (present results of both sets of Weibull parameters on one set of axes).

Hint: You will first need to bin wind speeds in 1 m/s increments and calculate the probability of each binned value of wind speed using the Weibull CDF for both sets of Weibull parameters.  Use this information to determine the number of hours per year that the wind is blowing within each bin range.  [4 marks]

(ii) Calculate the annual energy production and capacity factor for a single turbine installed at the wind site.                                                                                                                                         [3 marks]

Table 3. Wind Power Table Data [http://wind-data.ch/tools/powercalc.php]