A refinement of the Band spreadsheet for wind turbine collision risk allowing for oblique entry

Figures & data

Figure 1 An exported section of the revised spreadsheet showing the probability of collision for a South Island pied oystercatcher entering the turbine at an angle of 35° when the wind speed is 5 m/s is 8.6%. Columns G to J hold a simple application.

Table 1 Calculated collision risks for the South Island pied oystercatcher and white-tailed eagle.

		South Island pied oystercatcher			White-tailed eagle
Wind speed (m/s)		0	5	10	0	5	10
(a)	Standard Band sheet average risk (%)	6.3	6.3	6.3	8.5	8.5	8.5
(b)	Average of true upwind and downwind risks (%)	6.3	7.1	9.3	8.5	10.1	18.1
(c)	Average risk over 360° using the new sheet (%)	5.8	6.2	7.5	10.9	11.6	16.1

Figure 2 Probability of collision for the South Island pied oystercatcher at wind speeds of 0, 5 and 10 m/s calculated using the new spreadsheet. The dotted line shows the risk assumed by simple application of the Band spreadsheet ignoring wind speed.

Figure 3 Probability of collision for the white-tailed eagle at wind speeds of 0, 5 and 10 m/s calculated using the new spreadsheet. The dotted line shows the risk assumed by simple application of the Band spreadsheet ignoring wind speed.