1. Wake Influences on Power Wind Speed, Wind Direction, Stability

2. Plots chosen by: - Large enough sets of data to be representative - Some type of trend visible with potential explanation Other variables that could be similarly investigated: - Pressure (at turbine height) - Turbulence - Net Radiation (as an indicator of cloudiness) - Temperature - Precipitation - Heat Flux

3. Here the drop in wind speed throughout the line of turbines is clear, even for cases where most turbines are off. The corresponding power loss for East and West winds is also shown. There is significant spread to the even the middle 50% of data at each turbine (indicated by vertical lines). The following graphs investigate atmospheric factors behind this spread.

4. Power loss is plotted against wind speed for each turbine during East winds in the evening at the A line. Here power is lost but recovered through the line of turbines. This pattern changes at various speeds Wind Speed

5. The same plot, for the B line of turbines. Here the greatest observed loss in power is around 7 m/s. This is fairly consistent with other data from the A line, and from other times of day.

6. The same plot, for morning winds. Here the power lost after the first turbine recovers much better in the 5 - 6 m/s range. The greatest initial drop in power occurs at the second turbine, but varies up and down as wind speed increases.

7. Wind Direction Power loss is plotted against wind direction for each turbine during East winds at the A line. Power loss is most severe as winds move straight down the lines of turbines. Power seems to recover faster during winds from just South of East compared to North,, possibly due to interference from other turbines

8. The same plot, for West winds at the B line. Here the power recovery pattern is roughly symmetric to the 270 degree (due West) axis, with better recover from the South, possibly because there are no additional turbine wakes causing interference at that angle

9. Stability Power loss is plotted against stability for each turbine during East winds at the B line. Power recovery is quickest during in ranges of about +/- 400

10. The same plot, for East winds at the A line. This plot mirrors the previous, with optimal power recovery around the +/- 400 range for stability.