Theory 091/Energy & Environment /Wind energy
Wind Farms Are a Spacing Problem
Turbines are compared by efficiency. The farm's output may be set by how far apart they stand.
Wind farm power density is set by turbine spacing rather than by turbine efficiency, so larger, more efficient turbines in a tight array can produce less per hectare than smaller ones spaced further apart.
01The evidence
Farm-level power density varies widely and is lower than single-turbine efficiency would suggest, with the gap attributed to wake losses.
02The tension
Performance metrics focus on capacity factor per turbine, which predicts farm output by multiplication and ignores the wake interactions that set the limit.
03The mechanism
A turbine extracts energy from the wind, leaving a slower wake. Downstream turbines recover only as the wake mixes, so the fraction of the resource available to a farm depends on spacing relative to rotor size.
That makes the spacing-to-diameter ratio the determinant, and predicts farm power density should peak at an intermediate spacing rather than at maximum density.
04What this is not
Those metrics multiply by count. This accounts for wakes, which sets a density optimum.
05Predictions
- P1Farm power density should peak at intermediate spacing.
- P2Tight arrays should underperform despite efficient turbines.
- P3Spacing should predict better than turbine rating.
06Refutation
Farm output scaling with turbine count at controlled spacing would restore per-turbine metrics.
07What it changes
It would change wind farm layout planning.