Long-distance wake affects nearly all US sites

Almost 90% of all operational US wind farms in 2016 were close enough to other projects to either cause, or be affected by, wake effects.

Of the 994 US wind farms in 2016, nearly 90% were within 40km of another project (pic: GE)

The most severe wake effects can reduce an owner's revenue from a wind farm by several million dollars over a six-year period, according to the paper, published in the Nature Energy journal.

However, researchers from the University of Colorado Boulder (CU), the University of Denver (DU) and the National Renewable Energy Laboratory (NREL) found that wake losses can be anticipated and managed.

"This work argues for more thoughtful deployment of wind energy," said Julie Lundquist, a researcher at CU, and lead author of the study. 

Wake effects have been observed to extend typically up to 40km, the researchers stated.

Of the 994 individual wind farms in the US in 2016, nearly 90% were within 40km of another project — all of which could be subject to, or cause wake effects.

During the researchers’ one-month study, power production dropped by 8% at a downwind facility when an upwind site was included in their simulation.

The most severe wake effects also only occur less than 4% of the time — meaning wake losses can be anticipated and managed.

In "stably stratified atmospheric conditions", wakes can extend to more than 50km downwind, the authors wrote in the abstract for the paper, Costs and consequences of wind turbine wake effects arising from uncoordinated wind energy development.