Wind turbines, particularly en masse, reduce the energy production of their downwind neighbors. This wake effect has been observed up to 45 km (28 miles) and longer offshore. In the US 90% of wind farms are located within 40 km of another facility.
Lundquist et al. modeled the energy reductions and studies a test case in Texas. They write “In our Texas case study, the downwind wind farm suffered an estimated generation loss of roughly 5% from Nov 2009 to Dec 2015.”
I guess I’m not surprised by this in the slightest. The energy has to come from somewhere, and if you take it out of the wind “here” it stands to reason there’s a bit less “there”. I can observe the effect just by standing on one side of my house (which is wide open to the wind) and walking to the other (which is not.)
Nothing we do is without some kind of effect.
In another thread yesterday (and I don’t remember which) there was a video about the vast Tulare lake in California which was drained to make way for farming. According to the film the lake was so large it created enough evaporation and subsequent rainfall that parts of Nevada, now desert, were verdant and lush. I had not known this history, and found myself wondering - “except for the obvious detrimental effect on current farms there, why wouldn’t California want to reconstitute the lake, help its chronic water management problem, and get Nevada to help with it besides?” I suppose it would take a TVA scale project which only the Federal Government could achieve, and given the dysfunction in Washington and the opposition to anything Federal it seems unlikely.
Offshore wind farms reshape the North Sea
Downwind of the wind turbines, the so-called atmospheric wakes develop. These are characterised by reduced windspeed as well as specific pressure conditions and enhanced air turbulence. During stable atmospheric circumstances, the wind speed deficits spread up to 70 km behind the wind farms.
Using high-resolution hydrodynamic computer simulations, the team analysed the effects on the southern North Sea for the summer of 2013 (May to September)…The wake effects are sufficiently potent to redirect the existing currents. This results in shifting mean temperatures and a changed salinity distribution in the wind farm areas. “While the occurring changes remain within the range of interannual variability, they illustrate similar magnitudes as the presumed mean changes due to climate change or year-to-year variability,” says Nils Christiansen, from the Hereon Institute for Coastal Systems, who was lead author on the study.
Another wake effect is the reduction of shear-driven processes at the sea surface. In other words, the turbulent mixing of the water surface caused by shear wind is reduced dozens of kilometres around the wind farm…
"The magnitude of the induced mean changes does not indicate severe local effects, however far-reaching structural changes in the system occur“, says Christiansen.
This is very old information. All the wind turbine suppliers, the utilities, the grid operators and the government regulators know about these situations. Regulations and placement of wind turbines/farms have taken these situations into account.