Verzijlbergh explained that Belgian wind farms have an advantage over Dutch ones. “They are located southwest of the Dutch parks and the wind often comes from the southwest, so you often steal some of our wind,” he said.
Umm, my guy. It sounds like it’s their wind and they graciously pass on their leftovers instead of “extracting” all of the wind.
It was then that the Dutch poldered the Netherlands out to upwind of the Belgian wind farms.
In an interview with Belgian broadcaster VRT, Verzijlbergh said: “A wind turbine is designed to extract wind from the air. If you measure behind a wind turbine, the wind blows less hard. Behind a wind farm with many wind turbines together, you really see lower wind speeds.”
To me this does make ‘scientific or math sense’. But, how dramatic is it?
Let’s take windmill like in the example, it has 3 blades, each maybe at most 5 degrees wide (out of the 360 for a circle). So that covers 15 total degrees or 1/24th the wind area, so at absolute best, it’s about 4% of the wind power in that area being stopped. But the blades don’t actually capture 100% of the wind power, a good amount will deflect off, those blades are not 5 degrees wide, they’re less and they aren’t straight blades, so again they capture less. Further the blade only captures a small vertical section of its own footprint, so it captures dramatically less wind power. Lastly blades are spaced with a good amount of clearance from each other leading to even less wind power captured. In aggregate, even by entirely layman measure, these likely have an immeasurable impact on another wind farm.
I’d bet if you built a mile high, mile wide wind capture device that captured 100% of wind power going to it, and then put a 2nd one 1 mile directly behind that, you could just maybe get a few % measurable impact.
To add to this, it is literally impossible to capture 100% of wind power, even in theory, because that would mean bringing the air to a full stop, halting flow. The air must retain some of its energy to continue moving through the system. The theoretical maximum is a little under 60% according to Betz’s Law. See: https://en.wikipedia.org/wiki/Betz’s_law
