The website itself lists the output of the unit, and for a strong average wind, output is expected at about 3000 kWh per year (they don’t mention year, but the numbers work out). Since power is worth roughly 15 euro cents per kWh, you multiply and get 450 EUR of output per year. Divide the price tag by the output, and get:
Wind also has the interesting physical property of the energy content being relative to the CUBE of its speed. If the average wind speed were cut in half of this example, you can cut your output by 8x, and therefore multiply your time of return by 8, giving you 500 years.
I’m doubting something with that may rotating parts will last much more than 10 or 20, which makes this a net loss in energy, money and sanity.
Does no one check these things before propagating memes, articles, or investing?
Here is the link if you care to do the math yourself: