Community energy makes sense for 2,000,000-watt windmills like the ones in your first article, but not for a 600-watt rooftop windmill that's less than a meter across. The 2,000,000-watt windmill ought to cost less per watt, but it requires successfully coordinating the community to support it (cf. the note in your third link about a "de facto ban on new onshore wind projects" being lifted). And looking at https://www.canarymedia.com/articles/wind/chart-wind-turbine... it looks like over the period 02015 to 02022 the prices of big windmills consistently stayed in the range of 80¢ to 130¢ per peak watt, which is actually more than the 50¢ per peak watt of the mail-order Amazon rooftop windmill. (The rooftop windmill will probably enjoy significantly lower capacity factors, but it's clearly in the same ballpark.)

This was surprising to me, since I thought big windmills were much cheaper per watt, so I dug a bit further. The figures check out. The current https://www.bbc.com/news/articles/c80kv5d7lp7o says a £40 million (US$52 million) onshore Manx wind farm might have "up to 5 turbines", and thus up to 10 megawatts, putting the total project cost closer to US$5/Wp. https://www.eia.gov/analysis/studies/powerplants/capitalcost... from 02019 has a capital cost breakdown of a 200MW hypothetical wind project costing US$253 million, consisting of 71 2.8-MW windmills, totaling US$1265/kW (127¢/Wp). About 60% of that (80¢/Wp) is "WTG [windmill] procurement and supply". A 50MW hypothetical wind project in the next section comes in at 168¢/Wp, and a 400MW hypothetical offshore wind project in the next section is 438¢/Wp.

So it's not at all clear to me that community wind energy, or utility-scale wind energy in general, is even cheaper or more efficient than mail-order rooftop windmills. It might be more expensive!

Building my own solar power system