I've re-checked a few times now, and it's 3500 cf per MWh of heat, which means 7000 cf per MWh of *electricity* from a combined-cycle gas turbine that's 50% efficient.
But, of course, the 200T mass of the wind turbine is silly. It forgets the heavy concrete foundation, but I'm good with that as I bet the foundations last a century, like most concrete foundations, and you can wear out 5+ turbines planted in it. (I think that's why nobody mentions the concrete.)
Most of the mass is steel, and that's 95% recyclable by an existing waste stream we can assume. I think the generator parts are the same.
It's just the blades, and those seem to run about a ton per four metres, as they get big. I think the wind turbines of the future are going to be more like 10 MW, which is a 75m blade, so I'll go with 75/4 = 19T per blade, or 57 T/turbine (10MW)
But wait! I screwed up something else. Wind turbines on land are only at a 30% capacity factor, so over time, a 10MW turbine would be more like a 3MW generator, on average.
So the final numbers are 7000 cf/hour/MW X 3 MW X 0.0052 lbs/cf / 2.2 lbs/kg = 50 kg/hour (average of many hours).
So it would take 57000kg/50kg/hr = 1140 calendar hours. Or 48 days.
Summing up: in 48 days, a 3MW gas plant running 7x24, would produce about the same energy as a 10MW wind turbine running 48 days.
The 3MW gas plant would have burned 57 tonnes of methane to do that.
The 10MW wind turbine would have a coming debt of 57 tonnes of icky composite-material blades to get rid of somehow. 19.7 years later.