Metaefficient. The Enercon E-126. Rotor diameter is 416 ft.
Blades are much bigger than they used to be – the largest are now the equivalent of two end-to-end football pitches – and as a result turbines have to be significantly stronger to deal with the massive pressures imposed on the structure.
To make turbines stronger and minimize the risk of damage should they break, each blade on modern turbines now moves independently of the other blades, while high tech devices inside the turbine constantly measure loads on the blades and automatically adjust their calibrations in response to wind changes.
Further, with offshore wind clearly becoming a major, the turbines must be built to withstand severe weather, salt water corrosion, and be ultra rugged. Replacing a huge blade is difficult enough on land, doing so 15 miles out in the ocean might be nearly impossible.
Wind power is now at the point where economies of scale may make massive offshore wind a major force in renewable energy. Plus, unlike hydro, geothermal, and solar thermal, wind doesn’t require water, an increasing scarce resource.
One nit – strictly speaking, solar thermal doesn’t necessarily require significant quantities of water – you can dry cool the plant, at the cost of maybe a 5% loss in overall efficiency.