Back in 1985, a typical wind turbine stood around 25m tall (just over 82ft) and had a rotor diameter of 15m (49ft). Today, offshore turbines loom like skyscrapers over the water, some of them hoisting rotors with diameters that span almost 220m (722ft) – the Haliade-X turbine, installed in the Dogger Bank Wind Farm off the east coast of England, for example.
The reasons for this are two-fold. First, larger turbines are more efficient; doubling the length of its blades lets a turbine capture four times as much wind. Wind speed tends to increase with altitude, too, so taller turbines harness more energy and produce more electricity. Second, bigger turbines are smoother, steadier and more reliable.
This was always the case, of course. What has changed in recent years is…
