Gargantuan 22

Imagine something as tall as New York's Chrysler building, but spinning. China's Mingyang Smart Energy has announced plans for a colossal 22-megawatt offshore wind turbine, and standing in its presence will be an unprecedented human experience.

The feats of engineering in offshore wind are becoming almost comical in scale, for a simple reason: the amount of energy you can extract from a turbine depends mostly on its swept area. The bigger that swept circle gets, the more energy you can harvest – but also, the greater the bonus becomes for adding more length.

Put it this way: if your turbine has a 20-meter (85.6-ft) diameter, and you add one further meter (3.3 ft) to that diameter, you gain somewhere around 34 square meters (366 sq ft) of additional swept area. But if your turbine starts with a 50-m (164 ft) diameter, adding one extra meter of diameter brings in about 79 extra square meters (850 sq ft) of swept area, since that extra blade length is sweeping a bigger circle.

What's more, these huge offshore turbines are extremely expensive to install, and the economics of deployment and grid connection tend to work in favor of fewer, larger turbines than more, smaller ones.

Thus, the sheer size of these things is getting absolutely nutty. The H260-18MW turbine currently under construction by CSSC uses 128-m-long (420-ft) long blades for a ridiculous 260-m (853-ft) diameter and a 53,000-sq-m (570,490-sq-ft) swept area. That's 9.9 NFL football fields or 42.4 Olympic swimming pools when converted to standard journalistic units – ignoring the small area left unswept by its hub.

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