Financial pressures and the economics of expansion may mean it’s time to reconsider the assumptions that drive offshore wind designs.

Just over 20 years ago, the UK saw its first commercial offshore wind farm go into service close to north Wales resort Rhyl. Thirty turbines with rotors 80m in diameter each fed a maximum of 2MW into the grid. These windmills are now minnows compared with the behemoths that suppliers such as Siemens Gamesa and China-based Goldwind are now planting on the beds of shallow waters in the North Sea or Taiwan Strait.

The prototype of Siemens’ largest design installed in Denmark in late 2021 has a single rotor with a diameter of 222m. It can, at full pelt, generate 15MW of electricity: over seven times the power from each of the first crop of turbines off the north Wales coast.

Can they get much larger? The bigger you make the turbine, the less it costs to generate electricity. But there is another powerful driving force behind going beyond the height of the Eiffel...