The sea they plan to cover in turbines

Offshore wind power is about to hit the big time in northern Europe, yet 20 years ago many saw the plan to build such complex engineering in the middle of the sea as madness.

Laurence Knight investigates how the North Sea - once famous for its oil and gas industry - has now become the global centre for a carbon-free energy industry.

Wind enthusiast Dr Robert Gross of Imperial College London talks about the colossal scale of modern turbines. Mud enthusiast Dr Carol Cotterill of the British Geographical Survey describes the Ice Age landscape she has helped explore at the bottom of the sea. And sea enthusiast Michiel Muller of the North Sea Wind Power Hub describes his consortium's plan to build islands and generate lots of hydrogen.

(Picture: Wind turbines of the Thorntonbank offshore wind farm in the North Sea at sunset; Credit: Arterra/Universal Images Group via Getty Images)