Ross Jennings for The Conversation:  The world’s tides contain enough energy to power the entire UK’s electricity consumption. And, since it effectively harnesses the moon’s constant and predictable gravitational pull, tidal power overcomes one of renewable energy’s classic problems – the fact you never know quite how much sun, wind or rain to expect. Now, underwater windmills positioned just below the ocean surface could be a major breakthrough for tidal power.

Costly technology and inaccessible locations have thus far held things back. Large, heavy and expensive turbines mounted on the seabed have been developed, but these are aimed at commercial scale developments. Tidal power needs its equivalent of the rooftop solar panel.

Imagine then a wind turbine, but underwater, and not fixed to the seabed – these so-called “mobile floating turbines” are a cheaper and more adaptable alternative to big, fixed developments. Most floating turbines look something like this:  Cont'd...