Heat wave: how Orkney is leading a tidal power revolution

Strong tides make conditions in the Scottish islands ideal, but can the UK grasp the opportunity to become a leader in the sector?

On a small passenger boat about 10 miles north of Kirkwall, Orkney, at the point where the Atlantic Ocean meets the North Sea, an immense yellow structure heaves into view. This is the world's most powerful tidal stream energy generator, Orbital Marine Power's O2. Its shadow quickly dwarfs the tiny vessel.

Today, the generator's turbines are raised above sea level for maintenance. It is difficult to comprehend the O2's scale until a worker appears, a tiny stick figure against the hulking turbine.