Every day, twice a day, the broad sweep of Swansea Bay in South Wales presents a different face to the world. When the tide is high waves lap along its the three-mile promenade. When it ebbs a vast expanse of sand and mud stretches out half a mile to meet the line of the sea.

But the height of that tide, averaging twenty eight feet daily, is the reason a pioneering power company has chosen the area for a world’s first - the prototype of a giant lagoon to generate electricity from the awesome mechanical energy of the tide.

Swansea Bay has been a part of my life since I was a boy and I cherish memories of walks along its palm-lined promenade with my parents. The bay curves away from the entrance to the once bustling coal port of Swansea to the rocky headland of the Mumbles with its iconic Lifeboat station.