TIME and TIDE

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.

This is a stretch of the UK coast with a curious history: one remarkable for marking out the highs and lows of environmental sustainability. In medieval times the Normans built a castle to guard the bay and named it Oystermouth because of the fantastic bounty of shellfish in the bay nearby.

By the 17th Century the oyster harvest from West Wales was huge with two hundred boats landing nine million oysters annually; most of them destined for tables in London. Oystermouth was the centre of that trade until the 19th Century when the affects of two hundred years of the industrial revolution finally hit the oyster beds hard.

There’s no doubt overfishing played its part but the Swansea Valley, had become the world’s foremost producer of copper sheeting using processes which poured heavy metal pollution into the Bay. The harvest dwindled until the 1920’s disease had ravaged the weakened oyster beds and only the name of the Castle stood as a reminder of that bounty.

Then along came the Second World War and German bombers flattened Swansea with its strategic coal port and petrol refinery. The city centre underwent a post war regeneration, which has been largely viewed as a failure. Swansea has struggled to make it’s mark ever since.

What’s that got to do with a tidal power scheme you may ask? Well in my eyes everything. The River Tawe no longer spews out pollution into the Bay and a new project, led by the Mumbles Oyster Company, aims to re-seed the shellfish that made the area so successful. Another company is already commercially harvesting rope mussels in the old docks. What better complement to these new shoots of sustainability than a world’s first in clean power generation?

The tidal lagoon is indeed a remarkable concept. The idea is to build a roughly U-shaped 9.5 kilometre breakwater, twenty metres high, enclosing 11.5 square kilometres of seawater. They’ll use super strong geotextile bags, shaped like giant sausages, extruded with sand dredged up locally.

That geotextile array will be faced with stone to protect it from the sea and a roadway will be laid on top to service the lagoon but also as a public amenity. Within the lagoon sailing competitions and triathlons will be held. It will be a study resource for students from infant school to university and there’ll be aquaculture too with oyster beds, edible seaweed farms and health giving samphire will be grown.

Facing the sea will be an array of turbines, which will take power from the tide as it ebbs and again when it flows. That’s fourteen hours of generating time with the equivalent of 100,000 Olympic sized swimming pools flowing over the turbines daily.

That’s enough to power 150,000 homes and represents around 10% of the domestic needs of Wales. The working life of the lagoon is reckoned to be 120 years and the build cost around £1. 3bn.

Take a few minutes to watch this video, produced by the company involved, Tidal Lagoon Power. It explains the scheme far more eloquently than I ever could.

 

Opposition to the lagoon scheme is largely led by lobby groups who favour nuclear power or a discredited scheme to throw a barrage right across the Bristol Channel from Cardiff in Wales to Brean Down in Somerset.

They complain the cost of lagoon power will be too high but at Mojo we prefer to put the whole cost/benefit equation into the scales. So we ask how many nuclear power plants have the public enjoying a walk around their perimeters? How many sporting events do they host? And when did you last eat anything grown inside a nuclear power station?

Crucially, we ask, what happens to a nuclear plant at the end of, say, a sixty-year life span? It has to be capped to shield the environment from radiation and guarded against terrorist attacks. The truth is nuclear keeps on costing long after it stops generating.

For us the lagoon ticks all the boxes. It’s sustainable and it provides massive community assets as well as clean power. Hopefully it will provide thousands of jobs and act as a focal point for a new dawn for the city of Swansea.

Here at Bohemianmojo we’ve never been great fans of wind turbines. They’re expensive, wind is unpredictable, and let’s face it they kill birds. Solar power has its cons too. It requires massive amounts of mercury in the panels and we can’t help feeling they’re storing up environmental problems for the future. And, let’s face it, the UK is not famed for its optimal sunshine.

What we do have are tremendous tidal ranges with huge heads of power filled water to exploit. We feel strongly that tidal lagoons are the most effective and ecologically friendly way of harnessing that power yet proposed.

At the beginning of the year there was a very favourable review of he scheme by an independent expert. The UK government has yet to give the lagoon the go ahead. We hope they give this world beating prototype scheme at Swansea the green light. Others are planned around our coast and will surely follow.

And what will be left with at the end of the lagoon’s 120 years of working life? Nature will surely take care of that. The geotextile bags will eventually degrade and collapse and the boulders facing the wall will simply fall to the seabed. Swansea Bay will then be left with a fitting legacy; a reef teeming with life.

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