The Engineer Q&A: The Severn Barrage

The Severn Barrage is an idea that refuses to die. People have been proposing and dismissing building a barrage across the Severn Estuary since 1849 – meaning the concept is seven years older than The Engineer. The estuary holds an estimated 8 to 12GW worth of theoretically harnessable power, and now with climate change targets making the need for renewable energy more urgent than ever, the Severn Barrage is once again up for debate.

Over the last few weeks, MPs on the Energy and Climate Change Committee have been hearing evidence for and against building a barrage, so we’re likely to hear some kind of official pronouncement later this year. The government’s official position (based on a 2010 feasibility study) is that there is no strategic case for public investment in a Severn tidal scheme in the intermediate term, so if a barrage were to be built it would likely be a privately funded development.

The debate around such a scheme is a complex one due to the busy shipping lanes that run through the Severn and the potential environmental issues it could create. But given that very few tidal barrages of this size have ever been built anywhere in the world, there are also big questions around what building a Severn barrage would actually involve. Indeed, there’s also the question of whether a barrage is the best way to harness the immense tidal power of the estuary.

As the Commons hearings continue, we’ve assembled our own panel of experts to answer your questions on what are the engineering challenges in building a barrage in the Severn, whether and how we can physically and economically overcome them, and what other options might we pursue for generating electricity from the tides.

Answering your questions will be:

  • Hafren Power – a private consortium proposing the construction of a Severn barrage
  • Tidal Electric – a US firm that specialises in tidal pool technology
  • Prof Roger Falconer – president of the International Association for Hydro-Environment Engineering and Research, and director of the Hydro-environmental Research Centre at Cardiff University, an expert who has spent years studying the issue
  • Norman Haste – former project director for the Second Severn Crossing
  • Dr Peter Tavner – emeritus professor at Durham University’s School of Engineering and Computing Sciences, an expert in large renewable energy projects and the technology of turbines, generators and grid connectors.

If you wish to put a question to one or all of our experts, please post a comment below before midday on Thursday. We’ll then collate and forward the questions to our panel and publish the responses online next week and in the next digital issue of The Engineer.

While they may be able to address some environmental points, our experts are best positioned to answer questions related to the engineering challenges of generating electricity from a barrage or other tidal technology and the practical difficulties of building and operating a large structure in the constantly changing environment of the Severn estuary.

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