Your questions answered: building a Severn barrage

Plans for an energy-generating barrage across the Severn Estuary have been on and off the table for decades. The government has ruled out a publicly funded scheme but is currently listening toproposals for a privately funded one.

For our latest reader Q&A, we put your questions on the challenges of harnessing power in the Severn to a panel of experts.

Providing answers are:

Is it really necessary to build a barrage in order to harness the Severn’s tidal power?

Having studied all forms of the hydro-environmental aspects of the Severn, I believe a barrage provides by far and away the most effective means of harnessing this energy. The power that can be theoretically obtained from a basin is proportional to the wetted plan surface area and the square of the head difference across the structure. We know that the Severn Estuary has the second highest rise and fall of tide in the world, but in addition if a barrage is built roughly along a line from Lavernock Point in Wales to Brean in England then this captures a plan surface area at high tide of approximately 500 square kilometres. This is a huge surface area and offers us the opportunity to generate a unique large amount of secure renewable energy for at least 120 years, and probably many centuries well into the future.