Marine Renewables Industry

Brian Mathew Excerpts

Thursday 16th January 2025 Westminster Hall

[Brian Mathew (Melksham and Devizes) (LD)]

I thank my right hon. Friend the Member for Orkney and Shetland (Mr Carmichael) and everyone who has spoken so far in the debate.

Back in 2009 I was involved in an as yet conceptual tidal project known as the reef. It was projected to stretch from Aberthaw in south Wales to Minehead in Somerset, a distance of some 17 km. It was designed by Rupert Armstrong Evans at the behest of the University of Southampton, which asked Mr Evans to design a scheme that would be environmentally benign and would generate significant energy for the UK.

You will no doubt be aware, Ms Jardine, that the tidal difference in the Bristol channel is the second largest in the world. The idea of a tidal barrage in the Bristol channel is not new, and the location of the reef on the Aberthaw to Minehead line was first suggested in the 1930s as being the best place to generate electricity and energy from the tides in the Bristol channel.

In 2010, when the current Secretary of State for Energy Security and Net Zero was Secretary of State for the then Department of Energy and Climate Change, he announced funding for investigations of embryonic tidal technologies. Rolls-Royce and Atkins won the contract to do the study, and their work showed that a tidal scheme on the Aberthaw to Minehead route would generate per year 30.4 TW hours of electricity, significantly more than the Cardiff to Weston-super-Mare line, which was in the region of 20 TW hours per annum.

The Aberthaw to Minehead line has the added advantage that it has no mud—unlike Weston-super-Mare, as anyone who has visited Weston in the summer will know. Its seabed is rock all the way across and so has greater possibilities for locking tidal caissons holding large turbines to the sea floor. The design of the reef would allow for a maximum of 2 metres head on both the incoming and outgoing tides, which would mean that fish could safely swim through the large turbines without getting hurt. That is a big factor, and one reason for the rejection of previous tidal schemes in in the Bristol channel.

Other factors to consider are, first, that 30.4 TWh per annum is larger than the expected annual output of Hinkley Point C, which is 30.2 TWh. Secondly, a degree of energy storage from the reef would be possible.

[Gideon Amos]

I thank my hon. Friend for making an excellent point about the centrality of Somerset—in particular, the Minehead route just north of Taunton—to renewable energy. Does he accept that tidal range and tidal barrages and lagoons could make a significant contribution? As he pointed out so well, Swansea lagoon would have done up to 30 TWh, but we could do that across the UK. There could be tidal lagoons in Morecambe bay and in Cumbria, where one was proposed. That would bring investment to regions across the UK and not just benefit the south-west and Somerset.

[Brian Mathew]

I thank my hon. Friend for his points, which of course are true. This technology could be employed right across the United Kingdom and its amazing coastline.

A third advantage would be that ships could pass up and down the Bristol channel via large floating lock gates. Fourthly, the project could be upgraded over its life so that it would effectively be time-unlimited, even with sea level rises. A fifth point, which could well be applied to renewable schemes across the UK, is that the excess energy—or the energy that the grid cannot use at any particular time—could be diverted into the manufacture of synthetic fuels. That would be one way of dealing with the problem of what to do when we generate energy and there is no call for it. In short, this project is well worth further investigation.