Gareth Clubb says a Severn barrage could become one of the most expensive renewable energy schemes in history

January 30th, 2013

Writing on this site a few weeks ago (here) Peter Hain extolled the supposed virtues of a Cardiff to Weston barrage across the Severn. The former Secretary of State for Wales and his colleagues at Hafren Power are of course at an advantage in describing the new proposal. That’s because no-one else has seen it. The barrage proposal – described as ‘inchohate’ by the developers (that is to say, not fully formed) – has never seen the light of day. That means its proponents get bucketloads of free media coverage while those of us who have concerns are left to hypothesise.

Meanwhile, at the Welsh Affairs Select Committee a couple of weeks ago I presented evidence that contradicts many of Hafren Power’s claims. To my surprise, Peter Hain did the same the following day at the Energy and Climate Change Committee. It seemed like a peculiar strategy for the project’s principal cheerleader to dismantle his own side’s viewpoint so skilfully.

Peter Hain said that it would “clearly be necessary” to un-designate the Natura 2000 habitat in order to proceed with the project. This is something that has never happened before, and would need to be agreed by the European Commission. Let’s remember that Pembroke power station – itself the centre of a European Commission infringement procedure as a result of a Friends of the Earth Cymru complaint – related to one Special Area of Conservation. The Severn barrage would impact on 19 Special Areas of Conservation, 5 Special Protection Areas and 5 Ramsar sites. Suffice to say that un-designation would be contentious. Compensatory habitat would be of a scale 30-60 times greater than any previous scheme in the UK.

But let’s look at some of the claims of Hafren Power. Peter Hain said:

“It will generate fully 5 per cent of the UK’s electricity needs, that is… the equivalent of three or four nuclear reactors and over 3,000 wind turbines. There’s nothing like it on the horizon for renewable energy generation”.

The most authoritative anaylsis yet of the costs of generating electricity from solar power indicate that we’ll reach grid parity by 2016 (also for onshore wind). So in three years’ time, it will be cheaper for households to generate their own electricity on rooftops than it will to buy it from the grid. That’s a game-changer. We’ve seen Germany’s solar production go from less than 1 per cent of electricity in 2008 to 5 per cent in 2012 – and that’s in a situation where it has yet to reach grid parity. Given that Hafren Power’s contraption won’t be powering a single light bulb until 2025, that it expects subsidies for 25 years, and that in contrast to nuclear, renewable technologies are getting cheaper as time goes by, I’d say that both solar and wind are very much on the horizon. In just four years, Germany is producing more electricity from solar than Hafren Power’s barrage will ever do. What’s more, the jobs in solar are high quality and right across Germany, not in a few sectors in one small geographical area.

Ah yes, jobs. We’re told that there will be 20,000 jobs in construction. The Department of Energy and Climate Change and the Welsh Government have looked into this issue. Their analysis? A best guess that we’d end up with 120 net jobs provided in Wales and south-west England. At around £283 million per job, it would be the most expensive job creation scheme in history. We’re also told that 500km2 would be protected from flooding, when a previous government-commissioned study indicated that flooding problems would be worsened for 370km2 – and 45,000 residential properties – as a result of a barrage.

Friends of the Earth Cymru have long promoted tidal lagoons as part of a package of measures to make decent contributions to renewable energy generation in the Severn estuary. A 400 MW lagoon proposal in Swansea Bay is in the pre-application stage, while another one offshore at Aberthaw has also been suggested. What’s more, tidal lagoons can be replicated – with great learning and export potential – along the north Wales coast, as suggested by Sir John Houghton. Alongside tidal stream generation and the Atlantic Array wind development, the Severn will soon be generating plenty of electricity for Wales.

The siren call of the Severn barrage, a 10-mile concrete wall in the Severn estuary producing incredibly expensive electricity, destroying priceless habitats, making fish populations extinct and increasing flood risk in Wales. That’s the side of the story that Hafren Power don’t like to mention. And that’s why the Severn barrage will remain science fiction now and forever.

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Gareth Clubb is Director of Friends of the Earth Cymru

6 Responses to:“How Peter Hain contradicts himself”

  1. David Morris Jones says:

    An excellent letter from G Salter in the latest edition of the “Penarth Times” weekly newspaper also spells out some major concerns – not least that the barrage might, in effect, considerably reduce the tidal range of the Severn Estuary. This is what Mr Salter wrote: –

    “Certainly the debate up to now is curiously lacking in technical data. There are several major problems as I see it, about which, so far, I have seen no discussion.
    Some are as follows:

    1: The extraordinary range of the tide in the estuary is solely due to its shape. It is recognised that its unique height is due to an effect known as “tidal resonance”. Once this shape is altered by, say, a full width barrage, the tidal range may revert to that of the open sea. At best it will probably be halved, so reducing the “head” available for generation.
    2: The head available will depend upon the height of the impounded water behind the dam. If it is kept at maximum tide height then generation could be possible at most of Ebb and Rise. To achieve this, however, might result in the water above the barrage slowly becoming fresh or brackish due to the many now impounded rivers feeding it. But we all know what happened to Cardiff Bay in the years of transition with its plague of flies and need for oxygenation.
    3: The water impounded could be kept at lower or variable height but this would mean generation for a limited period each day and might call for reversible turbines.
    4: It is likely that full power would not be available for 24 hours in any barrage scheme. Accordingly conventional power stations of the same capacity or the grid generally would have to be available (on a tidal schedule) to ensure continuity of supply.
    5: It is thought that reducing the tidal flow would increase silting and that continuous dredging would be needed above the barrage after some years.
    These are just a few of the questions that occur to a layman and that our politicians do not seem to have addressed. We really need a new and comprehensive study by experts before rushing into a scheme that may not have as much promise as forecast. Certainly Tidal Flow schemes not needing a barrage would seem to pose less problems. G Salter”

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  2. Mark says:

    Quick comments….some good points, some not so in my view.

    Most renewables cannot supply predictable base load. The Barrage can and help fill an energy gap that will exist into the 2020s. The only other options for base load are gas (imported and not dependable), coal (really!) and nuclear (with unknown de-commissioning costs and well known safety risk) – but I accept we will need some of all these.

    With the smart grid becoming a likelihood in the 2020s, demand will be more easily matched to the generation patterns of a barrage.

    The flood analysis reference was based on the old barrage design of only energy production on the ebb tide. The new barrage will produce on both tides (~16hrs per day) and does not have a significant downstream impact and yet will protect a huge amount of low lying land upstream. A paper on this is I understand due to published shortly.

    It’s matter of basic physics that a Cardiff/Western Barrage is the most cost effective way of generating the most energy. The energy captured is based on converting the kinetic energy of a large volume of water, which for the barrage is the surface area multiplied by the height differential. All this water is forced through the turbines and is converted to mechanical energy in the turbines and then to electrical energy. A lagoon is, in effect, a smaller version of a barrage, but require more £/MW to construct as you have to impound water on all sides (whereas the coastline provides most of the impoundment for the barrage). The actual o/p of the barrage is also far in excess of a lagoon…Similarly a tidal fence only generates energy based on the water flowing directly through the fence turbine (in the same way as a wind turbine)…so much of the energy is not captured.

    The barrage can operate for >100 yrs (unlike wind, nuclear, etc) so will have the lowest overall costs for the life of the asset.

    I personally don’t doubt there could be a major economic impact from such a large project (from construction and thereafter as a regional legacy), we can argue over the quanta

    Also, in 100 years it is almost certain the sea level rises will have inundated some of the inter tidal feeding grounds. Whilst the barrage will also impact (although the new barrage to a lesser extent than the older design) it is likely that it will also afford some protection over the longer term from climate change impacts…

    I am all for other technologies and want to see them developed & exploited. However, given the potential for generating 5% of the UKs base load from a dependable and predictable renewable source, then we have to give it serious consideration – and yes that includes a full analysis of all its potential environmental impacts. More clarity and more data is needed.

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  3. Ian says:

    Mark. I am afraid that you have too been a little inaccurate in your statement. The proposed tidal lagoon in Swansea as with all the other likely proposals along the NE and SE coast of Wales will actually be land locked and not an island. They are to my knowledge no more expensive per KWH to construct and with maintenance, will last the 120 years that the barrage is planned for. Perhaps most importantly, the lagoon design is far more advanced than the barrage design and the Swansea barrage can be up and running by 2018. If it is a success (and surely all who truly support renewable energy want it to be a sucess), then the barrage proposal is very likely never to proceed, as larger land locked lagoons on the SE of Wales will be a more viable option-lower cost of construction, proven technology and a faster construction (they cannot operate commercially within a barrage).

    I cannot bring myself to write off the barrage option, but have always been a biigger fan of a smaller barrage further upstream near the 2nd Severn Crossing. This would do far less environmental damage, not get in the way of any lagoon proposals and unlike the main barrage project, would actually be a viable transport link. Perhaps my biggest suspicion of Peter Hain’s argument is that if he really believed in renewables, then he would not be so dismissive of lagoons. Clearly, he sees them as a threat to his dream of a large barrage, which for me sums up his unsustainable argument-full of leaks.

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  4. Mark says:

    Thanks – If lagoons can use some of the coast line then that will help. However, they will only be able to secure about 30~40% of their perimeter at most from the coastline, depending on size. Also, even a large coast connected lagoon would be power constrained as it will be limited by the volume of water it can impound given the shallower water nearer the coast. A Cardiff Weston Barrage will have a perimeter of 60~70 miles with the coastline making about 85~90% of the total perimeter. A barrage will also impound the maximum volume as it will include even the deepest parts of the channel. On that basis I am pretty sure the costs of construction per unit of generating capacity will be lower with a barrage than a lagoon. But as I said, if we can get some lagoons in the mix further downstream then all well and good.

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  5. Ian says:

    Mark. You are correct that a lagoon will be restricted by the volume of water it catches, but it has the added advantage over a large barrage in that it can mimic supply with demand to a greater extent than any other form of renewable energy (in Wales). This would be particularly effective if there were a series of lagoons up the coast say along the NE and SE as because the tides go in and out at different times, the spread of power production would be greater; something that the barrage does not have the same flexibility to do. I firmly believe that no final commitment should be given to the main barrage, until we have seen the success of otherwise of the Swansea Bay lagoon. If it does meet the claims, then it could well be a better option for larger land-locked lagoons than a large barrage. However, if it fails to meet expectations, then a large barrage may well be the best option. By then, the latest barrage proposals will hopefully be designed to a greater degree, including costing. I have heard 2 different costs just in the last week (£30B & £25B), and any significant design change will inevitably lead to a requirement for a new EIA – including sediment movement around the estruary. Do date, I have seen no definitive survey on this and as the new design is further down the estuary and the sediment works its way anti-clockwise around the esturine coast (apart from a storm surge), the potential implications for Gower etc are to my mind, not at all clear. It is not my intention to be scaremongering, but the sediment movement within this estuary is incredibly difficult to predict, even after all the surveys relating to the sand abstrction licenses.

    Whatever comes from this debate, I think we can all agree that sitting on our hands for another 10 years is not an option. I see 2018 (the projected completion date of the Swansea Bay lagoon) as the trigger date, in terms of deciding once and for all the best options for the whole estuary for tidal energy production.

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  6. A-Welshman says:

    Good article.

    For me the jury is still out on tidal lagoons. While they present us with a lower projected environmental impact than a barrage there remains a number of common black holes in the proposals of both Hafren and Swansea Bay Tidal Lagoon Ltd.

    We are still lacking any commercially tested and proven ebb and flow generating turbine design and any meaningful EIAs. Until we have them we have no way of fully appreciating the impact lagoons will have on the surrounding habitats.

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