Penarth Town Council heard last night that the proposed Cardiff/Penarth Tidal lagoon will reduce the height of high tide, increase the height of low tide and create muddier and much faster-moving water off the Penarth foreshore.
The powerful streams of water coming from the underwater turbines will also increase coastal erosion and create strong currents off Penarth Head for ships, fishing boats and leisure craft entering and leaving Penarth Barrage locks – but so far there has been little or no consultation with small boat owners.
Penarth Council’s Leisure and Amenities Committee last night heard a presentation by Cardiff Lagoon Development manager Joanna Lane and the firm’s Head of Environment Tim Carter.
Tidal Lagoon Power is to carry out three rounds of public consultations – starting in the Autumn of this year . It will then submit a Development Consent Order for the project midway through 2018 . There then follows a 15 month inquiry style process and the firm hopes to get approval in 2021 to begin building the project.
Tim Carter said the Environmental Impact Assessment would investigate how the proposed Lagoon would “change water flows in the Severn Estuary” – including the effects on over-wintering birds which feed in the estuary.
[ PDN Note: The massive rock-boulder walls of the Tidal Lagoon will obscure the sea view from Penarth Esplanade by – in effect – drawing a huge rock-armour curtain across the sea-front.From Esplanade level – and from Penarth Pier – it will no longer be possible to see Cardiff, Newport , the Severn Bridges, Bristol, Portishead , Clevedon or Weston Super Mare. Most of the Somerset coast will disappear behind the wall of solid rock and concrete. The massive wall will reach as far South as a point due East of Whitcliffe Drive – although people standing on Cliff Walk might just-about be able to see over the top of the lagoon walls – depending on their final height ]
In his briefing to Penarth Councillors, Mr Carter acknowledged that “in terms of landscape and seascape, clearly it’s the construction of a very large infrastructure project in the Severn Estuary. It’s an important consideration in terms of changes in views, in terms of landscape character – and those will be a test” .
Mr Carter produced a map indicating a large area of the Severn Estuary from which it would be possible to see the Lagoon Wall – and said further “modelling” was being carried out to verify the extent of the visual impact.
Mr Carter said “Clearly this is something which is going to be important for Penarth” and said the firm had identified various locations in Penarth including Penarth Sea Front, Paget Road and Lavernock. He said that local people would “want to get comment in on what are the important views for the community and from where they think important views should be recorded” .
He said “photo montages” would then be developed to show what the completed lagoon would look like “from those locations” .
Mr Carter said that the lagoon would be operating “out of phase” with the normal tide. Initial predictions estimated a drop of 10 centimetres to 30 centimetres the level of high water [ at the top of the tide] . He said the low water mark would be 10-30 cm higher than at present and low water would not be quite as low as it is now.
He said there would be faster water flows in the area of the lagoon because the Severn Estuary would be “narrowed” whilst flow-speeds would be increased. Mr Carter said that if flow speeds increased to a certain degree, the existing sediments in the water ” may be lifted”. [i.e. lifted from the sea bed]. There could be increased erosion and sedimentation both inside the lagoon and outside it.
As far as the project as a whole was concerned, Mr Carter said much depended on the development of the smaller Swansea Tidal Lagoon. “Without Swansea” – he said – “Cardiff is unlikely to progress” .
Cllr Mark Wilson (Labour Stanwell) queried figures quoted by Joanna Lane in the slide presentation. He asked whether the electricity generated would be 25,000,000 Megawatts or 25,000 Megawatts. He was told that the installed capacity would be “somewhere between” 1,800 to 2,800 Megawatts.
Cllr Wilson asked whether that figure was the amount generated “per day?” . He was told that the figures related to the “installed capacity” – it was the “potential energy created” – it would not be the actual electricity generated “for much of the time“ [ i.e. the actual power generated would be – for most of the time – a lot less].
Cllr Wilson pressed the point and asked “Have you got any idea how much energy you will actually be generating?”.
Joanna Lane said the lagoon would be generating – every year – between 4 and 6 “Terrawatt Hours” which would be enough for 1,150,000 homes – but there were “lots of different ways” of calculating the estimates. CllrWilson said he understood the average person consumed 34.82 megawatts . Joanna Lane said the average household in Wales consumed 3,928 kWH [kilowatt hours] per year.
As a private company, she said, the firm was privately financed to do the development work but once the lagoon was built, it was expecting to receive a “Contract for Difference” – much like a solar power “feed-in tariff” . It was essential that the UK Government and Treasury worked with the firm to establish what was the appropriate level of financial support. [ Power generated from the Lagoon would have to be subsidised by the taxpayer to a much higher level than nuclear power stations]
Cllr Wilson said he was also concerned about birds and noted that cranes from the West Country were now breeding here. He also asked what educational initiatives would be undertaken by the company . Joanna Lane said the company did a lot of “outreach” with schools and colleges and was working with Cardiff University on prehistoric landscapes.
Tim Carter said bird species like Redshank and Curlew were being fitted with very small GPS trackers top see how they used the Gwent Levels area. This would help to understand food resources in the light of changes in the water levels.
Cllr Clive Williams (Independent Plymouth Ward) said that government work he had once been involved with on Pendine Beach had ended up affecting beaches in Swansea, 30 miles away. Tidal forces, he pointed out, were often unpredictable.
Cllr Martin Turner (Conservative Plymouth Ward) said he was worried about the effect that changes in the tidal flow would have on Penarth Head – which was not protected. Tim Carter said predicting the effects of this would be part of the “coastal processes work” and the modelling being undertaken.
Cllr Anthony Ernest (Conservative Plymouth Ward) asked “Can you tel me the likely effect of the turbines on small craft, yachts, small fishing boats and so on.?
Tim Carter said engineers were still looking at the “optimal design” of the turbine housing and the actual arrangement of the turbines themselves. “When water is coming out that effect will be kilometres in terms of the power coming out” . Mr Carter said the firm was looking at setting up a “marine users group” . He admitted that the problems of small craft was still something that needed to be understood – so that the firm could see “what mitigation is possible”.
Joanna Lane said the company was also investigating any – what she called – “navigation risk issues” .
Cllr Ernest then asked about the proposed control mechanism and cabling which would feed the power generated into the National Grid . Would there be overhead pylons? – he asked – “Visually that would not be acceptable”.
Tim Carter said National Grid had not yet specified where the “connection point” might be – but there was a connection point at Uskmouth Power station and there was an option to go across the Severn Estuary with an undersea cable and connect at Avonmouth.
The Mayor Cllr Mike Cuddy (Labour St Augustines ) asked about Penarth’s involvement in the major public inquiry which would be set up in the event of the project going ahead.
Joanna Lane said she believed Penarth Town Council would be a statutory consultee in the process.
Cllr Neil Thomas (Labour Cornerswell) said the Westernmost turbines of the lagoon, nearest the land, appeared to be pointing straight at Penarth Head “which we know is fragile and liable to erosion” . He said ” a proposed Headland Link Walkway could be running past there as well – which could have a mitigating effect on the outflow of the turbines”. He asked whether there was scope for the Lagoon company to work with the Headland Link group to “strengthen the proposal for the Walkway so that it would act as a shield” .
Tim Carter said the starting point would be to look at the location of the turbines and possibly place them further out in the channel. If there were proposals for walkways that was something that could be assessed at the time .
Joanna Lane said the Lagoon Company had met with the Headland Walkway Group some time ago and was aware of the current “ambitions” . “We are always keen to know where there are opportunities for us to work with local groups”
Cllr Gwyn Roberts (Labour St Augustine’s) presumed that the whole lagoon was emptied twice a day . He was told there would be between 60 and 90 turbines in the turbine chamber and queried why the turbines needed to be concentrated together “in one tiny part of the wall”. If they were distributed around the walk they would work more efficiently and get rid of the enormous flow off Penarth Head.
Cllr Roberts also noted there had been recent tidal surges in the Bristol Channel – where would the [tidal] water go? The same was true of river-water from the Barrage and coming down the rest of the channel – but he was convinced tidal power was a preferable option to nuclear power – if it could be made to work.