Swansea Lagoon rejection leaves way clear for better-value Marine Energy

Friends of the Earth Barry&Vale say the huge cost of power from the Swansea Lagoon has long been clear.  It was not acceptable as “pathfinder” for a second larger lagoon off Cardiff, which has strong wildlife, fish and navigation impacts.  The government should have decided long ago, so to clear the way for other marine energy projects. Tidal stream and wave-power projects have been unable to proceed, when Welsh politicians focus all on the dodgy lagoon.

Our FoE group belongs to the Marinet network of coastal environmental groups, who are strongly supportive of renewable energy from the sea.  We were critical of the Swansea Lagoon proposal 5 years ago and agreed in January 2017 that the economics condemned it: “it would be folly for the Government to agree to progress the Swansea Bay project further”.

The Hendry report on power from tidal lagoons had a major problem. Power generation around high or low tide is interspersed with slack mid-tide periods  Charles Hendry still ignores how to fill in the gaps (W Mail, 10th May).

Hendry accepted TPL's claim that a series of lagoons around the coast would combine to give near steady generation. But their second lagoon at Cardiff would be in phase with Swansea and assessment of other lagoon sites (north Wales, Humber etc.) shows substantial gaps remain.  A related issue is the variation between spring tides and neap tides produces seasonable variations that are out of sync with demand.  

The Swansea lagoon on its own is not a 'pathfinder'.  It needs additions to fill in the gaps. The National Grid does not want gappy power.  Fossil-fuelled power plants to fill the gaps would be high cost and high in CO2.  Hendry did not consider the economics of such an overall system.

Alternatives of pumping to increase the peak and deliver on demand, or combination with a second 'storage' lagoon have been proposed.  Or modern high-power storage systems using batteries or fuel cells could be an option.  

These mean that the simple lagoon cannot be Hendry's "pathfinder" project; only a lagoon in combination with gap-filling generation could be that. That requires reconsideration of the whole design and assessment of upcoming technology.

Nor can it be a pathfinder to the much bigger Cardiff lagoon off the Penarth headland as TPL want [see separate button at top of this Page] .  Friends of the Earth argue as do RSPB (W.Mail 10 May) that the conservation designations make that location problematic.  TPL have no way to create bird feeding grounds in mitigation of those their scheme would destroy.  The same stumbling block helped sink the Severn tidal barrage from Lavernock to Weston-super-Mare.

Yet the company demanded a commitment to public funding for 90 years with huge subsidy - twice that for gappy power from off-shore wind which is for 6 times less (15 years only).  It requires the National Grid to cope with the system problems of its gappy power, a further hidden public subsidy.  Hendry's two-year old report was no basis for the public taking on these liabilities, or for Carwyn Jones's offer of Welsh subsidies on top. 

The scheme would have severely changed tidal currents and flows throughout the Swansea Bay, as angler groups have emphasised.  The picture shows a typical calculation of changes, with major new currents in and out of the turbine wall to the south-west of the lagoon structure. Swansea Bay beaches become a backwater, instead of swept by the general east-to-west circulation.  Would mud deposits replace the sand?  It's unknown.

Compare the progress with tidal power in Scotland:  a 6MW tidal array in the Pentland Firth entered its 25 year operational phase in April, a major milestone for the  MayGen project.

Its owner, Atlantis Resources, bought up the Welsh tidal current scheme for the Anglesey Skerries .  This has planning consents, but was put on hold pending the Pentland Firth scheme.  The company offers well below the Hinkley price (£75/MWh; 40% of the Swansea lagoon) for its follow-up tidal project, but is looking to France rather than Wales.  Atlantis also plan a ‘pathfinder’ tidal barrage project, but in the river Wyre rather than the Severn, half the capacity of the Swansea Lagoon for a sixth of the price.   

Wales has missed out by politicians concentrating on the Lagoon.  FM Carwyn Jones gaily offered £100 or £200 million towards it, but nothing to attract Atlantis back to Wales.

The PrivateEye exposure of the "Shorrock Horror" from the Commons hearing is here: