Tidal Power proposals on the Solway: an update

Out on the Firth

When I first blogged about this topic, back in October 2015, I explained why the Solway Firth is being considered as a suitable estuary for the construction of tidal power schemes, and the basic ideas and technology behind the schemes. Please do read that post first, if you have time, as the background of the companies – and the people involved – also provide good stories.

This post is a short, factual update – two of the original players have (probably) departed, and one (or two?) new players have entered the pool. The B-word has, of course, played havoc with decision-making, and as a result, with financial backing.

Barrages and weirs

  1. North-West Energy Squared.

A system of barrages (sorry – ‘gateways’) across estuaries in the NW of England, including across the Solway Firth from Workington to Kirkcudbright; read the earlier blogpost for details of the plan, and the CEO’s comments.

NWE2’s uninformative website no longer exists, though the company is still listed and took on 2 new directors in September 2018.

Note: ‘barrage’ is now a dirty word in the context of estuarine power generation – it’s considered an outdated and disruptive technology, very expensive to construct, with too many problems relating to environmental changes and remediation.

 2. Solway Energy Gateway

The idea of an ‘electric bridge’, proposed by Nigel Catterson, across the Firth between Bowness and Annan, along what has been called a ‘brownfield site’ (Arup) – the line of former Solway viaduct.

This would be a ‘weir’, fixed to the sea-bed and with 6m vanes which can be raised or lowered, creating a difference in head (see my earlier post for an explanation); the vanes could be dropped flat at slack tide. Power would be generated via Venturi turbines .

SEG also plans also to construct a foot- and/or cycle-bridge across the Firth – this idea has met with considerable enthusiasm in public consultations on the Scottish side. Nigel Catterson is working with Scottish councils. It has also been suggested that the scheme could contribute to flood defences of Carlisle.

Note: The bidirectional turbine technology is as yet untried in sediment-laden fast-flowing tides. At lowest Spring tides, there small amount of water in the channel is mainly from Rivers Esk & Eden – though the ‘weir’ would hold back water (salt and fresh) to create a head of pressure.

Lagoons

Russell lagoons are U-shaped, joined at each end to the coast

Ullman offshore lagoons are circular (‘doughnuts’), free-standing in the estuary

  1. Tidal Lagoon Power

TLP’s original proposal was for 6 Russell  lagoons – Wales (Swansea, Cardiff, Newport, Colwyn), Bridgewater Bay, and the Solway (Workington-Dubmill Point).

All emphasis has been on Swansea, the smallest:  Charles Hendry, in his January 2017 review of tidal power for the government, strongly recommended the Swansea project should be funded and built as a ‘pathfinder’ – ie allowed to run for 5 years, with its financial viability and its effect on the environment being monitored, before decisions were made about further schemes.

Despite the Environmental Impact Assessment having been carried out, and the supply-chain companies being on board, the Westminster government continually dithered about granting approval or approving the Contract for Difference price. In June 2018, Minister Greg Clarke stated the project would be too expensive, and would not give value for money, and so the government would not back the scheme.

The Welsh government is still keen to support the Swansea scheme and other players – financial and constructual – have come forward (December 2018). And TLP announced this month (February 2019) that it plans to go ahead without government backing, by signing Power Purchase Agreements (PPA) with other companies. TLP also has a new plan, to float solar panels in the lagoon, increasing power output by an estimated one-third.  As reported by the Guardian‘s energy correspondent Adam Vaughan, ‘The plan is to secure enough signed PPAs by the end of the year to enable a final investment decision in early 2020, with construction starting shortly afterwards. If that timetable were met, the project would be generating power in 2024 or 2025.’

But whether or not the Swansea lagoon will ever be built is still far from clear.

Tidal Electric (see below) submitted a response to the Hendry report, in favour of their own offshore lagoons

Note: Should Swansea ever go ahead, and be deemed successful as a ‘pathfinder’, Tidal Lagoon Power would then most probably focus attention on building another Welsh lagoon, eg Cardiff Bay.

TLP’s Solway project is now unlikely.

2. ARUP

A new suggestion since my 2015 blogpost: a Russell Lagoon.

These notes are from my conversations with Michael Osborne, Director, ARUP, Whitehaven. October 2018 and February 2019.

The wall of the proposed coastal tidal lagoon could be 18km (12 miles) long from just North of Maryport to Mawbray, effectively around the outside of the Allonby Bay Marine Conservation Zone.

The emphasis would be on local sourcing of rock materials. Ideas include: the bund core of waste slate from a quarry near Askam in Furness; outer rock armour – slate blocks or granite blocks from Askam in Furness or Kirkmabreck quarry near Creetown; inner rock armour might be red sandstone possibly from a quarry near Maryport – sandstone is more easily colonised by algae and marine animals. The water off Allonby Bay is fairly shallow so the wall would not need to be too large, but the deeper channel just NW of Maryport could be where the bi-directional turbines are sited.  The grid connection would be inshore of Maryport. .

Michael Osborne recognises the importance of the Allonby Bay Marine Conservation Zone. ‘It includes the sea-bed, and we must respect that – otherwise what would be the point of the designation?’

Note: this coastal lagoon option leaves Maryport harbour entrance and the mouth of the River Ellen open (unlike the Tidal Lagoon Power scheme); goes outside Allonby Bay MCZ; and the scheme could reduce the current rate of coastal erosion. This concept of a coastal tidal lagoon has been raised through the Maryport Delivery Plan.

This proposal currently has no financial backers. Michael Osborne thinks that the way forward for tidal power in general is for the government to support renewable energy schemes, including tidal, as a matter of policy. Regardless of policy tidal energy projects should be competitive with other energy sources.

The Labour Party have indicated an interest in renewables including wind, tidal and wave power.

3. Tidal Electric Consortium

A new suggestion since my 2015 blogpost: an Ullman lagoon (CEO of Tidal Electric is California-based Peter Ullman.)

Dr Amir Eilon (the sole Director of Ullman Offshore Lagoon; the rest of Tidal Electric’s Board are based in the US or Switzerland) has given two presentations to the Solway Firth Partnership in Dumfries, the most recent in association with syndicate members from Ecotricity and DEME (Dredging Environmental & Marine Engineering; Belgium)

Eilon has previously also discussed ideas for a Russell lagoon in the Solway (see ARUP, above).

This second presentation in December 2018 focussed only on the proposed Ullman lagoon – either off Hesten Island (D&G) or off Allonby Bay MCZ; the power generated would be onshore-d to Cumbria, where the existing grid has capacity.

The circular wall, 16km in perimeter, would be constructed of geotubes covered by locally-sourced external rock armour, with sluice gates and turbines in a block. The plan is for 55 turbines, producing 388 MW; the estimated cost of approximately £710m depends on rock source/price, turbine price etc – in other words, on several currently known unknowns.

Ovals indicate possible lagoon sites in the Firth (from Tidal Electric’s presentation slide)

As for siting, if the lagoon is constructed in 10m depth of water, fewer and bigger turbines are required; if in shallower water, for example 5m, 100-150 smaller turbines might be necessary. From the geological point of view, the English side is better, because of the sandstone bedrock, but it is also more exposed (and next to the Allonby Bay MCZ); on the Scottish side near Heston Island, the sea-bed is more pitted but is more sheltered.

Since the lagoon is not connected to the coast, there is no access other than by boat (‘We don’t do tourism’), so there would be no H&S constraints with regard to visiting tourists. The wall would therefore be cheaper to build, have a much lower profile and therefore much less visual impact than the wall of a Russell lagoon.

Note: The syndicate will not commit to further work on the project unless they receive assurances that the government is willing to support tidal power generation. Eilon was supposedly meeting with the UK government’s Energy Minister in January 2019, but that meeting has now been postponed until March. Interestingly, Tidal Electric’s website now refers to this as a ‘Scotland’ project, (rather than a Solway project, as previously): make of that what you will!

A general point about timescales

Even if a lagoon, of either sort, should be given approval tomorrow – the time to power generation is in the region of about 7-8 years.

Scoping, modelling, working out risk mitigation, gaining the necessary permissions, public consultations, planning applications, agreeing Contract for Difference price with the government and so on would take 3-4 years.

The actual construction phase – requiring movements of large amounts of material by land, rail and sea; dredging; cable-laying; building the walls and turbine housing; building onshore works and offices; environmental remediation etc – would take a further 3-4 years.

And my personal view

It is such a startlingly obvious idea, to capture the mighty energy of the seas that surround our islands – the waves, the predictable tidal flows – and to convert this into the electrical power that we will increasingly need (imagine all those electric cars). The technologies and designs are challenging – for unstartlingly obvious reasons – but are exciting and always advancing.

Until fairly recently I believed that nuclear power should also be part of the portfolio, partly because West Cumbria already has such a concentration of nuclear expertise, and the influx of jobs and the continuing necessary financial support would be vital for the area’s economy: but my opinion has changed (as has, it seems, the government’s, although for different reasons – the new nuclear build proposed for the Moorhouse site has been cancelled).

Wind, water and sunshine could together provide a smoothed-out supply of energy for our use. But we also need the technology to store the electricity and release at peak demand; we need large-scale technology to split water to release hydrogen, which can be burnt – cleanly – to generate power.

All this is possible, even though as a country we are coming to it much too tardily and with only a fragmentary long-term plan. We should be concentrating our research and resources on adding tidal and wave power to our portfolio. More than ever we need to stop using fossil fuels to provide energy. The current extremes in climate breakdown hint that we may already be too late.

So: power must be generated where there are ‘big tides’.

But in the Solway Firth?

I swither.

The Solway is so ‘unspoilt’ by humans, and most of the changes that occur are natural, the result of interactions between storms and tides and rivers.

So I hate the thought of the years’-long, major, disruptions to the Firth of constructing the lagoons: the noise, both air-borne and water-borne; the traffic on land and sea; the dumping of rocks; the hauling of cement; and around it all, the swirling sediment.

I swither again. I remember how the Solway’s margins – the mudflats and the saltmarshes – have changed over thousands of years, and I think that the Firth and its non-human inhabitants will, eventually, adapt.

And yet … This ‘intervention’ would be so dramatic, a mere eye-blink in geological and evolutionary terms, that it would require the Solway’s creatures – the salmonids that pass through to breed, the fish that browse on the sea-bed, the micro-organisms and invertebrate animals that live on or in the mud and sand and rocks, the algae and saltmarsh plants – to survive and feed and breed despite ‘the storm’.

Already the numbers of so many of the creatures and plants with whom we share this space have plummeted. For many more, in this precious and protected finger of the sea, this disruption could be the final straw.

NIMBY-ism? No: it’s not my backyard, is it? It’s their’s.

I cannot swither any more.

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