2015 DHI UK & Ireland Symposium Towards a British Isles Strategy for Tidal Range and Coastal Adaptation Stuart Anderson (Conwy County Borough Council), Tuesday 21 April 2015 at 15:40 - 16:00 Stuart has a long history with tides on the North Wales coast, working with a number of high level, and high profile, projects including MAREN2. He will present his thoughts and experiences on works carried out and proposed for combining coastal protection with tidal range schemes.

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1. North Wales’ coastal vision to 2050 & beyond...
‘The immediate need is for secure and reliable sources of
energy to keep the light of civilisation burning and in the
preparation of our sea defences against rising sea levels’
- James Lovelock in The Revenge of Gaia, 2006 -
2. British Isles’ clean energy blind spot
(i) ‘Twin drivers’ apply: clean energy & defence
of coastal town and transport infrastructure
(ii) Tidal range energy extractable from Irish
Sea (N Wales + Mersey + Morecambe Bay
+ Solway Firth etc) exceeds that of Severn
Estuary + Bristol Channel by around 2:1
(iii) Value of tidal energy reinforced by its
predictability, and alignment with likely
uses e.g. for green transport.
(iv) Value further reinforced by
N Wales’ centrality and other
key grid factors - e.g. likely
need for, and availability
of, big new conventional
pumped storage sites.
Regional heritage built to help
link or defend the British Isles:
(i) Thomas Telford (1826): the
Menai suspension bridge was
built to improve links to Ireland.
(ii) George Garrett (1879): ‘Resurgam’
submarine, built at Birkenhead, sunk Feb
1880 off Rhyl after her maiden voyage.
(iii) Iorys Hughes (1941-43): re-using D-Day
Mulberry caissons prototyped at Conwy, 1948
Netherlands polder repair (above) led to new
tunnel and tidal barrage construction methods.
Just as the blind spot is nearly central to our
human field of vision, the Irish Sea Maritime
Area (heavily dotted circle in map R) is key to
a coherent ‘Energy Islands’ strategy, since:-
3. Strategic Resource Assessment
(i) 33 GW of offshore wind farm capacity is
presently planned, 90% in the North Sea.
(ii) ‘Energy Islands’ can aim at 50-60GW
of marine RE capacity - 80% from tidal
range, but only 15% from the N Sea.
(iii) Multi-stakeholder leadership
is key to filling in the strategic
blind spot - by prioritising
adaptation and mitigation
over short term targets.
4. North Wales pilot tidal
scheme’s centrality
helps ensure:-
 Business focus
plus academic,
political & public
engagement
 Beacon project
status, catalysing
market preparation
in UK and elsewhere
Double arrows ( ):
show some key rail electrification desire lines,
for which wind power is of less predictable
value - as also for road transport electrification.
‘A clear idea of where we are going as a world will make action at the individual, community
and country level much easier and more coherent’ (Sir Nicholas Stern, 2007)
(v) Development of
fishing, aquaculture,
maritime leisure,
coastal cycle and
heritage trails etc by
all four British Isles
nations offers the
chance to help bring
back to life an ancient
Celtic vision, perhaps
now dormant more from
neglect than mistrust…......
Irish Sea Maritime Energy Park?
One response is that this idea cannot be realised.
for the number of countries involved. The counter-
point is that ‘visions remain dreams until they are
shared’ (Henry James) - so sharing is creating!
From the 6-8 sq km Llanddulas pilot tidal impoundment follow four others,
eventually enclosing 700 sq km of seabed, at 60% net energy extraction
yielding an average 3 GW – on a par with Wylfa B and 50% more than
a conventional Severn Barrage……
DECC’s SW Region ‘Marine Energy Park’
‘Business-as-usual……. will lead to disastrous sea level rises on the century time scale’ (James Hansen, 2008))

2. SOMESOMESOMESOME NOTES ON THENOTES ON THENOTES ON THENOTES ON THE INTEGRATED DESIGN CONCEPTINTEGRATED DESIGN CONCEPTINTEGRATED DESIGN CONCEPTINTEGRATED DESIGN CONCEPT (IDC)(IDC)(IDC)(IDC)
1. New legislation like the Future Generations Act strongly favours a complete IDC at the outset.
2. The brief requires imaginative boldness but is much easier without a local pilot scheme.
3. Instead of blocking estuaries the impoundment programme will allow ‘naturalised’ inflow
and outflow patterns while using the intervening geography to maximum advantage for
sustainable coastal protection and minimised hydro-environmental and visual impacts.
4. ‘Least unnatural’ through-flow patterns will obtain if plant arrays are sited towards the west end
of each impoundment (blue double arrows)- where natural seabed depths tend also to be more suitable.
5. In plan, sensible hydrodynamic design must mean rounded impoundment shapes, and two-way
pump/turbine plant arrays with enough capacity not to require additional functional sluicing.
6. Target areas, installed capacities and net outputs are then as shown. (Applying his own ready-reckoner
Prof David Mackay confirmed as fair a 2 GW+ figure for average total output potential from 700 sq km).
7. W1 (Clwyd Impoundment) must come first, both practically and politically, mainly because the coastal
protection cost-benefit argument is already urgent along this stretch of coast....
8. The illustrated landfall & shaping of the east end of W1, considered as the first project to go forward,
should allow smooth hydrodynamic continuity with the west flank of the Dee Estuary at Point of Ayr.
9. There is more ‘freedom’ at the west end of W1. But Llanddulas has big advantages - of ‘brownfield’
status, of allowing fairly even division of water space between W1 & W2, and of access to Constable Bank.
10. W2 (Llanddulas-to-Orme Impoundment) is the second project likely to go forward entirely within the
Welsh coastal domain. Following the line of Constable Bank must here be the preferred option on grounds
of energy yield, coastal protection value, synergy with neighbouring W1 and W3 projects, and minimised
visual impact. Early Dutch engineering opinion is thus urged to scope methods and feasibility.
11. W3 (Conwy Bay Impoundment) involves building a causeway across the Menai Straights in order to
realise its full coastal protection and output potentials, while minimising visual & environmental impacts.
12. WE (Dee & Wirral Impoundment) applies the same principle as in point 7, only to the Mersey Estuary.
13. At programme’s end, a newly engineered coast has a linear breakwater wall up to 7 km out from the
present beaches. Preliminary scoping of this ‘double defence system’ can go ahead without detailed
knowledge of pump/turbine Hill Charts. In all aspects of design, the general principle is that well
organised, non-turbulent flow maximises output potential and minimises sedimentation and other
environmental impacts. It is highly unlikely that currently available pump/turbine formats can do all this.
14. Red lines indicate likely useful causeway routes (e.g. Menai, new Mostyn Port facility at W1/WE junction).
15. Materials seabed and quarry sourcing should wherever possible be local or regional.
16. My 2008 Resurgam Project outline design brief included Tremadog Bay and
was the first attempt at a unifying IDC for all big UK tidal range schemes.
17. Synergy with programmes (e.g. red question marks) at all other key Irish Sea
perimeter locations is a key issue for early macro-modelling.
W3
W2
W1
WE
TIDAL IMPOUNDMENTS OFF THE NORTH WALES COAST:
SCHEMATIC PLAN FOR INTEGRATED DESIGN CONCEPT
© Stuart Anderson 7
th
December 2014
Scheme Area encl (km
2
) Inst Cap (GW)
W1 150 1.7
W2 100 1.2
W3 150 1.7
WE 300 3.4
TOTAL 700 8.0
Main sources: unpublished letter from Mark Bostock (Dec 2000); Functional Issues Appraisal (SHA April 2012, downloadable from MAREN website);
review of Morgan Horne papers for Prof. David MacKay (SHA, April 2014, unpublished)
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