FloWave Test Tank Facility Can Simulate Pentland Firth Conditions

9th April 2014

EDINBURGH UNIVERSITY'S MULTI-MILLION POUND BRAND-NEW 'FloWave TT' FACILITY IS A WORLD-LEADER THAT CAN SIMULATE ACTUAL PENTLAND FIRTH WAVE AND TIDAL SEA-CONDITIONS.

One of the biggest and most complex scientific instruments ever devised and built in Scotland will be 'in commercial action' for the first time this Spring (2014) at its site near Blackford Hill in Edinburgh.

Early tests have proven that the unique £13 million huge 'International All-Waters Combined Current and Wave Test Facility' (popularly known as the FloWave Test Tank) will be able to replicate the natural, but sometimes extreme, varying sea-conditions of key parts of the Pentland Firth at different stages of the twice-daily tidal cycle and with different 'incoming' wave-heights.

This will be 'on a controllable laboratory scale' and with a realistic complexity that has never previously been attempted nor seen, with FloWave TT hopefully playing a substantial part in efforts to devise the most efficient and reliable means of electricity generation from both tidal streams and waves.

Edinburgh University's world-leading FloWave TT onshore test facility, at its KIngs Buildings Science & Engineering Campus, can model the effects of swift-flowing sea-currents combined with big multi-directional swells in a laboratory scale. The circular tank, with a diameter of 30 metres, holds more water than Edinburgh's famous Royal Commonwealth Pool.

The aim of the brand-new FloWave TT is to aid the design of prototype turbines and associated devices and to speed-up the adoption of those being conceived for extracting large quantities of 'marine electricity' from the kinetic energy in the tide-streams, such as the Pentland Firth, in the future. This will be regularly done at a scale of 1/40 and FloWave TT is being seen as both cutting the cost and risk of the pre-production stage.

Bill Mowat , Chairman of community-owned Gills Harbour Ltd, has just been given a preview of FloWave TT 'in action' during its final commissioning trials.

Gills Harbour lies on the doorstep of the Pentland Firth tide-streams, where the first demonstration array is planned to be installed 'in the water' on the 30-metre deep seabed of its Inner Sound during next year (2015), The visit for the small group of Edinburgh University graduates was organised by Helmsdale-born Lady Muir Russell (nee Ms Eileen Mackay), a former top-level civil servant who is now a Governor of the Court of the University of the Highlands & Islands (UHI), who has Caithness family links.

The UHI, which includes its Thurso-centred North Highland College, recently appointed Scottish tidal-energy pioneer Professor Ian Bryden as it new Vice Principal, with overall responsibility for its research programmes.

Dumfries-shire born Prof Bryden who, until late 2013 headed Edinburgh University's Institute for Energy Systems, played a key part in the conception, fund-raising and building of FloWave TT; he is a director of FloWave TT Ltd, the Edinburgh University-owned company that owns and operates it and he also holds a non-executive board position at the European Marine Energy Centre (EMEC) in Orkney where prototype tidal turbines are tested in the powerful sea-currents of the Falls of Warness, off Eday, Orkney.

The massive circular tank is housed inside a purpose-built, highly-insulated building erected by Graham Construction of Belfast, Northern Ireland, a firm best-known in Caithness for constructing the 'low active' storage vaultsat Dounreay for Dounreay Site Regeneration Ltd (DSRL).

FloWave TT is ringed by a series of high-tech, computer-controlled, devices for producing currents and making waves, all of which can act independently, most of which have been supplied by Edinburgh Designs Ltd. It is the World's first marine test facility to be able to simulate normal and extreme conditions of waves and tidal-streams in combination.

Water can be pumped across the tank to an equivalent speed of up to 15 knots (0.8 metres per second). while 'model' waves can rear up to as much as 28 metres, while an overhead crane can precisely load devices into its circular 17-metre test zone; there is a wider surrounding 'curtain' aimed at keeping wave-refraction to near-zero, if required.

In his introductory remarks, FloWave TT's chief executive Mr Stuart Brown revealed that a deal has already been done for a share of data with EMEC's wave and tidal sites in Orkney, so that it can replicate actual sea conditions at Falls of Warness and at Billia Croo, iEMEC's 'wave converter' test -site in near-shore sea off Orkney's West Mainland, near Stromness.

The extended programme of 'Acoustic Doppler Current Profilers' (ADCPs) undertaken in 2013/14 under the waters of the Inner Sound by Exeter University scientists and engineers, has had a main purpose of relating actual conditions between Gills Bay and Stroma Island to those at EMEC's Eday sea-site, where full-scale prototypes of the turbines to be used have undergone testing.

Mr Stuart Brown said that FloWave TT can 'easily simulate extreme storm events in a calculated and controlled manner' to let turbine designs be improved before these are expensively tested in the water and so allow some problems to be solved before actual deployment; in other words, it will allow costs be cut, as well as reducing the chances of component failure.

The FloWave TT is managed by a not-for-profit subsidiary of the University of Edinburgh and was substantially funded through the UK's Engineering & Physical Sciences Research Council.

It can simulate sea-conditions anywhere in waters around Europe's entire Continental Shelf and could find possible uses in cost-reduction exercises for offshore wind-farms or deep-water oil & gas recovery systems, although electricity from the tides and waves have been the driving forces in its creation.

Chief Technician Mr Thomas Davey then put it through its paces, including simulation of multi-directional waves that are a feature of phenomena such as the Merry Men of Mey.

Yesterday Mr Mowat said : 'It has been a privilege to see this unique, Scottish, tool for tidal stream research and development in action during a pre-commercial test. It will become available to the nascent tidal industry within the next month or two.

'I have repeatedly said that Pentland Firth 'tidal stream electricity' will only become a long-term industry for Caithness, rather than a 'flash in the pan', IF costs can be significantly reduced with safety standards being retained or enhanced.

'We at Gills Harbour Ltd are determined to play a part of this, for much wider benefit.

'FloWave TT is showing that there is more than one way of metaphorically 'skinning a cat' and thanks to Professor Bryden and his team, Scotland now has a unique facility to help in this 'commercialisation' process.

'In future, there could be even be safety benefits in testing precision scale-models of standard multi-cat vessels actually known to be favoured in turbine-deployment in extreme conditions here to cut the risks to on-board technicians and crews to the absolute minimum'.