Tidal Energy Storage and Release


‘Tidal Energy Storage And Release’

How environmental science, politics and economics must redefine

the British Isles’ 21st C coastal leadership roles

Small variations in hydraulic efficiency can mean relatively big differences in water release, affecting overall energy extraction to a surprising extent when a hydro-electric scheme’s supply is from a reservoir.   A change in terminology seems essential to avoid overlooking this pitfall in two-way tidal range schemes, as evidenced at La Rance in Brittany in the 1970’s.  A workshop-based thought experiment suggests why, with singly mounted bulb turbines, otherwise good improvements are unlikely to correct this problem as efforts are made to increase two-way flows by of order three times. The 2010 UK government sponsored Atkins/Rolls-Royce SETS (Severn Embryonic Technologies Scheme) study outlined a superior alternative arrangement, broadly similar to the counter-positioned, contra-rotating (CPCR) format that the author had put forward at the outset of SETS in 2008. The Swansea Bay lagoon is well placed to serve as the generic pilot scheme then envisaged.  te times 3 newAs foreseen, the symmetric workings of such a format are essential to allow tidal impoundment schemes to offer ‘naturalised’ basin excursion patterns, dispensing with sluices to extract energy smoothly and effectively from inside and outside the enclosure.  But though such technology was confirmed by Atkins/Rolls-Royce as also ‘ideal for lagoons’, its wider generic implications are still ignored.  This is not just because their main was focus on a Severn Barrage, but also from failure to kill off the recurrent fallacy that bulb turbines’ technological maturity equates to being fit-for-purpose.  Such a mistaken view, alongside the Engineering Technology Institute’s notion of ‘over-extracting’ tidal energy (an idea slipped in as if definitive, yet itself without any definition, or reference to the overall climate threat) now risks exposing the UK to ridicule as a Cargo Cult.  How else could future generations judge once-proud maritime engineering nations for failure to collaborate in nurturing the market for a significant, predictably accessible clean energy resource for so many vulnerable coastal communities worldwide?  In the British Isles alone the list must eventually include Dublin, London, Cardiff and Edinburgh.  With a potential 50 GW installed capacity, helping efforts both to adapt and mitigate, the realistic potential dwarfs other marine renewables and arguably already exceeds offshore wind in strategic importance.  Regional devolution and the Paris Agreement combine to make early, multi-level debate and well-informed collaborative modelling essential.

For information incl. Energy Innovation 2016 application.

*With workshop assistance from Dr Hugh Hunt (Reader in Engineering at Cambridge University); and Dr. Ben Drakeford (Lecturer in Economics at Portsmouth University and UK Focal Point for the EU’s Atlantic Strategy).

Stuart Anderson Elected member for Conwy CBC & DECC Marine Energy Programme Board Member (Finance Subgroup)