A review of the UK and British Channel Islands practical tidal stream resource

Daniel Coles, Athanasios Angeloudis, Deborah Greaves, Gordon Hastie, Matthew Lewis, Lucas Mackie, James McNaughton, Jon Miles, Simon P Neill, Matthew D. Piggott, Denise Risch, Beth Scott, Carol Spalding, Tim Stallard, Philipp Thies, Stuart Walker, David White, Richard Willden, Benjamin Williamson

Research output: Contribution to journalReview articlepeer-review

Abstract

This review provides a critical, multi-faceted assessment of the practical contribution tidal stream energy can make to the UK and British Channel Is-lands future energy mix. Evidence is presented that broadly supports the latest national-scale practical resource estimate, of 34 TWh/year, equivalent to 11%of the UK’s current annual electricity demand. The size of the practical re-source depends in part on the economic competitiveness of projects. In the UK, 124 MW of prospective tidal stream capacity is currently eligible to bid for sub-sidy support (MeyGen 1C; 80 MW, PTEC; 30 MW, and Morlais; 14 MW). It is estimated that a further 124 MW would serve to drive down levelised cost of energy (LCoE), through learning, from its current level, of around 240 £/MWh,to below 150 £/MWh, based on a mid-range technology learning rate of 17%. Doing so would make tidal stream cost competitive with technologies such as combined cycle gas turbines, biomass and anaerobic digestion. Installing this 124 MW by 2031 would put tidal stream on a trajectory to install the estimated 11.5 GW needed to generate 34 TWh/year by 2050. The cyclic, predictable na-ture of tidal stream power shows potential to provide additional, whole-system cost benefits. These include reductions in balancing expenditure, that are not considered in conventional LCoE estimates. The practical resource is also de-pendent on environmental constraints. To date, no collisions between animals and turbines have been detected, and only small changes in habitat have been measured. The impacts of large arrays on stratification, and predator-prey interaction, are projected to be an order of magnitude less than those from climate change, highlighting opportunities for risk retirement. Ongoing field measurements will be important as arrays scale up in size, with a focus on the environmental and ecological impacts that cannot yet be modelled accurately enough. Based on the findings presented in this review, we recommend that an updated national-scale practical resource estimate is undertaken, that imple-ments high-fidelity, site-specific modelling, with improved validation from the wide range of field measurements that are now available at major sites. Quan-tifying the sensitivity of the practical resource to constraints will be important to establish opportunities for constraint retirement. Quantification of whole-system benefits will be important to fully understand tidal streams value in the energy mix.
Original languageEnglish
Article number20210469
JournalProceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
Volume477
Issue number2255
Early online date3 Nov 2021
DOIs
Publication statusPublished - 24 Nov 2021

Keywords

  • Tidal stream power
  • tidal stream energy
  • practical resource
  • cost of energy
  • System integration
  • environmental impact

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