Cumulative impact assessment of tidal stream energy extraction in the Irish Sea
Open Access funded by Engineering and Physical Sciences Research Council. Under a Creative Commons license:https://creativecommons.org/licenses/by/4.0/
As the tidal stream industry continues to develop and move towards commercial viability, strategic planning is required to maximise its full potential. A cumulative impact assessment of tidal stream developments in the Irish Sea has been conducted on a high-resolution depth-averaged hydrodynamic model, using Telemac2D. Eight sites were investigated, representing the proposed tidal developments at the time of study. These included: Ramsey Sound (10 MW), Anglesey (10 MW), Strangford Loch (1.2 MW), Mull of Kintyre (3 MW), Torr Head (100 MW), Fair Head (100 MW), Sound of Islay (10 MW) and West of Islay (30 MW). Only three of the eight projects modelled showed array-array interacted: Fair Head, Torr Head and Mull of Kintyre. A smaller domain model, for the three projects was then created for further analysis. Results showed the Mull of Kintyre farm had little overall impact on energy production on Fair Head and Torr Head with itself slightly improving with the presence of the other two projects (+0.09%). Fair Head reduced the energy production at Torr Head by 17%, whereas, Torr Head only reduced energy production at Fair Head by 2%. This was caused by the tidal asymmetry at the site whereby the flood (west to east) was stronger. As Fair Head lies to the west of Torr Head, its impact was greater. Despite both arrays having an installed capacity of 100 MW, the maximum power output during the flood tide is 98.1MW for Fair Head and 64.5 MW for Torr Head, when operating concurrently, representing 31% reduction at Torr Head. If Torr Head can still operate commercially in the presence of Fair Head, then the additional environmental impact of Torr Head, such as the change in bed shear stress, is small. Within the Irish Sea, very few of the tidal projects investigated are geographically within close proximity to each other, meaning their interaction is limited. As the industry grows and the technology matures, allowing sites with lower peak velocities to be exploited, the risk of interaction to these sites will grow when more intermediary sites are developed.
The Industrial Doctorate Centre for Offshore Renewable Energy is funded by the Energy Technologies Institute and the RCUK Energy Programme, grant number (EP/J500847/1). This work was carried out on the High Performance Computing Cluster supported by the Research and Specialist Computing Support service at the University of East Anglia.
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.
Published online 11 April 2017