1. 1 The Replanting of Lochaber Hydro Power Station by Andrew Thick

2. E V E N T S P O N S O R S

3. 3 Topics to be covered today Scheme modelling; Operating capability of Lochaber; Turbine Selection; Penstock works.

4. 4 Schematic of the Lochaber Scheme Loch Laggan & reservoir Loch Treig Spill Gravity Inflows Power- house Tailrace Spill Surge Chamber Loch Linnhe Spey reservoir Penstocks tunnel

5. 5 Schematic of the Lochaber Scheme Loch Laggan & reservoir Loch Treig Spill Gravity Inflows Power- house Tailrace Spill Surge Chamber Loch Linnhe Spey reservoir Penstocks tunnel

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7. 7 Schematic of the Lochaber Scheme Loch Laggan & reservoir Loch Treig Spill Gravity Inflows Power- house Tailrace Spill Surge Chamber Loch Linnhe Spey reservoir Penstocks tunnel

8. 8 Schematic of the Lochaber Scheme Loch Laggan & reservoir Loch Treig Spill Gravity Inflows Power- house Tailrace Spill Surge Chamber Loch Linnhe Spey reservoir Penstocks tunnel

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10. 10 Schematic of the Lochaber Scheme Loch Laggan & reservoir Loch Treig Spill Gravity Inflows Power- house Tailrace Spill Surge Chamber Loch Linnhe Spey reservoir Penstocks tunnel

11. 11 Schematic of the Lochaber Scheme Loch Laggan & reservoir Loch Treig Spill Gravity Inflows Power- house Tailrace Spill Surge Chamber Loch Linnhe Spey reservoir Penstocks tunnel

12. 12 Schematic of the Lochaber Scheme Loch Laggan & reservoir Loch Treig Spill Gravity Inflows Power- house Tailrace Spill Surge Chamber Loch Linnhe Spey reservoir Penstocks tunnel

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14. 14 Schematic of the Lochaber Scheme Loch Laggan & reservoir Loch Treig Spill Gravity Inflows Power- house Tailrace Spill Surge Chamber Loch Linnhe Spey reservoir Penstocks tunnel

15. 15 Schematic of the Lochaber Scheme Loch Laggan & reservoir Loch Treig Spill Gravity Inflows Power- house Tailrace Spill Surge Chamber Loch Linnhe Spey reservoir Penstocks tunnel

16. 16 Schematic of the Lochaber Scheme Loch Laggan & reservoir Loch Treig Spill Gravity Inflows Power- house Tailrace Spill Surge Chamber Loch Linnhe Spey reservoir Penstocks tunnel

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18. 18 Simplified Lochaber Scheme Model Q Tspill Q P/H Q Tin Laggan Q Tin Q Tunnel Treig Q Lspill Q Lin Q intakes

19. 19 Energy Modelling Results Trial1234567 Installed Cap. (MW)658060708090100 Overall Efficiency (%)7587 Headloss Coeff. (k)0.0210.0172 Operating ruleExt Max E Laggan Spill (mcm)2,0341,7944,1601,7091,2271,074801 Treig Spill (mcm)15412185720154107 Ave. Energy (GWh/yr)467569523574581583580

20. 20 Scheme Operating Capability Diagram 9.3 % Q 90.7 % Q Average Operation 0 % Q 100 % Q No Gravity Inflows 100 % Q 0 % Q Max. Gravity Inflows

21. 21 Turbine Selection The steps towards to turbine selection were: Analysis of historical data of scheme operation The number of generating units was selected – 5 Analysis of operating data from scheme model Performance data from tendering suppliers was fed into the scheme model

22. 22 Penstock works Key aspects of the penstock works were: Need to undertake the works minimising shutdown of generation. Existing penstock system was very complex. In order to maintain double isolation, the penstocks needed to be dewatered sequentially. The works were complex with poor access. Decision with RTA to laser scan the penstock system and create a 3-D model.

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25. 25 Penstock works Key aspects of the penstock works were: Need to undertake the works minimising shutdown of generation. Existing penstock system was very complex. In order to maintain double isolation for the penstocks needed to be dewatered sequentially. The works were complex with poor access. Decision with RTA to laser scan the penstock system and create a 3-D model.

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28. 28 Project Summary The generating plant has been replaced to give 25+ years life extension. The water to wire efficiency has been improved from 75% to 90+%. Energy production increased from 460 GWh/yr to 600+ GWh/yr. The scheme’s capability is better understood and limitations identified. The scheme was completed ahead of schedule and is operating successfully with minimal disruption to Smelter operations during construction

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30. Contact Details Andrew Thick BEng CEng MIMechE URS Infrastructure and Environment UK Limited International House, Dover Place Ashford Kent TN23 1HU United Kingdom Tel:+44 (0) 1233 658200 hydropower@urs.com Thank you for your kind attention