The Replanting of Lochaber Hydro Power Station

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• The Replanting of Lochaber Hydro Power Station

by Andrew Thick
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Topics to be covered today

• Scheme modelling
• Operating capability of Lochaber
• Turbine selection
• Penstock works.

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Schematic of the Lochaber Scheme
Gravity Inflows
Surge Chamber
Gravity Inflows
Spill
Spill
Spill
tunnel
Power-house
tunnel
tunnel
Tailrace
Penstocks
Loch Laggan reservoir
Spey reservoir
Loch Treig
Loch Linnhe
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Schematic of the Lochaber Scheme
Gravity Inflows
Surge Chamber
Gravity Inflows
Spill
Spill
Spill
tunnel
Power-house
tunnel
tunnel
Tailrace
Penstocks
Loch Laggan reservoir
Spey reservoir
Loch Treig
Loch Linnhe
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Spey Dam
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Schematic of the Lochaber Scheme
Gravity Inflows
Surge Chamber
Gravity Inflows
Spill
Spill
Spill
tunnel
Power-house
tunnel
tunnel
Tailrace
Penstocks
Loch Laggan reservoir
Spey reservoir
Loch Treig
Loch Linnhe
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Schematic of the Lochaber Scheme
Gravity Inflows
Surge Chamber
Gravity Inflows
Spill
Spill
Spill
tunnel
Power-house
tunnel
tunnel
Tailrace
Penstocks
Loch Laggan reservoir
Spey reservoir
Loch Treig
Loch Linnhe
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Laggan Dam
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Schematic of the Lochaber Scheme
Gravity Inflows
Surge Chamber
Gravity Inflows
Spill
Spill
Spill
tunnel
Power-house
tunnel
tunnel
Tailrace
Penstocks
Loch Laggan reservoir
Spey reservoir
Loch Treig
Loch Linnhe
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Schematic of the Lochaber Scheme
Gravity Inflows
Surge Chamber
Gravity Inflows
Spill
Spill
Spill
tunnel
Power-house
tunnel
tunnel
Tailrace
Penstocks
Loch Laggan reservoir
Spey reservoir
Loch Treig
Loch Linnhe
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Schematic of the Lochaber Scheme
Gravity Inflows
Surge Chamber
Gravity Inflows
Spill
Spill
Spill
tunnel
Power-house
tunnel
tunnel
Tailrace
Penstocks
Loch Laggan reservoir
Spey reservoir
Loch Treig
Loch Linnhe
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Loch Treig and Dam
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Schematic of the Lochaber Scheme
Gravity Inflows
Surge Chamber
Gravity Inflows
Spill
Spill
Spill
tunnel
Power-house
tunnel
tunnel
Tailrace
Penstocks
Loch Laggan reservoir
Spey reservoir
Loch Treig
Loch Linnhe
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Schematic of the Lochaber Scheme
Gravity Inflows
Surge Chamber
Gravity Inflows
Spill
Spill
Spill
tunnel
Power-house
tunnel
tunnel
Tailrace
Penstocks
Loch Laggan reservoir
Spey reservoir
Loch Treig
Loch Linnhe
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Schematic of the Lochaber Scheme
Gravity Inflows
Surge Chamber
Gravity Inflows
Spill
Spill
Spill
tunnel
Power-house
tunnel
tunnel
Tailrace
Penstocks
Loch Laggan reservoir
Spey reservoir
Loch Treig
Loch Linnhe
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Penstocks, Powerhouse and Smelter
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Simplified Lochaber Scheme Model
Gravity Intake Flows are combined with Reservoir
Inflows
Qintakes
Qintakes
QLin
QLspill
QTin
QTspill
QLin
QTunnel
QLin
QP/H
QTin
Treig
Laggan
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Energy Modelling Results
Trial 1 2 3 4 5 6 7
Installed Cap. (MW) 65 80 60 70 80 90 100
Overall Efficiency () 75 87 87 87 87 87 87
Headloss Coeff. (k) 0.021 0.0172 0.0172 0.0172 0.0172 0.0172 0.0172
Operating rule Ext Ext Max E Max E Max E Max E Max E
Laggan Spill (mcm) 2,034 1,794 4,160 1,709 1,227 1,074 801
Treig Spill (mcm) 154 121 857 201 54 10 7
Ave. Energy (GWh/yr) 467 569 523 574 581 583 580
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Scheme Operating Capability Diagram
Average Operation
9.3 Q
90.7 Q
No Gravity Inflows
0 Q
100 Q
Max. Gravity Inflows
100 Q
0 Q
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Operating Capability in terms of Loch Treig Level
Note 90.7 of water from Loch Treig9.3 of
water from gravity intakes
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Scheme Operating Capability Diagram
Average Operation
9.3 Q
90.7 Q
No Gravity Inflows
0 Q
100 Q
Max. Gravity Inflows
100 Q
0 Q
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Operating Capability in terms of Surge Shaft
Water Level
Note 90.7 of water from Loch Treig9.3 of
water from gravity intakes
Penstock Limitation
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Scheme Operating Capability Diagram
Average Operation
9.3 Q
90.7 Q
No Gravity Inflows
0 Q
100 Q
Max. Gravity Inflows
100 Q
0 Q
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Operating Capability in terms of Surge Shaft
Water Level
Note All water from Loch Treig
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Scheme Operating Capability Diagram
Average Operation
9.3 Q
90.7 Q
No Gravity Inflows
0 Q
100 Q
Max. Gravity Inflows
100 Q
0 Q
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Operating Capability in terms of Surge Shaft
Water Level
Note All water from gravity intakes
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Scheme Operating Capability Diagram
Average Operation
9.3 Q
90.7 Q
No Gravity Inflows
0 Q
100 Q
Max. Gravity Inflows
100 Q
0 Q
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Example Operation exceeding Penstock Pressure
Rise Limit
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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

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Scheme Operation Frequency Plot
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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

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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

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(No Transcript)
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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

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(No Transcript)
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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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Multiple buspipes
Numerous Valves
Bifurcations
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Penstock Area difficult terrain!
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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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Survey Point Cloud Data
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AutoCAD 3-D Model
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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 schemes 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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Contact Details
Thank you for your kind attention

• Andrew Thick BEng CEng MIMechE
• URS Infrastructure and Environment UK Limited
• International House, Dover Place
• Ashford
• Kent TN23 1HU
• United Kingdom
• Tel [phone]
• hydropower_at_urs.com