The Anonymous Widower

Repurposing The Conon Hydro-Electric Scheme

The Conon hydro-electric scheme was built in the 1950s, by the North of Scotland Hydroelectric Board.

  • The scheme is now owned by SSE Renewables and has a page on their web site.
  • There are six individual power stations; Achanalt, Grudie Bridge, Mossford, Luichart, Orrin and Torr Achilty.
  • There are six dams; Glascarnoch, Vaich, Luichart, Meig, Torr Achilty and Orrin.

This map from the SSE Renewables web site shows the layout of the dams and power stations.

The sizes of the power stations in the scheme are as follows.

  • Achanalt – 3 MW
  • Grudie Bridge – 18.6 MW
  • Mossford – 18.6 MW
  • Luichart – 34 MW
  • Orrin – 18 MW
  • Torr Achilty – 15 MW

This gives a total power of 107.2 MW.

This Google Map shows the same area as the SSE Renewables Map.


  1. Inverness is in the South-East corner of the map.
  2. The red arrow indicates the Western end of Loch Luichart.
  3. Loch Fannich is the large loch to the West of Loch Luichart.
  4. Loch Glascarnoch is the East-West loch to the North of Loch Luichart
  5. Loch Vaich is the North-South loch to the North of Loch Glascarnoch.

Is Inverness a City substantially powered by renewables?

Strathclyde University And Pumped Storage Power For Scotland

This page on the Strathclyde University gives a list of the pumped storage potential for Scottish hydrogen-electric dams and power stations.

These figures are given for the dams and lochs in the Conon scheme.

  • Glascarnoch – 23 GWh
  • Luichart – 38 GWh
  • Fannich – 70 GWh

It would appear that based on research from Strathclyde University, that the Conon scheme could support up to 131 GWh of pumped storage.

This Google Map shows the three lochs and Loch Vaich.


  1. Lochs Fannich and Luichart are named.
  2. Loch Glascarnoch is the East-West loch to the North of Loch Luichart
  3. Loch Vaich is the North-South loch to the North of Loch Glascarnoch.
  4. The locations of several power stations are shown.
  5. Cuileig is a 3.2 MW power station built in 2002.

This Google Map shows Loch Fannich.

Wikipedia says this about the loch.

Loch Fannich was dammed and its water level raised as part of the Conon Hydro-Electric Power Scheme, built by the North of Scotland Hydro-Electric Board between 1946 and 1961. An underground water tunnel leading from Loch Fannich to the Grudie Bridge Power Station required blasting out a final mass of rock beneath the loch, a procedure which was referred to popularly as “Operation Bathplug”.

The dam appears to be at the Eastern end of the loch, as this Google Map shows.

I wouldn’t be surprised to find that to obtain the potential 70 GWh of storage, that the dam will need to be raised.

This Google Map shows Loch Glascarnoch.

Loch Glascarnoch may be more difficult to expand, as a road runs along the Southern side of the loch.

This Google Map shows Loch Luichart

Lock Luichart may have possibilities as it is wide and could be deep.

But it will all be about the shape of the loch and the mathematics of the water.

Water Flows In The Conon Scheme

Looking at the SSE Renewables map of the Conon scheme, water flows appear to be as follows.

  • Loch Vaich to Loch Glascornoch
  • Loch Droma to Loch Glascornoch
  • Loch Glascornoch to Loch Luichart via Mossford power station
  • Loch Fannich to Loch Luichart via Grudie Bridge power station
  • Loch Achanalt to Loch Luichart via Anchanalt power station
  • Loch Meig to Loch Luichart
  • Loch Luichart to Loch Achonachie via Luichart power station
  • Orrin Reservoir to Loch Achonachie  via Orrin power station
  • Loch Achonachie  to River Conon and eventually the Cromarty Firth via Torr Achilty power station

Note that all the power stations date from the 1950s.

Repurposing The Conon Scheme

Perhaps as the power stations are now over sixty years old, one simpler way to both increase the generating capacity of the Conon scheme and add a degree of pumped storage might be to selectively replace the turbines, with modern pump/turbines, that can both generate electricity and pump the water back up into the mountains.

It should also be noted that Loch Vaich, Loch Glascornoch, Loch Fannich and the Orrin Reservoir are all about 250 metres above sea level, with the others as follows.

  • Loch Achanalt – 111 metres
  • Loch Luichart – 56 metres
  • Loch Meig – 87 metres
  • Loch Achonachie  – 30 metres

Loch Droma is the highest loch at 270 metres.

These height differences could create opportunities to put in extra tunnels and power or pumping stations between the various levels.

As water pumped to a greater height has a higher potential energy, perhaps it would be an idea to give Loch Droma, which is the highest loch, a bigger role.


I believe these improvements are possible.

  • Adding a pumped storage facility to the Conon hydro-electric scheme, with a capacity of upwards of 30-40 GWh.
  • Increasing the generating capacity by replacing the elderly turbines.
  • Improving control of the scheme, by replacing 1950s control systems.

It may even be possible to substantially improve the performance of the scheme without any expensive rock tunnelling.






February 19, 2022 - Posted by | Energy, Energy Storage | , , , , ,

1 Comment »

  1. […] analysis in Repurposing The Conon Hydro-Electric Scheme, showed the […]

    Pingback by Scotland’s Energy Storage « The Anonymous Widower | March 2, 2022 | Reply

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