Huge New Pumped Storage Hydro Scheme Planned

Scheme would be the largest hydro project to be built in Scotland

SSE Renewables, SSE’s renewable energy development division, has submitted an application to the Scottish Government for consent to construct a new pumped storage hydro electric scheme of up to 600MW capacity to the north-west of Loch Lochy in the Great Glen. The scheme would help meet peak demand and would extract, store (up to 30GWh) and release energy to and from the electricity transmission system to help balance supply and demand for power at a national scale.

Hydro electric turbineThe scheme would be the largest hydro project to be built in Scotland and the first brand new pumped storage scheme to be developed in Great Britain since work began on the Dinorwig scheme in Wales in 1974. With a cost currently estimated at £800m it would also be one of the largest construction projects in Scotland.

The scheme would require the construction of a new dam and upper reservoir at Loch a’ Choire Ghlais (the upper reservoir).  At an estimated height above ground level of up to 92m, this would be one of the largest dams in the UK. A powerhouse complex would be constructed underground, together with a series of  tunnels to provide access and convey water between the lower reservoir (Loch Lochy) and the upper reservoir. In addition, an outlet area comprising an administration building and jetty, tunnel portals and a tailrace structure would be constructed on the shores of Loch Lochy. Once completed the scheme would have minimal visual impact in the Great Glen. It is envisaged that the construction period would last up to five years, with an average workforce of around 150 throughout this time.

Jim Smith, Managing Director of SSE Renewables, said: “Hydro electric schemes, which use impounded water to generate electricity, are an excellent means of energy storage. Consequently, they naturally complement the variable output from the growing number of wind farms and play an important part in meeting peak demand. As the UK’s leading generator of renewable energy SSE is proud to be at the forefront of developing renewables and helping tackle climate change.”

If the project receives consent, a final investment decision is unlikely to be taken before 2014 at the earliest, and progress of this scheme (and other similar developments) will be dependent upon a satisfactory public policy and regulatory framework, including a change in transmission charging regime.


Previous article on Scots Renewables

SSE CoireGlas website 


One Response to “Huge New Pumped Storage Hydro Scheme Planned”

  • My vision for a LARGER hydro dam at Coire Glas, Scotland than SSE’s
    Read it at this link to see the images –

    I am presenting here my vision for a large pumped storage hydroelectric 2-square kilometres surface-area reservoir and 300+ metre tall dam which I have designed for the Coire Glas site, Scotland.
    View site using Google Earth where the convenient label is “Loch a’ Choire Ghlais”

    I was inspired to conceive and to publish my vision by learning of
    the Scottish and Southern Energy (SSE) proposal to build a smaller hydroelectric pumped-storage scheme at Coire Glas which has been presented to the Scottish government for public consultation.

    I have not long been aware of the SSE plan for the Coire Glas scheme, not being a follower of such matters routinely, but I was prompted by an earlier tangentially-related news story (about energy storage technology for renewable energy generators such as wind farms) to write to Members of the Scottish Parliament on the merits and urgency of new pumped storage hydroelectric power for Scotland on 14th February and a reply from Ian Anderson, the parliamentary manager for Dave Thomson MSP received the next day, the 15th February informed me about the SSE plan and Ian added “initially scoped at 600MW but, to quote SSE, could be bigger!”

    I replied to Ian “So the schemes proposed by the SSE are welcome and ought to be green-lighted and fast-tracked, but I am really proposing that Scots start thinking long term about an order of magnitude and more greater investment in pumped storage hydroelectric capacity than those SSE plans.”

    So I had in mind “bigger would be better” but it was not until the next day on the 16th February when
    a news story informed me that the SSE plans had been submitted to the Scottish government for public consultation that I thought “this needs consideration now”.

    So starting late on the night of the 17th, early 18th February and all through the weekend, I got busy, outlining my alternative vision for a far bigger dam and reservoir at the same location.

    So this is my vision as inspired by the SSE plan. If my vision is flawed then the fault is mine alone. If my vision is brilliant, then the brilliance too is mine.

    Image –

    The black contour line at 550 metres elevation shows the outline of the SSE proposed reservoir of about 1 square kilometre surface-area and the grey thick line shows the position of the proposed SSE dam which would stand 92 metres tall and would be the tallest dam in Scotland and indeed Britain to date though it seems our dams are several times smaller than the tallest dams elsewhere in the world these days.

    Part of the red contour line at 775 metres elevation, where the red line surrounds a blue shaded area, blue representing water, shows the outline of my larger reservoir of about 2 square kilometres surface-area and the thicker brown line shows the position of my proposed dam which would stand 317 metres tall which would be one of the tallest man-made dams in the world.

    Enhanced satellite photograph

    Image –

    Cross section of the Dow-dam

    The Dow-dam would be more than 3 times higher than the proposed SSE-dam. In this diagram, a horizontal line one third of the way up the Dow-dam indicates the relative height of the SSE dam although it is not aligned with this cross-section.

    Image –

    Maps showing the line of cross-section viewed from each side

    Image –

    Image –

    Cross section of the Dow-dam reservoir

    Image –

    Cross section along the major diameter of the elliptical excavation of the reservoir bed

    Excavated Reservoir Bed

    The green ellipse of major diameter of 1.5 kilometres and minor diameter of 1 kilometre represents an excavated reservoir bed, as flat and as horizontal as practical, at an elevation of 463 metres.

    Since an excavated reservoir bed is not, that I can see, part of the SSE plan, at any size, I will provide some more information about my vision for that now.

    The basic idea of excavating a flat or flattish reservoir bed is to increase the volume of the water stored in the reservoir because more water means more energy can be stored.

    Depending on the geology and strength of the rock of Coire Glas the walls of the reservoir bed perimeter could be as steep as vertical from the reservoir bed up to the natural elevation of the existing rock surface which would mean, presumably, blasting out rock to create a cliff which at places could be as much as about 290 metres tall.

    Near the dam, the reservoir bed perimeter wall would be only 40 metres or less tall. The further from the dam, the higher the wall will be and the more rock needs to be excavated.

    A vertical reservoir bed perimeter wall would be ideal to maximise reservoir volume wherever the geology provides a strong stone which can maintain a vertical wall face without collapse, (a stone such as granite perhaps).

    Where the geology only provides a weaker stone then a sloping perimeter wall at a suitable angle of repose for reliable stability would be constructed.

    So the reservoir perimeter wall could be as sloped as shallow as 45 degrees from the natural elevation at the perimeter of the eclipse sloping down to the reservoir bed at 463 metres elevation in the case of the weakest and most prone to collapse kinds of stone.

    Exactly how strong the stone is at each location I guess we’ll only find out absolutely for sure if and when engineers start blasting it and testing the revealed rock wall face for strength.

    The shape of the perimeter of the excavated reservoir bed is not absolutely critical. So long as it ends up as a stable wall or slope, however it is shaped by the blasting, it will be fine. There is no need to have stone masons chip the perimeter smooth and flat! The ellipse is simply the easiest approximate mathematical shape to describe and to draw. If the end result is not a perfect ellipse, don’t worry, it will be fine!

    OK, well I guess that’s the vision part over. The rest is fairly straight-forward engineering I hope. Oh, and there is always getting the permission and the funding to build it of course which is never easy for anything this big.

    OK, well if anyone has any questions or points to make about my vision or can say why they think the SSE plan is better than mine, or if you don’t see why we need any pumped storage hydroelectric scheme at Coire Glas, whatever your point of view, if you have something to add in reply, please do.

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