Pump Storage Hydro
Pump Storage Hydro
Loch Ness Pump Storage Hydrology Study
In With the electric grid increasingly reliant on intermittent renewable sources of generation there has been an upsurge in interest in pump storage hydro (PSH) in recent years, as it is a proven form of energy storage. However, it is important to remember that PSH is categorised as a non-renewable form of hydro, as it consumes more electricity than it produces. It requires more electricity to pump water uphill, into the upper reservoir, than is generated as it flows down though the turbines. The real function for PSH in the National Grid is for storage, as surplus, and cheap electricity, can be used to pump water uphill when demand is low and for generation when demand is high.
We are not against PSH, per se, but Loch Ness already has one scheme, with another consented, and others proposed. For the reasons given below we think Loch Ness is far too sensitive a location for any more PSH to be permitted, especially as there are lots of less sensitive sites also under consultation, or in the planning system. There is a proposal from a developer for a PSH on an existing hydro reservoir in the upper Ness system. That scheme would have 12 times the generation capacity of Red John, and be located where its impact on the freshwater environment, at least, is much lower than somewhere like Loch Ness.
Until recently the growth of pump storage hydro has been slow with only four schemes in the UK, the first being the Ffestiniog Power Station, Wales which was developed in 1963. In Scotland there are only two operating PSH schemes: Crunachan on Loch Awe, and Foyers on Loch Ness. Recently there has been an upsurge in interest in pump storage schemes, world-wide, with a tsunami of interest in developing pump storage hydro in Loch Ness.
The Coire Glas scheme centred on Loch Lochy was first granted planning permission in 2013, but although some exploratory works have been undertaken, at the time of writing (June 2025), building of the scheme has not yet commenced and recent press releases suggest that any further developments have been delayed. Similarly, The consented Cruachan PSH extension has also been put on hold by the operators Drax.
Loch Ness already has one pump storage hydro scheme, Foyers PSH on the east shore of Loch Ness which was built in the 1970s. In 2021, the Red John scheme was granted planning permission at the Dores end of Loch Ness. The rights to develop Red John were purchased by Statkraft, a Norwegian state-owned energy company, in December 2023, with construction due to start in 2026. The planning application for what would be a third PSH scheme on Loch Ness, proposed Loch Kemp scheme, was submitted in November 2023. In 2024 the proposed Glen Earrach scheme on the west shores of Loch Ness was put forward for scoping, with a planning application submitted in April 2025. If consented the cumulative impact of four PSH schemes on Loch Ness would be extremely damaging with a daily drawdown of over 1.2m possible.
The political climate for the development of PSH is currently very favourable with the recently published National Planning Framework 4 creating what appears to be a presumption in favour of this form of energy storage. However the National Planning Framework 4 says nothing about how much PSH capacity there should be in Scotland, nor where.
So, what are the problems with PSH? Ness DSFB have a number of concerns:
- The daily abstraction, and return, of huge volumes of water at multiple locations along the east shore of Loch Ness is almost certain to have an impact on wild Atlantic smolt migration. Smolts trying to find their way out of Loch Ness will be attracted to the PSH intakes during abstraction. They are unlikely to be sucked up, the screens will be appropriated sized, but smolts will be attracted to the intakes, where they will be delayed, and likely to be exposed to increased levels of predation. There is no published work investigating this issue, and we know that smolts already struggle to find their way out of, even natural lochs.
- During an abstraction cycle Foyers PSH varies the level of Loch Ness by up to 220mm (9”) although typically less, the Red John drawdown will be around 90mm, although potentially, greater if the owners are successful in restructuring the scheme. The cumulative effect if the proposed, and much larger, Loch Kemp scheme gets the go-ahead, is a daily drawdown of up to 73cm (2ft 5in). The proposed Glen Earrach scheme would be the largest of all with a potential drawdown of 52cm (1ft 8in). The combined drawdown if all four schemes were consented could be as high as 1.25m. This would have a huge impact on flows down River Ness, will have a detrimental impact of the shoreline ecology of Loch Ness, impoverishing the rich shoreline invertebrate ecology, and add to the considerable navigational, and operational difficulties already experienced by commercial, rescue and recreational boat users on the loch. To most people such a daily drawdown on one of the biggest lochs in Scotland is unimaginable.
- The powerhouse for the proposed Loch Kemp PSH will be twice the size of the Foyers powerhouse, which is already a prominent and incongruous presence on the east shore of the loch, and it will be located in the middle of the almost completely undeveloped shoreline from Foyers to Fort Augustus. Loch Ness is a global tourism brand, which should be nurtured; the construction of huge industrial buildings, with the light pollution it will bring, and the associated rock blasting, should not be allowed to mar an otherwise pristine shoreline.
- We are concerned that multiple PSH in Loch Ness will raise the temperature of Loch Ness itself, and the upper storage reservoirs. This aspect of PSH has been studied and various papers have shown that PSH has the potential to elevate reservoir temperatures due to frictional losses during pumping, and generation, and solar radiation when empty upper reservoirs are filled on a sunny day.
- A recent study commissioned by Ness DSFB highlighted the impact of these PSH on the natural hydrology of Loch Ness, including surface currents, temperature and thermocline effects.
- We have produced a Briefing Note summarising our concerns about the proposed Loch Kemp pump storage scheme on Loch Ness.
Others have expressed many other concerns about these developments, including road traffic impacts, navigational difficulties on Loch Ness, the industrialisation of an iconic tourism brand, and the loss of ancient, and highly protected woodland. As far as we are concerned Loch Ness is far too sensitive for any further PSH developments. If the PSH sector wants to develop further within Scotland it needs to do much more to understands its impacts on the environment, including wild Atlantic salmon and the ecosystem that iconic species supports.
This is also about more than salmon. In the Moray Firth, at Chanonry Point, a world-class wildlife spectacle occurs on a daily basis during the spring and summer. At the Point, bottlenose dolphins wait to ambush migrating salmon, and the feeding spectacle attracts visitors from far and wide. According to David Attenborough, Chanonry Point was “the best place in the world to view this type of dolphin behaviour”. In the salmon of the Ness, there can be few better examples of an ecosystem in operation. We should cherish and nurture our natural environment, we simply can’t allow our precious biodiversity to be trashed in the “gold rush” as developers seek sites for PSH. To that end we will be asking the Scottish Government to produce guidance for the PSH sector to ensure that the most appropriate sites are developed.