Why Loch Ness hydro schemes could be killing off Scotland's wild salmon

It has been described as a “gold rush”, but conservationists on Loch Ness believe pump hydro storage schemes could be killing off endangered wild salmon.

Ness District Salmon Fishery Board warned these schemes should be temporarily halted, as salmon numbers could be declining because of drastically altered water levels.

The board has asked the Scottish Government to step in and order the schemes to be stopped until more research is carried out into what impact they may be having on biodiversity.

Pump hydro storage splits water into two reservoirs at different elevations.

When demand on the electricity network is low, surplus electricity is used to pump the water into the higher of the two reservoirs - when the demand increases, the stored water is released into the lower reservoir, generating electricity. 

The Foyers scheme has been operational on Loch Ness since the 1970s, and a second has been granted planning permission - but another two schemes are in various stages of planning, meaning there could soon be as many as four on the iconic loch.

Brian Shaw from Ness District Salmon Fishery Board, said: “There is no published work on the impact this will have on salmon migration.

“We want to see research conducted so we can understand the impact these schemes have on precious biodiversity.

“Pump storage in general is a good thing and we need to see more of it, but we think there needs to be space left for nature.”

Mr Shaw said people “don’t appreciate” the volumes of water that go through the hydro schemes.

He says the Foyers scheme can pump water at twice the rate of flow as the River Ness, which has the third highest flow of any river in the UK.

“If there were four schemes, the level of Loch Ness could vary by a metre up or down,” Mr Shaw added. “That could have all sorts of impacts on shoreline ecology.

“Loch Ness is very deep, but the narrow band of shallow waters around the loch is the most productive part for invertebrates.

“And if there is a negative impact on salmon then there will be a knock-on impact on the dolphins at Chanonry Point, probably the greatest wildlife spectacle in the Highlands.”

The fisheries board has now submitted a petition to the Scottish Parliament asking for a moratorium on the use of these schemes on any lochs that contain wild salmon.

Members of the board have also spoken to various local MSPs as well in a bid to get the use of pump hydro storage on Loch Ness halted.

Mr Shaw said: “We are not against pump storage in principle, we just think Loch Ness is not the right place for it.

“We think there needs to be a pause on this gold rush until we know the impact on biodiversity.”

A spokesman for the Scottish Government said: “Long duration energy storage (including hydro) has the potential to play a significantly greater role in the energy transition - providing flexibility services to the grid and helping to ensure a continued resilient and secure electricity supply.

“While additional deployment of renewables will play an important role in lessening dependence on fossil fuels for electricity generation, large-scale, long-duration energy storage, such as pumped hydro storage, is also absolutely critical to achieving our collective goals.

“It can help to integrate and maximise our significant renewable electricity generating capacity, ensure security of supply and manage constraints across the grid.

“Our fourth national planning framework ensures that potential impacts on communities, nature and other receptors are important considerations in the decision-making process.

“All applications are subject to site-specific assessments.”