Aerial view of the Earba Pumped Storage Hydro Project. (Credit: Gilkes Energy)
Trial boreholes and pits being dig at the site. (Credit: Gilkes Energy)
A view of Loch na h-Earba. (Credit: Nigel Brown/Wikipedia)

The Earba Pumped Storage Hydro Project is proposed by Gilkes Energy within Ardverikie Estate, Kinloch Laggan in Scotland, the UK.

With an installed capacity of up to 1,800MW (up to 1.8GW), the project will be developed by Earba Storage, a company of Gilkes Energy.

A scoping report of the project was submitted to the Energy Consents Unit of the Scottish Government in January 2023. The report forms a part of the Environmental Impact Assessment (EIA) process.

The Energy Consents Unit published a scoping opinion based on the scoping report of the project in April 2023.

Once operational, the project will store up to 40,000-megawatt hour (MWh) of power. This makes the project the largest energy storing scheme in the UK.

Earba Pumped Storage Location and Site Details

The Earba Pumped Storage Hydro Project will be located in Loch Earba in Scotland. The project will lie within the planning authority of Highland Council.

The approximate location of the project will be to the south of Loch Laggan between Newtonmore and Spean Bridge.

The project site consists mostly of wet heath, but smaller areas of mire, scrub, dry heath, and woodland are also present. A narrow strip of ancient woodland lines the shore of Loch Earba (Lochan na h-Earba).

The site is situated within the catchment area of River Spean located upstream of Loch Laggan. Loch Laggan is drained by Loch Earba through the Allt Labhrach.

Loch Laggan is drained by Loch a’ Bhealaich Leamhain through the Allt Loch a’ Bhealaich Leamhain, River Pattack, and the Allt Cam.

The operations of the Ardverikie and Lochaber hydro projects have modified the catchment area of River Spean.

The project site will be accessible through Junction with the A86 trunk road, Moy Bridge over the River Spean, and the existing track between Moy Bridge and Loch Earba.

New tracks will be developed to access the Earba Reservoir and powerhouses. The Leamhain Reservoir will be accessible by a new road constructed from the west of Loch Earba to Loch Leamhain.

Earba Pumped Storage Hydro Project Details

The Earba Pumped Storage Hydro Project will consist of a Leamhain Reservoir, an underground waterway system, an Earba Reservoir, a pitridh aqueduct, powerhouses, access roads, mass balance, and accommodation.

The Leamhain Reservoir will act as the upper reservoir of the project. For its development, a rockfill dam will be built below the outflow of Loch Lemhain. The dam will have a storage capacity of approximately 45 million cubic metres of water (mm3).

The construction of the dam will increase the existing level (636m above ordnance datum (AOD)) of the Loch to 700m AOD.

The lower reservoir of the project will be Loch Earba. Loch Earba is being currently feeding the 1MW Ardverikie Hydro Project as a storage reservoir. The Ardverikie Hydro project discharges into Loch Laggan.

The lower reservoir consists of two small existing concrete dams with approximately 2m of drawdown into the existing lochs.

Two earth embankment dams, Shios and Shuas, will be built at both ends of Loch Earba creating a lower reservoir with a storage capacity of approximately 50mm3 of water.

The creation of dams will raise the existing top water level of 352m AOD to a maximum of 372m AOD.

The project will have an intake structure feeding one or two headrace tunnels. The headrace tunnels will carry water between the upper and lower reservoirs through the powerhouse.

The surge shafts, connecting the tunnels to the surface, will be located towards the powerhouse. The shafts will control the transient pressure changes in the waterway system.

The water intake in the system will be screened to prohibit the entry of fish and debris into the waterway system.

A buried pipeline, a pitridh aqueduct, will consist of several intake structures. The intake structures will divert the flow from Allt Coire Pitridh and Allt Corie a’ Chlachair watercourses around the Shuas Dam into the reservoir.

At Loch Earba shore will be located a tailrace inlet/outfall structure connecting the powerhouse through a tailwater conduit. The tailrace inlet will be screened to prohibit the entry of fish and debris into the waterway system.

The dams and associated structures will be built using the excavated material for powerhouse and tunnels. Access roads will be developed to access the site of the project.

Several accommodation sites for workers and related purposes will be built at the site of the project.

Power Supply

Several powerhouses will be built consisting of reversible pump/turbines, motors/generators, transformers, and switchgears.

The powerhouse surface buildings will be located on the shore of Loch Earba from the sloping hillside.

Contractors Involved

Various consultants have been appointed by the developer of the project for various environmental topics of the EIA.

Mott MacDonald will prepare the water management section of the EIA with Gilkes Energy.

The landscape, land use and recreation, and visual sections will be prepared by ASH Design + Assessment.

SLR Consulting is selected for preparing terrestrial ecology, geology, soils and water, noise and vibration, and air quality sections of the EIA.

The Ornithology section will be prepared by Mike Coleman Ecology and aquatic ecology will be developed by Gavia Environmental.

The socioeconomics and tourism will be developed by MKA Economics and Pell Frischmann will develop the traffic, access, and transport section of the EIA.

For developing cultural heritage, the developer has selected Catherine Dagg.