FAQs

The Glenmuckloch development is a new grid-scale pumped storage hydro (PSH) facility located near Kirkconnel, Sanquhar, Scotland. The project will provide approximately 210MW of flexible electricity generation and 1,700MWh of storage, helping to balance the UK electricity grid and support a cleaner, more reliable energy system.

Pumped storage hydro is a proven, large-scale energy storage technology. It uses two reservoirs at different elevations:

• When electricity demand is low, excess renewable energy is used to pump water uphill to an upper reservoir
• When demand is high, water is released back down through turbines to generate electricity instantly

This makes it one of the most effective ways to store renewable energy and provide grid stability.

As the UK transitions to net zero, more electricity will come from wind and solar. These sources are variable, meaning supply doesn’t always match demand.

Projects like Glenmuckloch provide long-duration energy storage, helping to:

• Store excess renewable power
• Release energy during peak demand
• Improve energy security and reduce reliance on fossil fuels

Located in Dumfries and Galloway in southern Scotland, approximately 3.5 kilometres north-west of Kirkconnel, the Glenmuckloch Pumped Storage Hydro project is being developed on the site of a former open-cast coal mine. The approximate site coordinates are 55.407562° N, -4.050063° W.

The Glenmuckloch site offers several key advantages for pumped storage hydro:

• A natural height difference between reservoirs
• An existing former open-cast mine, reducing the need for new excavation
• A short grid connection (~700m) with no long-distance tunnelling required
• Suitable geology and land availability with no tunneling required

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These factors make it a highly efficient and lower-impact location for development.

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The scheme will include:

• An upper reservoir formed adjacent to Lethans Hill
• A lower reservoir created from the restored opencast coal mining workings
• A powerhouse and penstock pipe linking the two reservoirs

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The design has been developed to integrate with the surrounding landscape and minimise visual and environmental impact where possible.

The project is expected to be fully commissioned in the early 2030s and, with ongoing maintenance, could operate for up to 100 years. This longevity is proven by existing UK pumped storage systems, some of which were built in the 1960s and remain in operation today.

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Construction traffic will be carefully managed through agreed traffic management plans, including:

• Defined delivery routes
• Controlled working hours
• Measures to minimise disruption to local communities

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Where possible, the project will optimise logistics and reduce unnecessary vehicle movements.

There may be some temporary disruption during construction, including noise and activity on site. However:

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• Strict planning conditions and noise limits will apply
• Monitoring will ensure compliance
• Operational noise levels once complete are expected to be low and tightly controlled

Environmental protection is central to the project design. Key measures include:

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• Reusing a former coal mining site to avoid new major land disturbance
• Lining reservoirs to prevent seepage
• Designing to minimise impact on peatland, water, and biodiversity
• Carrying out a full Environmental Impact Assessment (EIA) implementing the recommended mitigation and ongoing monitoring during the operational period

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The project supports decarbonisation while aiming to minimise local environmental effects.

The project will deliver significant local and regional benefits, including:

• Hundreds of jobs during construction and long-term operational roles
• Opportunities for local suppliers and contractors
• Investment in the local economy
• Potential for community initiatives and improved access or amenities

It also contributes to Scotland and the UK’s transition to a low-carbon energy system.