Why Scotland’s reservoirs could hold the key to future energy security

At a time when governments are increasingly focused on energy security, grid resilience and reducing exposure to future energy shocks, PSH is emerging as one of the most strategically important infrastructure investments Scotland can make.

Beyond net zero

Recent geopolitical events have exposed the vulnerabilities of energy systems that rely heavily on imported fuels and international supply chains.

At the same time, the rapid growth in renewable generation means that Scotland regularly generates more renewable electricity than it can immediately use.

There are periods when supply exceeds demand and others when demand outpaces available generation and that is where PSH comes into its own.

Put simply, it works by moving water uphill when electricity is plentiful, before releasing it downhill to generate power during periods of peak demand. In doing so, it transforms Scotland’s geography into a source of long-term energy resilience.

Crucially, PSH can operate at a scale few other technologies can match, absorbing large volumes of surplus renewable electricity that would otherwise go to waste and delivering reliable, on-demand power back into the system when required.

And as Britain moves towards a cleaner electricity system, large-scale energy storage will become increasingly essential to maintaining grid stability and ensuring reliable supplies.

For Scotland, this presents a significant opportunity. With its hydro heritage and renewable output, the country is uniquely placed to provide the storage capacity needed to support the wider British energy system.

Why coordination and grid investment matter

However, becoming Britain’s energy battery requires much more than building reservoirs.

Pumped storage schemes are major infrastructure projects, often located in some of Scotland’s most remote and challenging environments. They require skilled workers, specialist materials and careful coordination. Without that, there is a real risk of delays, rising costs and increased pressure on already stretched supply chains.

At present, much of the pipeline is being driven by individual developers, helping to build momentum. Greater coordination would help align projects, reducing competition for the same resources, supply chains and grid capacity while supporting a more strategic national approach.

There is a clear role for government here, not to control delivery, but to help bring the system together and ensure projects contribute to a coherent whole.

Grid infrastructure will be equally important. Without the capacity to connect and transmit electricity, even the best-designed generation and storage projects cannot perform as intended. Investment in network upgrades will be essential if Scotland is to unlock the full value of its renewable resources.

Then there are the communities at the heart of it all. For many parts of Scotland, these developments will bring significant change, but they should also deliver lasting benefits, from improved infrastructure and skilled employment to new economic opportunities.

The PSH boom now taking shape across Scotland matters because it goes far beyond energy generation. It is about building the infrastructure that underpins a secure and resilient energy system.

Get it right and Scotland will not only strengthen its own energy future but cement its place at the heart of Britain’s energy transition for decades to come.​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

David Lee, Technical Director in Renewable Energy at AECOM