Why Pumped Storage Hydro
As the UK energy system shifts to intermittent renewables, keeping supply and demand in balance becomes harder and more valuable. Long‑duration storage is built to solve this.
Surplus. Deficit. Waste. Cost.
The Challenge:
At times the system produces more low‑carbon electricity than the grid can use; at others, demand outstrips renewable supply. Today, gas often fills the gap while excess renewable generation can be curtailed, with costs ultimately borne by consumers.
Store it. Move it. Use it.
The Solution:
Energy storage reduces curtailment by absorbing surplus electricity, and it reduces reliance on gas by releasing stored renewable energy during periods of shortfall. Pumped storage hydro does this at very large scale - effectively acting like a long‑life, long‑duration battery.
Built for scale
A typical 50MW two‑hour battery stores around 100MWh. Glenmuckloch is designed to store around 1,700MWh - equivalent to around 17 such battery projects.
Why pumped storage hydro
- Proven technology: mature, established storage with long operating life (often 100+ years)
- Long duration: designed to cover extended balancing needs, not just minutes or hours
- System value: supports renewable build‑out by adding flexibility and reducing exposure to volatile fuel prices
How PSH works
When electricity is abundant, surplus power is used to pump water to the upper reservoir.
Energy is stored as water at height, ready to respond when needed.
When demand is higher or renewable output is lower, water flows back through turbines to generate electricity.