New large-scale pumped hydro storage for Scotland?

Commissioned by SSE Renewables, the report says that, compared to short duration storage batteries, long duration storage is able to continuously charge up the storage with excess renewables and also discharge power to the grid for several hours, or even days, when wind and solar output is low.

Last October, SSE Renewables received a revised consent from the Scottish Government for what would be the UK’s largest pumped hydro energy storage scheme – Coire Glas – located near Loch Lochy in the Scottish Highlands. The proposed 1.5 GW (30 GWh) Coire Glas scheme would more than double the current amount of pumped hydro storage capacity in Great Britain, providing an invaluable low carbon resource to help cost effectively manage the fluctuations of the electricity system.

The study found that 75% of the savings to the energy system from projects like Coire Glas would be from the avoided capital expenditure in higher cost electricity generation technologies that would otherwise be needed to meet the UK’s target of carbon neutrality by 2050 whilst meeting security of supply.

However, the report also suggested that, despite all of the benefits which new pumped hydro storage projects would bring, current policies and market frameworks are unlikely to bring forward investment in many new projects, because the long duration and low carbon capability of pumped hydro storage is not sufficiently valued.