A study by Imperial College London has found that 4500MW of new long duration pumped hydro storage could save up to £690m per year in energy system costs by 2050.
The study, for pumped hydro with 90GWh of storage, is focused on the benefits of new long-duration pumped hydro storage in Scotland, as the current most established long-duration energy storage technology.
It was commissioned by SSE Renewables via Imperial Consultants.
The main benefit of long duration storage, compared to short duration batteries, is being able to continuously charge up the storage with excess renewables and also discharge power to the grid for several hours or days when wind and solar output is low.
In 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 1.5GW (30GWh) Coire Glas scheme would more than double the current amount of pumped hydro storage capacity in Great Britain.
The study, by Imperial’s researchers, led by Goran Strbac, 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.
The report highlighted that despite all of the benefits which new pumped hydro storage projects would bring, the current policy and market framework is 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.
In response to the study, Scottish Renewables policy managed Cara Dalziel said: “Cost-effective electricity storage, at the correct scale, has the potential to neutralise one of the most popular criticisms of renewables: that they're not generating when the sun isn't shining or the wind isn't blowing.
"We already know the importance of storage technologies like pumped storage hydro in maintaining the resilience and stability of the electricity grid, but today’s publication clearly demonstrates the cost benefits of developing new pumped storage hydro in Scotland, with the potential to save up to £690 million per year in energy system costs by 2050.”