SSE pumps £100m into Coire Glas hydro storage scheme

SSE has committed £100 million to develop plans for its Coire Glas pumped hydro storage scheme, despite lack of certainty from government over a long-term funding mechanism.

The £100 million will be used to fund the next phase of detailed design and refinement, with construction procurement due to progress throughout the year. Almost half of the £100 million will be used for pre-construction work including site investigations which will take place later this year.

A revised application to increase proposed capacity from 600MW to 1,500MW was approved by the Scottish Government in October 2020. The project is expected to take between five and six years to complete and will cost around £1.5 billion with an operational life of more than half a century.

It will be the first large-scale pumped hydro storage scheme to be built in the UK for almost 40 years.

Despite the funding commitment, SSE said that it is unable to finalise plans until the government outlines how it intends to support the long-duration electricity storage schemes.

The British Energy Security Strategy pledged to develop a mechanism to support long-duration electricity storage.

However, almost a year on, the government is yet to outline exactly what that mechanism will look like.

It has previously been suggested that it is likely to be an extension of the cap and floor support mechanism currently used to support new interconnectors.

SSE finance director Gregor Alexander added: “While Coire Glas doesn’t need subsidy, it does require more certainty around its revenues and it is critically important the UK government urgently confirms its intention on exactly how they will help facilitate the deployment of such projects.”

According to SSE – whose highland infrastructure stretches back to the “hydro revolution” of the forties and fifties and spans 54 powers stations, 78 dams and more than 300km of underground tunnels – the scheme will be able to provide minute-by-minute balancing services to the grid but also sustain services for long periods, up to days at a time, if needed.

During periods of low demand or surplus generation, electricity will pump water from Loch Lochy to an upper reservoir more than 500m above, storing energy. This is then released by using the water to generate hydro-electricity at a time when demand is high or other variable generation – such as wind or solar – is low.