By rosebell
As the UK’s first large-scale pumped storage scheme in 40 years, SSE Renewables’ Coire Glas project has completed its exploratory tunneling.
While the date of commencing exploratory works was December 2022, Strabag UK completed the 1.2km-long tunnel in the Scottish Highlands and designe and supervising the ground investigation program is up to SSE’s technical partners, Stantec and Cowi.
Including construction of a tunnel almost 5m high x 4.5m wide through the hillside around the proposed location of the underground powerhouse complex, this tunnel is due to provide the conditions for project team to gather accurate information on the geological conditions to inform the detailed design for the main works.
In order to further investigate the ground in the area of the proposed underground powerhouse excavations, exploratory drilling and testing will continue for the next three months.
According to SSE Renewables: “The works went to plan, and samples of excavated materials were being analysed. This phase of the project is an engineering challenge in itself and we are learning a huge amount as we progress the works. The findings of the tunnelling works, alongside our wider site ground investigation works completed by Fugro in December 2023, will be used to inform the final design, including the detailed design of underground structures, and will be a key consideration in any final decisions related to the project.”
Providing 30GWh of long duration electricity storage, the suggested Coire Glas project would have an installed capacity of 1,300MW and is located at Loch Lochy in the Great Glen.
Considering that it is required to pump water 500m uphill from Loch Lochy to an upper reservoir created by the construction of a 90m-high dam, this scheme would take excess energy from the grid. The water could be released to power the grid when required, including when wind power output is low and customer demand is high.
The scheduled date for making a final investment decision on the project according to being successful in the administrative allocation of an investable cap and floor mechanism, SSE Renewables hopes to is late 2025 or early 2026, allowing for main construction to commence in the second half of 2026.
