The SSE Renewables’ scheme, at Loch Lochy in the Great Glen in the Scottish Highlands, will create enough long duration storage capacity to power three million homes for up to 24 hours.

Strabag UK was awarded the exploratory works contract in April. The company will construct a tunnel approximately 4m wide and up to 1km long, cutting into the hillside towards the proposed location of the underground powerhouse complex.

Samples of the materials in the hill will be analysed, and survey and assessment work will be carried out to give a detailed understanding of the geological conditions. The information will then be used in detailed design of underground structures.

The exploratory works findings will be used to inform the final design of the project and will be an important consideration in SSE Renewables’ decision whether to proceed with the project.

Coire Glas project director Ian Innes said the scheme was one of the most significant engineering projects to take place in the UK for decades.

“The commencement of these exploratory works is a great milestone for everyone on the Coire Glas Project Team and at SSE Renewables,” he said.
In June, SSE Renewables revealed the tenders received for the civil engineering and mechanical and engineering

The six shortlisted tenderers are:

For the civil engineering scope:

  • Bechtel Ltd, Acciona Construcción and Webuild consortium
  • BAM Nuttall Ltd, Eiffage Génie Civil and Marti Tunnel AG consortium
  • Dragados SA and BeMo Tunnelling UK Ltd consortium
  • Strabag UK Ltd

For the mechanical and electrical plant scope:

  • Andritz Hydro GmbH and Voith Hydro GmbH & Co KG partnership
  • GE Hydro France

It is expected that one preferred tenderer will be selected for the mechanical and electrical scope and two for the civil engineering works.