Scottish and Southern Energy has announced it expects to resume operations at its Glendoe hydroelectric project in the first half of 2012, with work on new tunnels at the scheme well underway.

The project – the biggest conventional hydro plant built in the UK for half a century – was shut down in August 2009 barely eight months after generation began when a substantial rockfall was discovered in the headrace tunnel.

UK contractor BAM Nuttall has been brought in to excavate a short access adit and the water diversion tunnel. As yet, no specific details have been given about the local geology, tunnel build or cause of the rockfall.

The scheme near Fort Augustus, Scotland, has approximately 16km of tunnel network, including the 6.2km long headrace. It was constructed under a design and build contract by the Hochtief Glendoe JV, led by Hochtief and including Poyry as the designer. The contract was awarded in late 2005.