To increase its portfolio of small scale hydro schemes, in light of European Union estimates that a further 600MW of exploitable hydro power projects exist in the UK, Innogy hydro is developing an 800kW hydroelectric power scheme. Costing in the region of US$2M, the Stanley Mills plant is located on the river Tay, north of Perth, Scotland, UK.

Water power at Stanley Mills was first exploited in the 18th century to run a corn mill and then used as the energy source for a cotton-spinning mill. In 1921, a hydroelectric power plant was constructed, but this stopped producing electricity in the mid 1970s after equipment became tired and it became cheaper to buy electricity from the National Grid.

However, Innogy Hydro has now awarded a turnkey contract to UK-based construction company, Amco Engineering, for the refurbishment of the existing structures, including a 250m long water supply tunnel and the listed 1920s power house.

‘The site is basically going to be completely replanted by Amco,’ explains John Baxendale, Innogy Hydro’s resources manager. ‘It is also derelict and overgrown, so Amco will be undertaking work that ranges from stripping out all the rubbish, through to repairing the concrete.’

‘Producing a design solution that met with Innogy’s environmental requirements and commercial constraints was quite a challenge,’ says Peter Brooks, Amco’s projects director. ‘To rise to this challenge we have compiled what we believe is a world class project team, from within our own resources and those of our supply chain partners. These include our turbine suppliers Esac Energie, from France, and consulting engineers Faber Maunsell, from Edinburgh.’

Preparatory site work began in January 2002 and it is envisaged the plant will be operational by the end of November 2002. The electricity produced at the station, sufficient to meet the demand of some 1400 homes, will be supplied to the local electricity network. The project has an existing contract under the Scottish Renewables Order scheme, which was established to encourage the exploitation of renewable energy sources.

During the planning and development process, Innogy Hydro has paid considerable attention to the environmental and heritage issues at Stanley Mills and measures will be put in place to protect young fish. Any fish entering the system will be safely transferred downstream by an efficient screen and bypass, according to the company.

‘A modern screening system, which is still being finalised, will be added to the site,’ says Baxendale. ‘Previously there was minimal fish protection, considering the river Tay is one of Scotland’s major salmon rivers. This new screen will be a major improvement.’

He adds that the company is also committed to minimising any disturbance to otters and bats on the site and is providing additional bat roosting boxes.

‘We have supported a variety of studies beyond those necessary to meet the planning requirements of Perth and Kinross Council,’ continues Baxendale. ‘These include one by Scottish Natural Heritage on Fresh Water Pearl Mussels in the river Tay and another to record in detail the industrial archaeology of the site to be displayed at an interpretative centre planned by Historic Scotland, the current owner of Stanley Mills.’

The refurbished hydro station will be fully automated and operated via satellite link at Innogy Hydro’s control centre in Dolgarrog, North Wales. A programme of environmental monitoring will be established to ensure the river and surroundings remain of a high quality. In addition, occasional maintenance visits will be made to check equipment.

‘We have a positive track record in running hydro plant in environmentally sensitive areas,’ says Baxendale. ‘Our experience will be invaluable in the development and operation of the Stanley Mills scheme.’

The Stanley Mills plant is the fifth in Scotland to be developed by Innogy Hydro. Plants currently in operation are located at Blantyre near Glasgow, Auchtertyre near Tyndrum in Perthshire and Glen Tarbert near Fort William. In addition to Stanley Mills, Innogy Hydro is also constructing a project at Garry Gulach near Invergarry.
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