Breathing room provided at renewable energy station

The UK is widely reported to be on track to achieving its target to deliver 15% of the UK’s energy consumption from renewable sources by 2020. One of the major players 
in providing renewable energies SSE (Scottish and Southern Energy), are involved with long term development and sustainability of renewable energies through a range of initiatives including off-shore and deep water wind farms, solar, wave and tidal energy. Of the SSE renewable energies, there is one that has played a key role since the late 19th Century when it first started successfully supplying electricity from Benedictine Abbey in Fort Augustus at the west end of Loch Ness.
The Loch Ness region contains some of Britain’s highest mountains and largest inland lochs which, combined with high rainfall, makes hydro-electricity a possibility.  It is therefore no surprise that the Foyers site, located in the centre of the eastern shore of Loch Ness was one of the first large scale commercial development for hydro-electricity when it was established by the British Aluminium Company back in 1896.
The Foyers site is one of eight hydro-electric schemes that is managed by SSE and has recently seen sections refurbished as part of their on-going maintenance programme.  Part of the maintenance project that was untaken by Morgan Sindall Plc was to replace the access covers for their Penstock, Penstock overflow and Flow meter chambers of which one was an impressive 7.3metres x 3.2 metres, with a vertical drop of 6.5 metres.
When Foyers is generating, water flows via tunnels from Loch Mhor through the turbines which produce electricity during peak demand, but during periods of low demand the surplus energy is drawn and fed to machine sets which now operate in reverse. These generators now acting as motors drive the turbines which in turn act as pumps and return the water from Loch Ness back to Loch Mhor ready for the next cycle. It is therefore critical that any new installations protect, provide access but more importantly do not disrupt the cycle of water and supply of energy to the national grid.
Peter Savage Limited proposed their 1680 series multiple leaf access cover as the system features a hinged design and utilises stainless steel torsion springs, in order to provide lift assistance. However, this particular penstock controls the flow of water from an enclosed 7.3metre diameter pipe into the hydro turbines which necessitates the cover system to essentially breathe and allow the free flow of air. Such a ‘breathing’ feature prevents a vacuum build up inside the chamber which in turn ensures the flow rates out of the gate are not impinged and output therefore not impaired.
The Peter Savage & Morgan Sindall teams forged an excellent working relationship in which their combined experience enabled them to arrive at a solution which facilitates the free passage of air via a large number of venting positions throughout the system without unduly inflating the cost to the client. But with so many vents needed, the cover system would be compromised unless additional protection was provided to prevent contamination from insects and other debris to the water, pipe and subsequently the turbines.  In addition whatever form of protection was applied, its effect could not be allowed to act against the flow of air otherwise; the consequence of its use would need to be incorporated within the air flow calculations. The resulting solution was a specially ven¬¬ted 1680 series multiple access cover fitted onto a raised fabricated frame. This provided venting along the circumference of the clear opening and was safeguarded as with the cover venting by a special insect proof stainless steel mesh.  
In addition to the 7.4 x 3.2 metre multiple access cover, a further 6 torsion spring assisted covers were supplied to the site. 
The professionalism and efficiency of the Peter Savage and Morgan Sindall teams is clearly demonstrated in this brief case study which also displays their ability to work in unison to provide a first time solution for the client. There is little doubt that hydro-electricity is an essential part of the UK’s efforts to achieve renewable targets and counter the effects of global warming. Peter Savage Limited is proud to be involved with such a prestigious project. and offer free site visits, measuring and CAD drawings for approval purposes and welcomes any enquiries you may have. 
Please click here  to view this case study in pdf.