Whether you are in the process of commissioning a new installation or involved in renewing and / or improving an existing water energy generation scheme, the penstocks (and, in relevant cases, their accompanying surge shafts) either to deliver water to the turbine or to act as a syphon spillway, are essential components of the hydropower facility.

The choice of materials used to construct penstocks (e.g. steel, concrete, galvanised steel, HDPE, GRP, uPVC or, on mini and micro HPPs, even cedar wood stave) is largely dependent on the geographic and physical location, the nature of the terrain, whether they are surface mounted (necessitating piers, anchors and possibly thrust blocks), buried underground or encased in concrete, the design pressure, the site accessibility, the welding or jointing process and the ease of installation, design life, known seismic activity, even vandalism or the likelihood of structural damage.

Different materials have different benefits and weaknesses in terms of friction, weight, corrosion, jointing, pressure capacity and, of course, cost.

Depending on scale, the penstock can comprise a surprisingly large proportion of the overall budget. So selecting the design partner, who in turn will be specifying the materials, will be crucial.

We’ve learned much through our years of hydropower project experience, not least of which is the criticality of the penstock design (and associated parts) to the overall efficiency of the HPP in maximising a consistent, sediment free, net head delivery to the turbine. We understand and, through CFD, hydraulic transient analysis and head loss calculations, can model and compensate for the various forces applying to the penstock and any bifurcation or other pipe feature.

KGAL’s professional hydro project team, including project managers, engineering designers and CAD technicians, can address all the issues related to penstocks: from initial feasibility and design through to installation and hand-over, for both new and refurbished installations.

The image shows the parallel penstocks at Storr Lochs on the Isle of Skye, Scotland. They take water from the dam to the power house over a vertical drop of 180m. KGAL is managing a refurbishment project at the site, originally built in the early 50s.