New GRP penstock for hydropower plant Ovadas, Portugal

Country

Portugal

City

Viseu

Timeline

2017-2018

Application

Hydropower

Total Length

2100 m

+

In the district of Viseu in central Portugal, an old concrete penstock has been replaced with GRP. The challenging installation works were carried out in two phases, allowing for the unhindered operation of the plant during peak production periods.

The run-of-river hydropower plant Ovadas is located at the Cabrum river, a tributary of the larger Duoro river, in the central inland of Portugal. After 25 years in operation, the plant’s original concrete penstock suffered structural damage, which led the energy company Energia de Portugal (EDP) to replace the pipeline. The renewal involved 2100 m of buried pipe between the water intake connection of the dam and the concrete transition block.

Several circumstances regarding the site and pipe route made the installation challenging: the space on site was limited, the area hard to access with heavier construction machinery, and the exact route and profile of the old buried pipe was in many spots unknown. What the client needed was a pipe material that was easy to install and flexible enough to recreate a new penstock along the same route and with the same longitudinal profile as the old one.

The solution was found in GRP. Unmatched benefits such as the pipes’ light weight, the possibility to realize curves via angular deflections in the couplings, and the availability of tailor-made pipe lengths and accessories enabled the team to successfully tackle all project conditions. With an extensive experience in penstock projects, Amiblu was commissioned to design and supply the 2100 m long pipeline.

Amiblu Flowtite GRP pipes DN 1000 in pressure classes of 6 to 20 bar, elbows, tees with flanges for air vacuum valves, and inspection manholes were installed in two phases during the summers of 2017 and 2018. This allowed for an unhindered operation of the plant during peak production periods.

The GRP pipes’ excellent hydraulic properties guarantee maximum energy output, and thanks to the material’s corrosion resistance the penstock will improve the production performance of the Ovadas hydropower plant over many decades.