Redundant Main Inlet Valves for Dinorwig Hydro-Power Station Upgrade

Collett have successfully delivered two Redundant 147Te Main Inlet Valves (MIVs) from Dinorwig Hydro-Power Station to a specialised facility in Bangor.

The deliveries are part of the ongoing essential upgrade scheme at the power station, with Collett having previously delivered two new MIVs earlier this year to replace existing equipment.

Operating within the mountain, each valve was loaded from the temporary storage area using an overhead gantry crane. The MIVs were securely loaded onto two 10-axle flat top trailers. Upon exiting the facility, we were challenged with the long exit tunnel, featuring a demanding 10% gradient. To overcome this, we implemented a double-headed approach utilising two 8×4 heavy tractor units to pull the valves up the tunnel.

Each Valve measured 5.3m(L) x 4.7m(W) x 3.7m(H)

The valves were transported in convoy along the 11-mile route to the specialist facility in Bangor.

The convoy was accompanied by a police escort, as well as Collett’s abnormal load escort fleet. The entire journey from site to site was completed in 1 hour and 40 minutes.

Before transportation, our Projects Department conducted thorough preliminary works, including a comprehensive route survey, lift plans, method statements and risk assessment report.

Additionally, our Heavy Lift Team had previously attended the site, setting up the JS-125 500Te capacity Jack-Up System.

Inlet Valves Leaving Dinorwig Hydro Power Station

12-mile journey to site

Inlet Valves being Lifted Using JS125 Jack Up System

Upon arrival at the specialist facility, each trailer was reversed under the lifting gantry, and the MIVs were offloaded directly from the trailer. This method provided an ideal solution for a situation where space was limited. 

Dinorwig Hydro-Electric Power Station, located near Llanberis in the Snowdonia National Park, is the largest pumped hydroelectric storage facility in the UK. With a maximum power supply of 1,728MW and a storage capacity of approximately 10GWh, the station efficiently manages water between the Marchlyn Mawr reservoir and the Llyn Peris Lake to generate power as needed.