Carter Jonas
Carter Jonas

Hydro E-brief Article


September marked the delivery of our 10th hydro scheme in Wales, following the successful commissioning of the Cochwillan Hydro Scheme on the Penrhyn Estate in mid-September. The 90kW ‘low head’ scheme on the Afon Ogwen utilises an existing weir and historic mill race dating back to the 1700’s, which used to feed water wheels at the Penlan Mill flint mill. The Afon Ogwen is a river in north-west Wales draining some of the highest peaks in Snowdonia National Park before discharging into the sea on the eastern side of Bangor.

The hydro scheme installed today is very different to that of the former Penlan Mill. The scheme comprises a concrete intake structure in the entrance of the mill race that is over 8 metres long and 4.5 metres deep, which channels the water into a 1.5 metre wide pipe routing 250 metres underground to a turbine house downstream of the weir. Installed below ground level in the turbine house is a 2 ton, over 2m wide ‘Crossflow’ turbine, through which the water is fed to generate electricity.

The hydro scheme is designed to abstract up to 140,000m3 of water a day (equivalent to 140,000,000 litres) and benefits from a secured Feed-In Tariff (FIT) and export tariff payable for all of the electricity generated. The scheme is anticipated to generate in excess of 480MWh of electricity per annum, which is enough electricity to power over 110 homes a year.

The project presented numerous challenges, including securing third party consents for the grid connection and pipe; the discovery and recording of archaeological finds during construction; the installation of over 100 metres of pipe through a 2 metre wide culvert which in part routes uphill; the repair of the weir spanning over 20 metres across the river; and the installation of fish and eel passes to ensure the safe passage of migrating fish from the Menai Strait up the Afon Ogwen into Snowdonia. This work all had to be completed within a two year development window in order to meet the FIT commissioning deadline.

This latest scheme brings the total number of FIT hydro schemes secured by the Carter Jonas Energy Team of behalf of our clients in Wales to over 1000MW of installed capacity, comprising a mix of low head and high head schemes ranging from 30kW to 100kW in scale.

Amy Souter

Amy Souter

Associate Partner

Associate Partner in the Energy and Marine team. Experienced Environmental Consultant and Project Manager with particular expertise in energy and infrastructure developments. Advises on and manages pr...

Read more

01423 707810