Knottingley Hydro Scheme
Overview
The 500kW Knottingley Hydropower Plant, built adjacent to Brotherton Weir, was opened on 3rd November 2017 after a construction period of 46 weeks, harnesses the flow of the River Aire and is the largest hydropower station built in England this century.
The £5.3 project was privately funded by Barn Energy, a client for whom EWCE has previously constructed two other Hydro-Electric plants on the Rivers Calder and Don, Yorkshire.
The scheme consists of twin 1.85m diameter, double regulated Kaplan turbines, and provides around 2,800MWhr of carbon free power annually to the adjacent Kings Island Flour-Mill, with surplus sold to the Grid.
Key Challenges
- The structure notably included walls 10m in height in a single lift in addition to bespoke funnel shaped “draft tube” outlets for the turbines. EWCE proposed design change of the final roof slab from cast in-situ to a composite steel frame and pre-cast concrete alternative. This, including sequencing was designed to improve constructability and reduce timescales to meet the project’s deadline. To minimise re-visits for heavy duty piling equipment, the inlet and outlet piles were burned down underwater with dive teams, reducing the programme
- EWCE produced an earthworks strategy that created a net cut/fill balance achieved through landscaping
- EWCE co-ordinated a multi-disciplinary, international team including; the Austrian turbine manufacturer (Gugler), specialist screen cleaning company, M&E contractor and other specialist supply chain partners. Working with the project’s professional team, Cobalt PM, ANF Consulting (Hydro-Power Consultant) and JNP Structural Engineers, a team that had developed the 3 hydropower projects, true collaborative working
- Barn Energy was to meet the Regulatory Date before the Feed-in Tariff reduced which would make the scheme unviable. Knottingley met the regulatory deadline some 14 months after commencement of design and construction, a testament to the collaborative relationship that had developed with the client over the 3 projects
Constructing structures in a large powerful river is a challenging activity. The reinforced concrete structure was constructed alongside and within the River Aire. The structure was constructed within a cofferdam formed from 18m sheet piles founded onto rock, with temporary support via heavy duty propping and large scale dewatering using deep wells.
Added Value
- A collaborative approach between all parties ensured a successful delivery model and resulted in a High Commended Project award by the Civil Engineering Contractors Association (CECA) North West
- In addition to the generation of a hundred years carbon free energy, the project provides significant environmental benefits opening the Aire and Calder catchments to salmonids, eels and lamprey
- The existing Brotherton Weir, had presented the largest obstruction to the free passage of fish on the catchment. A 4.6m wide Larinier fish pass was constructed permitting safe passage of migratory fish upstream to reach their historic spawning grounds. Eel and Lamprey were accommodated with a separate eel pass attached to the existing weir
- Salmon and Sea Trout can reach Leeds for the first time in 2 centuries. This increase in fish species has significant consequences for biodiversity securing attendant benefits for wildlife particularly pescatarians like otters, herons and kingfishers
- Local flour millers ADM Milling benefit from cheap electricity