A twin Archimedean screw turbine has been installed at a West Yorkshire housing development as part of hydroelectric project.
The Garnett Wharfe development includes the regeneration of a historic derelict paper mill site in Otley.
The hydroelectric project, which is being managed by Eric Wright Civil Engineering and Lowwood Products, has seen the installation of two 3.7m diameter screw turbines co-located near the new housing development on the River Wharfe. A turbine house is located above the turbines, which will house the electromechanical equipment, including the gearbox, generator, control system and transformer.
During its operation, the hydroelectric facility will match its output of energy to that delivered by the river, first ensuring sufficient water passes over the weir and down the fish passes. Any surplus will be taken through the screws up to maximum flow rate of 13.5t of water per second.
The installation will be connected directly to the housing development via a private grid network to supply Garnett Wharfe and surrounding areas, subject to demand and generation levels. In addition, the site will use the natural river flow and fall over the existing weir, which has a hydraulic head of 3.45m (3.25m net head) from weir crest to average downstream water level stage.
The scheme, which is rated at 350kW (175kW per screw) is expected to provide an annual energy output of 1,011MWh. This is sufficient to meet the average annual electrical usage of 290 UK homes, with an annual CO2 saving of 450t in comparison to imported grid energy.
Work on the new hydroelectric facility commenced in November 2015 and the latest phase builds on the recent installation of a sheet-piling cofferdam around the working area to block the river. The project is expected to be completed later this year, with the next phase involving completion of the build, before progressing to install the necessary electrical equipment, connect to the electricity grid and remove the cofferdams. The plant is scheduled to be commissioned in September.