When family-owned self-drive plant hire company Buckland Newton Hire (BNH) was building a new hydro project it turned to Apex Dynamics UK to supply the inline planetary gearbox used to ‘control the waterwheel with minimal power loss through transmission and ensure as much electricity as possible is generated’.

Based near Dorchester in Dorset, it is the largest waterwheel generating electrical power in Europe; and at 9m in diameter, it is larger than one at a National Trust site in Port Talbot, Wales. To achieve the required head of water for the project, BNH raised one of the lakes on the family farm by around 11m. The lake is supplied from a large spring and run-off rainwater from the valley slopes.

The galvanised-steel waterwheel, which has 92 individual buckets carrying a total of 6 tonnes of water at a time, now delivers an average flow of about 150 litres per second 24/7 — nearly all year round — supplying an average of 150kWh per day. This equates to about one-third of the total electricity needed for the site, which includes more than 20 industrial units (many with large power demands), five properties, and offices.

An Apex Dynamics NB-series linear three-stage planetary gearbox is in line with the waterwheel shaft and is connected to the generator via a pulley and belt system. The waterwheel rotates at 4.5rev/min and the Apex gearbox provides the flexibility to fine tune the speed up to 450rev/min at the 48mm gearbox output shaft. The high torque from the waterwheel is accommodated at the 140mm-diameter input shaft of the gearbox. A pulley and belt connection delivers the required 1500rev/min to the generator.

Brad Perrett, BNH manager and director, said: “As the lake is in front of his home on our family farm, my father wanted to watch a huge waterwheel from his window and we have made his dream come true, building the biggest wheel we can for him! Apex Dynamics UK has been an excellent partner for this project. We could easily have installed a cross-flow turbine, but we wanted to do something a bit different that showcases our capabilities and our green credentials as a company. We think we could replicate this project in the future to provide similar lake-based energy generation projects for clients.”

The grounds around the waterwheel will be landscaped by BNH so that visitors can come and view the ‘pioneering electricity generation project’ from summer 2025.