In 2007 Derwent Hydro completed the installation of a micro hydro project at Brignall Mill. It is a low head installation and is unusual in that there is no weir, the head is developed over a 150 m stretch of river that falls 3.1m around the property. Flow in the River is very inconsistent with its level prone to change frequently and rapidly, and although the mean flow at this point is more that 2m3/s, it was decided to opt for a minimally obtrusive system that would satisfy the mill’s demands for most of the year. Water is captured in a concrete inlet chamber built at the side of the river, it passes through a 10mm bar screen and enters a pipe of 450mm diameter. The pipeline is 130m long and feeds directly into a guide vane regulated propeller turbine designed and built by Derwent Hydro. The turbine drives an induction generator via a v-belt and the whole system is controlled by an SCS ‘Hydro Generation Pack’. The system runs smoothly and effectively, producing 2.9 kW from 170 l/s on a net head of 2.7m. You have the opportunity of seeing this neat little system, as the Mill provides holiday accommodation (www.brignallmill.co.uk) you will get a warm welcome from the owner!

DHPL turbine at Brignall Mill