Introduction
Hydro power is the extraction and conversion of energy from water into electricity. Hydroelectricity is generated by water flowing through a turbine. The water can either be stored behind a dam or be abstracted from run of river. All of the feasible sites for large hydroelectric schemes in the south west have been exploited so it is likely that only micro-hydro potential – that is sites up to a power rating of 100 kW - remains in the region In the south west there are a few small dams, but future opportunities are expected to be in micro-hydro sites using run-of-river devices.
South west focus
The South Somerset Hydropower Group, a group of 10 mill owners, was formed in 2001 to investigate the feasibility of using hydropower at traditional mill sites to generate electricity. The first three installations now have a combined capacity of 20kW. When installations are complete at all 10 sites they will generate about 300 MWh/yr to supply the equivalent of 120 homes and prevent the emission of 120 tonnes of carbon dioxide. The first mill to produce renewably-generated electricity was Gants Mill in April 2004. www.gantsmill.co.uk
A group of water mill owners on the River Frome in Somerset have installed the first in a series of hydro-electric projects. Tellisford Mill, near Frome, is the Mendip Power Group’s first installation. It is on course to produce 300 kWh of electricity per year, providing power for approximately 67 homes and cutting carbon dioxide emissions by 100 tonnes annually. The capacity of the turbines is approximately 75 kW, and the project was part funded by EDF Energy’s Green Fund. The group hope to power more than 400 homes in the area through their projects, by bringing old mills back into use. See www.edfenergy.com for more information.
The first ever UK installation of a hydro-dynamic screw used to generate electricity has been completed by the River Dart Country Park in Devon. The installation of the 48 kW turbine, on the River Dart at Ashburton, is based on the Archimedes screw and produces around £30,000 worth of electricity. It has a payback period of around 5 years.
The British Hydropower Association (BHA) represents and promotes the UK hydropower sector. See www.british-hydro.org for more information.
