"Why not generate your own electricity?" - a question often posed by visitors to the mill, but until recently, not a feasible proposition.
In 2003 a new turbine and electricity generator was installed at Gants Mill, to complement the 1888 Armfield turbine. An initiative by South Somerset District Council led to the formation of the South Somerset Hydropower Group, a group of 10 mill owners working together to install electrical generating equipment in their mills.
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The stimulus was provided by the need to reduce CO2 emissions, and the pledge by the Government to produce 10% of electrical energy from renewable resources by 2010.
At Gants Mill the new turbine was made by Valley Hydro of Cornwall, and the electronic mains connection unit by GP Electronics from Devon.
(Left: Lowering the S-shaped penstock pipe though the floor into the old waterwheel pit.)
(Below right: Lowering the turbine. Inside is the turbine rotor, showing the 30 blades that turn the generator.)
The plant was installed by Hydro Generation Ltd (now Renewables First). Installation of the new turbine started in September 2003, and the staff of Hydro Generation tackled with enthusiasm the variety of engineering problems encountered.
All the pieces of the pipe work, turbine and generator were lowered into the old wheel pit using specialised heavy lifting gear.
Assembly of the parts required particular attention to the stresses and weights involved, with around 2 tonnes to be supported by RSJs slotted into the walls of the wheel pit.
Gaskets between each section were carefully compressed for the prevention of leaks.
(Near right: Bolting the pipes together.)
(Far right: The turbine lowered into position.)
(Below left: Diagram of the layout of the two turbines in the old waterwheel pit, with the original one on the right and the new one on the left)
(Above: The support tower for the generator, keeping it above high water level.)
(Above: Mounting the generator on the support tower.)
At the same time electrical connections were being made, both to the external electricity pole on the grid, and within the mill itself. Finally the time came for the testing and adjustment of all the working parts under operating conditions.
The installation was inspected by engineers from the electricity board to comply with G59 regulations for connection to the grid.
(Above. Turbine and generator completed, connected by belts.)
(Above. Trenching for the electric cable between the generator and the local grid.)
(Above: The turbine control panel.)
(Above: Meter connection to the local grid.)
The equipment is designed to produce up to 12 kW of electricity in continuous operation fed into the local grid. The unit shuts down completely in the event of any system failure or power cut. The automatic operation also adjusts water flow through the turbine to maximise power output while maintaining a reserve flow of water in the main river. The actual output of electricity depends very much on river flow, being naturally greater during winter than in the summer months.
The turbine and generator's working life started on Friday 23 April 2004, when Adam Hart Davis visited to launch the scheme. Visitors are able to see it as part of their tour of the mill.
Over the centuries the mill has been adapted to society's changing requirements, as a corn mill, fulling mill, silk mill, then corn mill again, and is now a fine example of a small-scale hydropower scheme, producing electricity from a renewable resource.
(Above. Adam Hart David launching the hydropower scheme.)
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