Hydro-electric power
Small scale hydro-electric power schemes used to be common in the Exmoor area. All of the older schemes have fallen into disuse following the introduction of the National Grid. Mains power tended to be more economical and the different voltage and, in some cases, direct current of the local stations menat that ordinary appliances could not be used. Modern inverters, however, can convert current and some parts of the dams, weirs and leats used for former power supplies can be re-used. Advances in low-head technology (where the fall in water is between 4 and 2 metres) also mean that sites that could not be used previously now can.
Exmoor was a pioneering area for hydro-electric power. In 1890 Lynton and Lynmouth became one of the first settlements in Britain to have electric lighting. This was powered by hydro-electric generators beside the East Lyn river. They were chosen because they did not pollute like a proposed gas works. They also powered an ice-making machine for the fishing industry. To overcome variations in river flow, one of the world’s first pumped storage schemes was soon added, using off-peak electricity to pump water to a reservoir on the hill above. The generators were gradually improved until the station was destroyed by the flood of 1952. Other settlements such as Dulverton once had their own hydro-electric power and estates such as at Lee Abbey.
Former hydro-electric power station at Lynmouth
From 1983 markets for private electric power were opened up and now there are three hydro-electric power stations operating in the Greater Exmoor area. There is a new hydro-electric power station in Lynmouth. The power station was built on the West Lyn, making use of the huge drop of the river in its last mile. A 20 inch pipeline feeds two turbines, each generating about 300 kilowatts of power, enough to supply the basic needs of Lynmouth and send some surplus to the National Grid, depending on river flow. There is a display about this and the 1952 flood disaster in an old chapel. The Greater Exmoor LEADER project identified 9 sites on Exmoor, each with potential to generate over 10 kW, enough to contribute to the National Grid, and with total potential of 650kW. The site with the greatest potential is that of the former hydro-electric power station at Lynmouth, with a projected output of 350kW. A further 30 sites were identified with potential for large on site demand, such as at the National Park Authority's sawmill at Simonsbath, and domestic use, such as at the Authority’s Outdoor Education Centre at Pinkery.
Hydro-electric power station at Glen Lyn
Pinkery was investigated for hydro-electric power. The small streams around the centre were found to be too small to be viable sources of power. Above the centre is Pinkery Pond, which may have been planned in the 1820s as a source of water for powering farm machinery. However, the cost and environmental concerns of using that as a power source for the centre have also led to it being considered unsuitable. The sawmill proved more fruitful, although still expensive for the amount of power it could produce. The building dates from the 1850s or 60s. Originally it had a large overshot waterwheel of at least 30ft diameter. The building was renovated and the wheel replaced by a turbine in the mid 1890s. The turbine generated about 17 kW of power, driving, via shafts and belts, machinery and a dynamo that supplied electricity for the village. This ceased when the flooding that destroyed much of Lynmouth in 1952 silted up the leat system. The turbine was then replaced by a 40hp diesel engine, still working. The building was a multi-purpose workshop for the Fortescue Estate. Work ceased there in 1991, when much of the Fortescue land around Simonsbath was sold.
Simonsbath Sawmill
In 1996 the National Park Authority purchased, with the help of a Heritage Lottery Fund grant, the sawmill and 9.6 hectares of meadows surrounding the leat. Some time was spent cataloguing the contents of the building, including many old tools and machinery.
Workmen in Simonsbath Sawmill when used as workshop for the Fortescue Estate
Following further grants restoration work began in 2001, first with the leat, then the turbine and, a year later, on the buildings. The leat takes water from both the River Barle and its Bale Water tributary. A short length of leat carries water from a weir on the Barle to a weir on the Bale Water then by a 500 metre long leat to the sawmill. The leat system had not been in operation since the flood disaster of 1952. By 2003 restoration was complete and the building opened for use as a sawmill.
Leat at Simonsbath Sawmill
Sluice on Sawmill leat
The turbine and diesel engine were restored to drive the machinery, including the restored saw bench. The engine runs at times when the water level in the river is too low to extract water into the leat.
Turbine at Simonsbath Sawmill
Sawbench at Simonsbath Sawmill
Diesel engine at Simonsbath Sawmill
Now a generator that can be run from either turbine or deisel engine has been installed. A parallel hydro-electric system using the existing weir and leat was considered. Depending upon the type of turbine, it would be possible by this means to generate up to 16,000 kWh per annum. The periods when the electricity could be generated would be strictly regulated by the Environment Agency, as the River Barle, from which the water is extracted, is a Site of Special Scientific Interest and important salmon spawning ground. A minimum flow has to be maintained in the section of river by-passed by the leat, limiting the use of water power effectively to the wetter parts of the year. The limited production time for electricity would mean that it would take 25 years to pay back the cost of installation, assuming a 50% grant. Thus a smaller generator using the existing turbine was installed instead.
Electricity generator, input/output control box and heaters at Simonsbath Sawmill
The generator supplies direct current to a bank of batteries. An inverter then converts the electricity from the batteries to alternating current for use in the sawmill. If the batteries are fully charged and more power is coming from the generator than the sawmill is using, the excess power goes to wall heaters. The sawmill also has mains electricity, as it is less economical to use the diesel engine simply for electricity production: it is better to use the engine for electricity when it is also being run to operate machinery.
Batteries and inverter at Simonsbath Sawmill