There are several hydro-electric schemes on the Isle of Arran, an island in the Firth of Clyde, Scotland. Most of them were installed during the early 21st century, but one is considerably older.
Electricity supply
Brodick Castle was the first residence on the Isle of Arran to benefit from an electricity supply, when the owners installed a private turbine in 1909. The next development was the creation of the Arran Power and Light Company which began operating in 1933, initially supplying just the village of Brodick. Following the creation of the North of Scotland Hydro-Electric Board in 1943, they became responsible for electricity supply on the island in the early 1950s, and this resulted in the price paid by consumers dropping significantly, from 7.86 pence per unit to 1.80 pence per unit. The number of people using electricity rose rapidly, from 577 consumers prior to the Board taking over to 1,643 by April 1952.
Although the National Grid was developed from 1926 to supply consumers on the mainland of Britain, connections to the islands did not occur until much later. Arran is connected to it by two submarine cables that run across the Kilbrannan Sound from Carradale on the Kintyre Peninsula to Balliekine on the west coast of Arran. They are known as the north cable and south cable, as they follow different routes between the places where they reach land, and both operate at 33kV. The north cable, which was installed in 1993, was found to be in a poor condition when it was inspected in 2017, and plans were drawn up to replace the link during 2021. At that time, it was owned and operated by Scottish Hydro-Electric Power Distribution.
Hydro-electric schemes
There is a limited amount of electricity generation on Arran. As of 2018, there were no wind farms on the island. However, there are four hydro-electric schemes, one long-standing, and the others developed in the 2010s.
Claddoch Hydro-Electric Scheme
The Claddoch scheme was a private scheme installed by the owners of Brodick Castle in 1909. The present scheme, which is also known as Claddach or Cladach dam, uses water from the Cnochan Burn, on which there is a small dam close to the contour. An underground pipeline runs to the turbine house, which is located on the A841 road behind the sawmill on the north side of Brodick Bay. The dam was created in the 1940s, but ceased to be used in the 1950s. Following the death of the Dowager Duchess of Montrose and the need to pay huge death duties, the castle ceased to be a private residence and was acquired by the National Trust for Scotland from the Duchess's daughter Lady Jean Fforde in 1958. Subsequently, the hydro scheme was renovated by the North of Scotland Hydro-Electric Board, and is now operated by Scottish and Southern Energy, their successors. Data from the Office of Gas and Electricity Markets (Ofgem), the energy regulator, gives a commissioning date of 1949 for the scheme.
In 2006, a new pipeline was run from the intake to the turbine house. Topsoil was removed from a strip of land some wide, and the new pipe was buried close to the old pipe. A small quantity of chipped stone was found in Greenhyde Field during the work, but archaeological investigation found that it had been used as fill for a 19th century field drain, and so was not in its original context.
Glenkiln Hydro-Electric Scheme
The Glenkiln scheme is located near Lamlash in the south-east of Arran. Ideas for the scheme were first discussed in 2012, but planning was complicated by the fact that the works were to take place in an area designated as a Special Protection Area (SPA), where the habitat of migratory birds must be safeguarded, and as a Site of Special Scientific Interest (SSSI). The project was a collaboration between J K and C Bone, a long-established farming business that runs Glenkiln Farm, supplying beef and lamb to local restaurants, and MEG Renewables, who are a renewable energy developer. Planning consent to allow the project to proceed was obtained in September 2014, with construction work beginning in January 2015. Bones employed 12 men to install the pipework over a period of nearly two years, which was hampered by appalling weather conditions and record levels of rainfall, particularly during the winter of 2015/16. Work within the SPA and SSSI had to be completed by March 2016 for the project to qualify for higher levels of feed in tarriff. The work was completed by a local contractor, Murchie Sand and Gravel.