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SYNOPSIS
The Fair Isle
Wind/Diesel Electricity System, installed in 1982, was the first commercial
scheme to have wind as the
dominant generator. The initial scheme and its operation were reported in
conference papers many years ago. To meet increasing demand the scheme has
been extended by adding a second turbine,
also stall regulated and governed by load control, 1km east of the
original turbine. Either wind turbine may operate as sole generator for the
system. Automatic load control of heating appliances has been extended. The
distribution system has been modified to allow several modes of operation
and synchronisation of the turbines.
INTRODUCTION
Fair Isle, considered
by many to be the most remote inhabited island in the British Isles, lies
mid-way between the island groups of Orkney and Shetland, with the North
Atlantic to the west and the North Sea to the east. The island has an area
of 8.3 square kilometres, and the nearest landfall is Sumburgh Head at the
southern tip of the main island of the Shetland group, some 30 kilometres
due north of Fair Isle. The island is bounded by precipitous cliffs on all
sides, those to the west and north rising over 90 metres above sea level,
and has witnessed the final moments of many fine ships, including a remnant
of the Spanish Armada. The island has a long history and has seen many
visitors, both friendly and otherwise, but now they are mainly bird
watchers, keen to take advantage of the island's position on one of the main
European bird migration routes.
The island population
lives mainly at the south end of the island, to take advantage of the modest
shelter of a shallow valley, and to croft the more fertile land in this
area. There are currently some 80 permanent residents occupying 30 dwelling
houses. In addition, there are four public buildings in regular use, five
active workshops, and four dwellings subject to holiday let. The Islanders
derive their livelihood from a number of diverse occupations (some
part-time) from lighthouse monitor
to keeping meteorological records, serving on the island ship, the Good
Shepherd, crofting, knitting, having a share of the sheep flock on the north
end of the island, and from the manufacture of furniture, spinning wheels,
stained glass windows, traditional fishing boats and musical instruments.
The National Trust
for Scotland became responsible for Fair Isle in 1954, and was instrumental
in the provision of electric lighting to all households from five small
diesel generators in 1962. The electricity scheme was upgraded in 1975, with
advice from Hydroelectric, by installing two, three phase, 415 volt, diesel
generators rated at 20kW and 50kW, in a central generator house.
Distribution, because of the severe winds on the island, was by three-phase
underground cable, with single-phase spurs to the various dwellings. The
network has a radial configuration. An interrupted supply policy
was used to minimise operating
costs, but, by 1980, the rising cost of fuel, pushing up electricity prices,
was threatening the viability of the scheme.
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