Sròndoire has three Vestas V80 - 2.0MW, Mk 7.4 wind
turbines. Each turbine can produce
2,000kW at full output. The site produces around 6 MW, which when combined with
the 10MW output from Allt Dearg is enough to supply the electrical power needs
of around one fifth of the homes in Argyll. The turbines start to generate when
the wind speed at the hub height reaches 4 m/s (9 mph - Gentle Breeze), full
power output is reached at 16 m/s (36 mph - Moderate Gale), the turbines shut
down at 25 m/s (56 mph - Storm). Upgraded Power Plus / Power Performance Optimisation software was installed in December 2016. This operating system upgrade was part of the Vestas "through life" performance enhancement program, designed to maximise power production from each turbine, based upon its individual site conditions.
The V80 is a robust and well tested machine, that meets the IEC 1A wind classification. Wind Class 1 turbines are designed to cope with the 10 m/s (22mph) average wind speeds we experience on site. The "A" designation refers to the higher level of wind turbulence, characteristic of a complex upland topography. Class 1 turbines have smaller rotors and are on shorter towers to minimise structural loads. They are built for heavy duty service, which makes them relatively expensive. They are designed to withstand winds gusting to 155mph. We have seen winds up to 130mph on site.
The turbines are fully automatic and the combined site is
controlled by a central computer (SCADA). The
turbines are remotely monitored (from Warrington, Spain and Poland), 24 hours a day,
by Vestas, the Danish turbine makers who are in charge of the turbine operation
and maintenance. Day to day the turbines
are maintained by James and Robbie, other members of the local Vestas Service
Team provide weekend and holiday cover. They are joined by other
specialist service technicians when required. The Ormsary Farmers Engineering
and Estate team looks after the switchgear, cables and access roads.
The height from the ground to the S1 and S2 turbine hub
centre is 80m, and 60m at S3. The blade swept area is 80m in diameter (hence
V80), so the total tip height when a blade is at 12 o'clock is 120m at S1 and
S2, and 100m at S3. The nominal rotor speed is 16.7 rpm, when the blade tip is
travelling at around 160 mph. At maximum
rotor speed (19 rpm), the blade tip travels at 180 mph.
The nacelles and blades were manufactured in China. The towers were manufactured in Spain.
Each Turbines has its own name and personality, due to
the slightly different wind conditions at each location.
S1 – Spuggie - OS Grid Ref: NR 8254 7693
S2 - Betty the Belter - (Queen of the Hill) - OS Grid Ref: NR 8291 7678
S3 - The Dooker (Dookers are Natives of Tarbert – a
reference to a historical local taste for cormorant, shag or guillemot
(dookers) soup) - OS Grid Ref: NR 8285 7642