|
The UK Government's target is by 2015 to generate up to 15.4% of the UK's
energy needs from onshore and offshore wind power using turbines of up
to 1.2Mw each.
Modern wind turbines have two or three bladed rotors around 45 metres
in diameter, supported on tubular steel towers up to 40 metres in height.
The blades turn at a constant speed of about 30 revolutions a minute, driving
a generator that feeds the electricity grid. They typically produce 600Kw
each. A computer system turns the nacelle into the wind and changes blade
angle to maximise torque.
Denmark has emerged as an industry leader in this technology and about
15% of its energy needs are now met by wind power. The most recent developments
involve installing offshore monopylons in as little as 6 hours with just
4 pre-constructed components, The base shaft is first driven into the sea
bed as much as 30m, the tower is then assembled on top of it; the nacelle
and two blades are then fitted to the top of the tower and finally the
third blade is mounted on the turbine shaft. To reduce noise the 39m long
blades are wafer thin at the trailing edge. Canada is also a keen contributor
to this technology and the latest schemes use gearless turbines. A large
wind tunnel is being used to study the effects of turbulence on pylon vibrations
and fatigue life of the blades and suporting structure.
Wind energy systems are now being installed all over the world and businesses
have been set up in many countries to service this new industry.
| 
