New Site DesignWind Power FAQ
What is a wind turbine? A wind turbine is a mechanical device which transforms the kinetic energy of the wind into electrical energy. The linear movement of air travelling past the turbine is translated by the rotor into rotational movement to drive a generator.
Are wind turbines noisy? The evolution of rotor technology over the past decade or two has reduced mechanical and other noise from turbines significantly. The main noise heard from a wind turbine is a whooshing sound when the rotor blades pass the tower. As the wind strengthens, so does the volume of this whooshing. However, the ambient noise increases also, to the extent that the sound of the turbine becomes indiscernible.
What materials are wind turbines made from? Towers and masts are made of steel, generally painted light grey or whitish. The blades are typically made of glass-fibre reinforced polyester or wood-epoxy.
How strong does the wind have to blow for a turbine to work? This depends on the turbine and generator, but start-up values tend to be between 4 and 6 metres per second. Some turbines start operating at lower speeds. Rated speeds tend to be between around 9 - 12 metres per second. The lower the rated wind speed for a given output rating, the more energy you will produce over the year.
How long do wind turbines last? A wind turbine should typically last for around 20 - 25 years. Being a mechanical device open to the worst of the elements it is likely that some components may need replacing during its lifetime.
How much energy does a wind turbine produce? This depends greatly on the size of the turbine and its location. To get the greatest benefit it is necessary to site it in an exposed location away from objects affecting airflow, such as buildings and trees as these create damaging turbulence. Turbulence also reduces the potential output from the system. Another means of maximising turbine output is to ensure the hub height is as high as is possible, since wind speed increases with height.
Does twice the wind speed mean twice the energy captured? No. The energy available in the wind increases as the cube of wind speed. Therefore a doubling in wind speed translates into a fourfold increase in the power (and hence energy) available.
What happens when there is no wind? For grid connected system, when the wind resource is insufficient to power your home, you will simply import energy from the grid. Similarly, if you are producing more energy than you are using you can export any excesses to the grid.
You need to speak with your electricity supplier to find out what their buying and selling prices and terms are.
Are birds at risk if I install a wind turbine? Birds risk collision with any manmade structure including wind turbines and buildings. However, the threat posed by wind turbines is extremely low when compared with avian mortality rates from tall buildings, road vehicles, domesticated cats and intensive farming practices.
Do I need planning permission? We advise that you check with your local planning authority before committing to any installation projects.
What are the maintenance requirements of a wind turbine? Being a mechanical machine operating in often difficult conditions, the wind turbine will need periodic maintenance to ensure the correct functioning of all bearings, the gearbox and the generator. Specific maintenance details depend on the particular machine that is installed.