Frequently Asked Questions
Why wind?
Wind will not run out. Wind power provides electricity without producing harmful gas emissions such as carbon dioxide, the main gas contributing to global warming and climate change, and without depleting limited reserves of fossil fuels and uranium. Wind farms are sustainable developments i.e. they meet the needs of the present without compromising the ability of future generations to meet their own needs.
Will wind farms generate jobs in the UK?
Yes. There are employment opportunities in the development, construction, operation and maintenance of UK wind farms and there are a number of factories in the UK already manufacturing and assembling component parts for wind turbines.
For offshore wind particularly, the skills acquired over the decades in the oil and gas industry make the UK ideally positioned to exploit this abundant renewable resource.
Are wind turbines inefficient? Is it true that they only operate 30% of the time?
No, a modern wind turbine produces electricity 70-85% of the time, but it generates different outputs dependent on wind speed. Over the course of a year, it will generate about 30% of the theoretical maximum output. This fact is taken into account when calculating figures about electricity production and carbon dioxide savings.
What will happen to the turbines when there is a storm?
Wind turbines start operating at wind speeds of four to five metres per second (around 10 miles an hour) and reach maximum power output at around 15 metres/second (around 33 miles per hour). At very high wind speeds, i.e. gale force winds, (25 metres/second, 50+ miles/hour) wind turbines shut down.
When wind speeds reach around 25 metres/second (around 55 miles per hour) which are storm force winds more powerful than strong gales, the wind turbines will shut down to protect their internal machinery from excessive wear and tear. When the wind speed drops back down below about 55 mph the turbines will resume generation.
Wind energy is intermittent, doesn't that mean we need to generate more backup electricity from conventional power stations so we don't get black-outs?
For up to 10% of wind energy on the electricity system there should be no technical problems in managing intermittency and ensuring reliable supplies of electricity. All power stations need to be supported by backup or reserve capacity on the grid in case of electrical or mechanical failures, and it has long been standard practice to provide it. A capacity margin around 20% for demand uncertainties and plant failures is not untypical.
A report by the Department of Trade & Industry and the Carbon Trust ('Renewables Impact Study', 2004) states that intermittency of renewable energy is not a significant issue for the grid at current target levels.
How noisy are wind turbines?
Modern turbines are quiet in operation and you can hold a conversation underneath one without raising your voice. The final design of a wind farm will ensure that strict guidelines relating to noise are complied with.
If anyone has any concerns about noise from wind turbines, by far the best thing to do is to go and visit a wind farm. There's a full list of all the UK's wind farms at the BWEA web site. There really is no substitute for standing under a turbine and listening to it.
What about infrasound or low frequency noise?
At the beginning of 2004, the press highlighted that 'low frequency noise' or 'infrasound' could be produced by wind turbines, and that this was possibly a cause of sleep interruption and headaches.
A study called 'Low frequency noise and vibrations at a modern wind farm' (ETSU W/13/00392/REP), commissioned by the DTI in 1997, comprehensively assessed the vibrations from wind turbines and concluded that:
- vibration levels attenuated rapidly with distance
- there was no clear increase in vibration with wind speed
- 100 metres away from the turbine, levels were 10 times lower than the safety requirements for modern laboratories
Dr. Geoff Leventhall, an eminent UK acoustics expert who has specialised in problems of low frequency noise for about 35 years, stated in 2004 that there is negligible infrasound and very little low frequency noise from wind turbines - a few low level tones from the gearbox. He stated that there just isn't enough low frequency noise from modern wind turbines to make people ill.
What about wildlife local to a wind farm?
Recent scientific research indicates that, as early as the middle of this century, climate change could commit one third or more of land-based plants and animals to extinction, including some species of British birds.
The RSPB stated in its 2004 leaflet 'Wind farms and Birds', that "in the UK, we have not so far witnessed any major adverse effects on birds associated with wind farms." A report published in the journal 'Nature' confirmed that the greatest threat to birds in the UK is climate change. Carefully sited turbines should pose no significant risk to birds or wildlife.
Does it take more energy to make a wind turbine than it generates?
The average wind farm will pay back the energy used in its manufacture within six to eight months of operation. A modern wind turbine is designed to operate for more than 20 years and at the end of its working life, the area can be restored at low financial and environmental costs.
