Renewable Energy: Wind
Question: How much of the time do wind turbines produce electricity?
Answer: The output of a wind turbine depends upon the wind regime where it is located. In the UK the average capacity factor is around 30%. This means that over the course of a year the turbine would produce 30% of the amount it could theoretically have produce if it was working flat out all through the year.
Turbines on average turn, and therefore produce electricity, for about 80 - 85% of the time. Again this depends upon location.
Question: How long does it take for a turbine to 'pay back' the electricity used to manufacture it?
Answer: The comparison of energy used in manufacture with the energy produced by a power station is known as the 'energy balance'. It can be expressed in terms of energy 'pay back' time, i.e. as the time needed to generate the equivalent amount of energy used in manufacturing the wind turbine or power station.
The average wind farm in the UK will pay back the energy used in its manufacture within three to five months, and over its lifetime a wind turbine will produce over 30 times more energy than was used in its manufacture. This compares favourably with coal or nuclear power stations, which deliver only a third of the total energy used in construction and fuel supply. So if fuel is included in the calculation, fossil fuel or nuclear power stations never achieve an energy pay back.
Question: What are wind turbines made of ?
Answer: The towers are mostly tubular and made of steel, generally painted light grey. Some towers are made of concrete. The blades are made of glass-fibre reinforced polyester or wood-epoxy. They are light grey because this is the colour which is most inconspicuous under most lighting conditions. The finish is matt, to reduce reflected light.
Question: Why don't wind turbines have lots of blades?
Answer: People often wonder why there aren't more blades on wind turbines. The optimum number of blades for a wind turbine depends on the job the turbine has to do. Turbines for generating electricity need to operate at high speeds, but do no need much torque or turning force. These machines generally have three or two blades. On the other hand, wind pumps operate with plenty of torque but not much speed and therefore have many blades.
Question: What is the wind energy potential in Ireland?
Answer: The magnitude of the Irish wind resource and the potential for its development has been appreciated for some years within the European wind energy community. An estimate of the potential for wind is given in an ESBI study where they say "wind power could generate around 345TWh/y or around 19 times the current electricity production of the ESB system".
Question: What is called AER?
Answer: The Irish government decided in April 1994 that ESB should offer contracts to purchase power from new installations of CHP, wind, hydro and waste/ biomass sources totalling up to 75MW. This was called the Alternative Energy Requirement (AER1). New capacity was to be acquired by a competition, where proposers would compete for Power Purchase Agreements (PPAs), which are legal contracts of 10-15 years ’ duration not extending beyond the year 2010..All projects were required to be completed near the end of 1997.
The first round of the competition (AER1) awarded 73MW to wind. AER3 has resulted in an additional 137MW of power purchase contracts being awarded.
Question: Which is the first windfarm in the Republic of Ireland?
Answer: The first significant wind energy installation was the 6.45MW windfarm at Bellacorick.This consists of 21 Nordtank machines. It has performed very well with an average load factor of 30%. Subsequent installations have load factors around 40%.
Question: What is the current wind capacity installed in the Republic of Ireland?
Answer: Current wind power capacity installed in the Republic of Ireland is 137.625 MW with a total of 25 windfarms.
If you have any queries or suggestions, please contact us at:
Mayo Energy Agency Ltd
Arran Place
Ballina
Co. Mayo
Phone: (096) 76113
Fax: (096) 76199
Email: MayoEnergy@eircom.net