Questions 51 to 55 are based on the following passage.
As the windiest country in Europe, the United Kingdom's wind power potential is larger than the rest of Europe put together. Half of this resource is in Scotland. The UK's government has promised to generate 10% of their electricity using renewable resources. Wind power is seen to be the answer to doing this. The UK has issued wind farm licences to produce as much electricity as about six nuclear power stations. This policy has found favour with the public who support the search for cleaner energy sources.
Until 1989, Denmark was the only European state that had installed wind turbines for generating electricity. After 1989, other European countries followed suit developing support mechanisms for developing renewable energy and particularly wind power. Since 1994 the remaining European countries have also really started to support wind power station installation. Countries offer different levels of support. Some governments have paid companies premiums to maintain their competitive edge while others have given investment subsidies to foster the development of technology. Tax incentives have also been offered.
Nature provides us with indications for the best sites for wind turbine installation. Wind force and direction can be observed by leaning trees. This can most frequently be seen in open countryside and areas near coastlines and it is here, particularly in elevated spots clear of trees or buildings which obstruct the current of air, that wind farms have mostly been erected. Massive wind turbines, twice the size of conventional turbines, are also being developed for use offshore, as it is there that the strongest and most constant winds are found.
Believing that wind energy has no disadvantages is easy--it is clean, efficient and comparatively inexpensive and it creates no pollutants or emissions during operations. The electricity generated in the first 6 to 9 months of operation by a typical wind turbine will usually meet its manufacturing costs. However, wind farms are frequently regarded as a type of visual pollution because of their common locations on hilltops. It is inescapable that sites with the most wind are usually the most beautiful, and because they are built in wild, remote and untouched settings their impact is all the more noticeable. This is one of the most controversial questions when deciding on wind farm locations. Thus the setting of wind farms ought to be done with the greatest sensitivity. When turbines are due for decommission, the entire structure can be wholly recycled or removed and the cost of total site restoration can usually be completely met by the scrap value.
Wind turbines blades are made of glass fibre or wood epoxy and they can be of a diameter of 30 to 60 metres. The blades of the wind turbine generator are turned by the wind. The blades are joined to the hub that is in turn connected to the gear shaft. When the wind blows, the blades and hub turn the shaft that revolves within the generator; that then produces electricity. The power created is dependent on the blade size and the swept area. The speed of the wind and its availability are also key variables to be considered. The electricity is then moved to either the grid for regional use or to supply power to a stand-alone facility.
European operational capability was 2,500 megawatts in total by the end of 1995. By the end of 1996 it had increased to 3,400 MW and at the end of 1997 to 4,600 MW. There were steady increases in growth (40% per annum) over the following 6 years and the forecast is that this growth rate will persist. This is in contrast to practically zero growth in traditional fossil fuel energy production. Nonetheless, even at existing production levels, only 2% of potential energy is being exploited. In due course therefore wind farms may well satisfy 20% of total European power requirements. The European country with the most operational capacity is Germany. This is mostly down to the level of support given to wind power by Germany's government. It has also been helped by recent innovation in the field of turbine development.