(Swedish) Vanliga frågor

(Swedish) Var hittar jag aktuell samrådsinformation?

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How are people affected by shadows from wind farms?

When the sun is high in the sky, the shadow from a wind farm is relatively short, stretching for a few hundred metres at most. It is very unusual to find inhabited buildings so close to a wind farm. If the wind farm is around a kilometre away, there will be no cast shadow from the blades even if they pass in front of the sun. The reason is that, at that distance, the blades do not cover the entire disc of the sun, thus significantly reducing the effect. The shadows can be perceived at a distance up to around 1.5 kilometres, though only then in the form of a vague change of light.

Calculations of the shadow effect are based on the astronomically “maximum possible shadow effect”, which refers to the time at which the sun theoretically shines between sunrise and sunset from a cloudless sky and when the rotor surface lies perpendicular to the incident sunlight. The “actual shadow effect” refers to the actual overall time during which periodical shadow effects occur in a location sensitive to disturbance. This can be estimated with the help of statistics on number of hours’ sunlight, wind direction, etc. According to the guidelines, the shadow effect in a location sensitive to disturbance should not exceed 8 hours per year or 30 minutes per day. Exposure to rapid changes in shadow can cause temporary irritation and distraction but is not harmful and does not cause any lasting adverse effects.

Problems with shadows can be avoided by placing the wind farm such that shadow problems do not arise, or by providing the wind farm with automatic control equipment that closes down the farm during the period of disturbance. The blades of modern wind turbines are treated with an anti-reflective coating so as not to cause light reflections.

How much noise comes from a wind farm?

As developments have proceeded, it has been possible to reduce the noise from the gearbox. Indeed, a number of machines now operate without gearboxes. The predominant noise from a wind farm arises when the blades cut through the air. This sound is usually perceived as a hissing or swishing sound and has a lot in common with the noise generated by the wind passing through vegetation of various kinds.

There are guidelines on the noise levels that must not be exceeded when building a wind farm. In residential areas, the noise level should not exceed 40 dBA. In open-air recreational areas and areas with low background noise, the noise level should not exceed 35 dBA.

The “worst case scenario” is normally used in the calculation of the noise level. This is the noise generated by the wind farm when the wind is blowing at 8 metres per second at a height of 10 metres. Masking sounds (whistling of the wind, rustling of leaves, lapping of waves, road traffic) and other background noise are not taken into account in the authorisation.

Research is taking place to look at ways of reducing the possible negative effects on those who live in the vicinity. Improvements to the blade profiles lower the source noise, and it is already possible now to program new farms to minimise the noise during required periods, such as when the wind is blowing towards the residential area.

What effects on the environment does wind power have?

As wind farms use the energy contained in the wind to generate power, there are no emissions to the ground, air or water. Nor does any fuel need to be extracted or transported by tanker, pipeline or long-distance truck. There is no spent fuel to dispose of or place in terminal storage.

Wind power does, however, have a direct effect on the appearance of the countryside and generates noise which, at close quarters, can be perceived as a nuisance. So far, research has shown that animals soon become accustomed to wind farms, while studies show, among other things, that birds are not affected any differently than they are by other buildings. This negative effect can be avoided or minimised by good planning and siting.

Is wind power profitable compared with other electricity production?

An older production plant that was shut down long ago can obviously produce electricity at lower cost than a completely new plant. Wind power must therefore be compared with another new form of electricity production, and in this respect it is very competitive.

In the debate, wind power is often compared with nuclear power. Several studies show that wind power is cheaper than nuclear power, while others show the opposite. One difficulty in estimating the cost of nuclear power is that very little nuclear power is being built in this part of the world. A current example, however, is the building now underway at Olkiluoto in Finland, where costs have almost doubled compared with the calculations made at the start and now significantly exceed the cost of wind power.

How often does a wind farm produce electricity?

Wind farms produce no electricity when the wind is too weak (around 3–4 metres per second), and when the wind is too strong (above around 25–30 metres per second) they are closed down for safety reasons. At the height of the blades, there is very rarely no wind at all, and extremely high wind speeds are also uncommon. A wind farm can therefore supply varying levels of electricity for around 90 per cent of the hours in a year. Converted to so-called full load hours, wind farms produce electricity at full capacity around 30 per cent of the time. The production of wind power is also at its greatest during the autumn and winter, when electricity demand is at its highest.

It is important to point out that no type of power produces electricity all the time. This applies, for example, to nuclear power, which in 2009 and 2010 produced 15–20 TWh less electricity than during a normal year. Nuclear power, in fact, is often regarded as having a higher “value” than wind power as it is expected to have a high degree of availability throughout the year.

(Swedish) Var får vi elen ifrån när det inte blåser?

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How does wind power contribute to reduced carbon dioxide emissions?

Swedish electricity production, which mainly consists of hydropower and nuclear power, currently already emits very little carbon dioxide. However, with a continued vigorous expansion of wind power, Sweden will be able to export emission-free electricity to the rest of Europe, too. As the climate is affected equally wherever the emissions occur, it is important for Sweden to help reduce emissions beyond its national borders.

(Swedish) Hur stora subventioner får vindkraften?

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(Swedish) Hur påverkar vindkraftutbyggnaden konsumenternas elkostnader??

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