This page offers answers to frequently asked questions regarding wind energy. If you want to add a theme or ask us something privately, please do so via the contact page. Project specific information can be found on the project page.
1. Is wind energy profitable?
Energy industry, authorities and most political actors agree that the production capacities of renewable energy, such as wind power, should increase. Here are some reasons for that:
- Firstly, many old European nuclear power plants are at the end of their life cycle and must be closed soon. This increases the need for new forms of electricity production because to keep the status quo is not option. The relevant key to find the best alternatives is to compare production costs of new energy sources by kilowatt-hour.
The UN’s Intergovernmental Panel on Climate Change IPCC has earlier this year reported that renewable energy can already compete with nuclear and coal power plants (IPCC 2011). In addition, disasters such as Fukushima accident will increase safety demands on energy production, which leads to rising costs for nuclear power and can give an additional competitive advantage for renewable energy.
- Secondly, with the technological development the production costs of wind power have dropped. Prices have already decreased to such a low level that today the world wide new installed capacity of renewables is higher than that of fossils and nuclear together. However, experts point out, that “the financial risks associated with building new nuclear power plants are beyond the balance of many utilities. These risks need to be shared between the public and private sectors.” and “The [British] government must be prepared to share some of the financial risk with taxpayers money”. (Gray 2012) On the contrary, in the wind energy industry it is believed that wind energy production will soon be profitable without public subsidiaries.
- Thirdly, the electricity price is going down because additional wind energy production increases the amount of electricity on the market. According to a study performed by Aalto university in Finland wind power will reduce the electricity prices by 68 % during years 2001-2020 (Liski and Vehviläinen 2015).
Renewable energy is the future. With the combination of solar, wind, water, and bioenergy together with a smarter use of energy, it is possible to create a cost-effective and sustainable energy supply.
2. What about the landscape impact?
Wind turbines are tall constructions and inevitably visible. In fact, visual impact is the most common negative environmental impact of wind energy production (Wekman 2006). Wind energy developers in Finland have to consider landscape effects in the EIA process and surveys that are necessary for the planning of the wind park.
The landscape around most project areas and in their vicinity is already under human influence (e.g. forestry, agriculture, mining) so untouched landscapes are not at risk. However, a landscape analysis is conducted for each project area as a part of the EIA.
Visual impact aspects have been taken into consideration in the planning process already. Visualization of the wind parks have been used from the beginning of the project planning.
Landscape values are a matter of opinion: some consider turbines ugly while others see them beautiful. People also often change their opinion to a more positive direction once that the turbines are at place. This is demonstrated for instance by a Finnish gallup Tuulivoima ja asenteet conducted by Motiva and Wpd Finland Oy.
Further information on wind energy and its landscape impacts and their assessment can be found from a report by the Ministry of Environment “Tuulivoimalat ja maisema”.
3. Do wind park projects threaten national security and military radars?
Wind energy project don’t threaten national security. Licensing, planning, and statement procedures make sure of that. In addition, national land use guidelines clearly state that planning must consider military and national security (YM 2012/4).
4. Does wind power threaten the aviation safety?
The licensing process for aviation obstructions is two-phased: in the first phase a statement from Finavia is requested and in the second phase a license from TraFi is applied.TraFi makes the decision based on the Finavia statement.
In the beginning of January 2013 TraFi has published new guidelines for how aviation obstruction lights should be placed in a wind park.In these guidelines eg. the following are discussed: the color of wind turbines, aviation obstruction lights and how low intensity lights can be placed in a wind park. Here’s a citation of a part of the guideline:
“In order to reduce the amount of light pollution from wind parks aviation lights can be groups so that the outermost turbines are equipped with high intensity lights and the rest can be equipped with light of less intensity constant red lights.”
“To define the outermost turbines an arc of 2000 m is drawn according to the picture below. The arcs should overlap each other so that a continuous arc is formed”
In order to reduce the visual impact and energy consumption of the wind park low-intensive lights are used where possible.
5. Do wind parks threaten birds and white-tailed eagles?
In Finland, approximately one or two birds per turbine dies annually by flying at wind turbines (Koistinen 2004). This is not much when compared to the deaths caused by electric wires (200 000/a), radio masts (100 000/a), or road traffic (4 300 000/a) (Koistinen 2004). In addition to collisions, there are other risks that wind energy poses to birds. Turbines may frighten migratory birds or change the feeding habitats of birds (Birdlife Suomi 2011). However, wind parks in general do not threaten bird habitats, and impacts on birds can be influenced by careful siting of the turbines (Birdlife Suomi 2011). For instance, building an underground internal electric grid, considering the turbine layout and choosing turbines of certain types can lower the risk of bird collision. (Birdlife Suomi 2011).
Eagles and other large predator birds have difficulties to see the rotating blades of wind turbines. In order to protect the white-tailed eagle, WWF has published instructions for how to consider the predator when assessing the suitability of a location for wind energy production use (WWF 2015). The WWF instructions recommend that no wind turbines should be built within 2 km from a nest, and according to ELY the efe projects are well outside this safety distance.
Birds and eagles will be considered in the EIA or environmental studies that are required for the construction license and for the master plan. In the summer 2011, ornithologists conducted a bird study within the project area and did not find eagle nests. In addition to the summer study, also migrating birds have been studied during fall 2011 and spring 2012. All study reports will be published on this website.
More information on birds and wind energy:
A report from the Finnish Ministry of Environment: Tuulivoimaloiden linnustovaikutukset
6. Will wind energy production have an impact on the natural environment?
All human land-use has an impact on environment, and so does wind power production. However, efe’s project areas already have land-uses that heavily change the environment – forestry, mining – so they are not exactly untouched environments. Moreover, wind energy production does not require giving up the existing land use, because turbines and infrastructure take only a small fraction of the wind park area. Previous land-use can continue in all other areas. The vegetation of the projects area is studied in a nature survey that has to be done for all industrial scale wind energy projects regardless of whether EIA is necessary or not. In addition, nature survey defines the need for further studies regarding flora and fauna. This information is used in planning, project development, and in the EIA in order to describe the expected impacts of the wind park on nature. If special values are found in the studies, the wind park plan can be changed so that the values will not be in risk.
7. What are the impacts of wind energy production on employment?
Wind energy sector employed 238 000 people in EU-contries in 2010. Until 2020 the amount is expected to grow up to over 520 000 people (EWEA 2012). In Finland the industry employs in the manufacturing sector of components and in project development, construction, management and maintenance (Teknologiateollisuus 2014). The wind energy branch’s turnover in Finland in 2008 was ca 1 M €, of which the export stood for ca 90 % (Teknologiateollisuus 2009).
efe’s estimation is that in practice Nordanå-Lövböle project will employ about 16 people fulltime in operation and maintenance.
8. Will property values decrease nearby the wind park?
It is a common fear that wind parks decrease the values of the neighboring properties. However, a negative impact of wind parks has not been observed on the values of neighboring properties in a study by Hoen et al (2009). In this extensive study conducted by Berkeley Lab in the U.S, there was no statistically significant correlation observed between wind park visibility or distance to wind park and property value.
9. Does wind energy threaten tourism?
Wind turbines may have positive, negative, or neutral impact on tourism (Tuulivoimatieto 2011a). If tourism is based on the image of untouched nature, wind parks can cause decreasing in tourism, but they can also cause increase in tourism if the turbines are embraced as tourist attractions (Tuulivoimatieto 2011a).
10. Will icing and ice throw be an issue in the projects?
In cold weather turbine blades can accumulate ice that may fall or be thrown maximum three hundred meters from the turbine. No serious accidents caused by ice throw have been reported so far (VTT 2010: 21). This does not mean that the issue should be neglected.
Ice formation on buildings or metal constructions such as masts or towers can be an issue in cold and icing climates. This has for long limited the large-scale use of wind energy in those regions due to the lack of proven economic and technological solutions (VTT 2010: 7).
Ice formation on the rotor blade (Figure by efe)
Vi actively investigates the risks of ice formation on the project areas even though they are located in the most southern part of Finland. Today there are several advanced types of ice detectors available. These will be usedin the wind measurement campaign in order to get an indication of the risk for icing on the project sites. In addition, the Finnish Meteorological Institute (FMI) has developed a Ice Atlas which can be used to comparing icing conditions with local measurements.
Today there are proven solutions for many of the risks cold and icing climate can cause on wind turbines:
- Modern turbines are equipped with an array of noise and vibration sensors to monitor the major components, including tower, rotor blades, generator and their behaviour under working conditions and in interaction altogether. The detected signals are collected and analysed by software tools to help understanding if the turbine is working correctly.
- After the turbine is installed and tested the monitoring system takes a “sensor–signal -fingerprint” of the turbine in normal operation mode.
- If in winter the rotor-blades drive through humid air they can collect ice on their surface. Even thin layers of ice change the vibration of blades and the turbine itself and therefore detectable by the monitoring system.
- As soon as the monitoring system sense a layer of ice on the blades, the turbine stops automatically and the de-icing system will be activated.
There are three versions of de-icing systems on the market:
- Hot air
- The hot air de-icing system blows with a fan hot air into the hollow inside of the blades to increase the temperature of the blade material.
- Heated metallic foils on the outside of the blades
- Metallic foils on the surface of the blades as used on airplane wings: Electricity creates heat and melts the ice on the blades directly.
- Current conduction layers embedded inside the blade
- The most advanced de-icing method has the advantage of not being exposed directly to the weather: a fine conducting mesh is integrated into the blade composite. Intelligent controls send electricity in varying frequencies through the mesh to different parts of the blade to melt the ice where necessary. That system can also be activated during the normal operation of the turbines.
- Hydrophobic coating of the rotor blades can influence of how fast ice sticks on the surface of blades. Investigations are intense but there are tricky competing demands on the blade coating, for instance the blade surface should also be non-reflectant and stealth.
11. Are wind speeds lower in the winter time?
Many people seem to believe that the average wind speed is lower during wintertime. This might be true in extremely low temperatures (-30 degrees or less), which are often caused by clear sky radiation related to high pressure cells that coincides with still air (VTT 2010: 17). This type of weather conditions are rare and in fact during the winter months over half of the wind energy is produced (STY 2016).
In addition, cold air is denser than warm, so the rotor rotates slightly better in the winter than in the summer, even if wind speed is the same. Air density affects the power output of wind turbines. For example at air temperature of -30 degrees the air is 27 % denser than at +35 degrees resulting in a similar increase in power output at the same wind speed (VTT , 2010: 17). In addition there is one more wind speed increasing effect in winter time. Ice on water and snow on ground reduce significantly the roughness in the surrounding of the turbines, which causes a laminar wind flow.
12. Will noise from the turbines be disturbing for the people that live nearby the project area?
The noise from turbines comes from the aerodynamic sound when the blades pass the tower and also to some extent from the generator (Di Napoli 2007: 14).
According to the Ministry of Environment’s recommendation a wind park should be planned so that the noise does not exceed 45 dB at regular living houses and 40 dB at summerhouses during day (7 am-10 pm) and 40 dB during at regular living houses and 35 dB at summerhouses during the night (10 pm-7 am) (YM 4/2012).
In order to guarantee that the noise levels from the turbines will be according to the recommendations noise models are done as part of the planning process. Noise impact will be assessed using the guaranteed noise level of the wind turbine manufacturer in combination with the certified power curve, previous experiences of wind turbines, measurement results and model calculation of sound propagation. Potential disturbances on settlements nearby project areas will be assessed using the Decibel module in WindPro 2.8 software. The module takes into account turbine specific data about noise, turbine location, topography and distances to housing. The module does not consider the damping effect of vegetation or soft soil on sound propagation. This means that the results of the model are a worst case scenario since the background noise from the forest always will have an impact on the noise.
In the Environmental Ministry’s guidelines from today there is also a mentioning, that 5 dB should be added to the result of the calculation- and measurements if the quality of the noise from the wind turbine is especially disturbing meaning there is a tonality issue or the noise is impulsive (amplitude modulation). An issue with tonality was more common in older wind turbines. It is possible to detect tonality peculiarities by analyzing the guaranteed noise levels (as octave bands) the turbine manufacturer provides. The turbine types used in planning don’t have tonality features.
The 5 dB addition to the results of the calculation- and measurements because of impulsiveness character of noise is not applied in normal conditions.
Background noise means natural or industrial noise that does not have anything to do with the noise of the object in question. Natural noise can be for example the hum of the vegetation, wind and waves, and it depends on the terrain, weather, seasons and time of the day (Di Napoli 2007: 16). According to a study the noise from pure wind is about 34-42 dB, and the noise of wind combined to the trees would contribute to a sound level of 39-48 dB (Pesonen 2004: 22). Background noise plays a significant role in covering the noise from the wind turbines (Di Napoli 2007: 17). In efe’s project areas the forest will be an important contributor to the natural background noise and the traffic and industry for the industrial noise.
Noise level for different environments (Figure by Brüel & Kjær 2011)
The noise model will be run on all turbine types considered during the planning phase. Turbine technology is improving and the noise emissions of turbines have decreased (Rogers et al. 2006: 21). Our projects will be realized using the best available technique for minimizing the noise impact.
All studies regarding noise will be published on this website.
13. Do I have to worry about low frequency sound or infrasound?
Often low frequency sounds are thought to be an especially unsettling part of the wind turbine sound. The frequency range of 20-20 000 Hertz (Hz) is a typical level that people can hear (O’Neal et al. 2010), but audibility can also extend to the frequencies below 20 Hz. Low frequency sound refers to the range from 20 Hz to 200 Hz, while the sound below 20 Hz is called infrasound.
Modern wind turbines generate considerably few low frequency noise (O’Neal et al. 2010).
In a study by O’Neil et al. (2010) the modern turbines by Siemens (SWT 2,3 MW, 93 m) and GE 1.5sle were tested and the low frequency noise emission and infrasound was measured at the distance of 305 meters from the turbine. The results show that at this distance the low frequency noise and infrasound level is well below the requirements for example for bedrooms, schools and hospitals.
14. What is meant by use of reduced noise levels for wind turbines?
In the modern wind turbines it is possible to control the noise by using reduced noise levels on the wind turbine. In practice this means reducing the speed the rotor blade rotates on by adjusting blade pitch angles. This action impacts on the electricity production, but reduces the noise level even up to several decibels. The noise reduction can be programmed to be applied only during for example certain wind directions and time of the day which, makes the use of this technology feasible.
15. How can visibility sensors decrease the light output of aviation lights on turbines more than 90% of the time?
Now it’s possible in Finland to control the intensitity of aviation lights by using visibility sensors. In this brochure from Finnish company Obelux more information about how it works can be found.
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