Renewables: Facts for Residents

All human interventions in nature have an environmental impact. This applies equally to new settlements and road traffic, as well as agriculture and forestry. Building a wind farm is also an environmental intervention. 

Before we build a wind farm, we therefore use detailed and independent expert reports to check whether birds live in the area, and if so, which species. This is taken into account in planning (1). 

• For example, wind farms need to be located away from important breeding and roosting areas of bird species known to be sensitive to wind energy. Sensitive species include red kites, white-tailed eagles and cranes. 
• In Brandenburg, for example, a protective radius of 3 km applies around the eyrie of a white-tailed eagle or a lesser spotted eagle. The flight route between the eyrie and the respective hunting grounds must also be kept clear. 

Birds and Other Animals Benefit from Compensatory Measures

When a wind farm is constructed, the environmental impact has to be compensated elsewhere. The compensatory measures have to be at least equivalent to the impact of the intervention. We might create mixed woodland, for example, or plant orchards, or renaturalise former industrial sites. 

For birds of prey, we can create new hunting grounds specifically to lure them away from wind farms. Such new habitats not only benefit the birds, but also many other animal and plant species as well as the soil.  

In Comparison: Wind Turbines Less Dangerous than Domestic Cats 

Despite our best efforts at protection, birds do die at wind turbines. But the number of bird casualties caused by wind energy is low compared to other sources of risk. 

It is estimated that 100,000,000 birds die every year in collisions with windows (2). 70,000,000 birds die every year on our roads (3). Birds of prey are particularly at risk because they look for small animals that have been run over by cars. Domestic cats catch up to 60,000,000 birds per year (4), and at least 1,500,000 birds collide with high voltage cables every year (5). Compared to this, a mere 100,000 animals die in collisions with wind turbines (6). 

Protecting our climate also protects nature  

The biggest threat to our indigenous fauna is in fact climate change. Renewable energies such as wind and solar energy can help to slow it down. This is why we are building wind farms.  

Sources:

(1)    Agency for Onshore Wind Energy (Fachagentur Windenergie an Land): “Mitigation measures during the planning and approval of wind farms“, September 2015 (in German): https://fachagentur-windenergie.de/fileadmin/files/Veroeffentlichungen/FA-Wind_Studie_Vermeidungsmassnahmen_10-2015.pdf

(2)     German Association for Nature Conservation (NABU), “The extinction of birds”, 2017 (in German): https://www.nabu.de/tiere-und-pflanzen/voegel/gefaehrdungen/24661.html

(3)    Lars Lachmann, “The extinction of birds: fact or fake?” In: Loccumer Protokolle, 63/2017 (in German): https://www.nabu.de/imperia/md/content/nabude/vogelschutz/loccumer_protokolle_63-17lachmann.pdf

(4)    Ibid.

(5)    Naturschutz aktuell – NABU-Pressedienst 2017: “NABU: 1.5 million birds die each year in collisions with power cables”:  https://shop.nabu.de/presse/pressemitteilungen/www.birdlife.org/www.nabu.de/themen/naturschutz/index.php?popup=true&show=19992&db=presseservice

(6)    German Association for Nature Conservation (NABU), “The extinction of birds”, 2017 (in German): https://www.nabu.de/tiere-und-pflanzen/voegel/gefaehrdungen/24661.html

Experience shows that ground-living animals quickly get used to wind turbines in their vicinity and return to their usual habitats shortly after construction. This means that wind turbines have no permanent effect on deer, hares or red fox (1). The same applies to farm animals such as sheep, cattle or horses.  

Wind farms in forests therefore do not interfere with hunting, and farmers can continue to use wind farm areas for grazing or keeping livestock. 
 

Sources:

(1)    German League for Nature and Environment (Dachverband der deutschen Natur- und Umweltschutzverbände (DNR) e.V.), 2012, “Wind energy compatible with nature and the environment (onshore)”, p. 258 (in German): https://www.lubw.baden-wuerttemberg.de/documents/10184/61110/Windkraft-Grundlagenanalyse-2012.pdf/656de075-a3d2-4387-aa30-7ec481c46c5c

(2)    ibid.

Germany is home to 25 bat species (1), all of which are protected. Wind turbines are indeed a threat to bats. Even the sudden change in air pressure from the rotor blades can cause them serious injury.  

In the past years, we have learned a lot about bat behaviour. Much of this has come from bat observation carried out as part of wind farm construction. As a result, we can protect bats more effectively today. 

Bats predominantly fly in dry nights between July and September, when wind speeds are below 5.0 m/s and the air temperature is at least 10° Celsius.

In areas where we can expect bats to fly, we therefore turn off wind turbines during such weather conditions. As bats fly when wind speeds are low, yield losses are not significant. Today, bat-friendly operation is a condition for securing planning approval for a wind farm.  

Planners have to ensure that wind farms are sited at least 200 m away from regular flight corridors for bats. The same applies to bird migration routes and the hunting grounds of birds known or suspected to be at risk of collision.    

The nacelles of wind turbines contain systems that allow us to continuously monitor bat flight activities during operation. This allows us to check whether bats really only fly when expected and to adjust operating times accordingly. 

By the way: when we build a wind farm in a forest, we check every single tree for bat roosts before we clear the area. 

Sources:

(1) Wikipedia: https://de.wikipedia.org/wiki/Liste_von_Fledermausarten_in_Deutschland

Further Sources: 

• Agency for Onshore Wind Energy (Fachagentur Windenergie an Land): “Wind energy and bat conservation”, 2019 (in German):  https://www.fachagentur-windenergie.de/fileadmin/files/Veroeffentlichungen/FA_Wind_Dokumentation_Windenergie_und_Fledermausschutz_10-2019.pdf
• Bavarian Environment Agency (Bayerisches Landesamt für Umwelt): “Wind energy and bats” (in German): https://www.lfu.bayern.de/natur/windenergie_artenschutz/fledermausschutz/index.htm

Modern wind turbines generate "a moderate operating noise only, similar to a background murmur"(1). Most of the noise is caused by the rotor blades moving through the air, however the gearbox and generator also generate noise. 

We have to comply with strict limits to protect residents from noise pollution. The relevant legislation in Germany is set out in the Bundes-Immissionsschutzgesetz (Federal Emissions Protection Act) and in the Technische Anleitung zum Schutz gegen Lärm (Technical Guidelines on Noise Protection - TA Lärm). Wind turbines must comply with the same rules as other commercial turbines. The relevant calculations take account of their particular construction height. 

For example, noise emissions in "dedicated residential areas" must not exceed 50 dB(A) during the day and 35 dB(A) at night.(2) For comparison: 40 dB(A) corresponds to a quiet whisper (3) – outdoors rather than indoors. The noise emissions from a wind turbine with a hub height of 140 meters and a rotor diameter of 120 meters are lower than that already at a distance of 575 meters. A distance of 620 metres is sufficient for three wind turbines standing together (4). Generally speaking, the distance between wind turbines and the nearest residential area is even greater.

How do we ensure compliance with the noise threshold values?

Manufacturers use simulations and prototypes to analyse the acoustic properties of new wind turbines even during the development phase. The acoustic properties of new models are measured several times before they are launched on the market, so we have a very precise idea of the noise levels of a given wind turbine at the planning stage. Very wide tolerances are also applied to these levels.

We can predict at the planning stage how loud the wind turbines will be in the surrounding area based on the relevant sound power level data, because the propagation of sound follows fixed physical laws. 

• The noise emission prognosis is part of the approval procedure: before a wind turbine is erected, residents can view the sound propagation map to see what maximum noise could be reached at their place of residence.
• When calculating sound propagation, we begin with the worst-case scenario in which a turbine is at its loudest, which is when the wind blows just strong enough to drive the turbine at almost full power (approx. 10 m/s). At even greater wind speeds, the noise created by the wind and storm drowns out those generated by the wind turbine. Usually, however, the wind is less strong and the turbine much quieter.
• Of course, wind turbines already in operation at the site in question are also considered as an acoustic preload, and we also take account of other technical installations or operations. The total noise pollution, which includes the preload and additional noise pollution, must not exceed the legally defined limits.
• To ensure that the calculated sound levels are actually maintained following construction, we have to take measurements within a fixed period of time and at predefined emission points. 
• All sound propagation calculations and emission value measurements are carried out by independent experts.

Less Noise through Technical Optimisation

Wind turbines have undergone rapid technical development in recent years. An important objective for the engineers was to make them quieter.

• Rotor blade profiles, for example, have been optimised to generate less noise. 
• Serrations can be attached to the blades to reduce the turbulence and thus the noise they generate. It is possible to reduce the noise generated by wind turbines by between two and four decibels (6) which corresponds to about half of the noise they emit.
• Speed limitation is used to quieten the systems in "sound-optimised operating mode", which we use, for example, to ensure that a system is not too loud at night. Modern turbines no longer lose as much power as they once did in this thanks to technical improvements.
• An amendment to the guideline for calculating the sound propagation of wind turbines as high-altitude sound sources from 2016 now enables even more accurate forecasts. 

Sources:

(1)    The Baden-Württemberg State Office for the Environment (Landesanstalt für Umwelt Baden-Württemberg), Immission Protection, Noise: https://www.lubw.baden-wuerttemberg.de/erneuerbare-energien/laerm

(2)    Sixth General Administrative Regulation on the German Federal Immission Control Act (Technical Guidelines on Noise Protection – Technische Anleitung zum Schutz gegen Lärm – TA Lärm), August 1998: https://www.verwaltungsvorschriften-im-internet.de/bsvwvbund_26081998_IG19980826.htm

(3)    Vgl.: Hörex, „Kleine Dezibel-Kunde“, https://www.hoerex.de/service/presseservice/trends-fakten/wie-laut-ist-das-denn.html

(4)    The Baden-Württemberg State Office for the Environment (Landesanstalt für Umwelt Baden-Württemberg), Immission Protection, Noise: https://www.lubw.baden-wuerttemberg.de/erneuerbare-energien/laerm 

(5)    Fachagentur Windenergie an Land, Schallimmissionen (Agency for Onshore Wind Energy, Sound Immissions): https://www.fachagentur-windenergie.de/themen/schallimmissionen/ 

https://www.windkraft-journal.de/2018/09/06/neue-technik-macht-windenergieanlagen-deutlich-leiser-2/126995
 

One of the issues raised most vociferously by public action groups in recent years concerns infrasound. 

The human ear is not able to process very low sounds below a frequency of approximately 20 Hertz (Hz), which is why this frequency range is referred to as infrasound, as it is below (lat. "infra") the so-called hearing threshold: one cannot hear infrasound by definition.

Infrasound also involves a spatially and temporally periodic fluctuation of air pressure the amplitude of which is oriented parallel to the direction of propagation. As with all forms of sound, infrasound can excite mechanical vibrations, which can be “felt” at extremely high sound levels. 

Wind turbine sound emissions cover a wide range of frequencies with components in both the audible and inaudible range and, in fact, they do emit a low amount of infrasound. However, provided that the legal requirements are complied with, the associated sound levels are orders of magnitude lower than the human perception threshold. 
The extent to which wind turbines emit infrasound has been thoroughly researched. Research by the Landesanstalt für Umwelt Baden-Württemberg (LUBW) have shown that even from a distance of 150 meters, a distance already exceeded by the hub height of contemporary wind turbines, the levels are well below the human perception threshold. At 700 metres, the acoustic technicians were no longer able to detect any difference in terms of whether a wind turbine was in operation or not, i.e., they were unable to distinguish the noise generated by the wind turbines from the natural infrasound generated by the wind.(1)

Various studies completed in 2020 again confirmed that wind turbine infrasound immissions are harmless. The German Federal Environmental Agency (Umweltbundesamt) published a laboratory study in September 2020 in which test persons were exposed to four different infrasound sources for 30 minutes each. The research team measured their heart rate, blood pressure, cortical activity and balance perception both during and after the acoustic irradiation and found no connection between "infrasonic sounds around or below the perception threshold and acute physical reactions". (2)

The VTT Technical Research Centre of Finland published a major study under the title "Infrasound Does Not Explain Symptoms Related to Wind Turbines". Noise immissions were measured in two residential buildings, each located 1.5 kilometres away from a wind farm comprising 17 turbines (3MW) over a period of 308 days.

Different sound recordings of the previously measured peak values in which the infrasound components were partially filtered out, were then played back to two comparison groups. Neither residents nor test persons with no previous exposure were able to recognise the recordings which included infrasound. And not just at the conscious level: stress indicators such as their respiratory and heart rates, pupil movements and the electrical conductivity of their skin also showed no reaction.(3)

However, the authors of the study assume a nocebo effect because local residents continue to complain about symptoms, such as insomnia or headaches, which they attribute to the infrasound from wind turbines: these symptoms can occur just through the mere belief that they are caused by wind turbines. 

In a popular scientific and self-experiment, one staff member of the Bayreuth Center for Ecology and Environmental Research (BAYCEER) compared the extent of the infrasound pollution caused by a wind turbine with the everyday exposure level of a car trip and found that the infrasound energy to which we are exposed during a three-and-a-half hour car trip is similar to that which we would suffer if we were to live just 300 metres from a wind turbine for 27 years.(4) 

Whereas wind turbines are not relevant sources of infrasound, we are confronted with a multitude of infrasound emitters in our everyday lives, which, in addition to cars, include air conditioners, refrigerators, washing machines and pumps. However, even in these cases the levels are so low that they pose no threat. 

Sources:

(1)    Landesanstalt für Umwelt Baden-Württemberg (LUBS), „Tieffrequente Geräusche und Infraschall von Windkraftanlagen und anderen Quellen“, 2016, https://www.lubw.baden-wuerttemberg.de/-/bericht-tieffrequente-gerausche-und-infraschall-von-windkraftanlagen-und-anderen-quellen-veroffentlicht- 

(2)    Umweltbundesamt, “Lärmwirkungen von Infraschallimmissionen“, September 2020: Press release by the German Federal Environment Agency (Umweltbundesamt) about the infrasound study
(https://www.umweltbundesamt.de/presse/pressemitteilungen/infraschall-um-unter-der-wahrnehmungsschwelle). The full version can also be downloaded as a PDF at (https://www.umweltbundesamt.de/sites/default/files/medien/479/publikationen/texte_163-2020_laermwirkungen_von_infraschallimmissionen_0.pdf) 

(3)    The VTT Technical Research Centre of Finland, "Infrasound Does Not Explain Symptoms Related to Wind Turbines", 2020: VTT project website: (https://www.vttresearch.com/en/news-and-ideas/vtt-studied-health-effects-infrasound-wind-turbine-noise-multidisciplinary#-1),  download the complete study at 
(https://julkaisut.valtioneuvosto.fi/bitstream/handle/10024/162329/VNTEAS_2020_34.pdf?sequence=1&isAllowed=y / https://julkaisut.valtioneuvosto.fi/handle/10024/162329) and a summary of the results at Solariy (https://www.solarify.eu/2020/05/01/270-infraschall-von-windenergieanlagen/) 

(4)    The Bayreuth Center for Ecology and Environmental Research (BAYCEER), Infraschall im Auto” (Infrasound in Cars), October 2020, https://www.bayceer.uni-bayreuth.de/infraschall/de/forschung/gru/html.php?id_obj=157452

Citizens’ action groups opposed to wind turbines repeatedly accuse the German federal government of the “uncontrolled growth” of wind turbines and say that they are being built in an unplanned manner in unsuitable locations. That is actually incorrect.

The German Federal Building Code (BauGB) has granted “privileged permissibility” to wind turbines in outskirt areas since 1997 (1). German planning law defines “outskirt areas” as land located outside of municipal development plans and built-up areas. However, this does not mean that wind turbines could be erected just anywhere. 

The German federal states designate so-called priority areas for the construction of wind turbines, so care is already being taken at the regional planning level to ensure that wind turbines are only erected in areas where there are no conflicts with other land uses. 

• As a matter of principle, it is prohibited to erect wind turbines in nature reserves and national parks.
• Likewise, areas of particular cultural or historical importance are off limits for wind turbines.

Local authorities and municipalities also have the option of determining where wind turbines can be built in their development plans. Development plans are publicly accessible, and the public are able to participate in their preparation. 

Project developers planning to erect a wind turbine in a suitable area inform all “public interest groups” (the municipality, higher-level authorities, and associations). The impacts on residential development, the landscape, flora, and fauna are also examined and con-sidered during the approval process. 

Compliance with legal limits for noise emissions and shadow casting are an integral part of the assessment. The approval procedure is based on the German Federal Immission Control Act (Bundesimmissionsschutzgesetz), the Federal Nature Conservation Act (Bundesnaturschutzgesetz), the Environmental Impact Assessment Act (Umweltverträglichkeitsprüfung) and the Town and Country Planning Code (Baugesetzbuch). The approval process also includes a public hearing, in which local residents can voice their objections, followed by a subsequent discussion. 

It usually takes several years to clarify all issues and to prepare expert reports. Only then are we able to start construction. 

• cf: “20 Jahre Erfahrungen mit der Privilegierten Zulässigkeit von Windenergieanlagen im Außenbereich” (20 years of experience with the privileged permissibility of wind turbines in outskirt areas) by Fachagentur Windenergie an Land, February 2018: https://www.fachagentur-windenergie.de/fileadmin/files/Veroeffentlichungen/FA_Wind_Hintergrundpapier_Privilegierung_von_WEA_im_Aussenbereich_02-2018.pdf
• cf: Federal Ministry of Justice and for Consumer Protection (Bundesministerium der Justiz und für Verbraucherschutz), Building Code (BauGB), “§35 Bauen im Außen-bereich” (construction in outskirt areas)  https://www.gesetze-im-internet.de/bbaug/__35.html 

German Environment Agency (Umweltbundesamt), “Wind Energy”, 14th of August 2020: https://www.umweltbundesamt.de/themen/klima-energie/erneuerbare-energien/windenergie#mensch
 

Wind and solar energy are an important economic factor in Germany - and currently provide jobs for hundreds of thousands of people. In 2022, almost 130,000 people in Germany worked in the wind energy sector and around 85,000 in the solar energy sector. In total, almost 390,000 people were employed in the renewable energy sector, and around 13.7 million worldwide - more than in the fossil fuel industries.

The jobs differ both regionally and by sector: wind turbines are mainly planned, built and operated in the north of Germany, while companies that build the components for wind turbines are located in the south and west, and to some extent also in the east. Photovoltaic systems, on the other hand, are hardly ever manufactured in Germany, even though there are increasing calls for more support for the domestic production of solar modules. At present, however, the solar energy sector is primarily concerned with the installation and maintenance of solar modules on roofs and the planning and operation of solar parks on open spaces.

770.000 New Jobs by 2035

What both sectors have in common is that they are growing strongly, and labour and skilled workers are urgently needed. The demand for workers in the renewable energy sector almost doubled between 2019 and 2022 alone, and the expansion of wind and solar energy requires numerous skilled workers in the fields of technology, trades, project management and administration: from engineers, roofers and electricians to project planners, experts and specialised administrative staff.

Wind and solar energy are particularly labour-intensive sectors. In contrast to other fields of work, most of the processes involved in the construction and operation of wind and solar energy systems cannot be automated. A 2021 study has calculated that around 440,000 additional workers will be needed by 2030 and almost 770,000 by 2035 to make Germany climate-neutral by 2050. At a European level, several studies estimate that the transformation of the energy supply will create millions of additional jobs. The demand will shift over time: while in the first phase of the energy supply transformation in Germany, workers will primarily be needed in the areas of planning, approval and construction, later on more people will be needed in the operation and maintenance, dismantling, recycling and repowering of energy plants.

Wind and solar energy are therefore also long-term job engines.

Sources and further information:

(1) Federal Environment Agency: Indicator: Employees in the renewable energy sector, Dessau-Roßlau, 2024.

(2) IRENA: Renewable Energy and Jobs: Annual Review 2023. Abu Dhabi, 2023.

(3) Agency for Renewable Energies: The energy transition as a job engine, RENEWS kompakt, Issue 64, Berlin, 2023.

(4) Blazejczak, Jürgen/Edler, Dietmar: Labour demand by sector, qualifications and occupations to implement the investments for a climate-neutral Germany. Short study commissioned by the Bündnis 90/Die Grünen parliamentary group. Berlin, 2021.

(5) Detsch, Claudia: It's the jobs that count. Friedrich-Ebert-Stiftung, Bonn 2023.  

To become independent of fossil fuels, we need more solar energy. It will not be enough to build photovoltaic systems on roofs. More areas must also be built with so-called ground-mounted systems.

Does this mean solar energy installations must jeopardize plants and animals worthy of protection?

No, because nature conservation is considered right from the start.  

• Previously contaminated areas in particular are taken into consideration when selecting a site.
• Extensive nature conservation reports are prepared during the planning phase.
• Monitoring and nature conservation support enable nature conservation to be observed during operation.

Therefore, the opposite is the case. New biodiversity can develop in areas with ground-mounted PV systems in particular. Because:

• Solar installations are often built on areas that were previously used intensively. Or on conversion areas such as former landfill sites or military training areas.
• Nature can recover under the solar panels, creating so-called extensive permanent grassland. This means that the plants are not mown before they flower. No fertilizer is applied, and no pesticides are sprayed. This allows over-fertilized or depleted soils to recover, more plants settle, which in turn attracts more animal species.
• People hardly ever walk on the land and flora and fauna can develop undisturbed.

A study by the German New Energy Association (BNE) has shown that birds, reptiles, grasshoppers and butterflies, many of which have disappeared from the agricultural landscape or can only be found in small refuge habitats, are re-colonising in ground-mounted PV systems. Even endangered species such as wild bees, wheatears and hoopoes have been able to establish new populations.1

Common Standards for Even More Species Protection

In order to strengthen such win-win effects, the solar industry and conservationists from NABU have drawn up a catalogue of criteria for environmentally friendly ground-mounted PV systems. Wherever possible, they should be planned, built and operated in such a way that they also offer the best conditions for species conservation.2

• To this end, the requirements of nature and landscape conservation should be taken into account at an early stage of planning.
• During construction, care must be taken to ensure that no barriers are created for large mammals, small mammals or amphibians.
• The total degree of sealing of a ground-mounted PV system, including all parts of the building, must not exceed five per cent of the surface area.
• The rows of modules should be installed in such a way as to ensure sufficient infiltration of precipitation.
• The system area should be maintained extensively with grazing or mowing twice a year.

A number of companies have also committed themselves to applying the BNE standard ‘Good planning of ground-mounted PV systems’. In addition to nature conservation rules, it also includes obligations towards municipalities, farmers and citizens.

Sources:

(1) Federal Association of the New Energy Economy: Solar parks - gains for biodiversity, November 2019 https://www.bne-online.de/de/news/detail/studie-photovoltaik-biodiversitaet/

(2) German Solar Industry Association: NABU and BSW define solar park standards https://www.solarwirtschaft.de/2021/05/05/nabu-und-bsw-definieren-solarpark-standards/

A wind turbine is a technically highly complex system that is exposed to many different and highly variable loads during operation. When the rotor blades are turning, their tips reach speeds of 250 to 360 kilometres per hour (70 to 100 metres per second). At the same time, the rotor blades are exposed to rain, hail and sleet, as well as dust particles, salts, acids and other chemically active substances in the air and in precipitation. Over time, the leading edge of the blade in particular is subject to wear due to abrasion. This so-called erosion occurs primarily in the front third of the rotor blades.

Erosion initially affects the coating, the outermost layer of the rotor blade. This consists of a top coat, usually based on synthetic resins such as polyurethane or epoxy resin. In their liquid state, these substances can cause irritation. However, when fully cured, they have no harmful properties. The German Federal Institute for Risk Assessment (BfR) categorises polyurethanes as harmless to health and safe for use with food.

If erosion attacks the rotor blade more severely, the material layers under the top coat can also be damaged. They are usually made of glass fibre reinforced plastic. As a rule, wind turbines are serviced before their protective layer is eroded to such an extent that glass fibre-reinforced plastics, which are installed in the layers below, can be damaged. Should this happen anyway, it is unlikely that fibres will be released, according to the Federal Institute for Materials Research and Testing. After a few hundred metres in the air, they are also harmless and there is no evidence of a carcinogenic effect. Only workers who grind or cut rotor blades need to take protective measures. Damage to the rotor blades also has a major impact on the aerodynamics and yield of the wind turbine. This is why such damage is usually noticed very early on and quickly repaired.

To date, there have been no studies on how large the quantities of abrasion are. Estimates assume an annual material loss of around 2.7 kilograms per wind turbine. In summer 2024, there were around 28,600 wind turbines on land in Germany. The abrasion from all these turbines would then amount to around 78,000 kilograms per year. For comparison: car tyres produce 102 million kilograms of abrasion in Germany every year, shoe soles 9 million kilograms.

Wind turbines are inspected regularly. Operators generally have the mechanical and electrical parts of a turbine serviced twice a year. Erosion on the rotor blades is also checked during this inspection. If severe abrasion is detected, protective coatings can be applied subsequently. Leading edges affected by erosion can also be reground and sealed with protective film.

Sources:

(1) https://www.wind-energie.de/fileadmin/redaktion/dokumente/Aktuelles/Faktenchecks/20240801_BWE-Faktencheck_-_Erosion_an_Rotorblaettern.pdfhttps://www.bfr.bund.de/cm/343/XXVIII-Vernetzte-Polyurethane-als-Klebeschichten-fuer-Lebensmittelverpackungsmaterialien.pdf

(2) https://www.bundestag.de/resource/blob/817020/27cf214cfbeaac330d3b731cbbd8610b/WD-8-077-20-pdf-data.pdf

(3) Matthias Bau (Correctiv): Faktencheck Windkraft, TikTok-Video schürt unbegründete Angst vor Krebs durch Glasfaserpartikel , 2.5.2024

In order to become independent of fossil fuels, we need more solar energy in addition to wind energy. As we want to avoid additional land sealing, we are installing photovoltaic systems to generate electricity, where possible, as roof systems on existing buildings. However, this alone will not be enough to generate enough solar power in the future. That's why we also need ground-mounted solar installations, also known as ‘solar parks’, which are built on land that was previously mostly used for agriculture. Solar parks can be set up quickly, supply cheap, climate-neutral electricity and provide a protected habitat for many animal and plant species.

As with any power plant, the construction of a solar park naturally means an intervention in the ecosystem. However, generating electricity from solar panels is one of the least invasive ways of generating energy. Well planned and implemented, a solar park serves both climate-friendly energy generation and species protection.

Nature and Species Conservation Is Considered from the Outset

Nature conservation already plays a role in the selection of sites. This is because areas that have been heavily used or previously polluted are the main candidates for solar parks: intensively used agricultural land, former landfill sites, areas along motorways contaminated by noise and traffic pollutants or military training areas. During the planning stage, extensive nature conservation reports are drawn up to check whether rare animals and plants could be jeopardised by the future solar park. In most cases, however, the opposite is the case, as a solar park provides a new habitat for rare and endangered species

Today, the areas under the elevated solar panels are usually cultivated as extensive permanent grassland. This means that the meadows under and between the PV panels are only mown once they have flowered. They are neither fertilised nor treated with pesticides. This allows overused and depleted soils to recover and new plants and animals to colonise them. At the same time, hardly any people walk on the areas under the solar panels. Shy animals and plants that are sensitive to trampling can live there undisturbed

A study by the German New Energy Association (BNE) shows that birds, reptiles, grasshoppers and butterflies, many of which have disappeared from the agricultural landscape or can only be found in small refuges, are settling in ground-mounted photovoltaic systems. Even endangered species such as wild bees, wheatears and hoopoes have already demonstrably established new populations in the systems.

Common Standards for Even More Species Protection

In order to strengthen such win-win effects, the German Solar Industry Association (BSW Solar) and the German Nature and Biodiversity Conservation Union (NABU) have jointly developed a catalogue of criteria for environmentally friendly ground-mounted PV systems. This catalogue shows how ground-mounted solar installations must be planned, built and operated so that they serve to protect species and offer animals and plants the best possible conditions

These criteria include, among others:

• Nature-friendly site selection: Solar parks must not be built in nature reserves or protected biotopes. Instead, heavily contaminated or intensively utilised areas are suitable. Vacant buildings or sealed areas such as warehouses and car parks, which are first unsealed for the construction of the systems, are also well suited.

• Planning and design: Conservation and species protection considerations should be incorporated into the planning at an early stage. Generally, interventions in existing ecosystems must be kept to a minimum. Interconnected ecosystems must not be cut up, and the paths of wild animals such as red deer, but also smaller rodents, must not be blocked. In total, no more than five per cent of a solar park area may be sealed, including all parts of the building. Sufficient spacing between the panels ensures that water can continue to seep away. Hedges, rock piles or small bodies of water created by us as the operator on the solar park area provide a habitat for protected small animals.

• Care: A solar park should be managed extensively, either by grazing or by mowing twice a year.

• Supporting monitoring: In cooperation with authorities, nature conservation organisations and research institutions, the operator should record and document the ecological effects of the PV system, from construction through the operating period to dismantling. In this way, material is collected that can be scientifically analysed and provides a basis for improvements

• Plan subsequent utilisation: As early as the planning phase, consideration should be given to what should happen to the land after it has been used as a solar park to promote nature conservation. Regulations on dismantling should already be made during the authorisation process.

Self-Commitment by Companies

A few companies, including us at NOTUS energy, have also committed themselves to applying the ‘Good planning of ground-mounted PV systems’ standard developed by the German Association of the New Energy Industry (BNE). This standard includes compliance with strict rules on nature conservation and species protection as well as a commitment to municipalities, agricultural and forestry businesses and citizens.

Sources and more information:

(1) Federal Association of the New Energy Economy: Solar parks - profits for biodiversity, Berlin, 2019.

(2) Federal Association of the New Energy Economy: Studies on biodiversity in solar parks. Portal Sonne sammeln, Berlin, 2024.

(3) BSW Solar/NABU: Criteria for environmentally friendly ground-mounted photovoltaic systems. Berlin, 2021

(4) Federal Association of the New Energy Economy: Good planning of ground-mounted PV systems, Berlin, 2024.

A wind turbine only needs wind to generate electricity. No substances are burnt and no gases are produced that are harmful to the climate or the environment. Unlike electricity generated from coal, oil or gas, electricity from wind is climate-neutral.  

Of course, energy is also consumed to manufacture, transport, erect and dismantle a wind turbine at the end of its service life. However, depending on the location, it only takes between two and a half and four and a half months for a wind turbine to produce the necessary energy itself and feed it into the electricity grid.

For this reason, the following applies across the entire life cycle of a turbine: wind energy is currently the most climate-friendly way of generating electricity. Even if you include production, transport, cables, construction and plant materials, transformer stations, maintenance, logistics, dismantling and recycling, onshore wind energy only produces around 7.9 grams of CO2 equivalents, i.e. greenhouse gases, per kilowatt hour of electricity generated.[1] This was determined by the Federal Environment Agency in a detailed study. At 7.3 grams per kilowatt hour, only the carbon footprint of offshore wind turbines is more favourable.

This is only a fraction of the greenhouse gases emitted by electricity generation using fossil fuels. Generating electricity from lignite produces the most climate-damaging carbon dioxide: at 399 grams of CO2 per kilowatt hour generated, this is almost 50 times as much as wind energy. Electricity from hard coal still produces 338 grams of CO2 per kilowatt hour and natural gas 201 grams of CO2.

Compared to the current electricity mix in Germany, every single modern wind turbine with an installed capacity of 5 megawatts saves around 7,500 tonnes of CO2 per year. In 2023, each person in Germany caused an average of 7 tonnes of CO2 emissions - so the savings from one wind turbine correspond to the annual CO2 emissions of almost 1,100 people. Wind energy therefore clearly and effectively protects the climate.

More information:

(1) German Federal Environment Agency: Updating and evaluating the life cycle assessments of wind energy and photovoltaic systems, taking into account current technological developments. Concluding report. Climate Change 35/2021, Dessau-Roßlau, 2021.

(2) German Federal Environment Agency: Emissions balance of renewable energy sources. Determination of avoided emissions in 2022. Climate Change 49/2023. Dessau-Roßlau, 2023.

(3) German Federal Environment Agency: Greenhouse gas emissions in Germany. Dessau-Roßlau, 2024. https://www.umweltbundesamt.de/daten/klima/treibhausgas-emissionen-in-deutschland#emissionsentwicklung.

(4) Volker Quaschning, Specific carbon dioxide emissions of various fuels. 2022. Online: https://www.volker-quaschning.de/datserv/CO2-spez/index.php.

[1] CO2 is not the only climate-impacting gas in our atmosphere: methane and nitrous oxide, for example, also increase the greenhouse effect. In order to be able to compare the effect of the various gases with each other, it is converted into ‘CO2 equivalents’, i.e. compared with the climate effect of CO2. 

There are currently around 28,600 wind turbines installed on land in Germany. These are intensively utilised technical systems. Therefore, as with other power plants, damage can occur during operation. Accidents involving wind turbines are often reported in detail in the media. A buckled wind turbine or a fallen rotor blade produce spectacular images that spread rapidly, especially on social media. In addition, accidents involving wind turbines are extremely rare - which is why they are also reported nationwide.

The German Wind Energy Association (BWE) has been keeping internal damage statistics since 2005. By July 2023, a total of 129 incidents of damage had been recorded: eight times a turbine buckled, the other cases mostly involved fires or broken rotor blades.

Damage often occurs to older turbines. As in road traffic, the technology and safety of wind turbines have developed considerably, meaning that accidents are becoming increasingly rare.

Regular Inspections Ensure Safe Installation and Operation
Wind turbines are not only inspected before they are erected, but also regularly during operation. According to TÜV Nord, they are therefore among the safest structures in Germany.

Before a wind turbine can even be erected in Germany, the turbine type must be certified and approved. The basis for this is the guideline of the German Institute for Building Technology (DIBt). The inspection primarily assesses the stability: the experts check whether the wind turbine can stand safely and produce electricity even under high loads until the end of its estimated service life - at least 20 years.

On this basis, the wind turbine must then be authorised in accordance with the Federal Immission Control Act (BImSchG). As a rule, no wind turbine can be erected in Germany without such a licence. As part of the construction and approval process, the plans for the construction of the turbine are checked by a test engineer, a state-recognised expert.

How Often a Wind Turbine Must Be Inspected By TÜV
Just like a car, a wind turbine must be regularly inspected by experts. The ‘periodic inspection’, which takes place every two to four years, assesses the current condition of all components that are important for the safe stability and operation of the turbine. This includes the foundation and the tower, the machine with the electrotechnical systems and the rotor blades.

In addition to the ‘periodic inspection’, wind turbines are also inspected every six to twelve months. Manufacturers and insurers of the turbine specify the details of these inspections in their maintenance booklets and contracts.

Not least for economic reasons, wind turbine operators have a great interest in ensuring that their turbines generate electricity without interruption - and therefore keep them in perfect technical condition to prevent damage and costly breakdowns. Many wind farms in Germany are therefore monitored remotely around the clock. Possible problems are thus quickly recognised and resolved.

Sources and more information:

(1) TÜV Nord: Wind energy: This is how safe wind turbines are. Hannover, 2017.

(2) German Wind Energy Association: BWE background paper on the safety of wind turbines. Berlin, 2018.

(3) German Wind Energy Association: Principles for the ‘Periodic inspection of wind turbines’, Berlin 2012.

Even today, electricity from wind and sun is cheaper to generate than electricity from fossil fuels. This is because, unlike oil, coal or gas, wind and solar are free: once the plants are built, they supply electricity without the need to pay for additional ‘fuel’. And because wind energy and photovoltaic systems are becoming more and more efficient, they produce more and more electricity for less and less money.

The price difference will become even greater in the future. This is because electricity from fossil fuels is likely to become even more expensive. There are two reasons for this:

• On the one hand, the price of CO2 is rising. For every tonne of CO2 emitted during electricity generation, energy producers must buy corresponding emission allowances as part of the European Emissions Trading System. This applies to coal and gas-fired power plants, for example. Until 2017, the prices for the allowances were very low; at times, power plant operators paid just five euros for one tonne of CO2 emitted. However, in order to achieve the climate protection targets, the EU has since continued to reduce the number of allowances - which means that the remaining allowances are becoming more expensive.  In mid-2021, the price of a tonne of CO2 was already around 55 euros, and in the first quarter of 2023 it exceeded the 100-euro mark for the first time. As the EU plans to reduce the CO2 allowances that can be used under the scheme by 61 per cent by 2030 compared to 2005, the price is likely to rise further.

• Secondly, Germany and the EU cannot supply themselves with fossil fuels. However, the prices for fossil fuels on the global markets fluctuate greatly. The year 2021 has shown that wars, crises or political changes can cause the price of coal, oil and gas to shoot up abruptly.

Both developments also affect consumers, as the costs incurred by electricity producers due to more expensive CO2 allowances and higher prices for oil and gas can be passed on to their customers. The result: electricity becomes more expensive. And once implemented, price increases are often not reversed by suppliers, even if the prices for fossil fuels fall again.

Electricity from wind and solar power, on the other hand, is not affected by these developments: As its generation does not cause any greenhouse gases, no CO2 authorisations are required to market it. And as the electricity is generated locally, neither international crises nor global political upheavals have an impact on its price.

Electricity from wind and solar is therefore hardly susceptible to strong price fluctuations and is expected to remain at a stable price level. However, if, as is to be expected, more and more electricity is generated from renewable plants, the price will most likely fall.

Sources and more information:

(1) Federal Environment Agency: European emissions trading. Dessau-Roßlau, 2023.

Around a third of Germany is forested. In some federal states, forests cover even more land. In order to secure the energy supply in the future and achieve the climate targets, wind energy must be greatly expanded: #tThe installed capacity from wind is set to almost double by 2030. In 2022, the German government has stipulated that all federal states must make at least two per cent of their land area available for wind turbines. In order to achieve this, it is also necessary to build wind turbines in forests.

Around 10 per cent of all plants are already located in forests. This has many advantages: wind turbines are often located far away from residential areas and therefore do not disturb neighboring residents. For all those who visit the forest for leisure and recreational purposes - for example when walking or hiking - the turbines are barely visible above the treetops. Even if you are standing close to a wind turbine in the forest, you will hardly be able to distinguish the gentle whirring of the rotor blades from the rustling of the tree leaves. In addition, birds of prey are less at risk from forest locations, as they mainly hunt over open areas such as meadows or fields.

Wind turbines do less to harm the forest than they do to protect it

Nevertheless, many people are concerned when wind turbines are erected in forests. They fear that the construction of the turbines will destroy parts of the forest and put additional pressure on the already strained forest ecosystem.

Like any human intervention, the construction of wind turbines has an impact on nature. However, numerous rules and regulations ensure that these are minimised as far as possible. If planned and implemented correctly, the construction of a wind turbine can even help to protect our forests in two ways: on the one hand, accompanying measures contribute to the sustainable conversion of the forest. On the other hand, wind turbines mitigate climate change and thus contribute to the continued existence of native forests.

In this way, we ensure that the construction and operation of our systems does not cause any damage, but rather improves the overall condition of the natural ‘forest’ system.

• Selection of locations: Not all forests are the same. Ecologically valuable, natural old forests must not be used for the construction of wind turbines. Deciduous and mixed forests, protected areas or forests that are particularly important for recreation or the protection of biodiversity are also ruled out as sites. Possible sites are therefore primarily forest areas that are already being used intensively, such as forest monocultures with spruce and pine trees, and which therefore have a lower ecological value and lower biodiversity. In addition, so-called calamity areas, i.e. forest areas that have already been destroyed by storms or pest infestations (bark beetles), are also eligible. In intensively utilised forests, there is often already a well-developed network of paths so that no additional trees need to be cleared for access.

• Examine the impacts: Before a plant can be built, the impact of the project on the environment, the ecosystem, animals and plants are analysed and assessed in detail. To this end, independent institutes prepare numerous legally required expert reports. No project is authorised without these reports.

• Protection of animals during the construction phase: Based on the results of the expert reports, we take measures during the construction work to protect the animals in the vicinity of a new plant. For example, if sand lizards live in the area, we erect protective fences to keep the animals away from the construction site. We also build stone walls where the lizards can hide, find places to hibernate and lay their eggs. We also take care not to disturb the habitats of bats or native birds during the work.

• Reforestation: For every tree that is cleared along necessary access roads or for the construction of a wind turbine, we plant at least one new one. Often even significantly more. Where there were usually pine or spruce monocultures, we use reforestation to create ecologically valuable mixed forests that are more diverse and, above all, more resilient than the original forests. Transport, storage and construction site areas are also reforested with mixed forest after the construction period.

• Payments for nature conservation projects: In accordance with the Federal Nature Conservation Act, we make payments to compensate for the impairment of the landscape. The form and amount of compensation measures for interventions in the landscape can vary in the individual federal states. However, the money is often channeled into regional nature conservation projects.

• Protection against fires: Modern wind turbines are equipped with multiple safety systems. If smoke or heat develops, they switch off automatically. In addition, when building new turbines, we must provide fire water cisterns and access routes for the fire brigade. These can then also be used to fight forest fires that have nothing to do with the turbines.

• Dismantling: We must deposit a guarantee even before a plant is built. If the plant is no longer used after its average service life of 20-25 years, this money finances its dismantling. At the same time, any compacted soil is loosened up again. What remains are newly afforested, ecologically valuable mixed forests that are resilient to climate change.

Sources and further information:

(1) Baden-Württemberg Ministry of the Environment, Climate Protection and the Energy Sector: Wind energy and nature conservation. Legal basis and assistance. Stuttgart, 2023.

(2) Federal Agency for Nature Conservation: Wind Energy in Forests, Berlin, 2024. https://www.bfn.de/windenergie-im-wald

(3) German Wind Energy Association (BWE): Wind energy in the forest. How wind energy contributes to forest protection, Berlin, 2021.

(4) Federal Environment Agency: Wind Energy in Forests. Working document. Dessau-Roßlau, 2021.

(5) Specialist agency for onshore wind energy: Development of wind energy in forests. Analysis. Berlin, 2024.

(6) Specialist agency for onshore wind energy: Compact knowledge on wind energy in forests. Berlin, 2023.

(7) Federal Ministry of Food and Agriculture: Results of the Forest Condition Survey 2023, Bonn, 2024.

(8) Federal Agency for Nature Conservation: Wind Energy over Forests. Position paper of the Federal Agency for Nature Conservation, Bonn, 2001.

Yes, at first glance it seems absurd: trees that store CO2 are being felled to make way for wind turbines. Here, too, it is worth taking a closer look.

Anyone who walks through the forest with their eyes open can easily recognise this: our forest is not doing well. Almost all tree species show symptoms of damage such as thinning crowns. The latest survey on the state of the forest in 2023 confirms this: four out of five trees are diseased. Spruce trees on soils that are poorly supplied with water are most affected by the consequences of climate change. However, more resistant deciduous trees such as beech and oak are also suffering from drought and pests such as the bark beetle, which is spreading rapidly due to already weakened tree populations.

Wind Farms Help with the Necessary Forest Conversion
If the earth continues to warm as a result of climate change, periods of drought and extreme weather events such as severe storms will occur more frequently in future. The damage to forests is already immense: experts estimate that 500,000 hectares of forest in Germany currently need to be reforested - an area twice the size of Saarland. At the same time as reforestation, existing forests need to be reorganised to make them more resistant to pests and able to cope with the changed climate conditions. Spruce and pine monocultures must be replaced by more resistant mixed forests.

However, reforestation and forest conversion are expensive endeavours for forest owners. Income from the leasing of land for wind farms provides important financial support here. The compensatory measures taken during the construction of a wind farm also contribute to forest conversion: This is because young trees are planted for future, sustainable mixed forests to replace felled trees and compensate for cleared areas. This also considers the fact that the felled trees are often older and larger, which means that more young trees must be planted.

Wind Turbines Save Additional CO2
To secure the future of forests, it is urgently necessary to curb global warming. This is only possible by reducing emissions. And wind energy makes an important contribution to this. A look at the carbon footprint makes it clear: a wind turbine of the size commonly used today avoids huge amounts of CO2 every year - many times more than what forests can store on the same area.

How much CO2 an individual tree absorbs depends on many factors and is therefore difficult to calculate. As a rule of thumb, however, one hectare of forest stores around six tonnes of CO2 per year. A wind turbine with an installed capacity of 5 megawatts requires less than one hectare of land. It generates around 17.1 million kilowatt hours of clean electricity per year - and thus avoids around 10,000 tonnes of CO2 per year, around 1,600 times as much as the amount that forests could store on the same area.

Wind power in the forest therefore makes a double contribution to forest conservation: because it promotes forest reorganisation and because it helps to halt climate change - and thus secures the future of the forest.

More information:

(1) Federal Ministry of Food and Agriculture: Further massive damage - commitment to forests and forest conversion necessary, Bonn, 2024.

(2) Federal Ministry of Food and Agriculture: Results of the 2023 forest condition survey, Bonn, 2024.

(3) German Wind Energy Association (BWE): Wind energy in the forest. How wind energy contributes to forest protection, Berlin, 2021.

(4) Forest Enterprise Foundation: Wie viel How much carbon dioxide (CO2) does the tree or forest store? Hamburg, 2024.

(5) Lower Saxony Forest Owners Association: Forest owners' association calls for fair distribution - criticism of LROP draft, Hannover, 2021.

(6) Federal Ministry of Food and Agriculture: 2050 Forest Strategy, Bonn, 2021.

Forests are an important habitat for animals. Up to 14,000 animal species can be found in Germany's forests, including deer, roe deer and wild boar, as well as shy and endangered species such as the lynx. The construction of wind turbines means encroaching on their habitat. However, studies show that the impact is largely temporary. Strict regulations during construction and operation ensure that animals are not driven away or endangered.

No Wind Turbines in Valuable Forests
Nature conservation areas or habitats of endangered species may not be used for wind energy. Wind turbines are primarily erected in degraded forests with monocultures of trees, which are not of high ecological value and usually lack biodiversity.

Construction Time Adapted to the Annual Cycle
In order not to disturb birds that breed on the ground, in bushes or on trees, the construction of a wind farm must always be interrupted between 1 March and 30 September. Trees may not be felled during this period either, as birds breed on them and bats could use tree hollows as summer roosts.  Exceptions are only possible in rare cases and after detailed assessment. Overall, much stricter rules apply to wind energy than to forestry and agriculture, which also manage the forest during the breeding season.

Noise: A Temporary Problem
The construction of wind turbines causes noise. This can startle animals in the forest. However, this is a temporary effect, as a study by the University of Veterinary Medicine Hannover shows. The scientists investigated how the construction of wind turbines affects hares, foxes, partridges and crows. The result: after these animal species avoid the area around the wind turbines during the construction period, they all become accustomed to the presence and operation of the turbines once the construction work is complete and use the areas around them just like other areas. A study from Switzerland also came to the conclusion: ‘After temporarily avoiding the area during the construction phase, the habitats are utilised again. Negative consequences at population level have hardly been observed to date.’

Bats Lead the Way
The forest is not only a habitat for animals on the ground, but also in the air - among others, numerous bat species live and hunt here. Extensive surveys must therefore be carried out before wind turbines are erected: Which species occur in the area in question, what are their flight and breeding habits? If a turbine could additionally affect endangered species, it must not be built at that location. And installations in operation must take into account the flight habits of bats: Bats fly at dusk and only on windless, warm nights. Wind turbines are rigorously switched off at these times.

Safe Flight Corridors for Birds
We also take birds living in forests into consideration not only during the construction period, but also during operation. For example, we temporarily switch off individual turbines or entire wind farms during the breeding season of certain species or in certain weather conditions. In future, this will be done in an even more targeted manner: various technical monitoring and switch-off systems are currently being developed. They will also help to avoid collisions with birds: they use cameras or radar to recognise the type of bird approaching and switch off the wind turbine in the event of danger.

More information:

(1) Bavarian State Institute for Forestry and Forest Economics: Biodiversity and nature conservation. Freising, 2024.  

(2) University of Veterinary Medicine Hannover: Space utilisation of selected native small game species in the vicinity of wind turbines, Hannover, 2024.  

(3) FaunAlpin: Wind turbines and terrestrial mammals. Literature review and situation in Switzerland. Bern, 2013.

(4) Federal Agency for Nature Conservation: More protection for bats in forests when building wind turbines, Bonn, 2017. 

(5) KNE Competence Centre for Nature Conservation and Energy Transition: 10 questions - 10 answers on detection systems, Berlin, 2020.  

How much electricity a wind turbine generates depends primarily on two factors: its output and its location.

The higher the rated output of a wind turbine and the stronger and more consistent the wind at its location, the more electricity the turbine can produce.

Nominal power refers to the maximum power that the turbine can generate in continuous operation without affecting its service life or safety. Thanks to technical innovations, the output of wind turbines - i.e. their electricity production - has risen sharply over the last 20 years. In 2000, the average rated output of newly built turbines in Germany was still around 1.2 megawatts; in 2021, it was already almost 4 megawatts. This trend is continuing: the wind turbines installed in Germany in the first half of 2024 have an average capacity of 5.2 MW - nine per cent more than in the previous year.

Modern wind turbines for inland locations today usually have a rated output of 6 megawatts, but there are already turbines with more than 7 megawatts. The manufacturer Vestas calculates that its largest inland wind turbine, the V172 with a rated output of 7.2 megawatts, can produce up to 36 gigawatt hours of electricity per year in optimal wind conditions. That would be enough to cover the annual electricity needs of more than 8,000 households in Germany.

The strongest and most consistent wind blows over the open sea. This is where even larger wind turbines, known as ‘offshore turbines’, are located. Their rated output is now 15 megawatts and more. European and Chinese manufacturers are currently competing to build ever larger and more powerful turbines.

Sources and further information:

(1) Deutsche WindGuard GmbH: Status of onshore wind energy expansion in Germany. First half of 2024, Varel, 2024.

(2) Vestas: EnVentusTM Platform, 2024, online: https://www.vestas.de/content/dam/vestas-com/de/anlagentechnologie/EnVentus-Plattform_Q1-2022_VestasBrochure_DE_WEB.pdf.coredownload.inline.pdf

(3) German Wind Energy Association: Faktencheck: How many wind turbines does the country need? Berlin, 2022.

The forest is an important habitat for animals. Up to 14,000 animal species can be found there. If a wind farm is built in the forest, many fear that shy animals could be driven away by construction noise or that endangered species could be even more threatened by the wind turbines.

As a general rule, nature reserves, old tree stands or habitats of endangered species may not be used for wind energy. The first choice is damaged tree stands or forests with monocultures, which are less valuable for nature conservation.

But of course, animals live there too, and they must be protected as well as possible.

Construction Time: Adapted to the Annual Cycle
To avoid disturbing ground and woodland nesting birds, there is a break in the construction of a wind farm between March 1 and September 30. Trees may not be felled then either because birds can nest between the branches or bats can use tree cavities as summer roosts. 

Exceptions are only possible if it is proven in detailed expert reports that no birds or bats will be disturbed or killed by the construction. Environmental authorities are very strict about this "alternative construction period regulation." This means that stricter rules apply to wind power than to forestry and agriculture, which also manages the forest during breeding seasons.

Noise: a Temporary Problem
The noise from a construction site can startle animals in the forest. However, this is a temporary effect, as a study by the Hanover University of Veterinary Medicine shows. The scientists studied the population of hare, fox, partridge and raven in areas with and without wind turbines. They found that:

• All animal species use the areas near wind turbines in the same way as other areas.
• An exception was the time of erection.
• In principle, animals seem to be able to get used to the presence and operation of wind turbines, as they represent a source of disturbance that can be calculated in space and time.

Bats: Switching Off in Air Traffic
Other animals also come into focus when it comes to wind turbines in the forest. Numerous bat species, for example, depend on the forest as a habitat or hunting ground. In order to protect them, extensive studies of the population are necessary even before construction. Project developers must submit expert reports on the different species of bats present and their flight and breeding habits. This will help rule out locations where threatened species would be further endangered.

In addition, the operating hours of the facilities are adjusted to flight habits. Bats are active at dusk and only during certain weather conditions. Wind turbines will be shut down during these weather conditions.

Safe Flight Corridors for Birds
In addition to bats, the concerns of critics of wind energy in the forest mostly revolve around birds that could get caught in the rotors of the turbines. But here, too, with the help of environmental impact assessments in the permitting process, areas can be found for wind energy use that rule out any risk to endangered species. As in the case of bats, birds are also recorded during the planning phase. If sensitive species are discovered during this process, more intensive surveys are carried out to identify habitats and flight paths.

Other protective measures for birds during operation include the temporary shutdown of individual turbines or entire wind farms, especially during the breeding season or at certain times of day and weather conditions.

In the future, technical monitoring and shutdown systems could prevent collisions with birds. Several systems are under development. They detect the type of approaching bird either by camera or radar and switch off the wind turbine in case of danger.

Sources:

(1) Bavarian State Institute for Forestry and Forest Economics: Biodiversity, Nature Conservation, Hunting (https://www.lwf.bayern.de/biodiversitaet/index.php)

(2) Federal Wind Energy Association: Wind energy in the forest (https://www.wind-energie.de/fileadmin/redaktion/dokumente/publikationen-oeffentlich/themen/01-mensch-und-umwelt/03-naturschutz/20210831_BWE-Broschuere_Wind_im_Forst.pdf)

(3) University of Veterinary Medicine Hanover: Space utilisation of selected native small game species in the vicinity of wind turbines (https://www.tiho-hannover.de/itaw/forschung/projekte-terrestrisch/abgeschlossene-projekte/vor-2015-abgeschlossene-projekte-terrestrisch/windkraftanlagen)

(4) Federal Agency for Nature Conservation: More protection for bats in forests during the construction of wind turbines (https://www.natur-und-erneuerbare.de/aktuelles/details/mehr-schutz-fuer-fledermaeuse-im-wald-beim-bau-von-windraedern/

(5) KNE Competence Centre for Nature Conservation and Energy Transition: 10 questions - 10 answers on detection systems (https://www.naturschutz-energiewende.de/wp-content/uploads/KNE_10-Fragen-10-Antworten-zu-Detektionssystemen_2020.pdf)

In relation to the number of wind turbines in Germany - around 30,000 as of mid-2024 - it is very rare for a fire to break out in a turbine. Wolfram Axthelm from the German Wind Energy Association estimates that there are five to ten fires a year.

The technology of the turbines and their safety standards have continued to improve in recent years. Fires therefore occur, if at all, mainly in older turbines, which are gradually being replaced by repowering measures.

The cause of a fire at a wind turbine is usually a technical fault, and more rarely a lightning strike. However, neither is often a major problem: modern wind turbines are equipped with effective and tested fire protection mechanisms and have effective lightning protection systems. Even during construction, care is taken to ensure that the turbine does not catch fire and that a fire cannot spread in the nacelle by selecting the appropriate materials.  In addition, each turbine has an automatic and doubly secured fire warning and extinguishing system. If the sensors detect smoke, the turbine switches off automatically and stops rotating so as not to endanger the surrounding area with falling parts.

Automatic Extinguishing Systems and Health Hazards
Operators of wind turbines can now also install fixed extinguishing systems on the so-called nacelles. The technology can recognise a fire and extinguishes it automatically on site. In some federal states, this is already mandatory, especially for turbines located in forests.

Pollutants that occur during a fire are mainly emitted as smoke gases via the air. During and after a fire, it is important that nobody inhales or swallows soot particles or dust particles. In the rare event of a fire, we therefore inform the public via radio and television to close windows and doors.

When the flue gases cool down, soot particles are formed which adsorb liquid and gaseous substances. Due to this solid binding to the soot, the risk of pollutants being transferred to people is relatively low. The pollutants are mainly present in the soot deposits or in the fire residues and no longer in the air. A cold fire in the open air therefore poses no immediate health risk.

Operating materials that have escaped during a fire are also not a danger: soil analyses after fires at wind turbines have so far provided no evidence of harmful changes to the soil. The absorption of carbon fibres - the support beams in the rotor blades are partly made of carbon fibres, or more precisely of an epoxy resin reinforced with glass and carbon fibres - via plant roots is also extremely unlikely, according to state environmental agencies.

Wind Turbines as Lightning Rods In The Forest
The Federal Environment Agency generally emphasises that it sees no immediate danger to the population from fires caused by wind turbines. The impact of such accidents is only short-lived and occurs on a small scale.

Due to their height and structure, wind turbines are difficult to access for conventional fire engines. In the event of a fire, the fire brigade therefore cordons off a turbine within a radius of 500 metres, or much further in the event of strong winds.  They then allow the plant to burn down in a controlled manner.

Concerns about potential fire hazards are often particularly high when a wind farm is built in the forest. These concerns are also largely unfounded. For example, wind turbines conduct a lot of lightning, which would otherwise strike the trees and cause forest fires. The fire brigades also report that the aisles created by the access routes to the turbines make their work easier and tend to minimise the risk of forest fires, as potential sources of fire in forests are easier to reach.

As part of the approval process for a wind farm in the forest, it is also often stipulated that an additional supply of extinguishing water be installed near the turbines. Such new cisterns or extinguishing water wells also help the fire brigade if a walker carelessly throws away a cigarette in summer.

Sources and more information:

(1) German Fire Brigade Association: Deployment strategies at wind turbines, technical recommendation Nr. 1. Berlin, 2012.

(2) Märkische Allgemeine, ‘Fire sparks debate about wind turbines in the forest’, 20 June 2018

(3) MDR, Editorial Office Economy and Advice, ‘Extinguishing fires at wind turbines: Where the turntable ladder can no longer reach’, 20.4.2024

Electricity from wind energy is too expensive, critics argue from time to time. There was a time when they were right: at the beginning of the 2000s, when modern wind energy was still in its infancy, wind turbine operators received even higher payments in order to be able to operate profitably. But a lot has changed since then. The expansion and technical development of wind turbines have led to them becoming increasingly efficient and therefore more profitable. Today, wind energy is one of the cheapest ways to generate electricity.

Cost of Electricity Generation - Wind and Solar Are Ahead
In 2021, the Fraunhofer Institute for Solar Energy Systems (ISE) calculated the different electricity generation costs for newly built power plants. This technical term refers to the total costs incurred to generate one kilowatt hour of electricity. This includes the costs of building and financing the plant as well as the costs of fuel and operation. The results show that

• Lignite-fired power plants can generate electricity for 10.38 to 15.34 cents per kilowatt hour.
• Large hard coal-fired power plants cost between 11.03 and 20.04 cents per kilowatt hour.
• Gas and steam turbine power plants cost between 7.79 and 13.06 cents per kilowatt hour.
• At 11.46 to 28.96 cents per kilowatt hour, highly flexible gas-fired power plants have the highest electricity generation costs.

Electricity generation with onshore wind farms, on the other hand, is many times cheaper: according to the Fraunhofer study, wind turbines can generate electricity for between 3.94 and 8.29 cents per kilowatt hour, depending on the location.

These differences will become even more pronounced in the future: this is because the rapid further development of technologies means that the generation of wind and solar power is constantly becoming cheaper. At the same time, CO2 prices in Europe are rising, making the operation of coal and gas-fired power plants, which cause high CO2 emissions, even more expensive.

Hardly Any Environmental Costs
The differences are even greater when the so-called external costs are taken into account - such as the environmental damage caused by electricity generation, the costs of disposing of and storing incineration waste or the damage to health caused by air pollution.

According to the Federal Environment Agency, lignite causes 29.03 cents in environmental costs per kilowatt hour of electricity generated, hard coal 26.24 cents. Gas is also at 12 cents - far above wind energy, which at 0.33 cents hardly causes any environmental costs. However, the Federal Environment Agency bases its calculation on a CO2 price of 250 euros per tonne - a price that does not currently have to be paid, but which the Federal Environment Agency believes is justified in view of the climate damage caused.

Sources and further information:

(1) International Economic Forum Renewable Energies: EEG remuneration rates (2000 - 2004). Online: http://www.iwr.de/re/wf/e_preis.html.

(2) Fraunhofer Institute for Solar Energy Systems (ISE): LCOE of renewable energies, Freiburg, 2021.

(3) Federal Environment Agency: Social costs of environmental pollution, Dessau-Roßlau, 2024.