National Testing Centre for Large Wind Turbines in Østerild

At the National Testing Centre for Large Wind Turbines in Østerild Dune Plantation visitors can experience a unique glance into the future of wind turbine technology.

Det Nationale Testcenter for Store Vindmøller
Testcentervej, 7700 Thisted
Parking: Plantør Kroghs vej, 7700 Thisted

  • Open: The area is open to the public all the year round but certain areas may occasionally have restricted access and will be clearly marked
  • Booking: Only necessary in case of a guided tour
  • Admittance fee: Only in case of a guided tour
  • Parking: Public parking ground at Plantør Kroghs vej
  • Language: English / German / Danish.

 

Tour Suggestions – Groups

 

Index:

  • Visit the National Testing Centre for Large Wind Turbines in Østerild, Thy
  • The National Testing Centre for Large Wind Turbines in Østerild Dune Plantation
  • International Approval Schemes and Test Standards
  • Who is Behind the National Testing Centre for Large Wind Turbines in Østerild?
  • Experiencing the National Testing Centre for Large Wind Turbines
  • The Nature Surrounding the Testing Centre in Østerild Dune Plantation
    Landscape History

 

Visit the National Testing Centre for Large Wind Turbines in Østerild, Thy

Experience at close hand when the Technical University of Denmark, DTU, Department of Wind Energy, and wind turbine manufacturers are testing prototypes of large wind turbines.
The National Testing Centre for Large Wind Turbines has been established to secure Denmark’s leading position in the field of research and development of new wind turbine technology.
SWT-6.0-154 at Østerild (Oesterild) At the National Testing Centre in Østerild scientists and the wind power industry have the best possible conditions for developing and testing new wind turbines: The wind is strong, the area is extensive, there are no nearby neighbors and the area is not an internationally protected natural reserve.

The testing centre is a bustling workplace constantly evolving as new turbines are under construction and the turbines and components that have already been tested are being dismantled. Watching the meticulous process of the gigantic cranes erecting a turbine tower or putting into place the huge rotor blades is an experience that will stay with the spectator long after the visit.

Visiting On Your Own

The area is open to visitors on foot or bicycle but during construction / dismantling of turbines certain areas will have restricted access. Construction can be watched from a safe distance. The test area is not fenced and the landscape and footpaths are open to the public throughout the year.
The public parking ground on the fringe of the Testing Centre is a good starting point for excursions into the area. The parking ground is located 1.4 km up Plantør Kroghs Vej which is a side road to Gl. Aalborgvej about 4.5 km to the northeast of the village of Østerild. It is also possible to drive up Testcentervej to a public parking ground located just south of the southernmost wind turbine.

At the parking ground at Plantør Kroghs Vej are located four information boards describing the project.

With The Green App on your mobile phone you will have easy access to a wide range of information about the National Testing Centre for Large Wind Turbines and the surrounding area.

Visiting On a Guided Tour

It is possible to visit the National Testing Centre for Large Wind Turbines as a group on a guided tour. The visit is organized in cooperation with the Danish Technical University DTU Wind Energy.

SWT-6.0-154 Visit www.vindenergi.dtu.dk for information about DTU Wind Energy and www.naturstyrelsen.dk/Planlaegning/Planlaegning_i_det_aabne_land/Testcenter/ for information on the project from the Danish Nature Agency.

The National Testing Centre for Large Wind Turbines in Østerild Dune Plantation

In June 2010 the Danish Parliament passed a law regarding a National Testing Centre for Large Wind Turbines in Østerild Dune Plantation. The law aims at securing Denmark’s leading position in the field of wind turbine technology. In Østerild the Technical University of Denmark, DTU, and the wind turbine industry have received optimal conditions for developing and testing wind turbine prototypes. So far the test station in Østerild is the only facility in the world large enough to accommodate the testing of the next generation of wind turbines. By establishing the test station in Østerild the Parliament ensures that workplaces, development and know-how remain in Denmark, enabling manufacturers to perform tests here instead of having to move development activities abroad.

The test station fulfills the needs of both the industry and researchers for a future-proof test facility with a capacity for testing large wind turbines. Here testing of wind turbines measuring up to 250 meters in height, measured from the ground to the top position of the rotor blade, will be carried out. As a comparison regular wind turbines measure around 110 meters in height. The first wind turbines to be in place in Østerild are not of the 250 meters type, but reaching 170 – 200 meters into the air they are still impressive structures.

Furthermore the test station is part of the Government’s long term strategy of a future energy supply in Denmark where fossil fuel is replaced by sustainable energy sources like wind energy. To achieve that goal the effort to develop ever more efficient and affordable wind turbines must continue.

 

Why Offshore Wind Turbines Require Testing on Land

Denmark has already established offshore wind farms because the enormous wind capacity available at sea makes for a high degree of energy supply in Denmark and Europe. But offshore wind turbines are much more expensive than land based ones, and the challenge is currently to develop offshore wind turbines that are financially compatible to land based wind turbines and other energy sources. An important factor in the attempt to develop more efficient wind turbines is the availability of test facilities with the proper wind conditions.

Testing of new offshore wind turbines requires land based test stations for several reasons:

Easy access. During the development phase the manufactures need easy access to conduct frequent measurements and to examine and replace components. Access to offshore wind turbines is often prohibited by rough seas.
Proper wind conditions. Turbulence and roughness are keywords when testing wind conditions. The roughness equals the amount of resistance encountered by the wind moving towards the wind turbine offered by for example trees, other types of vegetation, buildings etc. The wind field in front of the wind turbine should preferably be roughness class 1-2, which means few trees and buildings, in order to conduct tests. A high roughness class of 3 to 4 refers to landscapes with many trees and buildings, while a sea surface is in roughness class 0.
Collaboration with the power grid. When many prototype wind turbines are gathered in one area it is possible to conduct full scale tests of the wind farm’s influence on the power grid. In Denmark research in Smart Grid technology is advancing. Smart Grid technology aims at securing a safe and efficient energy supply from the wind by making the supply chain work intelligently, meaning that appliances are made to increase energy consumption when there is a lot of wind and to decrease consumption when the wind declines. The trick is to achieve this without inconveniencing the consumer.

Choosing a Test Site

Implementeringsplan for det Nationale Testecenter for store vindmøller When the Danish Parliament in June 2010 passed a law enabling the establishment of a National Testing Centre for Large Wind Turbines, the Danish Ministry of the Environment conducted a screening of the whole country in order to find the best suited location. The selection was based on a series of fixed criteria:

  • Average wind speed must be at least 8 meters per second at 100 meters
  • The area must not be a SPA, classified in accordance with the EC Birds Directive
  • The distance to the nearest neighbour must be at least 1000 meters
  • The area must measure at least 346 ha
  • It must be possible to build the wind turbines on a straight north / south going line
  • The wind field to the west of the area must possess or be given the correct roughness class. The friction of the wind as it passes the surface of the earth and propagates upwards must be as regular as possible. This will result in a predictable wind profile which can be used in conducting reproducible and internationally accepted tests.

Furthermore the screening took into consideration other natural habitat protection schemes and conservation areas and the vicinity to residential and holiday home areas.

The screening resulted in a choice of 14 areas from which 8 were chosen for inspection by the Danish Nature Agency, the Danish Technical University, DTU, and the wind turbine industry: Østerild and Hjardemål Dune Plantations, Husby Dune Plantation, Blåbjerg and Kærgården Dune Plantations, Nørhede, Filsø and Kallesmærsk Heath. Østerild and Kallesmærsk were deemed most likely. The area of Kallesmærsk Heath is a SPA and is furthermore used by the military as training grounds, and so Østerild Dune Plantation was chosen as the site for the National Testing Centre For Large Wind Turbines.

International Approval Schemes and Test Standards

Testing the Test Lots

Prior to construction, the test station area underwent thorough investigation. A primary concern was to make sure the test area meets the demands set out in international standarts. This was of vital importance concerning the credibility of the measurements. The best placed test stations must have a yearly average wind speed of more than 8 metres per second at 100 metres. The area must have a homogeneous wind field and should be located in flat terrain where contours do not impair the measurements.

Furthermore it was important to determine to what extent clear-cutting of trees in the wind field was necessary with regards to achieving reliable test results. As a result of the measurements made by DTU Wind Energy the originally proposed clear-cutting area of 1500 hectares was reduced to merely 245 hectares. The wind conditions at the test station have been the object of thorough investigation, documenting a high probability of achieving reproducible high quality measurements throughout the relevant wind speed area. Important parameters are turbulence, roughness and wind shear.

Turbulence refers to irregular wind conditions as opposed to constant wind conditions. Turbulence is acceptable at a test station as long as it is not too much or too irregular, rendering test results useless at places with low turbulence like for instance at sea.

SWT-6.0-154 at Østerild (Oesterild) Vertical wind shear refers to the change of winds with height. Wind shear and turbulence can not be too outspoken at a test station if test results are to be transferred to test stations with more even shear and turbulence.

Roughness is the amount of obstruction the wind encounters moving across any given surface. The wind is obstructed by various obstacles like trees, buildings and crops. The roughness of a certain terrain is described by the overall obstruction of the wind created by obstacles on the surface the wind travels over. Roughness is described in roughness-classes from 0 to 3. Roughness-class 0 is a surface of water, even sand or snow. Roughness-class 1 is an open landscape with few buildings and trees. Roughness-class 2 has more trees, buildings and bushes while roughness-class 3 is cities, suburbs, forests and tall protection strips. Roughness affects turbulence: The higher the roughness-class, the more turbulence will occur. Turbulence over the wind turbine rotor area should be as even as possible which is achieved at terrains with a roughness of 1-2. This rules out large surfaces of water or forests as possible test station locations.

The Wind Field

According to international standards for test stations there must be an open wind field in front of the wind turbine. This means no changes in roughness caused by for instance trees affecting the flow pattern of the wind, and no sudden changes in the terrain passed over by the wind on its way towards the turbine. These conditions are valid up to a distance of 20 times of the rotor diameter. With an expected maximum height of up to 250 meters and a rotor diameter of 200 meters on some of the wind turbines at Østerild Testing Centre, an area of 4 kilometers in front of the wind turbines must be free.

According to measurements conducted by DTU Wind Energy at Østerild Testing Centre prior to the establishment of the test station, the distance from the edge of the forest to the wind turbines need not be more than 1.5 kilometers. Measurements show that at 100 meters turbulence and vertical wind shear are not noticeably affected by whether the distance to the forest edge is 4 kilometers or 1.5 kilometers. Measurements continue at the test station in order to assure consistent results that will ensure international acceptance.

The Measuring Instruments

Wind measuring at Østerild prior to establishing the test station was conducted by a variety of measuring instruments. Three LiDAR (Light Detection And Ranging) instruments were used. The LiDAR measures the distance to particles in the air by illuminating the particles with laser light and analyzing the backscattered light. Wind speed and wind direction is measured at different heights from 45 to 300 meters.

SWT-6.0-154 at Østerild (Oesterild) Supplementing the LiDAR instruments also cup anemometers and sonic anemometers placed in two 45 meters high masts at either end of the test station area were used. The masts were also fitted with sensors measuring temperature, humidity and radiation. The LiDAR does not make measurements below 40 meters but that part of the wind profile was taken care of by the cup and the sonic anemometer. The sonic anemometer uses ultrasonic sound waves to measure wind velocity. Furthermore it measures temperature in order to calculate the stability in the air’s boundary layers. This is important information when categorizing wind velocity profiles used for making models of wind conditions in forests.

The Wind Turbines Are Tested

Testing of prototype wind turbines in Østerild Testing Centre follows international standards. This implies that test results are accepted world wide but it also means that national deviations must be avoided. The purpose of the standards is to ensure reproducible tests independent of time and place but also to establish an accepted level of accuracy and inaccuracy in tests. Also a series of Danish laws and regulations must be complied with in full scale tests of new wind turbines.

The purpose of the Danish Ministry of Energy executive order no 651 of June 28th 2008 containing the technical approval scheme for construction, production, maintenance and servicing of wind turbines, is to ensure that a wind turbine and its foundation are constructed, produced, maintained and serviced according to established demands to safety, energy and quality.

The wind turbines in Østerild are tested according to current international requirements for the approval of wind turbines, the WT01 IEC System for Conformity Testing, determining requirements and procedures for assessment and verification of wind turbines. Furthermore a German test standard is used, the Technische Richtlinien für Windenergieanlagen, Teil 2: Bestimmung von Leistungskurve und standardisierten Energieerträgen, Revision 15, Stand 01.05.2008. Fördergesellschaft Windenergie e.V.

Power Curve Measurements

A wind turbine power curve is a chart of the electrical output at different wind speeds and is an important tool in the overall assessment of the efficiency of the wind turbine. The power of the wind is proportional to wind velocity to the third power and since the inaccuracy of the measuring instrument is increased with a factor of three with regard to wind turbine efficiency, it is important that measuring instruments be as accurate as possible.

DTU Wind Energy is accredited with performing power curve measurements by The Danish Accreditation and Metrology Fund, DANAK, and is part of a European wind turbine test station network, MEASNET. The purpose of MEASNET is to conduct comparative tests and calibrations and to ensure a uniform interpretation of the standards. The current international standard for power curve measurements is: IEC61400-12-1, Wind turbines – Part 12-1: Power performance measurements of electricity producing wind turbines, First edition 2005-12.

Power curve measurements are made by different types of instruments including the cup anemometer, the laser anemometer and the sonic anemometer.
The cup anemometer has been the wind turbine industry’s prime instrument for measuring wind velocity since it was developed in the 1920’ies. The cup anemometer is a simple instrument consisting of three “cups”, a shaft and a sensor counting the number of revolutions. The cup anemometer has not been the subject of much development since it first appeared, but with the ever increasing focus on wind energy a need for accurate measurements has arisen. At the Department of Wind Energy at DTU scientists have used cup anemometers for many years and the search for an insecurity in measurements of under 1% is of paramount importance.
The laser anemometer measures the distance to particles in the air by illuminating the particles with laser light and analyzing the backscattered light, while the sonic anemometer uses ultrasonic sound waves to measure wind velocity.

Noise Level Measurements

Wind turbines must comply with fixed noise levels at both low wind speeds (6 meters per second) and high wind speeds (8 meters per second). The noise level is determined in the Danish Ministry of the Environment executive order no 1518 of December 14th 2006 concerning noise from wind turbines. The order refers to the current international standard: IEC61400-11 – Acoustic noise measurement techniques. The appendix to the order describes general rules concerning measurements of acoustic noise from wind turbines, including measurements of low frequency noise from wind turbines.

All wind turbines produce a weak but characteristic noise from the movement of the rotor blades in the wind and from the machinery of the turbine. In recent years developers have had an increased focus on minimizing noise from wind turbines resulting in much more silent wind turbines being produced now compared to the wind turbines of the 1970s, 1980s and 1990s.

Several factors like the shape of the rotor blades and the insolation of the engine house influence the degree of noise made by the wind turbine. A microphone suspended at 10 meters records the sound of the wind turbine and compared to the wind velocity a noise level of the wind turbine is determined.

Load Measurements

Load measurements are carried out according to current international standard: IEC1400-13 – Measurement of mechanical loads. A wind turbine is exposed to massive forces during its expected lifespan of approximately 20 years. To make sure none of the parts will break, load measurements are performed on the wind turbines in the test station. To this end a certain amount of turbulence is ok, but not too much. Too much turbulence arrests the wind creating an average wind speed which is too low , while too little turbulence will not yield the correct impression of the fatigue load of the wind turbine.

Power Quality Measurements

Power quality measurements are carried out according to current international standard: IEC61400-21 – Measurement and assessment of power quality characteristics of grid connected wind turbines.

Measuring and testing the power produced by wind turbines is important for several reasons. Many appliances connected to the grid are sensitive to voltage fluctuations and power quality problems include voltage fluctuations, disruption and flicker.

 

Who is Behind the National Testing Centre for Large Wind Turbines in Østerild?

On June 4th 2010 the Danish Parliament passed an Act concerning a testing centre for large wind turbines at Østerild in the Northwestern region of Denmark (Act no. 647 of June 15th 2010). The Act was supported by a large majority of the political parties in the Parliament.

Several parties are involved in establishing and running the testing centre in Østerild. The Technical University of Denmark, DTU, Department of Wind Energy is responsible for establishing and running the centre. The costs of building and running the centre are held by the users. The Danish state has sold four of the seven testing plots at the centre. Two to Siemens Wind Power and two to Vestas Wind Systems.The remaining three lots are controlled by DTU Wind Energy. One is rented to the Chinese wind turbine company Envision Energy, while the remaining two are currently in the tender.

The Danish Technical University, DTU, is internationally recognized as a leading university in the areas of technology and sustainable energy. Due to research carried out at the centre in for example new measuring methods, the testing centre in Østerild will further strengthen cooperation between educational institutions and the wind turbine industry. Recently DTU Wind Energy coordinated the large scale joint European research project UpWind, bringing scientists and the wind turbine industry together in developing wind turbines of up to 20 megawatt. Preliminary results feature the development of new materials, construction and production methods resulting in lighter rotor blades. Currently DTU Wind Energy is coordinating the sequel to UPWind, INNWIND.EU, which is a new large scale EU research programme aimed at developing innovative systems for use in 20 megawatt wind turbines.

The Wind Turbine Industry

Siemens Wind Power has built the two first wind turbines at the two southernmost lots.

Vestas Wind Systems are planning on building test turbines in 2013 and 2014.

The Chinese company Envision Energy manufactures offshore wind turbines primarily for the Chinese market and the company’s development department is located in Silkeborg, Denmark. It is imperative to be able to test the prototypes in the vicinity of the development department. At Østerild testing centre conditions are optimal and developers may benefit from the scientific research results of DTU Wind Energy.

The Municipality of Thisted

The building of a National Testing Centre for Large Wind Turbines fits perfectly with the ambition of Thisted Municipality of becoming the foremost climate municipality of Denmark. Thisted Municipality and the Danish Nature Agency have agreed upon establishing new areas of woodland and other natural habitats close to towns in the municipality to compensate for the dune plantation lost to the testing centre in Østerild. Furthermore Thisted Municipality and the wind turbine industry are cooperating on establishing a visitor centre in connection to the testing centre. Here the story of the testing centre will be conveyed to visitors as well as schools and educational institutions that have green tech and sustainable energy on the curriculum.

 

Experiencing the National Testing Centre for Large Wind Turbines in Østerild

The Test Lots

Seven test lots have been laid out at the test station. Testcentervej, a 5 km long main work road, connects the seven test lots to the public road Gl. Aalborgvej to the south. The test lots are located on a straight north/south-ward line transversely to the prevailing wind-direction in order to achieve optimal wind speed and avoid possible disturbances to the neighboring wind turbine. The straight line also provides a visually egalitarian impression of the very distinctive features of the facility. There are 600 meters between the lots and each lot is surrounded by an area designated to testing equipment. Measurement towers up to 150 meters high are located 500 meters to the west of each wind turbine. Additionally the northern and southern boundaries of the testing area is marked with an aviation obstruction light tower.

The test station in Østerild is not a conventional wind farm. The purpose is to test wind turbines of varying brands and types and the area is characterized by activities relating to measurements, testing and erecting / dismantling of wind turbines and turbine components. When the huge cranes are at work constructing or dismantling wind turbines, the area will have restricted access for safety reasons.

Rising 250 meters up into the air the two light towers are possibly the most striking features of the testing area. Positioned to the north and south of the wind turbine line respectively, the light towers mark the extent of the test station warning aircraft of tall structures by white flashing lights positioned at three different heights the highest being at 250 meters. Even though wind turbines totaling 250 meters in height have not yet been constructed, the test station in Østerild must be able to accommodate such large structures in the future thus the very tall light towers. The towers are constructed like telecommunication towers and are supported by wires. They also carry meteorological measuring instruments and calibration tools.

To the west of each wind turbine lot is placed a measurement tower measuring wind conditions relating to each single wind turbine. These towers have the same height as the hub height of the individual wind turbine.

The Wind Turbines

Siemens Wind Power have already erected wind turbines at lot 6 and 7 and are conducting tests of two prototypes. The 6 megawatt wind turbine at lot 6 is 197 meters high, its rotor span measuring 154 meters. The SWT-6.0-154 wind turbine is equipped with the world’s longest rotor blades measuring 75 meters corresponding to the length of an Airbus 380 plane, the world’s largest aircraft. If located offshore the SWT-6.0-154 wind turbine is capable of producing 25 million kilowatt hours, enough to supply 6000 households.

The blades are manufactured using the patented IntegralBlade® process producing the blades from a single casting without adhesive joints. This results in blades up to 20 % lighter than blades manufactured with traditional methods.

At lot 7 a slightly smaller 4 megawatt wind turbine measures 170 meters in height.
Vestas Wind Systems are preparing for the building of a 3 megawatt wind turbine in 2013, rotor span 126 meters, and in 2014 an 8 megawatt wind turbine with a rotor span of 164 meters will follow.

 

The Nature Surrounding the Test Station in Østerild Dune Plantation

Landscape History

The dune plantation in Østerild is dominated mainly by coniferous trees with smaller areas of beech, oak and birch. This has not always been the case. Up until not more than 130 years ago the landscape was one of open heath and dunes. The dune plantation is one of many along the coastline of Western Jutland planted towards the end of the 19th century in an attempt to stop the devastating effects of sand drift threatening to destroy farmland even far inland. For centuries sand drift had been a serious concern of farmers in coastal areas.

DSC_3051-2 Written sources from the Middle Ages and the Renaissance confirm this. During that period priests throughout the country made official tax reports to the crown concerning tithes. In 1625 the parish priest of Østerild and Hunstrup relates how the sand has laid waste such a large part of the parish that he can no longer tithe the farms situated along the coast.

Archaeological excavations at lot 7 prior to establishing the wind turbine support the evidence of the written sources. The sand may have ruined the livelihood of the farmers in the area, but it also preserved the traces of their activities for posterity. Buried beneath an over one meter thick layer of drift sand appeared an entire landscape of heath with man made turf banks, ditches and an array of hoofprints. The hoofprints were visible in the dark heath surface like bright sand filled spots, and must have been filled with sand rather suddenly. The banks, ditches and hoofprints indicate that the area was common grassland.

On the heath surface and in the ditches along the banks was found well preserved moss, heather and bog myrtle. The plants are carbon dated to between 1450 A.D. and 1640 A.D. which fits well with the complaints of the priest in Østerild in 1625 about the stop in supply of butter from the farms in the dunes – sand had literally buried the cattle run.

The sand must also have proven troublesome to farmers occupying the area long before the Middle Ages. The archaeological excavations disclosed the characteristic criss cross pattern of Iron Age fields from around 500 B.C made from the primitive plough of the Iron Age farmer. The fields at the site in Østerild consisted of only thin layers of topsoil mixed with sand.
DSC_3194-2

Østerild Dune Plantation Today

The Testing Centre is not just a testing station for wind turbines but will also yield information about how large wind turbines influence the nature surrounding them making for better environmental Assessments in the future. Scientists from DCE – Danish Centre for Environment and Energy at Aarhus University will monitor the area and conduct systematic recordings of the changes during the first 10 years of the succession towards open dune habitat. Two baseline monitoring studies of plants and wildlife were carried out prior to the establishing of the Testing  Centre.
The plantation today consists mainly of Scotch pine, mountain pine, silver fir, sitka spruce and common spruce with smaller areas of beech, oak and birch. Also many varieties of dwarf shrubs can be found such as bog bilberry, crowberry, heather, bell heather and bog myrtle. Other herbs to be found in the area are: Grapefern, club moss, beak rush, sidebells wintergreen, bog hair-grass, floating club-rush, spoonleaf sundew, linnea, heath spotted orchid, narrowleaf bur-reed, heath milkwort, flatleaf bladderwort, shoreweed, lesser marchwort and water lobelia.

Restoring the Open Dune Habitat

The overall objective of the restoration project focuses upon creating open dune habitats and wet habitats following clear-cutting of the dune plantation in the National Testing Centre. The Atlantic dune heath is a unique habitat currently on the decline along the western shores of Europe due to plantations, farming, settlement etc. A mosaic of habitats like the ones the project proposes will confer with the demands for wind conditions of the Testing Centre.
The aim is to promote the development of primarily three different types of open dune habitats that are included in the Habitats Directive (European Communities 1992) about the conservation of habitat types: Gray dunes (Habitat type 2130), dune heaths (Habitat type 2140) and humid dune slacks (Habitat type 2190).

Prior to the plantation in the late 1800, the dune areas in Østerild were characterized by a high and highly fluctuating water table. Consequently moist and wet habitats were widespread in the area. Establishment of the plantation meant draining the area and a successful restoration of moist dune heaths and humid dune slacks will require a restoration of the original hydrological regime by closing drainage dykes and allowing temporary pools and shallow lakes to develop or expand.

Restoration of the original water table will not be enough though. The soil itself is also a determining factor in the development of habitats in the future. In coniferous plantations accumulation of needles, cones and twigs make for very slow decomposition resulting in acidic soil that may hinder the development towards the open dune heath. The project will therefore experiment with different post-cutting treatments of the accumulated organic matter like removing the litter layer in large patches or burning the litter.

To prevent the newly created open heath areas from overgrowing with self-sown shrubs and trees a plan for the preservation of the area is needed. The Danish Nature Agency in Thy is in charge of the preservation effort in similar areas in the vicinity and some of the already known treatments will be applied in Østerild: livestock grazing, burning of patches and cutting down trees and shrubs.

Gray dunes (Habitat type 2130)

Gray dunes are fixed coastal dunes with herbaceous vegetation more or less closed by a cover of grasses, herbs, mosses and lichen. Typical species are: Yellow hair-grass, soft brome, sand sedge, mouse-ear chickweed, gray hair-grass, pinweed, lady’s bedstraw, gentian, glaucous hair grass, early forget-me-not, restharrow, sand cat’s-tail, common milkwort, Spanish catchfly, dune pansy, narrowleaf hawkweed, cat’s ear, heath violet, blue bonnets, sheep fescue, red fescue, breckland thyme, goldmoss stonecrop, bloody crane’s-bill, dove’s-foot, bird’s-foot trefoil, sweet vernal grass, field wormwood, Burnet saxifrage, common meadow-grass and sea thrift.

Dune heaths (Habitat type 2140)

Dune heaths are decalcified, fixed low and even dunes with low vegetation dominated by crowberry, heather and other dwarf scrub vegetation. Other types of vegetation are: Sand sedge, dyer’s broom, round-leaved wintergreen, heather, bell heather, common polypody, bird’s-foot trefoil, wavy hair-grass, marram grass, narrowleaf hawkweed, cypress-leaved plait-moss, broom moss and Schreber’s moss.

Humid dune slacks (Habitat type 2190)

Humid dune slacks consist of wet and seasonally flooded depressions with pioneer swards, fens and pools on acidic or calcareous sand. The habitat is threatened by lowering of the water table which has been happening in the plantation in Østerild for over a hundred years. The vegetation in humid dune slacks consists of many different plant communities and encompasses a variety of subtypes such as dune lakes, reed swamps in dune depressions and fens. Typical species are:

  • In dune lakes: Aquatic plants like Characeae green algae, swamp horsetail and different Potamogeton (pondweed) species.
  • In reed swamps: Reeds, sea clubrush and other large sedges of the Cyperaceae family.
  • In dune depressions with moist sand: Toad rush, several species of Centuary of the gentian family, lesser water-plantain and marsh pennywort.
  • In fens: A variety of herbs and sedges together with creeping willow and possibly Salix rosmarinifolia of the willow family.
  • In dune depressions with semi-dry sand: A variety of meadow and grassland species together with creeping willow.

Wildlife at the Testing Centre

The recovery of the natural vegetation and habitats after clear-cutting of parts of the coniferous plantation at the Testing Centre will benefit wildlife in the area. The baseline monitoring study carried out by scientists from DCE – Danish Centre for Environment and Energy at Aarhus University, recorded seven species of bats at the proposed wind turbine sites, ponds and lakes in the test centre area and its vicinity: Pond bat, Daubenton’s bat, Nathusius’ pipistrelle, common pipistrelle, serotine bat, particoloured bat and brown long-eared bat. Several of these species were recorded in particularly large numbers in the vicinity of lakes and ponds where they forage. Restoring the humid dune slack habitats characterized by areas of small lakes and ponds will provide increased opportunities for the bats to forage.

The baseline study also included recordings of species of birds. Among the species recorded were: Nightjar, cormorant, whooper swan, tundra swan, pink-footed goose, taiga bean goose, greylag goose, light-bellied brent goose, hen harrier, buzzard, peregrine falcon, common crane, golden plover, wood pigeon, great grey shrike, common raven and passerines such as swallows, larks, wagtails, pipits, etc.

The restoring of an open landscape with plenty of wet areas will benefit the many species of birds that do not thrive in the dehydrated plantation. This mosaic of habitats which will be the result of the restoration of parts of the plantation will help a variety of animals that are found in the area such as the moor frog, the natterjack toad and the crested newt. Otters have been recorded in the plantation and know otter populations are found in the neighboring wetlands Vejlerne and in the Hanstholm Reserve. The birch mouse is rare in Denmark but is found in Thy in meadows, fields, grasslands, forests and heaths.

The test area is home to a substantial population of red deer and the nature restoration planned for the area with dunes, heath, bogs, fens, scrubs, grassland, forest, meadows and fields will attract even more animals. If the deer remain undisturbed it is likely that visitors will be able to spot them even during daytime.

Learn more about the nature of Østerild