Appendix A: Feasibility two new masts

Trysil kommune
Plan-, bygg- og miljøavdelingen
Til berørte parter og offentlige instanser
Vår ref.
Deres ref.
Arkiv
Saksbehandler
Direkte telefon
Telefaks
Dato
2014/2527 - 21071/2014
88/1
Christer Danmo
47 47 29 73
21 55 76 11
17.09.2014
Høring: Austri Vind - bygging av midlertidig vindmålemast - gnr. 88 bnr. 1 og 2
Austri Raskiftet DA søker Trysil kommune om dispensasjon fra gjeldende arealplan for plassering
av midlertidig vindmålemast i Sæterbekkbotninga i Trysil kommune. Det søkes om en periode på
inntil 3 år.
Tilsvarende er det søkt Åmot kommune om midlertidig vindmålemast på Kraggåsen, nord i
planområdet.
Formålet med målemasten er å detaljkartlegge vindressursen. Vindmålemastene vil være firkantet
fagverksmast med høyde på inntil 120 meter. Masten vil bli bygget ved hjelp av helikopter, men det
vil også være behov for beltegående gravemaskin og noe transport av pukk/anker. Slik transport må
tilpasses forholdene og kjøreveg må avklares med kommunen i forkant med tanke på trasevalg, jf.
motorferdselloven. Ved endt måleperiode vil bardunforankringer, fundament og annet utstyr fjernes
så godt det lar seg gjøre, slik at inngrepet i naturen minimeres.
Det er også innkommet byggesøknad og søknad om kjøretillatelser i utmark.
Det anmodes med dette om uttalelse til søknaden i henhold til plan- og bygningslovens kapittel 19
om behandling av dispensasjonssøknader.
Denne informasjonen sendes berørte parter og offentlige instanser. Naboer skal være varslet
gjennom byggesak og varsles ikke på nytt nå i samsvar med reglene i plan- og bygningslovens
kapittel 19 om dispensasjon.
Høringsfristen er satt til 20.10.2014.
Dokumentene er utlagt på servicetorget i rådhuset og www.trysil.kommune.no/tema/kunngjoringer.
Bruk helst elektronisk høringsskjema som fins på www.trysil.kommune.no, eller sende e-post til
[email protected], eller eventuelt brev i posten til Trysil kommune, postboks 200,
2421 Trysil. Merkes med saksnummer 2014/2527.
Postadresse: Postboks 200, 2421 Trysil
Telefon: 62 45 77 00
E-post: [email protected]
Giro:
Org.nr:
6167.05.01328
864 948 502MVA
Med hilsen
Christer Danmo
Arealplanlegger
Dette brevet er elektronisk godkjent og sendes derfor uten signatur.
Sendt til:
Sveen Vel
Åmot kommune
Søre Osen Grendeutvalg
Norges vassdrags- og
energidirektorat Region Øst
Osensjøen Turistsenter
Osensjøen Hyttegrend
Hytteforening
Osensjøen reiselivslag
Elverum kommune
Naturvernforbundet i Hedmark
Naturvernforbundet i Elverum
og Åmot v/ Gjermund
Gjestvang
Norges Miljøvernforbund
region Østlandet
Forum for natur og friluftsliv
Hedmark c/o NJFF-Hedmark
DNT Elverum
DNT Engerdal og Trysil Turlag
Norsk Ornitologisk Forening
Forsvarsbygg
Luftforsvaret
Fylkesmannen i Hedmark
Miljøvernavdelingen
Hedmark Fylkeskommune
Fylkesdirektøren
La Raskiftet Leve v/ Snefrid og
Ragnar Reutz-Håkenstad
v/Oddbjørn Nordnes
Torget 1
Osensjøen Vest 195
Postboks 4223
2428
2450
2428
2307
Søre Osen
RENA
Søre Osen
HAMAR
v/Yngve Grambo
Nedre Berglia 68
2428
1353
Søre Osen
Bærums Verk
Osensjøen øst 982
Postboks 403
2428
2418
SØRE OSEN
ELVERUM
Bakkehågån 43
2849
KAPP
Postboks 191
2402
ELVERUM
Postboks 83
2256
GRUE FINNSKOG
Sandgata 30 B
Postboks 405 Sentrum
7012
0103
TRONDHEIM
OSLO
Postboks 4034
2306
Hamar
Postboks 4404 Bedriftssenteret 2325
Hamar
Osensjøen Øst 1152
SØRE OSEN
Vedlegg:
1 Vedlegg 4 Byggtekniske detaljer 100 m mast
2 Vedlegg 5 Bilde av målemast på Raskiftet
3 Vedlegg 2 Dispensasjonssøknad målemast Sæterbekkbotninga
4 Vedlegg 6 Masteplasseringsanalyse
5 Vedlegg 9 Gjennomføringsplan
2428
Austri Raskiftet DA
Postboks 64
2801 Gjøvik
Trysil Kommune
Postboks 200
2421 Trysil
Deres ref.:
Besøksadresse:
Energihuset,
Merkantilvegen 2
2815 Gjøvik
Saksbehandler:
Vår ref.:
Dato:
28.05.2014
Søknad om dispensasjon fra kommunens arealplan for plassering av
midlertidig vindmålemast i LNF-område
Austri Raskiftet DA søker Åmot kommune om dispensasjon fra gjeldende arealplan for
plassering av midlertidig vindmålemast ved Sæterbekkbotninga i Trysil kommune. Rød sirkel i
figur 1 viser lokalisering av mastepunktene. Det søkes om en periode på inntil 3 år. Tilsvarende
søkes det også Åmot kommune om midlertidig vindmålemast På Kraggåsen, nord i
planområdet.
Figur 1: Rød sirkel viser lokalisering av nytt mastepunkt. De 6 sorte sirklene viser hvor lidar har målt vind. Den
eksisterende vindmålemasten er markert med rød sirkel.
Søknaden gjelder i utgangspunktet følgende masterkoordinat (WGS84 UTM sone 32):
X
Y
Sæterbekkbotninga 655242
6783036
Av praktiske årsaker er det nødvendig at selve mastepunktet må være noe fleksibelt, anslagsvis
en sirkel med radius på 100 meter med utgangspunkt i koordinatene ovenfor. Dette vil gjøre
det enklere å tilpasse byggingen av vindmålemasten til terrenget for å minimere
naturinngrepet. Det vil være hensiktsmessig at kommunen og tiltakshaver gjør en felles
befaring på barmark i forbindelse med byggesøknad og søknad om kjøretillatelser i utmark.
Hvorfor en målemast
Målemastens formål er å detaljkartlegge vindressursen i området. Det måles fortsatt i
vindmålemasten på Ulvsjøfjellet. I tillegg har det vært et omfattende måleprogram med Lidar i
hele planområdet. Vindressursen er derfor på et generelt grunnlag godt kartlagt. Metoden som
er benyttet er av eksperimentell art, og det kan vise seg at internasjonale investorer og
turbinleverandører krever at det måles i flere vindmålemaster. Det er mer kunnskap om, og
nøyaktigheten til nedenforliggende parametre som en ny målemast vil gi tilgang til. Disse
parametrene benyttes til under detaljplasseringen av vindturbinene.








midlere vindhastighet
retningsfordeling
hastighetsfordeling
turbulens
vertikalvind
ekstremvind
temperatur
is
Det er viktig for Austri å sørge for at nødvendige tillatelser er til stede slik at en eventuell
vindmålemast kan settes opp før vintersesongen starter.
Melding om luftfartshinder vil bli sendt til Luftfartstilsynet i god tid før mastene reises.
Litt om målemasten og bygging av disse
Vindmålemastene vil være en firkantet fagverksmast med høyde på inntil 120 meter. Man
ønsker å måle vinden i relevant nav-høyde for turbinene. I konsesjonssøknaden og i
konsekvensutredningen er det tatt utgangspunkt i vindturbiner med navhøyde på 120 meter.
Vindmålemasten på Ulvsjøfjellet er på 100 meter.
Målemasten skal barduneres og forankres i løsmasser/fjell. Nøyaktig metode kan først velges
etter en befaring og viser hvor viktig det er med noe fleksibilitet rundt selve mastepunktet. Det
vil være behov for beltegående gravemaskin og noe transport av pukk/anker. Slik transport må
tilpasses forholdene og kjøreveg må avklares med kommunen i forkant. Masten vil bli bygget
ved hjelp av helikopter.
Ved endt måleperiode vil bardunforankringer, fundament og annet utstyr fjernes så godt det lar
seg gjøre, slik at inngrepet i naturen minimeres.
Målemast ene og konsekvensutredningen
I konsekvensutredningen
beskrives området slik : Størstedelen av planområdet oppe på
Raskiftet og Ulvsjøfjellet består av store, sammenhengende, fattige fastmattemyrer
med
furuskog og omkringliggende blåbærgranskog og bjø rkeskog. Myrterrenget er flatt og
homogent, med mindre områder av strengmyr og bakkemyr. Innimellom finnes rikere
bekkedrag og myrområder
Selve Sæterbekkbotninga
har ikke blitt fremhevet i særlig grad, noe som tolkes dithen at
området i KU sammenheng oppleves som vanlig for regionen. Området ru ndt er mer brukt i
tursammenheng , til jakt og bærplukking. Det beskrives også at det er god kontinu itet i skogen,
og konsek vensutredningen vurderer barskogen Halvorsberget/Vestrehø gda til å ha middels
verdi for naturtyper og vegetasjon.
En Vindmålemast kan være synlig på store avstander,
den også gjennomsiktig. Det vil gjøre vindmålemasten
omgivelser.
Med vennlig hilsen
Austri
Raskiftet
Håkon Rustad
Prosjektutvikler
men ettersom det er en fagverksmast, er
litt kamuflert i forhold til sin høyde og
Austri Vind sin vindmålemast på Ulvsjøfjellet ved Osensjøen. Masten er 100 meter høy. Det omsøkte
tiltaket er tilsvarende konstruksjon.
Raskiftet,
Trysil and
kommune, Hedmark
Åmot
Analysis of the need for more measurements
Rapport: KVT/REBHS
/201 4/R023 Rev. 1
KVTIREB/2014/R023 Rev1
Report number
Date
KVT/RE B/201 4/R023 Rev 1
18.03.2014
Report Title
Availability
Raskiftet, Trysil and Amot kommune, Hedmark
Limited to client
Revisionnumber
Analysis of the need for more measurements
Client
Numberof pages
Austri Vind DA
22+Appendix
Client Reference
Status
Hakon Rustad
Final
Summary
An evaluation of the ongoing measurement campaign at the planned Raskiftet wind farm has been given.
The current wind measuring campaign consists of measurements from one meteorological mast (100 m) and
one LlDARmeasuring at 6 different positions in addition to the met mast position. The analysis of the ongoing
campaign suggests that the wind resources at Raskiftet will be adequately mapped by the current campaign
when it is finished.
The largest uncertainty for whether the campaign will be accepted in the wind energy community is
connected to the accuracy of LlDARsin complex terrain . We wlll therefore recommend applying for permission
to erect one or two met masts at one or two LlDAR positions given in the table below. We recommend a mast
height of 120 m. Analysis of the ongoing phase II of the LlDARcampaign will clarify the need for the additional
measurement mast(s).
New masts (WGS 84 UTM zone 32)
B Kraggasen
- C Sceterbekkbotnin a
X
655242
y
6789802
6783036
With the current campaign all turbines in the current turbine layout are within a distance of 1 700 m from the
existing mast or one of the 6 LlDAR pOSitions. This maximum distance is within the recommendation of
2 km(Measnet 2009) for complex terrain. If two masts are erected at two of the existing LlDARpositions, the
maximum distance to a mast position from a turbine location is reduced from 9 000 to 3 000 m. Combined with
the LlDAR campaign this may reduce the uncertainty in the final production estimate for the Raskiftet wind
farm.
Disclaimer
Although this report, to the best of our knowledge, represents the state-of-the-art in wind energy assessment
methods, and effort has been made to secure reliable results, Kjeller Vindteknikk AS cannot in any way be
held responsible neither to the use of the findings in the report nor for any direct or indirect losses ariSing
from such use or from errors of any kind in the contents .
Revisionhistory
Rev.
Date
number
o
Number
copies
of Comment
Distribution
14.03.2014
Draft
Electronic
18.03.2014
Final
Electronic
Name
Rolv Erlend Bredesen
Prepared by Hanna Sabelstrdm
Martin S. Gmnsleth
Reviewedby Lars Tallhaug
Approved by Finn K. Nyhammer
KVT/REB/2014/R023 Rev 1
Content
1
INTRODUCTION .................................................................................................. 3
1.1
BACKGROUND
3
1.2
RESOURCE MAPPING AND METHODS
3
1.2.1 Key parameters ...................................................................................... 4
1.2.2 Factors that have influence on the location of the mast ....................................4
1.3
WIND FARM AREA
6
1.4
MEASUREMENTS
7
2
EVALUATION OF CAMPAIGN .................................................................................. 8
2.1
TURBINE LAYOUT
9
2.2
WIND SPEED AND TERRAIN ELEVATION
9
2.3
DISTANCE TO MAST
12
2.4
MESO SCALE EFFECTS
12
2.5
ICING
12
2.6
RUGGEDNESS OF TERRAIN (RIX)
12
2.7
MEASURED LIDAR TURBULENCE
15
2.7.1 Discussion ........................................................................................... 18
2.8
WIND SPEED MEASUREMENTS BY LIDAR VS. CUP ANEMOMETERS
19
3
SUMMARY ........................................................................................................ 20
3.1
4
POSSIBLE EXTENSION OF THE CURRENT CAMPAIGN
20
REFERENCES .................................................................................................... 22
APPENDIX A: FEASIBILITY TWO NEW MASTS ......................................................................... 23
2/22
KVT/REB/2014/R023 Rev 1
1 Introduction
1.1 Background
Based on measurements by a met mast and LIDAR measurements at 6 different locations in
addition to a short period next to the met mast, an evaluation regarding the need of an
extended measurement campaign at the planned Raskiftet wind farm has been made.
The existing met mast has been measuring since 2011-03-29. In addition to the met mast a
LIDAR has been used at 6 different locations. To take account for the seasonal variations, the
LIDAR has been moved around in the area with the purpose that at each location it will be
measuring for one month in each season (spring, summer, autumn and winter). This measuring
campaign is further described in the report (KVT/YY/2011/R104 2011). This measuring
campaign is ongoing, and when it is finished we will have around 4 months of data available at
each measuring location. The different locations are shown in Figure 1-1.
1.2 Resource mapping and methods
When proposing a measurement campaign intended for wind power it is important to know
clearly how and why the measurements should reduce the uncertainty in the energy yield
calculation for a wind farm. The mapping of the wind resources should also result in an optimal
turbine layout for production and a classification leading to the correct selection of turbines
that can also sustain the environmental loads.
Measurements are also important in removing biases and reducing uncertainties in models and
calculation methods. In this sense the interaction between measurements and models is
important. Measurement should take place at locations that will challenge the weaknesses of
the models and the calculations methods. If the weaknesses in the models and the methods are
not challenged, the measurements might in the worst case not be useful.
There is no standard that determines exactly how a mapping of the resources should be
accomplished. The demands specified for how the measurement of the power curve should be
measured is described by (IEC 61400-12-1 2005). This is a standard of how to measure the
power curve of wind turbines and provides illustrations and recommendations regarding the
instrumentation of the wind measurement mast. For wind measurements we recommend that
this standard is followed as closely as it is practically achievable. The standard does however
not state how the resource assessment of a large wind farm should be carried out. In order to
map the resources in a larger area the guidelines of (Measnet 2009) are recommended to use as
the starting point.
When considering the design loads on land based wind turbines one can make use of the
standard (IEC-61400-1 2003). This standard describes the physical loads and methods for load
calculation on turbines. It also includes the load classes corresponding to the wind and
turbulence which simplifies the choice of the appropriate turbine model for a specific position.
This standard can assist to ensure that the correct wind turbine class is selected for a specific
site.
3/22
KVT/REB/2014/R023 Rev 1
1.2.1 Key parameters
There are several parameters that can be obtained through the use of measurements. When
using mast measurements one wishes to assess information mainly regarding:
•
•
•
•
•
•
•
•
Mean wind speed.
Directional distribution.
Wind speed distribution.
Turbulence intensity.
Vertical wind speed.
Extreme wind speed.
Temperature.
Icing.
1.2.2 Factors that have influence on the location of the mast
Based on our experience from prior measurement campaigns in Norway and Sweden there are a
number of factors that are essential for the placement of the masts.
•
•
•
•
•
•
The measurement masts’ representativeness for the turbine positions.
The measurement masts’ representativeness depending on specific mapping needs (e.g.
mean wind speed, turbulence and extreme winds).
Meso scale differences in the wind climate. This is particularly important when the farm
cover vast areas and when there are substantial geographical variations in the close
surroundings and within the farms boundaries. This includes the variation in terrain
elevation in the wind farm and close surroundings.
The terrain complexity; Different ruggedness indices (RIX) within the park.
Vegetation variations.
Distance from each turbine to the nearest mast.
4/22
KVT/REB/2014/R023 Rev 1
Figure 1-1 The wind farm area of Raskiftet and locations of met mast and LIDAR.
5/22
KVT/REB/2014/R023 Rev 1
1.3 Wind farm area
The area of Raskiftet stretches approximately 14 km in the south-east towards north-west
direction. A proposal for the layout of the farm is shown in Figure 1-2. The elevation in the
terrain varies from approximately 680 to 800 meters above sea level (m.a.s.l.), with ruggedness
index (RIX) values below 8 % (assuming a threshold of 17 degrees within a 2 km radius). There
are some steeper slopes in the east of the area, towards the lake. The vegetation in the wind
farm area consists of a mixture of forest and swamps.
Figure 1-2 Layout of wind farm and locations of met mast and LIDAR measurements.
6/22
KVT/REB/2014/R023 Rev 1
1.4 Measurements
A preliminary wind analysis of Raskiftet wind farm was carried out in May 2012
(KVT/YY/2012/R043 2012). The long term wind speed at the met mast position at 102.3 m
a.g.l. was estimated to 7.6 m/s. The wind direction distribution is shown in Figure 1-3, Southwesterly winds are pre-dominant. Figure 1-4 shows the corresponding turbulence intensity
distribution.
Figure 1-3. Long term wind rose based on measurements from the 14602 Raskiftet met mast.
Figure 1-4 Turbulence distribution by velocity based on measurements from the 14602 Raskiftet met
mast at 102.3 m.
In addition to the met mast, an ongoing intensive measurement campaign with LIDAR
(Windcube v2 with FCR option) is measuring at 6 different locations (in addition to the mast
location). Preliminary results from this campaign and further discussion on turbulence are given
in Section 2.7.
7/22
KVT/REB/2014/R023 Rev 1
2 Evaluation of campaign
The number, and specific location, of the met masts and LIDARshave direct impact on the total
uncertainties in the project. The process of finding representative measurement sites is an
iterative interaction between the different requirements that should be considered. The
number and specific locations of masts and LIDARsare dictated by the requirement to measure
typical wind conditions experienced by the turbines. Specifically, we have considered the
turbulence levels at Raskiftet in addition to the other parameters.
In the following subsection we discuss the results from the analysis of the key parameters for
mast placement. The current wind resource is shown in Figure 2-2 as an average wind speed
map. The terrain elevation is also shown. At the location of each turbine and each mast/LI DAR,
values are specified for the wind speed, elevation, RIX and horizontal distances between
turbines and masts. Sorted distributions for these parameters are presented below in Figure
2-4, Figure 2-5 and Figure 2-7. These distributions are valuable for verifying the
representativeness of the mast and LIDAR positions. At the end of this chapter a thorough
discussion of the turbulence levels as measured by the LIDARand mast is given.
Turbines
Mast
LIDARs
Park area
Figure 2-1 Location of current wind turbine layout as white markers with identifying
position is shown in blue while the 6 LIDARpositions are shown in grey.
8/22
ID. The existing mast
KVT/REB/2014/R023 Rev 1
2.1
Turbine layout
The turbine layout considered in this report is the Vestas V112 3.0 MW layout given in
(KVT/YY/2012/R043 2012), consisting of 36 turbines with hub height 120 m. See Figure 2-1 for
the location of each named turbine .
2.2
Wind speed and terrain elevation
In Figure 2-3 the mean wind speed and terrain elevation for the turbine positions are shown
together with the mast and LIDARpositions. There is a relation between the increase in wind
speed and increase in elevation but other effects than the height are also important for the
wind speed. The correlation coefficient between the wind speed and terrain elevation
considering in the turbine layout is 0.52 (without de-trending) . The low correlation coefficient
motivates measurements in both varying wind regimes and varying elevations. It is not
sufficient to only consider one of these parameters for each mast but they should both be t aken
into account.
With respect to the wind speed, the current mast is at the 95 percentile of the turbines, Figure
2-4, while the terrain elevation corresponds to the 70 percentile, Figure 2-5. This means that
95 %of all turbines are expected to experience lower wind speedsthan at the mast, while 70 %
of all turbines are located at a lower elevation above sea level than the mast. LIDAR
measurements are performed at locat ions near the 0 and 40 percentile with respect to the wind
speed. With respect to the terrain elevation the LIDAR measurements are performed at
elevations between the 20 and 80 percentile with a good spread.
Figure 2-2. Spatial wind speed distribution at Raskiftet (119 m, not RIX-adjusted ). The turbine layouts are
represented with white circles, mast with a black square, and LIDARpositions with blue squares.
9/22
KVT/REB/2014/R023 Rev 1
Figure 2-3. Modelled wind speed at 120 m (vertical axis) plotted against terrain elevation (x-axis) for all the
wind turbine positions. The solid blue horizontal and vertical lines indicate the mean wind speed (y-axis) and
elevation (x-axis) at the met mast location. The dashed blue horizontal and vertical lines indicate the mean
wind speed and elevation at the LIDAR positions. The horizontal line for the mean wind speed at Skinnarstien
(green) is covered by Kraggåsen (red).
10/22
KVT/REB/2014/R023 Rev 1
Figure 2-4. Sorted distribution of the 120 m wind speed for the turbine layout (grey lines with marker). The
solid blue horizontal lines indicate the value at the existing mast location while the dashed line indicates the
value at t he LIDARpositions. The percentiles indicate how many percent of the turbines that are expected to be
below the wind speed value. 14604 Skinnarstien (green) is overlapping 14613 Kraggåsen (red) .
Figure 2-5. Sorted distribution of the terrain elevatio n for the turbine layout (grey line with marker). The solid
blue horizontal lines indicate the value at the existing mast location while the dashed line s indicate the value s
at the LIDAR positions . The percenti les indicate how many percent of the turbines that are locat ed lower than
the elevation value.
11/22
KVT/REB/2014/R023 Rev 1
2.3
Distance to mast
The terrain in the planned Raskiftet wind farm is considered to be complex. For complex
terrain the representativeness radius of a mast (maximum distance of any wind turbine to the
next mast) is 2 km (Measnet 2009) and it is recommended to place turbines within this distance
to the nearest measurement mast. To achieve this goal, more than one mast is required. From
Figure 2-6 we observe that the recommendation is fulfilled when the LIDARmeasurements are
included.
Figure 2-6. Sorted distribution of the distance to the nearest mast or LIDAR for the turbin e layout. The
percentiles indicate how many percent of the turbines that are expected to be closer to a mast than the
specified distance.
2.4
Meso scale effects
There may be a gradient in the wind speed due to mesoscale effects at Raskiftet. A zoomed
version of the wind map for Norway (Byrkjedal och Åkervik 2009), valid at 120 m.a.g.l., based
on meso scale data and terrain adjustment, shows wind speeds between 7.0 and 8.0 with the
highest winds along the north -south ridge. The current campaign is well suited to capture this
effect.
2.5
Icing
Ice measurements are currently performed in the met mast.
2.6
Ruggednessof terrain (RIX)
Based solely on the ruggedness index (RIX) the terrain complexity in the planned wind farm is
low (Figure 2-7) and 70 %of the turbines have a value below 0.03. The RIX index are calculated
using a slope threshold of 17 degrees and a RIX radius of 2 km. The areas with higher
ruggedness indices are associated with the steep slope east of the wind farm in the direction
towards Osensjøen. The highest RIX-values are found in this area. The wind rose at the mast
has an eastern component but the main wind direction is from north and south-west.
12/22
KVT/REB/2014/R023 Rev 1
The RIX value at the mast location is 0.05 (85 percentile).
Figure 2-7. Sorted distribution of ruggedness indices (RIX) for the turbine layout (grey lines with marker). The
solid blue horizontal lines indica te the value at the mast location while the dashed lines indicate the value at
LIDAR positions. The percentiles indicate how many percent of the turbines that are below the specific RIXvalue.
13/22
KVT/REB/2014/R023 Rev 1
Figure 2-8 Map of mean turbulence intensity calculated by Windsim and scaled to mean turbulence
intensity at the met mast. In the circles showing the LIDAR positions, the measured mean turbulence
intensities are given.
14/22
KVT/REB/2014/R023 Rev 1
2.7 Measured LIDAR turbulence
The measurements in the met mast 14602 Raskiftet show relatively low turbulence intensities
(Figure 1-4). The mean TI at 15 m/s (TI15) is 8 % and the 90 percentile of TI15 is 13 % which is
below the limits of IEC class B.
To investigate the variation of turbulence levels in the wind farm area a turbulence map has
been produced by using Windsim (Figure 2-8). The map has been scaled according to the
measured TI at the met mast position. In addition, the mean turbulence intensity at each LIDAR
position has been added to the map. It can be seen that according to the Windsim model the
mean TI varies between 8-13 %. The higher areas of turbulence are found in the north and east
parts of the wind farm area.
The turbulence measured by the LIDAR is higher than what the Windsim predicts but there are
no significant variations of TI between the different locations. This is in accordance to what the
turbulence map shows. A difference in TI measured by LIDAR and Cup anemometer is expected
since these two measurement devices operates differently. However, the TI limits in the IEC
standard are based on measurements by cup anemometers. As a comparison, 2 weeks of data
(2013-08-23 to 2013-09-06) has been collected from a LIDAR located next to the met mast. Cocurrent data of turbulence intensity has been plotted in Figure 2-9. The result shows that
turbulence intensity measured by the LIDAR shows higher values than measured by the met
mast and a cup anemometer. One should keep in mind that this comparison is only based on 2
weeks of data.
Figure 2-9 Scatter plot of TI measured by LIDAR and met mast during a period of 2 weeks.
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Figure 2-10 Data coverage at the different LIDAR locations. Technical availability and the data
coverage of data actually used after filtering are shown in red and black, respectively.
Figure 2-10 shows the data coverage at the different LIDAR positions for the ongoing campaign.
The seasonal coverage can be seen for the first (LIDAR positions 14603-05) and the second year
(LIDAR position 14611-13) which will be finished in June 2014. At the end of the campaign, we
will have a good seasonal coverage at all positions.
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The turbulence distribution by velocity for each LIDAR position is shown in Figure 2-11. It can
be seen that the amount of measurements at 15 m/s is small for most of the positions which
increases the uncertainty in the TI15 values.
Figure 2-11 Turbulence distribution by velocity based on measurements from the 6 different LIDAR
positions.
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Table 2-1 summarizes the measured TI values at the different LIDAR locations, as comparison
the IEC limits of TI is added. At the locations Kjolmyrakampen (14603) and Skinnarstien (14604)
the measured TI exceeds the IEC B limits.
Table 2-1 Measured mean TI and TI15 (90 percentile) at the different LIDAR locations and IEC limits.
14603
14604
14605
14611
14612
14613
Kjolmyrkampen
Skinnarstien
Sillemyra
Saeterbekkbotninga
Ratoppen
Kraggasen
Mean TI
[%]
13
11
11
12
11
12
TI15 (90 percentile) IEC A IEC B
[%]
[%]
[%]
17
18
16
16
18
16
15
18
16
14
18
16
14
18
16
15
18
16
The TI at the LIDAR locations 14603 and 13604 exceeds the IEC class B TI levels (marked as red).
These locations are in the north part of the wind farm area, which is also the area on the
turbulence map with the highest levels of TI (Figure 2-8). The mean turbulence as function of
direction is shown in Figure 2-12. It can be seen that for location 14603 the mean TI is high for
wind coming from east-south-east and South.
Figure 2-12 Mean TI as a function of direction for LIDAR locations 14603 (left) and 14604 (right).
2.7.1 Discussion
Both LIDAR measurements and Windsim model shows that the northern area of the wind farm is
experiencing the highest levels of turbulence intensities. The levels in the southern part seem
to lie well below the limits of IEC B. In the northern part the LIDAR measurements show TI15
levels above the IEC B limits. Since the LIDAR seems to show higher TI than when measuring
with a cup anemometer it is likely that the TI15 levels are below IEC class B in whole wind farm
area.
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If one additional met mast would be installed, it is recommended to locate it in the northern
part of the wind farm area with respect to the turbulence levels. However, based on the
current analysis we do not considerer additional measurements beyond the ongoing program to
be necessary to further map the turbulence levels in the area.
2.8 Wind speed measurements by LIDAR vs. cup anemometers
As mentioned earlier, the LIDAR has been positioned next to the mast for a short period.
Comparison of measured wind speeds by the LIDAR and cup anemometers in the met mast have
been reported in (KVT/MSG/2014/N009 2014) and also presented at Winterwind 2014 (M. S.
Grønsleth 2014). We have found good agreement in mean wind speeds for complex terrain when
the LIDAR data is corrected with the installed FCR (Flow Complexity Recognition) module or by
using a CFD (Computational Fluid Dynamics) model.
However, it should be noted that the use of LIDAR measurements for wind resource assessment
in non-benign (i.e. complex) terrain, currently is at its development stage (stage 2) according
to (GL Garrad Hassan 2012). The aforementioned technical note states that data from the
remote sensing device (i.e. the LIDAR) may be used quantitatively within a formal wind speed
and energy assessment provided that, where appropriate, site-specific validations against
conventional anemometry data are undertaken. At Raskiftet, we already do have such
conventional measurements from the existing met mast that is used for validation.
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3 Summary
In summary, we consider that
• The ongoing LIDAR campaign has so far mapped the wind resources in the area well. The
chosen LIDAR positions gives a good spread in height, mean wind speed, RIX values and
covers variations in turbulence intensity as well.
• The LIDAR measurements show acceptable turbulence intensity values.
• The method with moving the LIDAR between sites is new, and the campaign is not yet
completed. A few months of data collection remains, especially the remaining
comparison with the mast is important before the full evaluation of the campaign can be
done. The results from the LIDAR measurements in this report are therefore preliminary.
However, we expect no major surprises in the final analysis.
• Although we are confident that the method with intensive movement of LIDAR between
positions gives a good wind resource mapping, we can not vouch for what claims others
might ask (consultants, banks, etc.). This is because the technique with a moving LIDAR
in complex terrain is not yet fully accepted as a wind-industry standard.
• Based on this, we keep open the possibility that others may recommend a mast and
include two recommended mast positions so that applications may be sent to the
relevant authorities.
• These two positions coincide with the LIDAR positions at Kraggåsen and
Sæterbekkbotninga.
3.1 Possible extension of the current campaign
If the current measurement campaign is extended by two met masts we propose using two
existing LIDAR positions to complement the existing results. With respect to the parameters
discusses before, a campaign with additional met masts at Saeterbekkbotninga and Kraggåsen is
suitable.
The distance between a turbine location and a met mast (not LIDAR) is reduced from 9 000 m to
3 000 m using these two positions (see Figure 3-1). We note that the maximum distance to
existing mast or LIDAR is 1 700 m. For a discussion of the representativeness of other
parameters we refer to Chapter 2. In summary the 3 mast campaign will cover high to low
turbulence relative to the turbine layout as well as good spread in RIX, terrain, elevation,
modelled wind speed levels and the mentioned distances. If the campaign is extended we
recommended to measure with both mast and LIDAR to get concurrent measurements for a
shorter period. This will be used to reduce biases between mast and LIDAR.
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Figure 3-1 Distance to nearest mast (not LIDAR). The current mast is show at the top while th e
distance using two additional masts is shown at the bottom.
A feasibility study is performed for the two locations in Appendix A.
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4 References
B. Canadillas, A. Bégué, T. Neumann. ”Comparison of turbulence spectra derived from LiDAR
and sonic measurements at the offshore platform FINO1.” 10th German Wind Energy
Conference (DEWEK 2010). Bremen, Germany, 2010.
Berge, E, F Nyhammer, L Tallhaug, and O Jacobsen. "An evaluation of the WAsP model at a
coastal mountainous site in Norway." Wind Energy, 9, 2006: 131-140.
Byrkjedal, Ø., och E. Åkervik. Vindkart for Norge. KVT Report, Kjeller Vindteknikk,
KVT/OB/2009/038: KVT Report, Byrkjedal, Ø; Åkervik, E.; Berge, E., 2009.
GL Garrad Hassan. GL GH Position Statement on the WINDCUBE Remote Sensing Device.
Technical note, GL Garrad Hassan, 2012.
IEC 61400-12-1. International standard Wind turbines - Part 12-1:Power performance
measurments of electricity producing wind tubines. First edition. IEC, 2005.
IEC-61400-1. Wind turbines - Part 1: Design requirements. IEC, 2003.
KVT/MSG/2014/N009. 2014.
KVT/YY/2011/R104. ”Målekonsept med fjernmålingsutstyr.” 2011.
KVT/YY/2012/R043. ”Fremdriftsrapport:
produksjonsberegning.” 2012.
Vurdering
av
lidarmålekampanje
og
foreløpig
M. S. Grønsleth, A. L. Løvholm. ”Winterwind 2014 - Comparison of Lidar and mast
measurements in complex terrain with/without FCR and CFD correction.” 2014.
http://www.winterwind.se/presentations-2014/.
Measnet. “Evaluation of site-specific wind conditions, Version 1.” 2009.
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Appendix A: Feasibility two new masts
The suggested coordinates (WGS 84 UTM zone 32) for the new masts are given in the table below:
New masts
B Kraggåsen
C Sæterbekkbotninga
X
647640
655242
Y
6789802
6783036
KVT/REB/2014/R023
Praktisk gjennomførbarhet
I kupert norsk terreng kan det være en utfordring å finne forankring både til selve masten og til
barduner i tre eller fire retninger. Som regel er det enklere i finne bardunpunkter for tre
retninger enn fire bardunretninger, og muligheter må vurderes opp i mot t erreng og mastetype.
Det er også viktig å vite mest mulig om mastens konstruksjon, antall bardunhøyder og antall
innfestningspunkter. Antall innfestningspunkter kan være avhengig av mastekonstruksjon og
lasteberegninger for det spesifikke punktet. Man må også se på hvor store høydeforskjeller det
er i terrenget fra senter mast og til bardunfester. Vi ønsker en så liten høydeforskjell som
mulig. Mulighet for avvik i høyder er avhengig av utnyttelsesgrad i mast og barduner.
Plassering av mast er også avhengig av grunnforhold. Myr er lite egnet. Det samme er forvitret
fjell som krever oppigging med gravemaskin. Pigging er mulig men vil fordyre forankringen.
Tilkomst med gravemaskin eventuelt borrerigg er en stor fordel . Dersom avstanden blir stor og
tilkomst med borrerigg er vanskelig, vil vi fly inn utstyr for handboring.
Oversikt over området med turbinlayout
master (blå firkanter).
(hvite markører), eksisterende mast (grå firkant) og forslag til 2 nye
KVT/REB/2014/R023
Mast B Kraggåsen
Praktisk plassering av mast fra flyfoto
bardundradius ved mast på 100 m.
og høydekotekart med ekvidistanse 1 m. Ring viser normal ytterste
Vurderinger
Navn på mast
Koordinater WGS84UTMsone 32
Kommune
Forankringsmetode
Fjellkvalitet
Forangringsdybde
Behov for graving
Skogrydding
Makshøydeforskjell bardunfester -senterpunkt
Tilkomst (vei, traktorvei, atv)
Avstand til riggplass (helikopterdistanse)
Kommentar
Kraggåsen
E647640 N6789802
Åmot
Løsmasseanker/fjel lanker?
Uvisst
Uvisst
Ja
Ja
6 m ved 4 bardunretninger
1500 m
Xxx km. Riggplassikke fastsatt.
KVT/REB/2014/R023
Mast C Sæterbekkbotninga
Praktisk plassering av mast fra flyfoto
bardundradius ved mast på 100 m.
og høydekotekart med ekvidistanse 1 m. Ring viser normal ytterste
Vurderinger
Navn på mast
Koordinater WGS84UTMsone 32
Kommune
Forankringsmetode
Fjellkvalitet
Forangringsdybde
Behov for graving
Skogrydding
Makshøydeforskjell bardunfester -senterpunkt
Tilkomst (vei, traktorvei, atv)
Avstand til riggplass (helikopterdistanse)
Kommentar
Sæterbekkbotninga
E655242 N6783036
Trysil
Løsmasseanker/fjellanker ?
Uvisst
Uvisst
Ja
Ja
1 m ved 4 bardunretninger,
1000 m til skogsvei
Xxx km. Riggplassikke fastsatt.

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