Niels-Erik Clausen

Dr. Niels-Erik Clausen

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Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 December 2010 in Climate Dynamics
Verified
Journal Article
Closed access
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S. C. PryorS. C. Pryor
S. C. Pryor
RBRebecca J Barthelmie
Rebecca J Barthelmie
NCNiels-Erik Clausen
Niels-Erik Clausen
Martin DrewsMartin Drews
Martin Drews
NMN. MacKellar
N. MacKellar
EKE. Kjellström
E. Kjellström

1 September 2014 in Renewable Energy
Verified
Journal Article
Open access
NNNikolai Nawri
Nikolai Nawri
GPGuðrún Nína Petersen
Guðrún Nína Petersen
HBHalldór Bjornsson
Halldór Bjornsson
AHAndrea Hahmann
Andrea Hahmann
KJKristján Jónasson
Kristján Jónasson
NCNiels-Erik Clausen
Niels-Erik Clausen
Downscaling simulations performed with the Weather Research and Forecasting (WRF) model were used to determine the large-scale wind energy potential of Iceland. Local wind speed distributions are represented by Weibull statistics. The shape parameter across Iceland varies between 1.2 and 3.6, with the lowest values indicative of near-exponential distributions at sheltered locations, and the highest values indicative of normal distributions at exposed locations in winter. Compared with summer, average power density in winter is increased throughout Iceland by a factor of 2.0–5.5. In any season, there are also considerable spatial differences in average wind power density. Relative to the average value within 10 km of the coast, power density across Iceland varies between 50 and 250%, excluding glaciers, or between 300 and 1500 W m−2 at 50 m above ground level in winter. At intermediate elevations of 500–1000 m above mean sea level, power density is independent of the distance to the coast. In addition to seasonal and spatial variability, differences in average wind speed and power density also exist for different wind directions. Along the coast in winter, power density of onshore winds is higher by 100–700 W m−2 than that of offshore winds. Based on these results, 14 test sites were selected for more detailed analyses using the Wind Atlas Analysis and Application Program (WAsP)

30 September 2015 in Wind Energy
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Journal Article
Closed access
NDNeil Davis
Neil Davis
PPPierre Pinson
Pierre Pinson
AHAndrea Hahmann
Andrea Hahmann
NCNiels-Erik Clausen
Niels-Erik Clausen
MŽMark Žagar
Mark Žagar

1 February 2014 in Journal of Applied Meteorology and Climatology
Verified
Journal Article
Closed access
NDNeil Davis
Neil Davis
AHAndrea Hahmann
Andrea Hahmann
NCNiels-Erik Clausen
Niels-Erik Clausen
MŽMark Žagar
Mark Žagar
This paper introduces a method for identifying icing events using a physical icing model, driven by atmospheric data from the Weather Research and Forecasting (WRF) model, and applies it to a wind park in Sweden. Observed wind park icing events were identified by deviation from an idealized power curve and observed temperature. The events were modeled using a physical icing model with equations for both accretion and ablation mechanisms (iceBlade). The accretion model is based on the Makkonen model but was modified to make it applicable to the blades of a wind turbine rather than a static structure, and the ablation model is newly developed. The results from iceBlade are shown to outperform a 1-day persistence model and standard cylinder model in determining the times when any turbine in the wind park is being impacted by icing. The icing model was evaluated using inputs from simulations using nine different WRF physics parameterization combinations. The combination of the Thompson microphysics parameterization and version 2 of the Mellor–Yamada–Nakanishi–Niino PBL scheme was shown to perform best at this location. The distribution of cloud mass into the appropriate hydrometeor classes was found to be very important for forecasting the correct icing period. One concern with the iceBlade approach was the relatively high false alarm rates at the end of icing events due to the ice not being removed rapidly enough.

22 July 2015 in Wind Energy
Verified
Journal Article
Closed access
NDNeil Davis
Neil Davis
ØBØyvind Byrkjedal
Øyvind Byrkjedal
AHAndrea Hahmann
Andrea Hahmann
NCNiels-Erik Clausen
Niels-Erik Clausen
MŽMark Žagar
Mark Žagar

1 September 2021 in Energy Policy
Verified
Journal Article
Closed access
JPJohannes Pohl
Johannes Pohl
DRDavid Rudolph
David Rudolph
ILIvar Lyhne
Ivar Lyhne
NCNiels-Erik Clausen
Niels-Erik Clausen
SASara Bjørn Aaen
Sara Bjørn Aaen
JKJulia K. Kirkegaard
Julia K. Kirkegaard