Vilde Stueland Nysted

Ms. Vilde Stueland Nysted


Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

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

Representative Publications

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17 May 2022 in Solar Energy
Verified
Journal Article
Open access
TKTorunn Kjeldstad
Torunn Kjeldstad
VNVilde Stueland Nysted
Vilde Stueland Nysted
MKManish Kumar
Manish Kumar
SOSara Oliveira-Pinto
Sara Oliveira-Pinto
GOGaute Otnes
Gaute Otnes
JSJosefine Selj
Josefine Selj

19 October 2023 in Energies
Verified
Journal Article
Open access
PDF file
MDMaarten Dörenkämper
Maarten Dörenkämper
MJMinne de Jong
Minne de Jong
JKJan Kroon
Jan Kroon
VNVilde Stueland Nysted
Vilde Stueland Nysted
JSJosefine Selj
Josefine Selj
TKTorunn Kjeldstad
Torunn Kjeldstad
The power output of a photovoltaic system is dependent on the operating temperature of the solar cells. For floating PV (FPV), increased wind speeds can result in increased yield due to lowered operating temperatures, which has long been stated as a key advantage for FPV. So far, this effect has not been included in commercial software packages for yield estimation. Typically, only standard settings are provided, taking into account the mounting type (PVsyst) or mounting and module type (Sandia). This may result in an underestimation of the yield, and consequently, the estimated Levelized Cost of Electricity (LCOE) of the FPV project. In this study, a linkage between recorded module temperatures from FPV systems located in The Netherlands and Sri Lanka and the prevalent models employed within PVsyst and Sandia software for estimating module temperatures are established. Our findings reveal that the models within PVsyst and Sandia tend to overestimate module temperatures by 2.4% and 3%, respectively, for each 1 m/s increment in wind speed. We present two methods for determining the single heat loss coefficient, or U-value, tailored to specific sites accounting for local wind conditions. The first method computes the U-value based on the average monthly wind speed, whereas the second employs the irradiance-weighted average monthly wind speed. The latter method can be advantageous for locations characterized by significant fluctuations in wind speeds between night and day. Through a statistical residual analysis comparing measured and modeled module temperatures, we demonstrate that our proposed methods offer a more accurate representation of module temperature compared to the PVsyst and Sandia models when default settings are used. When we subsequently compute the specific yield using both measured and modeled temperatures, we observe that the approach using irradiance-weighted average wind speed shows a higher yield of up to 2% compared to the traditional methods.

17 June 2024 in EPJ Photovoltaics
Verified
Journal Article
Open access
PDF file
VNVilde Stueland Nysted
Vilde Stueland Nysted
DLDag Lindholm
Dag Lindholm
JSJosefine Selj
Josefine Selj
TKTorunn Kjeldstad
Torunn Kjeldstad
Floating photovoltaics (FPV) is rapidly emerging as a promising alternative to ground-mounted PV (GPV) where available land area is scarce or expensive. Improved cooling has often been reported as a benefit of FPV, as cell temperature is an important parameter for the performance of a PV system. However, more recent literature shows that the cooling effect depends strongly on FPV technology and that it is not always superior to that of open rack GPV systems. There is still a need for more information on how to estimate cell temperatures for FPV systems, and how to consider the influence of various environmental factors such as wind speed and direction. Operating cell temperature may be estimated with the PVsyst model, where heat loss coefficients (U-values) denote the heat transfer capabilities of the PV system. In this work, cell temperatures and U-values for a small footprint FPV system with east-west orientation and a 15° tilt located in Sri Lanka are studied using both module temperature measurements and computational fluid dynamics (CFD) modelling. CFD modelling allows for investigating the influence of both wind speed and direction on cell temperatures, as well as to look at the distribution of cell temperatures within the system under different wind conditions. Calculations based on measurements give Uc = 22.6 W/m2K and Uv = 4.9 Ws/m3K and correlate well with CFD calculations. We also show that wind direction, system configuration and sensor placement influence the estimated U-values, complicating the use of tabulated values for any given technology.

2 April 2025 in Solar Energy
Verified
Journal Article
Open access
VNVilde Stueland Nysted
Vilde Stueland Nysted
LSLars Einar S. Stieng
Lars Einar S. Stieng
MKManish Kumar
Manish Kumar
NRNathan Roosloot
Nathan Roosloot
GOGaute Otnes
Gaute Otnes
JSJosefine Selj
Josefine Selj

24 March 2025 in IEEE Journal of Photovoltaics
Verified
Journal Article
Closed access
HWHarsha Lakmal Walpita
Harsha Lakmal Walpita
NRNathan Roosloot
Nathan Roosloot
GOGaute Otnes
Gaute Otnes
BABjørn L. Aarseth
Bjørn L. Aarseth
JSJosefine Selj
Josefine Selj
EMErik S. Marstein
Erik S. Marstein
Floating photovoltaic (FPV) systems are emerging as a promising solution to the scarcity of suitable land for ground-mounted solar PV (GPV) installations. By the end of 2022, global FPV capacity reached 5.7 GWp following a remarkable compound annual growth rate of approximately 87.5% from 2015 to 2022. This growth introduces a significant new frontier for operation and maintenance (O&M) practices in the solar industry. As the industry matures and more FPV assets come under operation, the need for innovative, efficient, and environmentally sensitive O&M strategies becomes imperative. This review presents the existing information on the O&M of FPV systems, highlighting the unique challenges and opportunities that set FPV systems apart from conventional GPV installations. Through an examination of recent advancements, best practices, and areas requiring further research, this study aims to provide valuable insights for optimizing the performance and sustainability of FPV systems.

8 October 2025 in IEEE Journal of Photovoltaics
Verified
Journal Article
Closed access
VNVilde Stueland Nysted
Vilde Stueland Nysted
TKTorunn Kjeldstad
Torunn Kjeldstad
DLDag Lindholm
Dag Lindholm
MUMarit Sandsaunet Ulset
Marit Sandsaunet Ulset
JSJosefine Selj
Josefine Selj
Floating photovoltaics (FPVs) are gaining traction as a land-saving alternative to ground-mounted photovoltaics (GPV). A commonly cited advantage of FPVs is their potential for lower operating temperatures due to the cooling effect of water. However, existing literature shows that the thermal performance of FPV systems may not consistently exceed that of GPV systems, as it is influenced by technology and location. Consequently, studying the thermal properties of a range of FPV systems is crucial to optimize power output and enable accurate energy yield modeling for new sites. This work investigates the thermal properties and calculated heat loss coefficients, or U-values, associated with the Faiman model for an FPV system using Ciel & Terre's Hydrelio Air floats, located in a pond in South Africa. A dependence of U-values on wind direction was observed, with improved cooling when the wind approaches from the rear side of the system. The estimated U-value components were U0 = 21.6 W/m2·K and U1 = 3.60 W·s/m3·K for wind from the front and U0 = 19.4 W/m2·K and U1 = 7.10 W·s/m3·K for wind from the rear side. The impact of the observed cooling variation due to wind direction on system performance was also evaluated, revealing a 1.7% increase in median performance ratio when the wind originates from the rear side.