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Wind energy is a field with a large number of uncertainties. The random nature of the weather conditions, including wind speed, wind direction, and turbulence intensity, influences the energy output and the structural safety of a wind farm, making its performance fluctuate and difficult to predict. The uncertainties presented in the energy output and structure lifetime lead to increased investment risk. There are possibilities to reduce the risk associated with these uncertainties by optimizing the design of the farm or the wind turbine, with respect to the stochastic parameters. The goal of this project is to improve the wind farm optimization problem by providing accurate and computationally efficient annual energy production (AEP) estimates, which is a uncertainty quantification that is required in every optimization step. Uncertainty quantification has been recognized as a challenge in the wind energy industry, as the chaotic nature of the weather condition complicates the prediction of energy production. High-fidelity wind farm models usually employ advanced models like Large Eddy Simulation or Reynolds averaged Navier-Stokes equation for better accuracy. However, the prolonged computation time of these high-fidelity models make the traditional uncertainty quantification approach like the Monte-Carlo simulation or other integration techniques infeasible for larger wind farms. To overcome this limitation, the report proposes the use of generalized polynomial chaos expansion (PCE) to characterize the AEP as a function of wind speed and wind direction. PCE is a technique that approximates a random variable using a series of orthogonal polynomials, the polynomials are chosen based on the target distribution. This report explains how a surrogate model of the AEP can be constructed using PCE, which can be used in optimization or model analysis. The objective of the thesis work is to minimize the number of model evaluations required for obtaining an accurate energy response surface. Different ideas of non-intrusive PCE are implemented and explored in this project. The report demonstrates that, the multi-element polynomial chaos fitted by point collocation, with a dependent polynomial basis, is not only able to make accurate and stable (with respect to the placement of the measurements) energy predictions, but also produces realistic energy response surface. Vindkraft är en bransch med många osäkerheter, där väderförhållandena påverkar energiproduktionen och strukturens livslängd. Denna osäkerhet ökar investeringsrisken, men kan minskas genom optimering av vindkraftverkets design med hänsyn till de stokastiska parametrarna. Syftet med denna rapport är att förbättra optimeringsproblemet för vindkraftverk genom att ge noggranna och effektiva årliga energiproduktionsberäkningar (AEP), vilket krävs vid varje optimeringssteg. I rapporten används polynomial chaos expansion (PCE) för att approximera AEP och minska antalet nödvändiga modellutvärderingar. Resultaten visar att PCE är en effektiv metod för att göra energiprognoser.

In this study, the local similarity theory functions were calculated with two different approaches and on the other hand the mean hub height wind speed was compared with the rotor equivalent wind speed. Both calculations are based on two independent data-sets from measurement campaigns Hornamossen and Ryningsnäs which were conducted in the south of Sweden between May 2015 and June 2017, and November 2010 and February 2012. The first campaign includes measurements between 100 and 173 m and the second 98 and 138 m. In general, the aims were to validate if the results with reference functions and to compare the results from both approaches. The local similarity theory was used, because well above the ground, the assumption of a constant flux layer typically does not hold especially in the stable boundary layer. The used approaches are the flux-gradient and Richardson number formulation. Based on those, the non-dimensional universal functions for momentum and heat could be calculated and those could be presented as functions of the stability parameter. As shown in this study, the scatter the Richardson number formulation results are significant smaller compared to the flux-gradient formulation. One reason can be that the stability parameter and the universal functions for momentum and heat depend solely on the Richardson number. Despite the higher scatter, the medians of the universal function for momentum based on the flux-gradient formulations for both data-sets agree also with the references. Furthermore, for the results of the universal function for heat based on the flux-gradient formulation agree with the references if the minimum limit for the kinetic heat flux is significantly higher than for the universal function for momentum. Furthermore, in the publication from England & McNider 1995, who derived the Richardson number formulation, includes two erroneous equations for stable stratification. One of them has a tipping error and the other was incorrectly derived. Thus, the corrected equations are presented in this work. This work also presents new equations which are not based on the assumption that the constants of the empirical formulation for the universal function for momentum and heat with the same value. A comparison of the old and new equations show for a generated Richardson number vales a agreement of the results over the defined Richardson number range. Finally, in the wind industry it is a common practice to use the mean wind speed at the hub height as the representative mean wind speed over the entire rotor swept area. However, this assumption differs increasingly from the reality, because turbine sizes increase constantly. Thus, in this study, this common method is compared with another averaging concept. Hence, the work focuses on a area-weighted mean wind speed which is called the rotor equivalent wind speed. This average gives a better estimation of the existing wind field because it is based on multiple measurements at various heights. Since the wind gradient changes with height, those two velocities are plotted as functions of the same stability parameter as above. The main results in unstable stratification are that the hub height wind speed underestimates the rotor equivalent wind speed by about 1 to 1.5 %. In stable stratification the results vary: Two calculations show a overestimates by about 1 % and another shows no difference between those averages. Hence, the conclusion based on those findings are that the hub height wind speed is a source for a higher modelling uncertainty. On the contrary, the rotor equivalent wind speed gives more accurate modelling results. I denna studie beräknades de lokala likhetsteorifunktionerna med två olika tillvägagångssätt och å andra sidan jämförs genomsnittliga vindhastigheten vid navhöjden med rotorekvivalent vindhastigheten. Beräkningarna är baserad på två oberoende datamängder från mätningskampanjer Hornamossen och Ryningsnäs som genomfördes i södra Sverige mellan maj 2015 och juni 2017 och november 2010 och februari 2012. Första kampanj innehåller mätningar mellan 100 och 173 m och den andra 98 och 138 m. Generellt var målet att validera resultaten med referensfunktioner och jämföra både tillvägagångssätt med varandra. Lokala likhetsteorinen används eftersom för mätningar långt över marken håller antagandet om ett konstant flödesskikt vanligtvis inte. Det gäller särskilt i det stabila gränsskiktet. De två tillvägagångssätten är flödesgradientförhållandet och Richardson-talformuleringen. Baserade på de formuleringarna kan de icke-dimensionella universella funktionerna för momentum och värme beräknas och de visas som en funktion av stabilitetsparametern. I denna studie visas att spridningen av Richardsons talformuleringsresultat är signifikant mindre jämfört med andra metoden. En anledning är att stabilitetsparameter och både universella funktioner beror endast på Richardson tal. Trots den högre spridningen överensstämmer medianerna för den universella funktionen för momentum baserat på flödesgradientformuleringarna med referenserna. Detsamma gäller för resultaten av den universella funktionen för värme baserat på flödesgradientformuleringen om minimigränsen om kinetiska värmeflödet är betydligt högre än för den universella funktionen för momentum. Dessutom innehåller publikationen från England & McNider 1995, som innehåller härledning av Richardson talformulering, två felaktiga ekvationer för stabila gränsskiktet. En av dem har ett tippfel och den andra var felaktigt härledd. Detta arbete presenteras de korrigerade ekvationerna. Dessutom presenteras en uppsättning nya ekvationer där de konstanterna av den empiriska formuleringen för den universella funktionen för momentum och värme inte antas att har samma värde. Slutligen är det i vindindustrin en vanlig praxis att använda den genomsnittliga vindhastigheten vid navhöjden som den representativa medelvindhastigheten för hela "rotor swept area". Turbinstorlekarna ökar dock ständigt och därför får skillnaden mellan realitet och beräkningen alltid större. Således fokusera denna studien en areaviktad medelvindhastighet som heter rotorekvivalent vindhastighet. Den beräknar medelvindhastigheten med ett mindre osäkerhet eftersom den är baserad på flera vindmätningar på olika höjder. På grund av ett ojämt vindgradient i gränsskiktet visas resulten som funktion av densamma stailitetsparameter från likhetsteorien. Huvudresultaten för instabil gränskiktet är att navhöjdens vindhastigheten underskattar rotorekvivalent vindhastigheten med cirka 1 till 1,5 %. För det stabila gränskiktet finns olika resultaten: Två beräkningar visar att navhöjdens vindhastigheten överskattningar rotorekvivalent vindhastigheten med ungefär 1 % och en beräkning visa inget skillnad mellan medelvärdarna. Slutsatsen är att navhöjdens vindhastigheten är ett källa till ett högre modelleringsosäkerhet. Däremot visades att användningen av rotorekvivalent vindhastigheten leda till ett bättre prognosresultat. In dieser Studie wurde einerseits die lokale ähnlichkeitstheorie mit zwei unterschiedlichen Ansätzen berechnet und andererseits die durchschnittliche Nabenhöhen- mit der rotor-äquivalenten Windgeschwin- digkeit verglichen. Dafür standen zwei unabhängige Datensätze zur Verfügung, welche Messwerte zwischen 98 und 173 m beinhalteten. Die Messungen wurden in Südschweden durch die Messtürme Hornamossen und Ryningsnäs in den Zeiträumen von Mai 2015 bis Juni 2017 und von November 2012 bis Februar 2012 erhoben. Das Ziel dieser Studie war es, die Ergebnisse aus den Berechnungen mit Referenzfunktionen zu validieren und den ausgewählten Ansätzen zu vergleichen. Für Messungen mit mehr als 100 m über der Erdoberfläche ist die lokale ähnlichkeitstheorie anstelle der ähnlichkeitstheorie basierend auf der konstanten Flussschicht besser geeignet, da letztere von einem konstanten Wert ausgeht. Die Ansätze, die hierfür verwendet wurden, sind die „Flux-Gradient Formulation“ und die „Gradient Richardson Number Formulation“. Mit beiden kann die universelle Impuls- und Wärmefunktion berechnet und als Funktion des Stabilitätsparameters dargestellt werden. Wie diese Studie zeigt, ist die Streuung um die Referenzkurven sehr klein für die „Gradient Richardson Number“ Ergebnisse im Vergleich zur „Flux-Gradient Formulation“. Dies liegt daran, dass sowohl der Stabilitätsparameter und die universellen Impuls- und Wärmefunktion nur von der Richardson-Zahl abhängen. Trotz der höheren Streuung für die „Flux-Gradient Formulation“ stimmen die Mediane der universellen Impulsfunktionen von beiden Datensätzen und die Referenzkurven überein. Das Gleiche gilt für die Ergebnisse der universellen Wärmefunktion basierend auf der „Flux-Gradient Formulation“, wenn der Mindestwert für den kinetischen Wärmefluss signifikant größer ist als für die universelle Impulsfunktion. Ausgangspunkt ist die Veröffentlichung von England & McNider 1995, welche die „Gradient Richardson Number Formulation“ dargestellt haben. Diese enthält zwei fehlerhafte Gleichungen, wovon eine einen Tippfehler aufweist und die andere auf einer fehlerhaften Herleitung basiert. Diese Arbeit stellt daher ebenso die korrigierten Gleichungen dar. Zusätzlich werden neue Gleichungen vorgestellt, bei denen nicht angenommen wird, dass die von England & McNider angenommenen Konstanten der empirischen Funktionen für die universelle Impuls- und Wärmefunktion den gleichen Wert haben. In der Windindustrie ist es üblich, dass die durchschnittliche Nabenhöhen-Windgeschwindigkeit als Durchschnittsgeschwindigkeit für die gesamte „rotor swept area“ angenommen wird. Diese Annahme weicht immer mehr von der Realität ab, weil Windkraftwerke kontinuierlich größer werden. Daher wird in dieser Arbeit auf eine flächengewichtete mittlere Windgeschwindigkeit mit der Bezeichnung Rotor-äquivalente Windgeschwindigkeit gearbeitet. Diese produziert realistischere Durchschnittswerte, weil sie Messungen von mehreren vertikal verteilten Messpunkten einbezieht. Aufgrund des sich verändernden Windgradientens in der Grenzschicht wird die Abweichung zwischen diesen beiden Geschwindig- keiten als Funktion der Schichtungsstabilität dargestellt. Die zentralen Ergebnisse dieser Studie zeigen zusammenfassend, dass bei labiler Schichtung die Nabenhöhen-Windgeschwindigkeit die Rotor-äquivalente Windgeschwindigkeit um etwa 1 % bis 1.5 % unterschätzt. Für die stabile Schichtung unterscheiden sich die Ergebnisse: Zwei Berechnungen zeigen, dass die Nabenhöhen-Windgeschwindigkeit die Rotor-äquivalente Windgeschwindigkeit um ca. 1 % überschätzt und eine andere Berechnung zeigt keinen Unterschied zwischen den Mittelwerten. Daraus kann gefolgert werden, dass die Nabenhöhen-Windgeschwindigkeit eine höhere Fehlerquelle aufweist. Im Gegensatz dazu liefert die rotor-äquivalente Windgeschwindigkeit genauere Prognosewerte.

This chapter examines how evolutionary and institutional economic theory can improve our understanding of the politico-economic dynamics of the green transition. The authors focus on how path dependency in technological systems perpetuate and reward unsustainable business practices, while mission-oriented policy programs can break the feedback loops that keep the trajectory in place. Significantly, policy programs creating sizable markets for renewable energy have generated sufficient learning curves to move renewable energy sources within the cost range of fossil fuels, thereby enabling private profit incentives to accelerate the transition in our immediate future. These gains have depended on managerial decisions to co-evolve their businesses with the institutional environment shaped by policymaking despite uncertainty of technological progress, market evolution, and political credibility. We explore the case of how the Danish energy company Dong Energy was transformed from a fossil fuel company to the world’s leading offshore wind developer. These dynamics point to the need to create markets through political institutions for the coming generations of sustainable technologies to enable potential gains from learning, network effects, and economies of scale to be identified and exploited.

Uppsala universitet Campus Gotland producerar årligen en sammanställning av svensk forskning om vindkraft i serien Ny och pågående forskning om vindkraft i Sverige. Syftet med dessa publikationer är att intresserade ska få en lättillgänglig överblick av vad som skett under året inom vindkraftsforskningen i landet. Sammanställningen är indelad i två avsnitt. Det första är en presentation av de forskningsprogram och forskningscentra som är verksamma inom vindkraftsforskning i Sverige med fokus på deras pågående projekt. Därefter följer en ämnesindelad förteckning över publicerad forskning om vindkraft under aktuellt år vid svenska universitet, högskolor och institutioner. Där ingår vetenskapliga artiklar och rapporter, doktors- och licentiatavhandlingar samt uppsatser på kandidat-, magister- och mastersnivå samt sammanfattningar med statistik och jämförelser med tidigare år. The Node for education and competence in the National network for wind utilization annually publishes a summary of new and ongoing wind power research in Sweden. The aim of this summary is to provide an easily accessible overview of what is happening annually in wind power research for interested parties. This compilation is divided into two sections. The first is a presentation of the research centres and research programmes active in wind power research in Sweden. Then a topic-based list of the wind power research published in 2019 follows where at least one of the authors is active at a Swedish university. Here one also can find doctoral and licentiate theses as well as theses at bachelor and master levels that have been published during the year. Noden för Utbildning- och kompetensfrågor finns vid Vindenergigruppen på Uppsala universitets Campus Gotland Nätverket för vindbruk

This study uses a unique set of hourly wind speed data observed over a period of 16 years to quantify the potential of collective offshore wind power production. We address the well-known intermittency problem of wind power for five locations along the Norwegian continental shelf. Mitigation of wind power intermittency is investigated using a hypothetical electricity grid. The degree of mitigation is examined by connecting different configurations of the sites. Along with the wind power smoothing effect, we explore the risk probability of the occurrence and duration of wind power shutdown due to too low or high winds. Typical large-scale atmospheric situations resulting in long term shutdown periods are identified. We find that both the wind power variability and the risk of not producing any wind power decrease significantly with an increasing array of connected sites. The risk of no wind power production for a given hour is reduced from the interval 8.0 %–11.2 % for a single site to under 4 % for two sites. Increasing the array size further reduces the risk, but to a lesser extent. The average atmospheric weather pattern resulting in wind speed that is too low (too high) to produce wind power is associated with a high-pressure (low-pressure) system near the production sites.

Som et resultat av en stadig økende etterspørsel, opplever oppdrettsnæringen utfordringer i forbindelse med sykdom, tilgjengelig areal og miljøkonsekvenser i områdene de etableres i. På bakgrunn av dette åpnet Fiskeridepartementet i 2015 for at bedrifter kunne søke om utviklingskonsesjon for særlig bekostede og innovative oppdrettsteknologier. Roxel Aqua søkte i 2017 om utviklingskonsesjon til å fremstille deres forslag, Octopus. Octopus benytter en jackup-rigg som forsyningsbase til et offshore oppdrettsanlegg som dermed kan etableres utenfor kysten. Som en konsekvens av oppdrettsanleggets offshoreplassering, vil det oppstå utfordringer i forbindelse med miljøvennlig konsumering av energi, da jackup-rigger forbruker energi fra dieselaggregat. Fornybar energiteknologi montert på oppdrettsanlegg er for tiden svært aktuelt, og det har derfor vært ønskelig å implementere denne teknologien på Octopus. På bakgrunn av dette er det beregnet at et oppdrettsanlegg bestående av 12 merder og 60 m2 bruksareal, vil ha et årlig energibehov på 339 080 kWh. Ved hjelp av sol- og vindenergi vil energiproduksjonen kunne variere mellom 22% og til tider mer enn det dobbelte av energibehovet. Den teknologiløsningen som gir høyest andel lokalprodusert fornybar energi, er kombinasjonen av solenergi og vindturbinmodell med 100 kW installert effekt. Sammen vil disse produsere i overkant av energibehovet til anlegget, med unntak av mars. Av teknologiene med lavest klimaavtrykk er det landstrøm og kombinasjonen av sol- og vindenergi med 100 kW installert effekt som gir lavest utslipp gjennom teknologienes livssyklus. I vurderingen av økonomi er det landstrøm som oppgis med lavest investeringskostnad, men dette vil avhenge av avstanden mellom Octopus og tilkoblingspunkt med nødvendig infrastruktur på land. Landstrøm vil også ha en årlig utgiftspost i forbindelse med forbruk av elektrisk strøm fra strømnettet. Teknologikombinasjonen solenergi og 100 kW installert vindeffekt vil i følge beregningene ha en investeringskostnad større enn landstrøm, men den forbrukte energien vil i dette tilfelle være egenprodusert og dermed kostnadsfri. As a result of an increasing demand, the aquaculture industry is experiencing challenges due to fish disease, available area and environmental impacts in the established areas. In view of this, The Norwegian Ministry of Fisheries opened in 2015 to allow companies to apply for a development license for particularly costly and innovative farming technologies. In 2017, Roxel Aqua applied for a development license to present their suggestion, Octopus. Octopus uses a jackup rig as a supply base for an offshore fish farm. As a consequence of the facility's offshore location, environmentally friendly consumption of energy will become a challenge, as jackup rigs consume energy from diesel aggregates. Renewable energy technology installed on fish farms is currently very relevant, and it has therefore been desirable to implement this technology on Octopus. Based on this, it is estimated that an aquaculture plant consisting of 12 fish cages and 60 m2 of utility area will have an annual energy requirement of 339 080 kWh. Using solar- and wind energy, the energy production on Octopus can vary between 22% and sometimes more than twice the energy requirement. The technology solution that provides the highest production of renewable energy is the combination of solar energy and wind turbine model with 100 kW installed power. Together, these will produce in excess of the energy requirement of the plant, with the exception of March. The technologies with the lowest climate footprint is power from onshore electricity grid, and the combination of solar and wind energy with 100 kW installed power. In the economical calculations, the connection to onshore electricity grid is stated with the lowest investment cost, but this will depend on the distance between Octopus and the connection point with the necessary infrastructure on land. The connection to onshore electricity grid will also have an annual expense item due to consumption of electricity from the electricity grid. The technology combination with solar energy and 100 kW installed wind power will, according to the calculations, have a higher investment cost than onshore electricity grid, but the energy consumption will in this case be self-produced and thus free of charge. M-FORNY

Denne masteroppgave undersøker om hvilke faktorer som påvirker den samfunnsøkonomiske lønnsomheten i Norge for vindenergi. Samtidig om vindenergien er konkurransedyktig forhold til oppgradert vannkraftverk. For å kunne undersøke dette benytter jeg Roan vindkraftverk, oppgradert Harpefossen vannkraftverk og oppgradert Øvre Vinstra vannkraftverk. Metoden som blir brukt for å løse problemstilling, blir det benyttet en samfunnsøkonomisk analyse. Det man kommer frem til er at faktorer som påvirker den samfunnsøkonomiske lønnsomheten for vindenergi er samfunn- og miljømessige virkninger, økonomiske virkninger som blir tatt med beregning av netto nåverdi, samt usikkerheten og risiko ved et prosjekt. Roan vindkraftverk er samfunnsøkonomisk lønnsomt, som gir en positiv netto verdi. Roan har lavere netto nåverdi enn oppgradert vannkraftverk. Det er ulike faktorer som påvirker lønnsomheten til vindkraft enn for et oppgradert vannkraftverk.

This paper is a result of the WOW project (Wind power On Wikipedia) which forms part of the SAPIENS (Scientometric Analyses of the Productivity and Impact of Eco-economy of Spain) project (Sanz-Casado et al. in Scientometrics 95(1):197–224, 2013). WOW is designed to observe the relationship between scholarly publications and societal impact or visibility through the mentions of scholarly papers (journal articles, books and conference proceedings papers) in the Wikipedia, English version. We determine (1) the share of scientific papers from a specific set defined by Wind Power research in Web of Science (WoS) 2006–2015 that are included in Wikipedia entries, named data set A; (2) the distribution of scientific papers in Wikipedia entries on Wind Power, named data set B, captured via the three categories for the topic Wind Power in the Wikipedia Portal: Wind Power, Wind turbines and Wind farms; (3) the distributions of document types in the two wiki entry data sets’ reference lists. In parallel the paper aims at designing and test indicators that measure societal impact and R&D properties of the Wikipedia, such as, a wiki reference focus measure; and a density measure of those types in wiki entries. The study is based on Web mining techniques and a developed software that extracts a range of different types of Wikipedia references from the data sets A and B. Findings show that in data set A 25.4% of the wiki references are academic, with a density of 17.62 academic records detected per wiki entry. However, only 0.62% of the original WoS records on Wind Power are also found as wiki references, implying that the direct societal impact through the Wikipedia is extremely small for Wind Power research. In the second Wikipedia set on Wind Power (data set B), the presence of scientific papers is even more insignificant (10.6%; density: 3.08; WoS paper percentage: 0.26%). Notwithstanding, the Wikipedia can be used as a tool informing about the transfer from scholarly publications to popular and non-peer reviewed publications, such as Web pages (news, blogs), popular magazines (science/technology) and research reports. Non-scholarly wiki reference types stand for 74.6% of the wiki references (data set A) and almost 90% in data set B. Interestingly, the few WoS articles in wiki entries on Wind Power present on average 34.3 citations received during the same period (2006–2015) as WoS Wind Power publications not mentioned in wiki entries only receives on average 5.9 citations. Owing to the scarcity of Wind Power research papers in the Wikipedia, it cannot be applied as a direct source in evaluation of Wind Power research. This is in line with other recent studies regarding other subject areas. However, our analysis presents and discusses six supplementary indirect indicators for research evaluation, based on publication types found in the wiki entry reference lists: share of (WoS) records; density; and reference focus, plus popular science knowledge export, non-scholarly knowledge export and academic knowledge export. The same indicators are direct measures of the Wikipedia reference properties. This paper is a result of the WOW project (Wind power On Wikipedia) which forms part of the SAPIENS (Scientometric Analyses of the Productivity and Impact of Eco-economy of Spain) project (Sanz-Casado et al. in Scientometrics 95(1):197–224, 2013). WOW is designed to observe the relationship between scholarly publications and societal impact or visibility through the mentions of scholarly papers (journal articles, books and conference proceedings papers) in the Wikipedia, English version. We determine (1) the share of scientific papers from a specific set defined by Wind Power research in Web of Science (WoS) 2006–2015 that are included in Wikipedia entries, named data set A; (2) the distribution of scientific papers in Wikipedia entries on Wind Power, named data set B, captured via the three categories for the topic Wind Power in the Wikipedia Portal: Wind Power, Wind turbines and Wind farms; (3) the distributions of document types in the two wiki entry data sets’ reference lists. In parallel the paper aims at designing and test indicators that measure societal impact and R&D properties of the Wikipedia, such as, a wiki reference focus measure; and a density measure of those types in wiki entries. The study is based on Web mining techniques and a developed software that extracts a range of different types of Wikipedia references from the data sets A and B. Findings show that in data set A 25.4% of the wiki references are academic, with a density of 17.62 academic records detected per wiki entry. However, only 0.62% of the original WoS records on Wind Power are also found as wiki references, implying that the direct societal impact through the Wikipedia is extremely small for Wind Power research. In the second Wikipedia set on Wind Power (data set B), the presence of scientific papers is even more insignificant (10.6%; density: 3.08; WoS paper percentage: 0.26%). Notwithstanding, the Wikipedia can be used as a tool informing about the transfer from scholarly publications to popular and non-peer reviewed publications, such as Web pages (news, blogs), popular magazines (science/technology) and research reports. Non-scholarly wiki reference types stand for 74.6% of the wiki references (data set A) and almost 90% in data set B. Interestingly, the few WoS articles in wiki entries on Wind Power present on average 34.3 citations received during the same period (2006–2015) as WoS Wind Power publications not mentioned in wiki entries only receives on average 5.9 citations. Owing to the scarcity of Wind Power research papers in the Wikipedia, it cannot be applied as a direct source in evaluation of Wind Power research. This is in line with other recent studies regarding other subject areas. However, our analysis presents and discusses six supplementary indirect indicators for research evaluation, based on publication types found in the wiki entry reference lists: share of (WoS) records; density; and reference focus, plus popular science knowledge export, non-scholarly knowledge export and academic knowledge export. The same indicators are direct measures of the Wikipedia reference properties.

Studien har vært en fortsettelse av fjorårsstudien til Steffen Aasen (2016), og har vært en del av REDWIN-prosjektet. REDWIN-prosjektet har som mål å redusere de høye kostnadene i offshore vindindustrien gjennom å ta i bruk bedre jordmodeller. Det har blitt brukt National Renewable Energy Labratory (NREL) sin 5 MW vindturbin og de samme karakteristikkene for havbunnen som i Offshore Code Collaboration (OC3)-prosjektet. I simuleringene ble det brukt det samme komprimerte diagrammet som i UpWind-prosjektet (Fisher et al. 2010), og utmattingsberegningene ble utført med Miner Palmgren. Fire forskjellige jordmodeller ble undersøkt for å se på effekten av demping i havbunnen. Modell 1 bruker kun en enkel stivhetsmatrise på havbunnen som ble utviklet av Passon (2006) for OC3-prosjektet. Modell 2 brukte den samme stivhetsmatrisen som Modell 1, men brukte også en rotasjonsfjær for å få med demping fra havbunnen. Modell 3 har blitt utviklet av NGI for REDWIN-prosjektet og er en kinetisk fastningsmodell. Modell 4 bruker p-y metoden som er industristandarden i dag. Studien har utført åtte simuleringer med jordmodellene uten retningsforskjell for å undersøke usikkerheten fra simuleringer med ulike bølgerealiseringer. Resultatene indikerte at delskaden synker med en økende demping fra havbunnen, spesielt i tilfeller hvor vindturbinen er parkert. Dette støtte under resultatene til Steffen Aasen. Mer demping fra havbunnen førte til mer stabile resultater med en mindre usikkerhet i den totale delskaden. Resultatene indikerte at mellom fem til åtte simuleringer var tilstrekkelig. Det har blitt sett på effekten av å simulere med en retningsforskjell mellom vind og bølger. Delskaden på monopælen og bunnen av tårnet var nesten den samme for en retningsforskjell opp til 30 grader, noe som kan begrunnes med at delskaden fordeler seg mer i tverrsnittet. En retningsforskjell på 60 og 90 grader førte til en betydelig større delskade. For monopælen økte delskaden med henholdsvis 67,2 % og 130,5 % i forhold til uten retningsforskjell. For bunnen av tårnet økte delskaden med henholdsvis 120,7 % og 228,1 % i forhold til uten retningsforskjell. For tilfellene der vindturbinen er parkert har retningsforskjellen liten effekt på delskaden. Dette kan forklares ved at det er lite aerodynamisk demping i disse tilfellene. Modell 3 er en ikke-lineær modell og kan derfor gi feil respons fra havbunnen når belastningen ikke kommer fra 0 grader på vindturbinen. En følsomhetsanalyse av denne modellen indikerte at den største feilen ved bruk av modellen fås når belastningene kommer fra 45 grader. Dette førte til maksimum feil på 4,1 %, 9,0 % og 2,3 % for henholdsvis monopælen, bunnen av tårnet og toppen av tårnet. For bladroten ga den ingen feil. Dette kan forklares med at de aerodynamiske kreftene dominerer og demping fra havbunnen betyr lite for delskaden her. This study is a continuation of last year’s masterthesis done by Steffen Aasen, and has been part of the REDWIN project. The REDWIN project was started due to high-cost in the offshore wind industry, and the goal is to reduce cost through a better soil-pile interaction model. A better soil-pile interaction model will give a more realistic response from the soil, which lead to a more optimally design and increased lifetime. M-IØ

A single pulsed Doppler wind lidar, deployed at the FINO1 platform in the North Sea, has been used to monitor the lateral and vertical coherence of the along-wind component. To maximize the sampling frequency of the monitoring system, a particular configuration based on small sweeping angles around the mean wind direction is used. The set-up provides wind velocity measurement with an increasing cross-flow separation with increasing distances from the lidar. We present hereby preliminary results from the analysis of the Plan Position Indicator scans carried out with a sampling frequency of 0.13 Hz, and the Range Height Indicator scans sampled at 0.19 Hz. The mean velocity and the turbulence intensity indicated a sufficiently uniform flow, which was verified by the calculation of the along and crosswind turbulence length scales. The lateral and vertical coherence was estimated based on multiple 10-minutes samples, for a mean wind velocity ranging from 10 to 14 ms􀀀1. For the conditions examined, the measured coherence showed a good agreement with the IEC model for low and medium cross-flow separations, and a fairly good agreement with the Frøya model for large separations. A single pulsed Doppler wind lidar, deployed at the FINO1 platform in the North Sea, has been used to monitor the lateral and vertical coherence of the along-wind component. To maximize the sampling frequency of the monitoring system, a particular configuration based on small sweeping angles around the mean wind direction is used. The set-up provides wind velocity measurement with an increasing cross-flow separation with increasing distances from the lidar. We present hereby preliminary results from the analysis of the Plan Position Indicator scans carried out with a sampling frequency of 0.13 Hz, and the Range Height Indicator scans sampled at 0.19 Hz. The mean velocity and the turbulence intensity indicated a sufficiently uniform flow, which was verified by the calculation of the along and crosswind turbulence length scales. The lateral and vertical coherence was estimated based on multiple 10-minutes samples, for a mean wind velocity ranging from 10 to 14 m s -1. For the conditions examined, the measured coherence showed a good agreement with the IEC model for low and medium cross-flow separations, and a fairly good agreement with the Frøya model for large separations.

The original publication is available at www.springerlink.com The paper reports the developments and citation patterns over three time periods of research on Renewable Energy generation and Wind Power 1995&-2011 in EU, Spain, Germany and Denmark. Analyses are based on Web of Science and incorporate journal articles as well as conference proceeding papers. Scientometric indicators include publication collaboration ratios, top-player distribution as well as citedness and correspondence analyses of citing publications, relative citation impact, distributions of top-cited as well as top-citing institutions and publication sources and cluster analysis of citing title terms to map knowledge export areas. Findings show an increase in citation impact for Renewable Energy and Wind Power research albeit hampered by scarcely cited conference papers. Although EU maintains its global top position in producing Renewable Energy and Wind Power research the developments of EU and German world shares as well as citation impact are negative during the most recent 7 year period. During the same time the citation impact of Spain and Denmark increase and place both nations among the top-ranking countries in Wind Power research. Spain is the only EU country that increases its world production share from 2000. China is currently ranked three after EU and USA in research output, however with a very low citation impact. Spain, Denmark and Germany each demonstrates distinct collaboration patterns and publication source and citation distribution profiles. More than half the citations to EU Wind Power research are EU-self citations. An expected intensified EU collaboration in the Wind Energy field does not come about. The most productive research institutions in Denmark and Spain are also the most cited ones. This research was funded by the Spanish Ministry of Economy and Competitiveness under the project CSO2010-21759-C02-01 titled "Análisis de las capacidades científicas y tecnológicas de la eco-economía en España a partir de indicadores cuantitativos y cualitativos de I+D+i"(Analysis of scientific and technological capacities of Eco-economy in Spain, throughout I+D+i quantitative and qualitative indicators), and by Carlos III University of Madrid-Banco de Santander Chairs of Excellence Program for 2011/2012 academic year. Publicado

Ocean winds in the Baltic Sea are expected to power many wind farms in the coming years. This study examines satellite Synthetic Aperture Radar (SAR) images from Envisat ASAR for mapping wind resources with high spatial resolution. Around 900 collocated pairs of wind speed from SAR wind maps and from 10 meteorological masts, established specifically for wind energy in the study area, are compared. The statistical results comparing in situ wind speed and SAR-based wind speed show a root mean square error of 1.17 m s−1, bias of −0.25 m s−1, standard deviation of 1.88 m s−1 and correlation coefficient of R2 0.783. Wind directions from a global atmospheric model, interpolated in time and space, are used as input to the geophysical model function CMOD-5 for SAR wind retrieval. Wind directions compared to mast observations show a root mean square error of 6.29° with a bias of 7.75°, standard deviation of 20.11° and R2 of 0.950. The scale and shape parameters, A and k, respectively, from the Weibull probability density function are compared at only one available mast and the results deviate ~2% for A but ~16% for k. Maps of A and k, and wind power density based on more than 1000 satellite images show wind power density values to range from 300 to 800 W m−2 for the 14 existing and 42 planned wind farms.

Increasing levels of wind power penetration in modern power systems has set intensively high standards with respect to wind turbine technology during the last years. Security issues have become rather critical and operation of wind farms as conventional power plants is becoming a necessity as wind turbines replace conventional units on the production side. This article includes a review of the basic control issues regarding the capability of the Doubly Fed Induction Generator (DFIG) wind turbine configuration to fulfill the basic technical requirements set by the system operators and contribute to power system security. An overview of ancillary services provided by wind turbine technology nowadays is provided, i.e. , fault ride-through capability, reactive power supply and frequency-active power control.

An analysis of flow tilt angles from a fetch-limited beech forest site with clearings is presented in the context of vertical advection of carbon dioxide. Flow angles and vertical velocities from two sonic anemometers by different manufacturers were analyzed. Instead of using rotations, where zero-flow angles were assumed for neutral flow, the data was interpreted in relation to upstream and downstream forest edges. Uncertainties caused by flow distortion, vertical misalignment and limited sampling time (statistical uncertainty) were evaluated and found to be highly significant. Since the attack angle distribution of the wind on the sonic anemometer is a function of atmospheric stratification, an instrumental error caused by imperfect flow distortion correction is also a function of the atmospheric stratification. In addition, it is discussed that the sonic anemometers have temperature dependent off-sets. These features of the investigated sonic anemometers make them unsuitable for measuring vertical velocities over highly turbulent forested terrain. By comparing the sonic anemometer results to that of a conically scanning Doppler lidar (Dellwik et al., 2010b), sonic anemometer accuracy for measuring mean flow tilt angles was estimated to between 2° and 3°. Use of planar fit algorithms, where the mean vertical velocity is calculated as the difference between the neutral and non-neutral flow, does not solve this problem of low accuracy and is not recommended. Because of the large uncertainties caused by flow distortion and vertical alignment, it was only possible to a limited extent to relate sonic anemometer flow tilt angles to upwind forest edges, but the results by the lidar indicated that an internal boundary layer affect flow tilt angles at 21m above the forest. This is in accordance with earlier studies at the site. Since the mean flow tilt angles do not follow the terrain, an estimate of the vertical advection term for near-neutral conditions was calculated using profile measurements of carbon dioxide. The estimated advection term is large, but it is not recommended to include it in the surface carbon balance, unless all terms in the carbon dioxide conservation equation can be precisely estimated.

We present a study on the characteristics of the sea breeze flow at a coastal site located in the centre of the Mediterranean basin at the southern tip of Italy. This study is finalized to add new data on breeze circulations over a narrow peninsula and present a unique experimental coastal site at about 600 m from the coastline in a flat open area at the foot of a mountain chain located in a region of complex orography. We study the seasonal behaviour of the sea-land breeze circulation by analysing two years of hourly data of wind speed and direction, temperature, radiation and relative humidity from a surface meteorological station, eighteen-months data from a wind profiler, and two-year data from the ECMWF analysis. Results show that breezes dominate the local circulation and play a major role for the local climate. They are modulated by the season, through the sea-land temperature difference and the large-scale flow. The large-scale forcing acts in phase with the diurnal breeze and opposes the nocturnal breeze. In summer, the daytime difference between the land surface temperature and the SST (Sea Surface Temperature) reaches its maximum, while the nigh-time difference has its minimum. This causes a strong, frequent and intense diurnal breeze and a weak nocturnal breeze. In winter and fall the nocturnal difference between the sea and land surface temperature reaches a maximum value, while the diurnal difference is at its minimum value. This causes a strong, frequent and intense nocturnal breeze despite of the large-scale forcing that is usually opposed to local-scale flow.

This work presents a method to determine flutter and divergence instability limits for a two-dimensional (2-D) airfoil section fitted with an actively controlled trailing edge flap. This flap consists of a deformable trailing edge, which deformation is governed by control algorithms based on measurements of either heave displacement, local angle of attack or aerodynamic pressure difference measured over the airfoil. The purpose of the controlled deformable flap is to reduce fluctuations in the aerodynamic forces on the airfoil, which, according to recent studies, have a significant potential for fatigue load alleviation. The structural model of the 2-D airfoil section contains three degrees of freedom: heave translation, pitch rotation and flap deflection. A potential flow model provides the aerodynamic forces and their distribution. The unsteady aerodynamics are described using an indicial function approximation. Stability of the full aeroservoelastic system is determined through eigenvalue analysis by state-space formulation of the indicial approximation. Validation is carried out against an implementation of the recursive method by Theodorsen and Garrick for flexure-torsion-aileron flutter. The implemented stability tool is then applied to an airfoil section representative of a wind turbine blade with active flap control. It is thereby observed that the airfoil stability limits are significantly modified by the presence of the flap, and they depend on several parameters: flap structural characteristics, type of control, control gain factors and time lag. Copyright © 2009 John Wiley & Sons, Ltd.

The present work contains an extension of the Beddoes–Leishman-type dynamic stall model. In this work, a deformable trailing-edge flap has been added to the dynamic stall model. The model predicts the unsteady aerodynamic forces and moments on an airfoil section undergoing arbitrary motion in heave, lead-lag, pitch, trailing-edge flapping. In the linear region, the model reduces to the inviscid model, which includes the aerodynamic effect of a thin airfoil with a deformable camberline in inviscid flow. Therefore, the proposed model can be considered a crossover between the work of Gaunaa for the attached flow region and Hansen et al. The model is compared qualitatively to wind tunnel measurements of a Riso/ B1-18 blade section equipped with deformable trailing-edge flap devices in the form of piezoelectric devices. Copyright © 2009 John Wiley & Sons, Ltd.

The goals are to compare lidar volume averaged wind measurement with point measurement reference sensors and to demonstrate the feasibility of performing 3D turbulence measurements with lidars. For that purpose three pulsed lidars were used in staring mode, placed so that their beams crossed close to a 3D sonic anemometer mounted at 78 m above the ground. The results show generally very good correlation between the lidar and the sonic times series, except that the variance of the velocity measured by the lidar is attenuated due to spatial filtering. The amount of attenuation can however be predicted theoretically by use of a spectral tensor model of the atmospheric surface-layer turbulence.

In seeking to advance the understanding of the production, diffusion and negotiation of meaning in and between organisations, we introduce below the notion of mise-en-sens. Mise-en-sens refers to the performing art term of mise-en-sce` ne and builds on the French term sens denoting meaning as well as direction. Starting from a qualitative analysis of how Swedish wind farm developers manage the permit-application process for their projects, we suggest in a first-order analysis that the activities of the developers consist in contextualising the project, ontologising it and neutralising criticism addressed to it. In a second-order analysis, we conceptualise these activities as a mise-en-sens. Miseen- sens spells out the way in which developers, as meaning managers, stage the project and provide it with direction. Having positioned mise-en-sens in relation to the notions of sensemaking and sensegiving, we suggest in conclusion that mise-en-sens could serve to describe not only the activity of wind farm developers but also, for example, that of project managers or entrepreneurs in general since they too are engaged in the management of mean (Less)

I denne masteroppgaven har meteorologiske data fra Kjøllefjord vindpark og data fra mesoskalamodellen WRF blitt analysert. Analyseperioden er fra mars 2007 til juni 2009. Innledende analyser utført av Kjeller Vindteknikk viste store hastighetsforskjeller mellom de to vindmålemastene i parken i måleperioden, og denne oppgaven skulle utforske om disse forskjellene kunne relateres til stabilitet eller grenselagshøyde. Målingene fra parken kunne ikke brukes til å beregne disse parametrene, derfor ble verdier fra mesoskalamodellen WRF benyttet. Simulerte verdier fra modellen ble også sammenlignet direkte med målinger fra parken, for å se om WRF klarte å gjenskape trendene i det observerte vindklimaet. Karakteriseringen av stabiliteten på Kjøllefjord, basert på beregnede verdier av Richardson-tallet, gav fordelingen 16,5 % : 48,1 % : 35,4 % (ustabil : nøytral : stabil). Uten observasjoner fra parken kunne ikke denne stabilitetsfordelingen valideres. Det har i oppgaven blitt valgt ut fem caseperioder som skulle analyseres nærmere. Disse periodene ble valgt ut fordi de representerte forskjellige stabilitetsforhold, sesonger og vindretninger. I hver caseperiode ble vindhastighet, vindretning, vindskjær og temperatur fra WRF sammenlignet med målinger fra hver av målemastene. WRF klarte tidvis å gi riktige verdier, men det var flere perioder med stor forskjell mellom modellen og målingene, spesielt for vindhastigheten og vindskjæret. Det skyldes trolig at terrengeffekter og overflateruhet på Kjøllefjord ikke er godt nok oppløst i modellen. I de fem caseperiodene ble også målinger av vindhastighet, vindskjær og turbulensintensitet fra de to mastene sammenlignet. Det ble funnet flere perioder med høyere vindhastighet i KVT-masten enn i Siemens-masten, disse periodene ble i stor grad karakterisert av vind fra sørvest, stabile forhold og lav grenselagshøyde. I periodene ble det også observert høyere turbulensintensitet i Siemens-masten. Periodene med høyest vind ved Siemens-masten hadde en større andel av vind fra vest og nordvest, og størst hyppighet av nøytral sjiktning. I disse periodene kan KVT-masten ligge i vake fra flere lokale topper. Hastighetsforskjeller gjennom hele måleperioden ble klassifisert ut fra stabiliteten fra WRF. Resultatene viste en større hyppighet av stabile forhold når det var høyest hastighet ved KVT-masten, men det var også stor hyppighet av nøytrale forhold. Hastighetsforskjellene gjennom hele måleperioden ble også klassifisert ut fra grenselagshøyden. Her viste resultatene en større hyppighet av lave grenselagshøyder ved høyest vindhastighet ved KVT-masten. Grenselagshøyden og stabiliteten i parken henger sammen, og fra resultatene har det ikke vært mulig å avgjøre hvilken faktor som påvirker hastighetsforskjellene mest og om samme trend kan observeres for andre retningssektorer enn sør og sørvest. M-MF

PhD thesis in Offshore technology

Two parallel experiments involving the evolution and runup of plunging solitary waves on a sloping bed were conducted: (1) a rigid-bed experiment, allowing direct (hot film) measurements of bed shear stresses, and (2) a sediment-bed experiment, allowing for the measurement of pore-water pressures, and for observation of the morphological changes. The two experimental conditions were maintained as similar as possible. The experiments showed that the complete sequence of the plunging solitary wave involves the following processes: Shoaling and wave breaking; Runup; Rundown and hydraulic jump; and Trailing wave. The bed shear stress measurements showed that the mean bed shear stress increases tremendously (with respect to that in the approaching wave boundary layer), by as much as a factor of 8, in the runup and rundown stages, and that the r.m.s. value of the fluctuating component of the bed shear stress is also affected, by as much as a factor of 2, in the runup and hydraulic jump stages. The pore-water pressure measurements showed that the sediment at (or near) the surface of the bed experiences upward-directed pressure gradient forces during the downrush phase. The magnitude of this force can reach values as much as approximately 30% of the submerged weight of the sediment. The experiments further showed that the sediment transport occurs in the sheet flow regime for a substantial portion of the beach covering the area where the entire sequence of the wave breaking takes place. The bed morphology is explained qualitatively in terms of the measured bed shear stress and the pressure gradient forces.

A NACA0015 airfoil section instrumented with an array of high frequency microphones flush-mounted beneath its surface was measured in the wind tunnel at LM Wind Power in Lunderskov. Various inflow speeds and angles of attack were investigated. In addition, a hot-wire device system was used to measure the velocity profiles and turbulence characteristics in the boundary layer near the trailing edge of the airfoil. The measured boundary layer data are presented in this report and compared with CFD results. A relative good agreement is observed, though a few discrepancies also appear. Comparisons of surface pressure fluctuations spectra are used to analyze and improve trailing edge noise modeling by the so-called TNO model. Finally, a pair of hot-wires were placed on each side of the trailing edge in order to measure the radiated trailing edge noise. However, there is no strong evidence that such noise could be measured in the higher frequency range. Nevertheless, low-frequency noise could be measured and related to the presence of the airfoil but its origin is unclear.

Wind turbines play a major role in the transformation from a fossil fuel based energy production to a more sustainable production of energy. Total-cost-of-ownership is an important parameter when investors decide in which energy technology they should place their capital. Modern wind turbines are controlled by pitching the blades and by controlling the electro-magnetic torque of the generator, thus slowing the rotation of the blades. Improved control of wind turbines, leading to reduced fatigue loads, can be exploited by using less materials in the construction of the wind turbine or by reducing the need for maintenance of the wind turbine. Either way, better total-cost-of-ownership for wind turbine operators can be achieved by improved control of the wind turbines. Wind turbine control can be improved in two ways, by improving the model on which the controller bases its design or by improving the actual control algorithm. Both possibilities have been investigated in this thesis. The level of modeling detail has been expanded as dynamic in ow has been incorporated into the control design model where state-of-the-art controllers usually assume quasi-steady aerodynamics. Floating wind turbines have been suggested as an alternative to ground-fixed wind turbines as they can be placed at water depths usually thought outside the realm of wind turbine placement. The special challenges posed by controlling a floating wind turbine have been addressed in this thesis. Model predictive control (MPC) has been the foundation on which the control algorithms have been build. Three controllers are presented in the thesis. The first is based on four different linear model predictive controllers where appropriate switching conditions determine which controller is active. Constraint handling of actuator states such as pitch angle, pitch rate and pitch acceleration is the primary focus of this controller. The wind turbine is a highly nonlinear plant and a gain scheduling or relinearizing model predictive controller forms the next step to improve performance compared to a linear controller. Finally, a nonlinear model predictive controller has been devised and tested under simplified conditions. At present, the nonlinear model predictive controller is however not expected to be an realistic option for real world application as the computation burden is to heavy to achieve real-time performance. This thesis is comprised of a collection scientific papers dealing with the various topics presented in this summary.

VirtuelGalathea3 yearly report for 2010 contains an update of results in the project during 2010. VirtuelGalathea3 (vg3.dk) is a project providing research-based educational material to upper secondary schools using input from the Galathea 3 expedition. The Galathea expedition took place from 11th August 2006 to 25th April 2007 (8 months). The ship ‘Vædderen’ sailed from Copenhagen and around the globe. Most of the 50 scientific projects took place on board, however several projects took place on land in various countries. In VirtuelGalathea3 the scientists from Galathea cooperate with skilled teachers in order to provide educational material across several disciplines with focus on the physical sciences. The homepage vg3.dk contains material which includes 3 new projects developed in 2010, plus 46 projects developed in 2007-2009, and 40 developed in the Satellite Eye project in 20062008. There are also near-real-time satellite images of several parameters and a large satellite images database archive from August 2006 to present day – updated every day. Furthermore many short videos and photos from the expedition are shown. Three documentary films on Galathea 3 ‘Jorden rundt med Galathea 3’ were shown on TV2 in July 2010 and an educational video ‘Den naturvidenskabelige metode’. These films and video are now available at vg3.dk. As of 13 January 2011 over 102.900 unique users have visited the web page with an average time of 2:35 minutes on the site since the opening in October 2008. There was an average of 7.500 users per month from September to December 2010. The number of new users in 2010 was 60.000 which is a strong increase since 2009. The number of unique visitors is more than doubled from year 2009 to 2010. Marketing effects were through Skolebogmesse 2010, two international conferences and a visit at the A.P. Møller high school in Schleswig. VirtuelGalathea3 yearly report for 2010 contains an update of results in the project during 2010. VirtuelGalathea3 (vg3.dk) is a project providing research-based educational material to upper secondary schools using input from the Galathea 3 expedition. The Galathea expedition took place from 11th August 2006 to 25th April 2007 (8 months). The ship ‘Vædderen’ sailed from Copenhagen and around the globe. Most of the 50 scientific projects took place on board, however several projects took place on land in various countries. In VirtuelGalathea3 the scientists from Galathea cooperate with skilled teachers in order to provide educational material across several disciplines with focus on the physical sciences. The homepage vg3.dk contains material which includes 3 new projects developed in 2010, plus 46 projects developed in 2007-2009, and 40 developed in the Satellite Eye project in 2006- 2008. There are also near-real-time satellite images of several parameters and a large satellite images database archive from August 2006 to present day – updated every day. Furthermore many short videos and photos from the expedition are shown. Three documentary films on Galathea 3 ‘Jorden rundt med Galathea 3’ were shown on TV2 in July 2010 and an educational video ‘Den naturvidenskabelige metode’. These films and video are now available at vg3.dk. As of 13 January 2011 over 102.900 unique users have visited the web page with an average time of 2:35 minutes on the site since the opening in October 2008. There was an average of 7.500 users per month from September to December 2010. The number of new users in 2010 was 60.000 which is a strong increase since 2009. The number of unique visitors is more than doubled from year 2009 to 2010. Marketing effects were through Skolebogmesse 2010, two international conferences and a visit at the A.P. Møller high school in Schleswig.

Taylor’s frozen turbulence hypothesis is tested in its applicability for wind turbine applications. In this research full field measurements are performed at a test site for multi-megawatt wind turbines by means of a pulsed LIDAR with a scanning device. The system is installed at the top of the nacelle of a 5MW wind turbine. It provides simultaneous wind speed, with a maximum sampling rate of 5 Hz, at different stations parallel to the mean wind. Measurements in a range between 0.4 and 1.6 rotor diameter are performed following several two and three dimensional trajectories. The spectral characteristics of measurements taken simultaneously at different separation distances are studied. The scanning strategy which maximizes the wavenumber region where results are consistent with Taylor’s hypothesis is assessed. The best results are achieved by a horizontal sliding trajectory with valid wavenumbers up to 0.125 rad/m.

System imbalance due to power fluctuation is the first concern of power grid with large scale wind power integration. Traditional studies are limited in time domain, where the modeling is not convenient enough. In this paper, a model based on frequency domain is proposed. This model is more precise, and capable to take some important factors, such as the layout of wind farm, into account. This paper also presents a fast engineering implementation of this model, which can be applied on different power system studies. The case studies show this model can perfectly evaluate the ramp rate and reserve requirement of power systems, no matter under normal or extreme weather condition, therefore the validity and flexibility of this model get proved.

The power curve of a wind turbine is the primary characteristic of the machine as it is the basis of the warranty for it power production. The current IEC standard for power performance measurement only requires the measurement of the wind speed at hub height and the air density to characterise the wind field in front of the turbine. However, with the growing size of the turbine rotors during the last years, the effect of the variations of the wind speed within the swept rotor area, and therefore of the power output, cannot be ignored any longer. Primary effects on the power performance are from the vertical wind shear and the turbulence intensity. The work presented in this thesis consists of the description and the investigation of a simple method to account for the wind speed shear in the power performance measurement. Ignoring this effect was shown to result in a power curve dependant on the shear condition, therefore on the season and the site. It was then proposed to use an equivalent wind speed accounting for the whole speed profile in front of the turbine. The method was first tested with aerodynamic simulations of a multi-megawatt wind turbine which demonstrated the decrease of the scatter in the power curve. A power curve defined in terms of this equivalent wind speed would be less dependant on the shear than the standard power curve. The equivalent wind speed method was then experimentally validated with lidar measurements. Two equivalent wind speed definitions were considered both resulting in the reduction of the scatter in the power curve. As a lidar wind profiler can measure the wind speed at several heights within the rotor span, the wind speed profile is described with more accuracy than with the power law model. The equivalent wind speed derived from measurements, including at least one measurement above hub height, resulted in a smaller scatter in the power curve than the equivalent wind speed derived from profiles extrapolated from measurements at hub height and below only. It is well established that the turbulence intensity also influences the power performance of a wind turbine. Two ways of accounting for the turbulence were tested with the experimental data: an adaptation of the equivalent wind speed so that it also accounts for the turbulence intensity and the combination of the equivalent wind speed accounting for the wind shear only with the turbulence normalising method for turbulence intensity suggested by Albers. The second method was found to be more suitable for normalising the power curve for the turbulence intensity. Using the equivalent wind speed accounting for the wind shear in the power performance measurement was shown to result in a more repeatable power curve than the standard power curve and hence, in a better annual energy production estimation. Furthermore, the decrease of the scatter in the power curve corresponds to a decrease of the category A uncertainty in power, resulting in a smaller uncertainty in estimated AEP.

Results are summarised for the project "Improved design for large wind turbine blades (Phase 4)", partially supported by the Danish Energy Agency under the Ministry of Climate and Energy through the EUDP journal no.: 33033-0267. The aim of the project was to develop new and better design methods for wind turbine blades, so that uncertainties associated with damage and defects can be reduced. The topics that are studied include buckling-driven delamination of flat load-carrying laminates, cracking along interfaces in material joints (fracture mechanical characterisation and modelling), cyclic crack growth with large scale bridging and the use of cohesive laws in finite element programmes for simulating wind turbine blade failure. An overview is given of the methods and the major research results of the project. The implementation of the knowledge in the industry is discussed. Finally, some ideas for future research activities are considered.

The purpose of wind turbines and their predecessors the windmill, is to convert the energy in the wind to usable energy forms. Whereas windmills of the past focused on the conversion of wind power to torque for grinding, pumping and winching, modern wind turbines convert the wind energy into electric power. They do so through incorporation of generators, which convert mechanical torque into electricity. Wind turbines are designed to keep the overall cost per produced Kilo Watt hour as low as possible. One way of improving the performance and lifetime of the wind turbine is through active flow control. Active control is often considered costly but if the lifespan of the components can be increased it could be justifiable. This thesis covers various aspects of ‘smart control’ such as control theory, sensoring, optimization, experiments and numerical modeling.

This thesis includes the results of a PhD study about complex terrain and wind lidars. The study mostly focuses on hilly and forested areas. Lidars have been used in combination with cups, sonics and vanes, to reach the desired vertical measurement heights. Several experiments are performed in complex terrain sites and the measurements are compared with two different flow models; a linearised flow model LINCOM and specialised forest model SCADIS. In respect to the lidar performance in complex terrain, the results showed that horizontal wind speed errors measured by a conically scanning lidar can be of the order of 3-4% in moderately-complex terrain and up to 10% in complex terrain. The findings were based on experiments involving collocated lidars and meteorological masts, together with flow calculations over the same terrains. The lidar performance was also simulated with the commercial software WAsP Engineering 2.0 and was well predicted except for some sectors where the terrain is particularly steep. Subsequently, two experiments were performed in forested areas; where the measurements are recorded at a location deep-in forest and at the forest edge. Both sites were modelled with flow models and the comparison of the measurement data with the flow model outputs showed that the mean wind speed calculated by LINCOM model was only reliable between 1 and 2 tree height (h) above canopy. The SCADIS model reported better correlation with the measurements in forest up to ∼6h. At the forest edge, LINCOM model was used by allocating a slope half-in half out of the forest based on the suggestions of previous studies. The optimum slope angle was reported as 17º. Thus, a suggestion was made to use WAsP Engineering 2.0 for forest edge modelling with known limitations and the applied method. The SCADIS model worked better than the LINCOM model at the forest edge but the model reported closer results to the measurements at upwind than the downwind and this should be noted as a limitation of the model. As the general conclusion of the study, it was stated that the lidars can be used in complex terrain with the known limitations and the support of flow models.