This research delves into the complex interplay between wind turbine operations and bat conservation efforts, focusing on mitigating bat mortality caused by wind turbines in France. Despite comprehensive legal safeguards and conservation measures, bat fatalities remain a pressing concern, necessitating innovative solutions to reconcile environmental protection with energy production. The problem statement revolves around the challenge of optimising bat curtailment plans to minimise bat mortality while mitigating energy losses. With over 80% of bat species in France affected by wind turbine collisions, the urgency of this issue is underscored by the significant ecological implications and regulatory imperatives. Despite the existence of curtailment plans, there is a lack of comprehensive understanding regarding their effectiveness and potential trade-offs. This problem warrants a Master’s thesis project due to its multifaceted nature and practical implications. It requires a nuanced understanding of bat behaviours, wind turbine operations, and regulatory frameworks, making it both intellectually stimulating and socially relevant. Previous efforts have largely focused on static curtailment plans, leaving room for exploration of dynamic approaches and optimisation strategies. The methodology employed in this study involves the development of a Power BI tool and key performance indicators (KPIs) to evaluate different curtailment plans. Through comparative analysis, insights are gained into the efficacy of static versus dynamic curtailment plans, as well as the influence of weather conditions, such as rain, on curtailment decisions. Additionally, sensitivityanalysis is conducted to identify the most influential parameters and optimise curtailment plans accordingly. The key results of this study demonstrate the superiority of dynamic curtailment plans in reducing energy losses while maintaining sufficient protection for bat activity (higher than the 90% protection rate required by law) compared to static approaches (50% reduction in losses over an entire curtailment season). Insights gleaned from sensitivity analysis highlight the critical parameters influencing energy losses, informing targeted modifications to curtailment plans. Furthermore, the study underscores the importance of considering continuous variables, such as humidity, and site-specific factors, such as sunrise and sunset times, for more precise conservation strategies. The implications of this research extend beyond academia, informing policy-making and industry practices in wind energy and biodiversity conservation. By optimizing curtailment plans, stakeholders can achieve a balance between environmental protection and renewable energy generation, paving the way for sustainable development. Future research avenues include refining curtailment strategies based on continuous variables and conducting field studies to validate findings across diverse wind farm locations. / Denna forskning utforskar det komplexa samspel mellan vindkraftverkens drift och fladdermusbevarande insatser, med fokus på att mildra fladdermusdödlighet orsakad av vindkraftverk i Frankrike. Trots omfattande lagliga skydd och bevarandeåtgärder förblir fladdermusdödsfall ett påtagligt bekymmer, vilket kräver innovativa lösningar för att förena miljöskydd med energiproduktion. Problemformuleringen kretsar kring utmaningen att optimera fladdermusbegränsningsplaner för att minimera fladdermusdödlighet samtidigt som energiförluster mildras. Med över 80% av fladdermusarterna i Frankrike påverkade av kollisioner med vindkraftverk, understryks brådskan i detta ärende av dess betydande ekologiska konsekvenser och reglerande krav. Trots att begränsningsplaner existerar, finns det en brist på en heltäckande förståelse för deras effektivitet och potentiella avvägningar. Detta problem motiverar ett magisterprojekt på grund av dess mångfacetterade natur och praktiska konsekvenser. Det kräver en nyanserad förståelse för fladdermusars beteenden, vindkraftverks drift och reglerande ramar, vilket gör det både intellektuellt stimulerande och socialt relevant. Tidigare insatser har i stor utsträckning fokuserat på statiska begränsningsplaner och lämnat utrymme för utforskning av dynamiska tillvägagångssätt och optimeringsstrategier. Metoden som används i denna studie innefattar utvecklingen av ett Power BI-verktyg och nyckelprestationsindikatorer för att utvärdera olika begränsningsplaner. Genom jämförande analys får man insikter om effektiviteten hos statiska jämfört med dynamiska begränsningsplaner, samt påverkan av väderförhållanden, såsom regn, på begränsningsbeslut. Dessutom genomförs känslighetsanalys för att identifiera de mest inflytelserika parametrarna och optimera begränsningsplanerna därefter. De viktigaste resultaten av denna studie visar överlägsenheten hos dynamiska begränsningsplaner när det gäller att minska energiförluster samtidigt som tillräckligt skydd för fladdermusaktivitet bibehålls (högre än den 90% skyddsnivå som krävs enligt lag) jämfört med statiska metoder (50% minskning av förluster under en hel begränsningssäsong). Insikter från känslighetsanalysen belyser de kritiska parametrarna som påverkar energiförluster och ger vägledning för målinriktade modifieringar av begränsningsplaner. Dessutom betonar studien vikten av att beakta kontinuerliga variabler, såsom luftfuktighet, och platsspecifika faktorer, såsom soluppgångs- och solnedgångstider, för mer precisa bevarandestrategier. Denna forsknings betydelse sträcker sig bortom akademin och informerar beslutsfattande inom politik och branschpraxis inom vindenergi och biologisk mångfaldsbevarande. Genom att optimera begränsningsplaner kan intressenter uppnå en balans mellan miljöskydd och förnybar energiproduktion, vilket banar väg för hållbar utveckling. Framtida forskningsvägar inkluderar att förädla begränsningsstrategier baserade på kontinuerliga variabler och att genomföra fältstudier för att validera resultat på olika vindkraftsplatser.

Climate change is mankind’s biggest challenge and scientists around the globe agree that civilization is pushing towards a breaking point. Renewable energy are alternatives that are capable to remove the need for fossil fuel. Wind power will play a vital role and has the possibility to confront the challenges that face the globe. In order for wind power to reach its full potential constructors need to take into account the distance between each wind power turbine, as it can cause energy loss and generate less electricity into the system. These energy losses decrease the potential of wind power and thus also for renewable as a whole. Energy losses that emerge within the space between wind power plants are named wake losses. Once the wind has passed the plant, a distance equal to seven rotor diameters is needed for the wind to regain its full force. By positioning the plants within the announced distance, the production of each plant decreases since downstream turbines are not able to generate a full effect.       This Bachelor thesis in Energy Engineering aims to analyse these wake losses for the wind power plant Skäppentorp, which is situated in Mönsterås County. The nearby wind power plant Brotorp is affecting Skäppentorps production and the authors of this degree project chose to present the wake losses as a percentage. A third wind power plant named Idhult functioned as a reference. Idhult is of course not affected before the positioning of Brotorp but neither after it, therefore the plant was used to ensure that weak winds were not ascribed to Brotorp but are a result of a weak wind year. The Bachelor thesis covered thus three wind power plants, Skäppentorp which interacts and is affected by Brotorp and Idhult which served as reference. The wake losses were calculated in Microsoft Excel and set against the software windPRO to validate the programmed produced losses for the same plant. Skäppentorp’s surrounding were divided into 12 sectors, where each sector covers an angle of 30 degrees. By doing so a full circle, 360 degrees, surrounding the plant was established. The wind speed and the production before respectively after Brotorp deployment was produced by using a nearby measuring post. Via an average production value for each sector, before and after Brotorp, a percentage wake loss was calculated. This was set against Idhult to sort away better respectively worse wind years. The period before covered the year 2012 until 2015 and the period after covered 2016 until 2018.  The result from Microsoft Excel indicates that sector four and sector nine were subjected to the highest percentage of losses. The results from the software windPRO however indicated the highest loss in sector four. Three sectors obtained the same percentage loss as windPRO while remaining values came out dissimilar. The distinction between some of the sectors may be caused by the positioning of some of the Brotorp turbines, where some are located on the borderline between sectors. This implies that some turbines affect two sectors when calculated with Microsoft Excel, which it does not when simulated with windPRO. The sum of all sections indicated that Brotorp turbines caused a wake loss of 3,8 %. This was compared to the simulation in windPRO which resulted in 5,7 %.

Due to the increase of rotor size in horizontal axis wind turbine (HAWT) during the past 25 years in order to achieve higher power output, all wind turbine components and blades in particular, have to withstand higher structural loads. This upscalingproblem could be solved by applying technologies capable of reducing aerodynamic loads the rotor has to withstand, either with passive or active control solutions. These control devices and techniques can reduce the fatigue load upon the blades up to 40% and therefore less maintenance is needed, resulting in an important money savings for the wind farm manager. This project consists in a study of load control techniques for offshore wind turbines from an aerodynamic and aeroelastic point ofview, with the aim to assess a cost effective, robust and reliable solution which could operate maintenance free in quite hostile environments. The first part of this study involves 2D and 3D aerodynamic and aeroelastic simulations to validate the computational model with experimental data and to analyze the interaction between the fluid and the structure. The second part of this study is an assessment of the unsteady aerodynamic loads produced by a wind gust over the blades and to verify how a trailing edge flap would influence the aerodynamic control parameters for the selected wind turbine blade. / På grund av ökningen av rotorstorleken hos horisontella vindturbiner (HAWT) under de senaste 25 åren, en design som har uppstod för att uppnå högre effekt, måste alla vindkraftkomponenter och blad stå emot högre strukturella belastningar. Detta uppskalningsproblem kan lösas genom att använda metoder som kan minska aerodynamiska belastningar som rotorn måste tåla, antingen med passiva eller aktiva styrlösningar. Dessa kontrollanordningar och tekniker kan minska utmattningsbelastningen på bladen med upp till 40 % och därför behövs mindre underhåll, vilket resulterar i viktiga besparingar för vindkraftsägaren. Detta projekt består av en studie av lastkontrolltekniker för havsbaserade vindkraftverk ur en aerodynamisk och aeroelastisk synvinkel, i syfte att bedöma en kostnadseffektiv, robust och pålitlig lösning som kan fungera underhållsfri i tuffa miljöer. Den första delen av denna studie involverar 2D- och 3D-aerodynamiska och aeroelastiska simuleringar för att validera beräkningsmodellen med experimentella data och för att analysera interaktionen mellan fluiden och strukturen. Den andra delen av denna studie är en bedömning av de ojämna aerodynamiska belastningarna som produceras av ett vindkast över bladen och för att verifiera hur en bakkantklaff skulle påverka de aerodynamiska styrparametrarna för det valda vindturbinbladet.

This study aims to explore the ability of a multi-criteria decision making with analytical hierarchy process (MCDM-AHP) model to emulate the results of a cost benefit analysis (CBA) model in the context of offshore wind farm siting within the Swedish exclusive economic zone (EEZ). The research question addressed is whether the MCDM-AHP analysis produces similar results to the CBA analysis. In addition to this, the strengths and weaknesses of each model is explored. The MCDM-AHP model employs the spatial criteria in a more basic manner compared to the CBA model, simplifying the evaluation process while still explaining 89.5% of the variation in the CBA model and defining similar areas as suitable. Thus, it can be concluded that the MCDM-AHP model adequately emulates the CBA model within the context of offshore wind farm siting within the Swedish EEZ. However, it is crucial to note that the two models produce outputs on different scales. While the CBA model provides levelized cost of energy (LCOE) values that can be thresholded for investment viability comparisons, the suitability score generated by the MCDM-AHP model remains a relative and arbitrary score within the model. Both models entail uncertainties, limiting their usage beyond making general assumptions or identifying areas of interest. The findings reveal that the CBA model demonstrates greater robustness when confronted with changes in spatial input parameters compared to the MCDM-AHP model. This discrepancy is attributed to the iterative computation process and consideration of flat cost inputs in the CBA model, whereas the MCDM-AHP model represents a linear combination of various spatial parameters. However, the calculated LCOE values in the CBA model are highly sensitive to changes in modeling assumptions regarding external parameters, resulting in significant linear variations. The LCOE values obtained from the CBA model baseline case fall within a range of 52.1 - 98.9 EUR/MWh, which aligns with similar studies, validating the CBA model. Nonetheless, caution should be exercised when considering these results as an accurate representation of the real world due to inherent uncertainties in cost inputs and the LCOE measure. The strengths of the MCDM-AHP model lie in its robustness when the order of relative importance remains stable for key spatial evaluators. It is sensitive to significant changes in water depth and wind speed, which heavily influence its output. The model's simplicity allows for a quick overview of the problem, but it requires assumptions that introduce uncertainties. Validation of the MCDM-AHP model using existing and planned offshore wind farms within the Swedish EEZ was possible but limited by the arbitrary scale and limited validation areas. The comparison between the two models could be enhanced with more comprehensive spatial and economic data for an in-depth CBA model, which could serve as a ground truth for the MCDM-AHP model. Nevertheless, the comparison made in this study considers the CBA model to be closer to the truth, acknowledging the underlying assumptions that should be considered during evaluation. In conclusion, within the context of offshore wind farm siting, the MCDM-AHP model produces outputs that are similar to the CBA model.