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Thesis (MScIng)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The Spier Estate - a wine estate in the Western Cape Province of South Africa - is engaged in a transition towards operating according to the principles of sustainable development. Besides changes in social and other environmental aspects, the company has set itself the goal to be carbon neutral by 2017. To this end, Spier is considering the on-site generation of electricity from renewable energy sources. This study was initiated to explore the technical and economic feasibility of a concentrating solar power plant for this purpose on the estate. The investigation was carried out to identify the most appropriate solar thermal energy technology and the dimensions of a system that fulfils the carbon-offset requirements of the estate. In particular, potential to offset the annual electricity consumption of the currently 5 570 MWh needed at Spier, using a concentrating solar power (CSP) system, was investigated. Due to rising utility-provided electricity prices, and the expected initial higher cost of the generated power, it is assumed that implemented efficiency measures would lead to a reduction in demand of 50% by 2017. However, sufficient suitable land was identified to allow electricity production exceeding today’s demand. The outcome of this study is the recommendation of a linear Fresnel collector field without additional heat storage and a saturated steam Rankine cycle power block with evaporative wet cooling. This decision was based on the system’s minimal impact on the sensitive environment in combination with the highest potential for local development. A simulation model was written to evaluate the plant performance, dimension and cost. The analysis was based on a literature review of prototype system behaviour and system simulations. The direct normal irradiation (DNI) data that was used is based on calibrated satellite data. The result of the study is a levelised cost of electricity (LCOE) of R2.741 per kWh, which is cost competitive to the power provided by diesel generators, but more expensive than current and predicted near-future utility rates. The system contains a 1.8 ha aperture area and a 2.0 MWe power block. Operating the plant as a research facility would provide significant potential for LCOE reduction with R2.01 per kWh or less (favourable funding conditions would allow for LCOE of R1.49 per kWh) appearing feasible, which results in cost competitiveness in comparison a photovoltaic (PV) solution. Depending on tariff development, Eskom rates are predicted to reach a similar level between 2017, the time of commissioning, and the year 2025. The downside is that the plant would not solely serve the purpose of electricity offsetting for Spier, which may result in a reduced amount of electricity that may be generated. Further studies are proposed to refine the full potential of cost reduction by local development and manufacturing as well as external funding. This includes identification of suitable technology vendors for plant construction. An EIA is required to be triggered at an early stage to compensate for its long preparation. / AFRIKAANSE OPSOMMING: Die Spier wynlandgoed in die Wes-Kaap Provinsie van Suid-Afrika is tans in ‘n oorgangsfase tot besigheids-praktyke gebaseer op volhoubare ontwikkeling. Afgesien van die sosiale en omgewingsaspekte het die groep hom ook ten doel gestel om koolstof neutraal te wees teen 2017. Ten einde hierdie doel te bereik, moet die maatskappy sy algehele elektrisiteitsverbruik vervang met hernubare bronne. Hierdie studie is dus geloods om die tegniese en ekonomiese uitvoerbaarheid van 'n gekonsentreerde sonkragstasie op die landgoed te ondersoek. Hierdie ondersoek is gedoen om die mees toepaslike sontermiese tegnologie en die grootte van 'n termiese sonkragstelsel te bepaal, wat aan die koolstof vereistes van die landgoed voldoen. Die potensiaal om die jaarlikse elektrisiteitsverbruik van 5 570 MWh met 'n gekonsentreerde elektriese sonkragstelsel te vervang, is ondersoek. Weens die toename in die elektrisiteitsprys en die verwagte hoërkoste van opgewekte elektrisiteit word aanvaar dat die implementering van voorgestelde doeltreffendheidsverbeteringe, sal lei tot 'n afname in die aanvraag na elektrisiteit van tot 50% teen die jaar 2017. Voldoende beskikbare grond is geïdentifiseer om genoeg elektrisiteit te produseer om die huidige vraag na elektrisiteit te oorskry. Die uitkoms van die studie is die aanbeveling van 'n lineêre Fresnel kollektorveld sonder addisionele warmte storing, asook 'n versadigde stoom Rankine sikluskragblok met ‘n nat-verdamping verkoelingstelsel. Die besluit is gebaseer op die stelsel se minimale impak op die omgewing, tesame met die hoogste potensiaal vir plaaslike ontwikkeling. 'n Simulasie is ontwikkel om die aanleg se werkverrigting, grootte en koste te evalueer. Die analise is gebaseer op 'n literatuuroorsig van 'n prototipe stelsel gedrag en stelsel-simulasies. Die direkte normale sonstralings data wat gebruik is, is gebaseer op gekalibreerde satelliet data. Die bevinding van die studie is 'n gebalanseerd koste van elektrisiteit van R2.74 per kWh, wat mededingend is met die koste van elektrisiteit wat deur diesel kragopwekkers verskaf word, maar is aansienlik duurder as die huidige en toekomstige voorspellings van Eskom-tariewe. Die stelsel bevat 'n 1.8 ha son kollektor oppervlakte en 'n 2.0 MWe krag-blok. Daarbenewens, sal die gebruik van die aanleg as 'n navorsingsfasiliteit die potensiaal hê om die gebalanseerd koste van elektrisiteit te verminder na R2.01 per kWh of minder (gunstig befondsing voorwaardes sal gebalanseerd koste van elektrisiteit van R1.49 per kWh tot gevolg hê), wat mededingend is met die koste van 'n fotovoltaïese alternatief. Daar word voorspel dat Eskom-tariewe dieselfde sal bly vanaf 2017, die jaar van inbedryfstelling van die aanleg, tot en met die jaar 2025. Die nadeel is dat die aanleg nie noodwendig uitsluitlik vir die opwek van elektrisiteit vir Spier gebruik sal word nie, en daarom kan dit lei tot 'n vermindering in die hoeveelheid elektrisiteit wat deur die aanleg opgewek word. Daar word voorgestel dat verdere studies onderneem word om die moontlikheid van koste-besparings vir die aanleg te ondersoek deur gebruik te maak van plaaslike ontwikkeling en vervaardiging, asook eksterne befondsing. Dit sluit die identifisering van geskikte tegnologie verskaffers vir die aanleg-kostruksie in. 'n Omgewingsimpakstudie, volgens die EIA regulasies, moet ook so gou as moontlik gedoen word aangesien dit n langsame proses is.

European Commission (2011) aims to reduce the greenhouse gas emission sby 85-95% by 2050 in comparison to 1990’s levels. Wave energy could be an important step to archiving this goal. This report aims to develop a quantitative risk assessment for the Uppsala University's wave energy converter. Failure rates have been collected from various databases and reports and have been processed accordingly in order to implement them in the risk analysis. CAPEX, OPEX and possible downtime windows have been estimated. A fault tree analysis (FTA) has estimated the total unavailability, unreliability and downtime. Furthermore an economical assessment model using Monte Carlo and the unreliability data from the FTA has been developed, estimating the expected LCOE and OPEX/WEC for parks consisting of 20, 100, and 200 WECs (wave energy converters). The result show that the O-ring seal has the largest impact on both the unavailability, and the economy of the OPEX/WEC. Second biggest contributor is the translator bearing failure. The study also shows that the CAPEX cost has to be reduced to make the LCOE competitive in comparison to other renewable sources. A comparison between the system unavailability and unreliability has also been done in terms of different component parameters.

The master thesis has evaluated the specific combination of bifacial solar cells and extensive green roofs. This was done in terms of energy production per year, profitability as well as discussions around ecosystem services. Three cases have been simulated with different temperature profiles for both bifacial, vertical bifacial and monofacial. The reason for three cases was due to the uncertainty in temperature decreasing properties of vegetation i Sweden. One case was simulated for a normal black bitumen roof for the three types of solar PV. The result with the best energy production was found in the configuration with azimuth -10o, inclination 40o and height above roof at 40 cm. This was the case with the largest simulated temperature decrease. Albedo was set to 0.2 and this resulted in a bifacial gain of 9-10% for the three cases with green roofs installed. Albedo was found to be a larger factor in the energy production outcome than the temperature decrease from the vegetation. The solar cells contributes to shading the green roof partially which increases the local biodiversity as well as expands the lifetime of the vegetation. The combination was deemed profitable since the middle case had an annuity of 1841 SEK/year, but the case with the bitumen roof was found to be even more profitable with an annuity of 4160 SEK/year. This indicates that the extra cost of installing a green roof does not pay itself back with a higher energy production. / Det här examensarbetet har undersökt kombinationen bifacialsolceller med extensivt grönt tak med avseende på optimal utformning av en sådan anläggning på ett tak samt systemproduktion och lönsamhet hos anläggningen. Då det inte finns något klart modelleringsverktyg för hur stor temperatursänkning det gröna taket kan åstadkomma så har tre olika fall med olika temperaturprofil simulerats. Resultaten visade på att ju högre temperatursänkning det gröna taket kan bidra med desto lägre höjd bör bifacialsolcellerna installeras på. Den bästa systemproduktionen fås vid vinkeln 40o samt azimuth -10o för alla tre fall. Detta gav för medelfallet en bifacial gain på 9,6% vid jämförelse mot vanliga enkelsidiga solceller. Resultatet för vertikalt installerade bifacialsolceller gav minst 12% lägre systemproduktion än de med vinkel 40o men med hög osäkerhet kring tillförlitligheten i resultatet. Vertikal bifacial kan vara intressant då det ligger ett värde i att producera elektricitet efter ett normalt hushålls elkonsumtionskurva, men är mindre intressant för kontorsbyggnader där elkonsumtionen är relativt konstant under dagen. Lönsamhetskalkylen visade att kombinationen bifacialsolceller med grönt tak var lönsam, men inte lika lönsam som att installera på svart tak. För medelfallet gav bifacialsolceller på grönt tak en annuitet på 1841 kr/år medan annuiteten för bifacialsolceller på svart tak var hela 4160 kr/år. Ur ett rent ekonomiskt perspektiv är kombinationen alltså inte den mest lönsamma. Från känslighetsanalyserna konstaterades att albedo är den aspekt som har störst påverkan på systemproduktionen och denna är relativt låg för det gröna taket. Ett högre albedo hade därför varit att föredra till bifacialsolceller, vilket kan erhållas genom att exempelvis varva grönt tak med vita stenar. Vidare är kombinationen en platseffektiv lösning för tak som oftast är en outnyttjad ytresurs, där de olika installationerna bidrar med olika positiva nyttor var för sig. Bifacialsolcellerna bidrar till en ökad självförsörjningsgrad samt hjälper till att driva på den tekniska innovationen framåt. Gröna tak bidrar med många ekosystemtjänster såsom bullerreducering, dagvattenfördröjning, rening av luftpartiklar, lokal temperatursänkning. Kombinationen bidrar till en ökad biologisk mångfald och en lägre växtperiod för det gröna taket mot om den hade varit fristående.

The aim of this study is to act as a pre-study for AirSon Engineering AB regarding a small scale wind turbine they want to install. This by means of collecting data about the windspeeds present at said location, taking into consideration local regulations and doing calculations on the turbulence in the wind, which is affected by nearby obstacles and by the house which the wind turbine is planned to be installed next to. The study puts specific focus on three main questions, namely: What kind of production is to be expected? What is the economy like for the installation of the wind turbine? What are the possibilities/limitations from a construction perspective? An analysis of the location of the installation and a comparison of the selected wind turbines and their respective dimensions, potential for production and economics is presented in this study. The emphasis of the analysis is on examining the respective wind turbines and determining which of them that best fits AirSon with regard to all three aspects. Different graphs have been used to compile wind data and the program used for this study is Matlab. In addition to that the program Excel has been used to compile and present the results for the various wind turbines.  A total of nine small scale vertical axis wind turbines with rated output powers between 1 kW and 10 kW have been examined and are presented as potential suggestions for installation. The manufacturers whose wind turbines are presented are Aeolos, Toyoda and Ropatec. By the end of this study a recommendation from the authors, to AirSon is presented for which windturbine the authors think might fit best. The plan for this study is furthermore to act as a guidance so that AirSon can, following up on the study, directly work toward acquiring and installing said wind turbine. / Syftet med detta arbete är att genomföra en förstudie åt AirSon Engineering AB rörande ett småskaligt vindkraftverk som de vill installera. Arbetet innefattar insamling av data om vindhastigheter från den befintliga platsen samt hänsynstagande till de lokala omständigheterna, till exempel vad gäller turbulensen i vinden, som påverkas av närliggande hinder och av huset vilket vindkraftverket planeras att installeras intill. Examensarbetet har sitt fokus specifikt på tre huvudfrågor, nämligen: Vad för produktion förväntas från platsen? Hur ser ekonomin ut för installationen av vindkraftverket? Vad finns det för möjligheter/hinder ur ett kontruktionsperspektiv? I arbetet presenteras en analys av platsen som vindkraftverket ska installeras på samt en analys av utvalda vindkraftverk med hänsyn till storlek, produktion och ekonomi. Analysens tyngdpunkt ligger i att undersöka det vindkraftverk som passar in bäst för AirSon med hänsyn till alla tre aspekterna. Till analysen har olika grafer använts för att sammanställa vinddata och programmet som användes till detta är Matlab. För att sammanställa och presentera de olika vindkraftverken har Excel använts.  Totalt sett har nio småskaliga vertikalaxlade vindkraftverk med märkeffekter mellan 1 kW och 10 kW undersökts och tagits fram som potentiella förslag för installation. De tillverkare vars vindkraftverk presenteras är Aeolos, Toyoda och Ropatec. I slutet av detta arbete presenteras en rekommendation för vilket vindkraftverk som författarna anser vara lämpligast för AirSon. Avsikten med arbetet är att vägleda AirSon tillräckligt mycket för att de ska kunna använda analysen för att installera verket.

This thesis aims to analyze how different temperature deviations affect the components of wind turbines. A study of the temperatures in several different components was carried out to get a clearer picture of how these affects operational reliability. By trying to link, for example, extreme values of temperatures to possible alarms and downtime in the wind power plants, the hope is that this study will be able to contribute to safer and more maintenance-free wind turbines in the future. The 12 wind turbines that have been evaluated in this study are localized in southern Sweden. The time period for the collected data extends over 6 years. In the thesis, an analysis has been carried out with the help of the computer program Matlab to examine different types of data collected from the components in the wind turbines. The data was plotted with the help of various functions in Matlab and with the help of mathematical equations. The data was then observed ocularly by the authors, which led to the discovery of different connections between temperature variations in the components and different error codes. The generator bearing was the component that was found to have the highest correlation between temperature deviations and specific error codes related to various yaw-errors, which can be explained as error codes that occur when the wind turbine fails to adjust itself to the wind. An analysis has also been made to determine whether there was a temperature-related upward trend in any of the components in the wind turbines. This was carried out with the help of various standard deviation calculations and calculation of the mean temperature value of different components. The standard deviation in this case describes how much the temperature of each component varies from the mean value. It turned out that there was such an upward trend for the Generator Bearing and Generator Phase 3 components. Some turbines also turned out to have a more distinct upward trend than others

The transition to renewable energy sources is vital to mitigate global warming and achieve the climate targets set by the EU. The availability of natural gas in Europe is challenged due to the Russian invasion of Ukraine, leading to a shift towards fossil-free alternatives. In collaboration with Siemens Energy, this thesis investigates the availability of green fuels for gas turbines in Europe, specifically in Germany, Poland, and the UK. The methodology includes analysing literature, internal and official documents, and conducting a customer survey.  The fuel availability outlook indicates an upcoming expansion of hydrogen infrastructure, with Germany and the UK expected to have operational hydrogen infrastructure within the next 5-10 years. While green ammonia and e-methanol may have limited roles in the energy transition, ammonia's capacity to transport hydrogen makes it a potential energy carrier, and the existing distribution network could facilitate the early adoption of large-scale ammonia transportation. Biofuel availability varies across regions, feedstocks, and production methods, with biogas, biomethane and HVO showing significant potential. Natural gas remains the most cost-effective fuel until 2040, with blue hydrogen and ammonia, along with carbon capture, utilisation, and storage (CCUS), identified as the best alternative green fuels. After 2035, green hydrogen will emerge as the most cost-effective green option. The customer survey highlights the preference for hydrogen and ammonia, driven by governmental requirements and environmental responsibility. This study emphasises the promising transition fuels and the need to explore CCUS technologies' impact on fossil-based fuel prices.

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 %.

För att en kvalitativ och driftsäker kraftomvandling från vind till elkraft skall erhållas ställs krav på en mängd olika faktorer. Klimatologiska och tekniska faktorer kräver korrekt dimensionering och anpassning av omvandlingstekniken för att största möjliga energimängd skall kunna omvandlas på ett driftsäkert och energieffektivt vis som vindkraftsägare, nätägare kräver. Vinden är som bekant en oberäknelig kraftkälla. Variationerna i styrka och tid kan innebära en hel del driftoptimeringsproblematik med efterverkningar för vindkraftsverket, nätet och belastningen. Konsekvenserna kan bero på vilken typ av teknik som är installerad i de olika delarna av energisystemet och i områdets elnät. Varierande effektbehov och effektfaktor i tiden har också en signifikant betydelse för elnätets stabilitet.  Anpassning av drift i elnätet mot den turbulenta vinden ger ofta avvikelser på spänning och effektflöden, speciellt i extrema situationer där svaga elnät existerar. God samverkan med vindkraftverket och nätets varierande aktiva och reaktiva effektbehov till energianvändaren kan ge förutsättningar för god elkvalitet och därmed optimerad och säker drift med få avbrott över tiden. Ofta kan och är det mekaniska, elektrotekniska val i vindkraftverket och tillhörande elsystem som spelar en avgörande roll för hur lönsam investeringen blir under verkets tekniska livslängd. Nätägaren eftersträvar en god interagering mellan elnät och elproduktion som ger upphov till få medeltalsfel mellan avbrott och elfel, detta kallas i branschen för ”Mean time between failures” MTBF.  Enligt Svensk energi skall långsamma och snabba spänningsvariationer samt övertoner och erforderlig kortslutningseffekt utredas och jämföras mot de krav och villkor som råder vid elektrisk integrering av elproduktion i elnätet. Förstudien har kommit fram till två lämpliga anslutningsförslag med vindkraftsprojektering. Det beskrivs senare i rapporten förslag på två tillhörande Smart Grid varianter med energilagring för anslutningsförslagen i det befintligt svaga lokala elnätet. / To achieve a reliable and qualitative power conversion from the wind into electric power, a variety of factors and demands need to be obtained. Climatological and technological factors requires proper dimensioning and adjustment of the conversion technology, to harvest the greatest possible amount of energy and to be converted in a reliable and energy efficient way, that windmill owners, power grid owners require. The wind is as familiar an unpredictable power supply. The variations in intensity over time could mean a number of drive optimization problems with after-effects of the wind turbine, power grid and load. The consequences may depend on which type of technology that is installed in the different parts of the energy system. The area's power grid and varying power needs with characteristics over time, also has a significant importance. The turbulent wind gives deviations of voltage and power flow, especially in various extreme situations in weak power grids. Good interaction between the wind turbine and power grid with varying active and reactive power demand for the energy users, provides conditions for a good power quality and thus, an optimal and safe operation with few interruptions over time. It can be, and often is the mechanics, electro-technical choices in the wind turbine and associated electrical systems that play a critical role in how profitable installation is during the wind turbines technological life. The power grid owner strives for a good interaction between the power grid and electrical generation which rise for few faults between interruptions and errors. In the branch this is known as "Mean time between failures" MTBF.  According to the Swedenergy, harmonics, slow and fast voltage variations including required short-circuit power should be investigated and compared with those requirements and terms that prevails with electrical integration of power into the grid. The feasibility study has concluded two suitable power connection proposals including wind mapping research, later in this report it is described and suggested two related Smart Grid variants with energy storage for the two power connection proposals in the existing weak local grid. / Judith Saari var betygsättare på muntlig presentation.

La tesi analizza una politica climatica dal punto di vista economica, concentrandosi sul ruolo delle tecnologie, dell'innovazione e delle foreste, con una particolare attenzione alla modellizzazione dell'incertezza. / This thesis provides a comprehensive economic evaluation of long term global warming mitigation policies, by focusing on the role of technologies and innovation, forestry ecosystem, and of uncertainty.