This master’s thesis is focused on current possibilities of solar energy utilization – especially on concentrating solar power systems – and their optimization using solar tracking systems to maximize energy gain. The thesis also deals with solar position algorithm and offers an Arduino based automatic dual axis solar tracker design which provides various solar devices the ability to pivot using stepper motors, DC motors or servos. The motion might be driven by calculated solar position or by actual illuminance.

MESHWR / Department of Hydrology and Water Resources / Greenhouse gases (GHGs) from coal power station affect the behaviour of climatic parameters such as the temperature, rainfall and evaporation, over a long period of time, hence causing climatic trends. This study focused on investigating the impacts of Greenhouse gases (GHGs) from coal power stations on climatic and hydrological trends in Witbank area. To accomplish this, linear regression (LR) and Mann-Kendall (MK) trend test were used to detect the hydro-climatic trends and their significance. GHG emissions were obtained from Eskom’s sustainability report on the Eskom website. Temperature data for the years 1950- 2000 and 1993-2016 and rainfall data for the years 1925-2000 and 1993-2016 were used. Double Mass Analysis (DMA) was used to check the homogeneity and consistency of temperature and rainfall data from South African Weather Services (SAWS) station with the Lynch database and Water Research Commission (WRC) data. Data was patched and extended using LR where necessary. Trends in temperature, precipitation and flow were assessed using MK trend test and LR based on monthly, seasonal, and annual scales. GHG emissions were compared with the hydro-climatic data over time in order to detect the impacts of GHG emissions on temperature, rainfall and streamflow. The MK results indicated that GHG emissions had some impacts on temperature with statistically significant increase in annual, monthly and seasonal time scales for the period 1950-2016. LR also produced the same results for annual temperature. Monthly and seasonal temperature could not be produced with the LR method because of data gaps. The MK and LR models produced similar results, indicating that there was a non-significant increase in temperature before coal power stations were introduced (1950-1974) and a significant increase in temperature after the commissioning of coal power stations (1975-2016). MK and LR also produced the same results for annual rainfall data, indicating that there was a significant increase in rainfall before coal power stations were introduced (1925-1974) and a non-significant increase after the commissioning of coal power stations (1975-2016). For monthly time scales MK and LR indicated increasing and decreasing trends before and after coal power stations were introduced. MK and LR results for streamflow stations B2H004 and B2H007 showed similar results indicating non-significant increase in annual and seasonal streamflow, but differed in monthly streamflow where MK showed significant increases whilst LR showed non-significant trends. The study concluded that GHGs from coal power stations had significant impacts on the hydro-climatic trends in Witbank area. GHGs from coal power stations caused significant increase in temperature as temperature increased by 3.7°C after coal power stations were introduced, whereas temperature had increased by 1.7 °C. It is recommened that more research should be done on alternative sources of energy such as wind and solar energy to check their suitability and applicability in South Africa. / NRF

Die Software alaska ist zunächst ein allgemeines Werkzeug zur Modellierung und Simulation der Dynamik mechanischer/mechatronischer Systeme. alaska wird am Institut ür Mechatronik in Chemnitz entwickelt. Mit dem Erweiterungsmodul alaska/Wind erhält alaska Funktionalitäten die erforderlich sind, um das dynamische Verhalten von Windkraftanlagen (WKA) mit dem Ziel zu simulieren, die resultierenden Belastungen zu ermitteln. Bestandteile von alaska/Wind sind u.a. Komponenten zu Beschreibung der aerodynamischen Umgebungsbedingungen und der Berechnung der daraus resultierenden, an der WKA angreifenden Windkräfte sowie ein Basis-WKA-Simulationsmodell. Inhalt des Vortrages ist es zu zeigen, wie dieses Basis-Simulationsmodell vom Anwender, also vom Entwickler/Hersteller von Windkraftanlagen, an seine spezifischen Anforderungen angepasst wird, wie es in seinen Produktentstehungsprozess eingebunden wird und wie mit dem Einsatz der alaska- Komponente alaska/DC (DistributedComputation) weitestgehend automatisch auf der Basis mehrerer Tausend Simulationsrechnungen Design-treibende Belastungen ermittelt werden.

The thesis Temelín Nuclear Power Station and Czech-Austrian Relations deals with the Temelín Nuclear Power Station and nuclear industry and its influence to the Czech-Austrian relations. The study aims to analyse the relations between the Czech Republic and Austria in the context of the power station from 1993 to 2013. Initially, the thesis introduces the theory of constructivism in the International Relations. Afterwards, it aims to explain the differences between the relations to the nuclear energy by Czechs and by Austrians on the basis of the theory of constructivism. Moreover, the thesis introduces the historical, legal and technical circumstances of the Czech-Austrian dispute. The main objective of the thesis is to ascertain, what effect on the Czech-Austrian relations have mediums, which publish articles about the Temelín Nuclear Power Station. There are four Czech relevant newspapers (Blesk, MF DNES, Právo and Lidové noviny) and four Austrian relevant newspapers (Kronen Zeitung, Kurier, Der Standard and Die Presse) inquired in the thesis. Particular articles are evaluated by the stances on the issue (pronuclear, antinuclear or impartial). The thesis identifies, which of the mediums have impact on deterioration/improvement of the Czech-Austrian relations. The study also deals with the process of...

>Magister Scientiae - MSc / Chemical speciation and the evaluation of species distribution is the key to understanding the potential of brines to form scale or corrode the water circuit as well as the potential of mobility and release trends of the pollutants into the environment. It is important to identify highly soluble free ions in water chemistry because toxicity of ions is related to mobility and consequently bioavailability. The chemical composition, character and chemical speciation modelling of saline effluents (brines) at Tutuka Power Station and Sasol Synthetic Fuels Complex in Secunda were studied. The form in which chemical species exist (chemical speciation) and the physical and chemical interactions of species in saline effluents at these two study sites is not fully understood. This study investigated how pH, temperature, alkalinity and chemical composition influenced chemical speciation, species distribution, scale forming and corrosion potentials of the different saline effluent streams at the two sites using computer programs PHREEQC and Aq.QA. Characterizations of the results were presented in Stiff and Piper diagrams generated by the Aq.QA computer software. Chemical speciation modelling of the brines showed that scale-forming minerals aragonite, calcite, hematite, anhydrite and gypsum have positive saturation indices between 0 and 20 in mine water, RO brine at Tutuka and Sasol Secunda, EDR brine at Sasol Secunda and VC brine at Tutuka Power Station. The water types at Tutuka Power Station were found to be mainly Na-S04 water types and those at Sasol Secunda were a mixture of Na-Cl and Na-S04 water types. Water treatment chemicals playa major role in increase were absent in the intake water. It was found that Sasol Secunda water streams are much more heavily contaminated than Tutuka water streams. The study also found that the mine water utilised at Sasol Secunda is two-fold more polluted than the mine water utilised at Tutuka although these sites are a mere 40 km apart. The sodium adsorption ratios showed that all the saline effluent streams at Tutuka and Sasol Secunda were unsuitable for irrigation, except for desalination product waters. Chemical speciation showed that the predominant species in the most concentrated saline effluent (VC brine) at Tutuka were the free cr ion at approximately 100 % with very minute quantities of FeCI+ and ZnCI+ and the predominant sodium species were the free Na+ ion which existed at 85 %. Magnesium species had the predominant form as the ionic compound MgS04 at 73 % and the carbonates were mainly in the form of NaC03- (53 %), HC03- (28 %) and CO{(7 %). The most concentrated brine analysed at Sasol Secunda was the TRO brine. PHREEQC did not predict the precipitation of CaC03 from the TRO brine at Sasol Secunda. The most abundant calcium species were Ca2+(59 %) ions and CaS04 (40 %). The brine was at a pH of 5.76 with dissolved CO2 at 73 % of the carbonate species. Trace elements were evaluated and the toxic trace elements varied from 0.07 mg/L (As) to 26.75 mg/L (Sr) at Sasol Secunda. At Tutuka Power Station the toxic trace elements in brines varied from 0.02 mg/L (As/Se) to 16.85 mg/L (Sr). Sr and B were found to be the most highly concentrated toxic elements. The major and trace ion chemistry, alkalinity, pH, sodium adsorption ratios, change in concentration of the water streams and the brine chemical composition after contact with ash was also evaluated. When saline effluents at Tutuka Power Station and Sasol Secunda are combined with ash, pH, Ca content and alkalinity of the resulting solution increased. The chemical composition of saline effluents can be influenced by the ingress of CO2 from the atmosphere. The study shows conclusively that brine composition and concentration is highly variable at these South African power utilities and processes such as RO, contact with ash and C02 ingress can have an impact upon the overall brine quality. Aq.QA was found to be a more accurate tool for classifying waters according to dominant ions than Stiff diagrams but Stiff diagrams still have the superior advantage of being a mapping tool to easily identify samples of similar composition as well as quickly identify what has been added or what has been removed from a water stream. Chemical speciation could identify effluent streams where C02 dissolution had taken place.

This diploma thesis deals with the design of repairs to the asphalt concrete facing of the upper reservoir of the pump-storage power station Dlouhé Strána. The first part summarizes the knowledge about asphalt concrete facings, experience from foreign constructions and a description of the damage on this hydraulic structure. The second part defines the variants of repairs and the selection of the most suitable on the basis of decision analysis.

<p> Three symbiotic systems are considered. These include the possibility of coupling the tritium production in a fission reactor with the fertile conversion in a fusion blanket. Equations for the fuel dynamics, power output, efficiency and costs of a symbiotic, selfcontained power station are developed and evaluated for a specific, 1500 MWe fission reactor operating on a thorium cycle and some fusion parameters. It is concluded that a system using the tritium produced in a fission reactor has lower costs and increased power output when compared to an alternate system. </p> / Thesis / Master of Engineering (MEngr)

In this thesis, an anomaly detection framework is assessed and fine-tuned to detect and explain anomalies in a power station, where EtherCAT, an Industrial Control System, is employed for monitoring. The chosen framework is based on a previously published Graph Neural Network (GNN) model, utilizing attention mechanisms to capture complex relationships between diverse measurements within the EtherCAT system. To address the challenges in graph learning and improve model performance and computational efficiency, the study introduces a novel similarity thresholding approach. This approach dynamically selects the number of neighbors for each node based on their similarity instead of adhering to a fixed 'k' value, thus making the learning process more adaptive and efficient. Further in the exploration, the study integrates Extreme Value Theory (EVT) into the framework to set the anomaly detection threshold and assess its effectiveness. The effect of temporal features on model performance is examined, and the role of seconds of the day as a temporal feature is notably highlighted. These various methodological innovations aim to refine the application of the attention based GNN framework to the EtherCAT system. The results obtained in this study illustrate that the similarity thresholding approach significantly improves the model's F1 score compared to the standard TopK approach. The inclusion of seconds of the day as a temporal feature led to modest improvements in model performance, and the application of EVT as a thresholding technique was explored, although it did not yield significant benefits in this context. Despite the limitations, including the utilization of a single-day dataset for training, the thesis provides valuable insights for the detection of anomalies in EtherCAT systems, contributing both to the literature and the practitioners in the field. It lays the groundwork for future research in this domain, highlighting key areas for further exploration such as larger datasets, alternative anomaly detection techniques, and the application of the framework in streaming data environments. / I denna avhandling utvärderas och finslipas ett ramverk för att detektera och förklara anomalier på ett kraftverk, där EtherCAT, ett industriellt styrsystem, används för övervakning. Det valda ramverket är baserat på en tidigare publicerad graf neurala nätverksmodell (GNN) som använder uppmärksamhetsmekanismer för att fånga komplexa samband mellan olika mätningar inom EtherCAT-systemet. För att hantera utmaningar inom grafiskt lärande och förbättra modellens prestanda och beräkningseffektivitet introducerar studien en ny metod för likhetsgränsdragning. Denna metod väljer dynamiskt antalet grannar för varje nod baserat på deras likhet istället för att hålla sig till ett fast 'k'-värde, vilket gör inlärningsprocessen mer anpassningsbar och effektiv. I en vidare undersökning integrerar studien extremvärdesteori (EVT) i ramverket för att sätta tröskeln för detektering av anomalier och utvärdera dess effektivitet. Effekten av tidsberoende egenskaper på modellens prestanda undersöks, och sekunder av dagen som en tidsberoende egenskap framhävs särskilt. Dessa olika metodologiska innovationer syftar till att förädla användningen av det uppmärksamhetsbaserade GNN-ramverket på EtherCAT-systemet. Resultaten som erhållits i denna studie illustrerar att likhetsgränsdragning väsentligt förbättrar modellens F1-poäng jämfört med den standardiserade TopK-metoden. Inkluderingen av sekunder av dagen som en tidsberoende egenskap ledde till blygsamma förbättringar i modellens prestanda, och användningen av EVT som en tröskelmetod undersöktes, även om den inte gav några betydande fördelar i detta sammanhang. Trots begränsningarna, inklusive användningen av ett dataset för endast en dag för träning, ger avhandlingen värdefulla insikter för detektering av anomalier i EtherCAT-system, och bidrar både till litteraturen och praktiker inom området. Den lägger grunden för framtida forskning inom detta område, och belyser nyckelområden för ytterligare utforskning såsom större dataset, alternativa tekniker för detektering av anomalier och tillämpningen av ramverket i strömmande data-miljöer.

This master thesis explores the application of Pumped-Storage Hydroelectricity (PSH) within an electricity market characterised by a substantial share of renewable and intermittent electricity production. The purpose of PSH is to enhance the alignment of supply with demand by storing energy at electricity surplus and releasing it during shortage. The Juktan Power Station, once the largest pumped hydro storage facility in Sweden with a storage capacity of about 25 GWh and maximum generation of 335 MW, serves as a case study. An in-depth analysis of the properties of the Swedish electricity market and its influencing factors is conducted. Wind speed data is successfully used to increase accuracy of price prediction. Furthermore, a model is developed to calculate potential profitability employing various operation methods. In conclusion, large-scale PSH provide significant benefit to the stability of the electricity system with a clear increase in value after 2020. However, concerns about grid tariff design, electricity market development and energy storage incentives means that investments are not obviously profitable. / Detta examensarbete utforskar tillämpningen av pumpkraftverk på en modern elmarknad med betydande andel förnyelsebar och intermittent electricitetsproduktion. Syftet med pumpkraft är att förbättra anpassningen av tillgång och efterfrågan genom att lagra energi vid elöverskott och frigöra den vid underskott. Juktan Kraftstation, tidigare Sveriges största pumpkraftverk med en lagringskapacitet på ca 25 GWh och maximal generatoreffekt på 335 MW, används som fallstudie. En analys av den svenska elmarknaden och dess påverkande faktorer genomförs. Vindhastighetsdata används framgångsrikt för att förbättra träffsäkerheten för elprisförutsägelser. Vidare utvecklas en modell för att beräkna potentiell lönsamhet med olika driftmetoder. Sammanfattningsvis visas att storskalig pumpkraft ger betydande fördelar för elsystemet med tydlig förstärkning efter 2020. Däremot identifieras potentiella problem såsom elnätsavgiften, svårigheten att långsiktigt förutspå elmarknadens utveckling samt incitament för energilagring, vilka sammantaget gör att pumpkraftinvesteringar inte är självklart lönsamma.

The need for constructive and effective sustainable community development in South Africa is recognised as a cornerstone for national development. Having a clear understanding of sustainable development and sustainable community development is a prerequisite in developing sustainable communities. A current rate of unemployment and low skills level pose a threat to sustainable development within the communities. There is growing interest within businesses and organisations to contribute towards corporate social responsibility (CSR) programmes and initiatives. However, this is an enormous task to address socioeconomic challenges in South Africa due to limited resources and high expectations. The businesses should implement well-structured plans for corporate social responsibility. Furthermore, planned initiatives generally tend to appropriately promote social harmony within targeted community. Skeptics of CSR often claim that business should focus on profits and let the government or non-profit organisations deal with social and environmental issues. The Eskom’ power stations under this study do make some contribution to social and economic development in South Africa, which is realised through corporate social responsibility (CSR) policy within the areas of Ermelo and Balfour. Most people in these communities feel they have been neglected for a long time as their social concerns have not been resolved. The community have recently pressurised these power stations to become corporate citizens; to take on CSR and work towards sustainable community development in their areas. There is a perception within the community that the management of Camden and Grootvlei power stations is not actively involved in executing CSR programmes; hence the intention of the study is to present an interesting analysis of these perceptions by exploring the experienced outcome of CSR initiatives around Ermelo and Balfour in improving the livelihood of the people, inter alia: unemployment and education. The case study research design was adopted for this research and employed a qualitative approach to understand the individual perceptions about the phenomenon under study. The data were collected by means of semi-structured interviews and electronic email. The responses from the participants were analysed using ATLAS.ti software to identify codes and patterns in primary data. The total selected sampling was 25, but those who participated were only 17. From the key findings, it was evident that these power stations do make some contributions towards CSR within their community. However, this study revealed a gap in the way CSR is practiced and implemented: social responsibility and real sustainable development do not reach the community. The findings also brought to light vast differences in the perceptions of various stakeholders regarding available programmes that support sustainable development within the community. These vast differences could mean that this study represents the start of a long-term process. Moreover, the study suggests some critical underlying factors that should be dealt with to close this gap: communication, awareness of available programmes, budget challenges and commitment, and identifying who should take responsibility for various aspects of development. The outcomes of this study are based on how stakeholders view community development needs and challenges by means of three cases that emerged during data analysis: case 1) community; 2). CSR project manager; 3) Top Management. Overall, this study contributes to the applied research area of; proper community engagement programmes, management engagement, employment, training and development, and education. / Business Management / M. Tech. (Business Administration)