Access to energy is an important part in the development of most countries and societies, linked to both social and economic growth. Nevertheless, 70% of the population in sub-Saharan Africa does not have access to electricity, which brings consequences to several of these areas. A country to which this largely applies is Mozambique, where the percentage of the country's population that had access to electricity in 2021 was only 31.5%. Working towards the goal of electrifying the least developed countries in a sustainable way, solar technology is believed to have potential to play a vital role, as 60% of the best terrestrial-based global solar resources of the world are located in sub-Saharan Africa. Mini-grids and solar off-grid solutions can further help address the issue of lack of electricity access, especially in rural areas. In previous studies carried out in the village Linga Linga in Mozambique, off-grid solar solutions have been implemented for a small energy demand. With the intention of giving a larger part of the village’s population access to energy services such as light, phone charging and computer access, this thesis will investigate and design an off-grid PV system for a community center in the village. The main research question that will be answered in this report is "How can solar energy be used to supply a community center in the village Linga Linga with a low-cost, reliable and sustainable electricity supply?". To answer the research question, relevant data and information were collected through a literature study on the situation in Mozambique, off-grid PV systems and on PV system components such as inverters, batteries, PV panels and charge controllers. Interviews were also carried out in the village to be able to calculate the expected energy demand of the community center. The community center’s daily energy demand for weekends was estimated to be the highest, at 7 544 Wh with a maximum power demand of 1 230 W. To meet this requirement, the main components were dimensioned so that the system had a maximum power of 2 000 W, a battery storage capacity of 750 Ah and a system voltage of 24 V. For this system, the approximate total cost of the main components was calculated to 56 120 SEK. / Tillgång till energi är en viktig del i utvecklingen av de flesta länder och samhällen, kopplat till både social och ekonomisk tillväxt. Ändå har 70% av befolkningen i Subsahariska Afrika inte tillgång till el, vilket får konsekvenser för flera av dessa områden. Ett land som detta till stor del gäller är Mozambique, där andelen av landets befolkning som hade tillgång till el 2021 endast var 31.5%. I arbetet mot målet att elektrifiera de minst utvecklade länderna på ett hållbart sätt tros solteknik ha potential att spela en avgörande roll, eftersom 60% av världens bästa jordbaserade globala solresurser finns i Subsahariska Afrika. Mininät och solenergilösningar utanför nätet kan ytterligare hjälpa till att lösa problemet med bristande tillgång till elektricitet, särskilt på landsbygden. I tidigare studier utförda i byn Linga Linga i Mozambique har off-grid solenergilösningar implementerats för att tillgodose energibehov för små system. Med avsikten att ge en större del av byns befolkning tillgång till energitjänster som ljus, telefonladdning och datoråtkomst, kommer detta examensarbete att undersöka och designa ett off-grid solcellssystem för ett kultur- och fritidscentrum i byn. Den huvudsakliga forskningsfrågan som kommer att besvaras i denna rapport är "Hur kan solenergi användas för att förse ett kultur- och fritidscentrum i byn Linga Linga med en låg kostnad, pålitlig och hållbar elförsörjning?". För att svara på forskningsfrågan samlades relevant data och information in genom en litteraturstudie om situationen i Mozambique, off-grid solcellssystem och om systemkomponenter såsom växelriktare, batterier, solpaneler och laddningsregulatorer. Intervjuer genomfördes även i byn för att kunna beräkna det förväntade energibehovet för kultur- och fritidscentrumet. Kultur- och fritidscentrumets dagliga energibehov för helger uppskattades vara högst, 7 544 Wh med ett maximalt effektbehov på 1 230 W. För att möta detta krav valdes huvudkomponenterna så att systemet hade en maximal effekt på 2 000 W, en batterilagringskapacitet på 750 Ah och en systemspänning på 24 V. För detta system beräknades den ungefärliga totalkostnaden för huvudkomponenterna till 56 120 SEK.

Due to the result of the sudden fossil fuels over-night price rises of 1973/1974, coupled with the depletion of the traditional energy resources, many initiatives globally have addressed the efficient use of these resources. Since then, several renewable energy sources have been introduced as alternatives to traditional resources to protect environmental resources and to improve quality of life. Globally, there are more than a quarter of the human population experiencing an energy crisis, particularly those living in the rural areas of developing countries. One typical example of this is Nigeria. This is a country with approximately 80% of her population consistently relying on combustible biomass from wood and its charcoal derivative. Nigeria has an abundant amount of both renewable and fossil fuel resources, but due to the lack of a reasonable energy policy (until recently), it has concentrated on traditional fossil fuels alone. Renewable energy is now Globally considered as a solution for mitigating climate change and environmental pollution. To assess the sustainability of renewable energy systems, the use of sustainability indicators is often necessary. These indicators are not only able to evaluate all the sustainability criteria of the renewable energy sources,1 but also can provide numerical results of sustainability assessment for different objective systems.

Mauritius is an isolated island with ambitious targets for renewable energy generation and plans to invest in more solar power. The aim of this study is to assess how the implementation of photovoltaic technologies might affect the frequency stability in Mauritius and thus assess whether solar power can help the country obtain their targets for green energy generation. The research question is answered by conducting a literature study and simulating relevant scenarios in Matlab and Simulink. By simulating the frequency response for a production disturbance with different values for system inertia and PV capacity, the inertia requirements for frequency stability is assessed. Mauritius appears to have a high potential for increasing solar power generation. Based on the simulations, their electrical grid seems to be able to maintain frequency stability with PV capacity corresponding to the generation targets for 2020, 2025 and 2030, even for low amounts of system inertia. However, the significance of these results are called into question because of the varying quality of input data. With more accurate, specific data, the applicability of the results can be improved. Nevertheless, the study can be used as a guideline on how to use the given model to evaluate frequency stability in isolated power systems in island states. Ways to further this study is to evaluate other stability challenges related to PV production such as the reactive power in the system, voltage stability and rotor angle stability. / Mauritius är en isolerad ö som har sett en stor ekonomisk växt de sista åren. För att möta en ökande efterfrågan på el på ett hållbart sätt har Mauritius satt ambitiösa mål för förnybar energiproduktion som bland annat innebär betydande investeringar i solkraft. Målet med denna studie är att utvärdera hur implementeringen av utökad solcellskapacitet skulle kunna påverka frekvensstabiliteten i nätet på Mauritius och således fastställa ifall solenergin kan bidra till deras mål om ökad grön energiproduktion, utan att öka risken för strömavbrott. Frågeställningen besvaras genom att först utföra en litteraturstudie och sedan använda en matematisk modell, utvecklad av Danilo Obradovic från KTH, för att simulera relevanta scenarier i Matlab och Simulink. Simuleringarna visar frekvenssvaret vid produktionsbortfall som relateras till den mängd svängmassa som behövs för att säkerställa frekvensstabilitet vid olika mängder solceller. Litteraturstudien visar att Mauritius har god tillgång på solinstrålning och solceller verkar vara en lämplig teknologi för att utnyttja denna energin. Enligt de simuleringar som genomförts verkar Mauritius kunna bibehålla frekvensensstabilitet om den installerade solcellskapaciteten ökas till de planerade nivåerna i 2020, 2025 och 2030, även för låga värden på systemets svängmassa. Slutsatserna bör dock analyseras kritiskt då indatan som används för simuleringarna är av varierande kvalitet. Med bättre och mer specifik indata kan den föreslagna metodiken och modellen användas för att dra mer relevanta slutsatser för Mauritius. Metodiken som använts i denna studie kan därav ses på som en riktlinje för hur frekvensstabiliteten i isolerade elnät kan undersökas. Vidare kan studien utökas genom att utvärdera sociala och ekonomiska aspekter och även andra stabilitetsfrågor relaterade till en ökad mängd solceller, så som den reaktiva effekten i systemet, spänningsstabilitet och rotorvinkelstabilitet.

Indonesia’s energy demand has been growing rapidly driven by increasing population, urbanization, and rapid economic growth. With increasing energy demand, the emissions associated with the energy sector continue to increase. With the gradual increase in demand and dominant share of fossil fuels in the energy mix, implementing the energy efficiency measures is crucial for Indonesia to achieve its energy and climate goals. From the policy perspective, National Energy plan of Indonesia aims to achieve higher levels of energy efficiency to reduce the overall energy intensity. Indonesia also has commitments to reduce greenhouse gas emissions and achieve SDG targets. This report reviews the current status of energy demand and energy efficiency in Indonesia and evaluates the potential of implementing energy efficiency measures and fuel switching options to achieve future low carbon energy future. Long term energy model of Indonesia is modelled using the open-source modelling tool OSeMOSYS. Different scenarios have been developed to investigate the outcome of implementing energy efficiency and fuel switching measures in the Residential, Commercial, and Transportation sectors. The results are presented in terms of reduction in total final energy use, greenhouse gas emissions, and local air pollution. Cost-Benefit analysis of the applied measures present their financial feasibility. With the deployment of efficient appliances, up to 30% electricity savings can be achieved in the residential and commercial sector. Vehicle electrification can contribute towards reduction in annual energy use by 48% by the end of modelling period. Measures in the residential and commercial sector directly contribute towards emission reductions. Vehicle electrification does not show proportionate reduction in emissions compared to energy use reduction due to high carbon intensity of the electricity grid. However, significant reduction in local air pollutants can be achieved. Cost benefit analysis shows that deployment of efficient appliances is financially feasible with maximum 2 years of payback period. On the other hand, successful deployment of electric vehicles will require tangible support from government due to its high price premium compared to conventional vehicles. Energy efficiency measures and fuel switching also contribute substantially to achieving Sustainable Development Goal 7.3. In conclusion, this study presents a set of technically and economically feasible energy system development options for Indonesia. From the modelling perspective, this study identifies ways to implement demand side management measures in the energy supply modelling system OSeMOSYS. / Indonesiens energibehov har ökat snabbt drivet av ökande befolkning, urbanisering och snabbekonomisk tillväxt. Med ökande energibehov fortsätter utsläppen i energisektorn att öka. Medden gradvisa ökningen i efterfrågan och den dominerande andelen fossila bränslen ienergimixen är genomförandet av energieffektivitetsåtgärderna avgörande för att Indonesienska uppnå sina energi- och klimatmål. Ur politiskt perspektiv syftar Indonesiens nationella energiplan till att uppnå högre nivåer av energieffektivitet för att minska den totala energiintensiteten. Indonesien har också åtaganden att minska utsläppen av växthusgaser och uppnå SDG-mål. Denna rapport granskar den aktuella statusen för efterfrågan på energi och energieffektivitet i Indonesien och utvärderar potentialen för att genomföra energieffektivitetsåtgärder och alternativ för bränsleomkoppling för att uppnå framtida energiförbrukning med låg koldioxid. Indonesiens långsiktiga energimodell modelleras med hjälp av open-sourcemodelleringsverktyget OSeMOSYS. Olika scenarier har utvecklats för att undersöka resultatet av genomförande av energieffektivitet och bränsleomkopplingsåtgärder inom bostads-, kommersiellt och transportsektorn. Resultaten presenteras i termer av minskning av den totalaslutliga energiförbrukningen, växthusgasutsläpp och lokal luftföroreningar. Kostnadsnyttoanalys av de tillämpade åtgärderna utgör deras ekonomiska genomförbarhet. Med användning av effektiva apparater kan upp till 30% elbesparing uppnås i bostads- och affärssektorn. Fordonselektrifiering kan bidra till minskning av den årliga energiförbrukningen med 48% i slutet av modelleringsperioden. Åtgärder inom bostads- och kommersiell sektor bidrar direkt till utsläppsminskningar. Fordonselektrifiering visar inte proportionell minskning av utsläpp jämfört med energiförbrukningen på grund av hög kolintensitet i elnätet. Emellertid kan en betydande minskning av lokala luftföroreningar uppnås. Kostnads för delningsanalys visar att distribution av effektiva apparater är ekonomiskt möjlig med maximalt 2 års återbetalningsperiod. Å andra sidan kommer framgångsrik distribution av elfordon att kräva konkret stöd från regeringen på grund av dess höga prispremie jämfört med konventionella fordon. Energi effektivitetsåtgärder och bränsleomkoppling bidrar också väsentligt till att uppnå mål för hållbar utveckling 7.3. Sammanfattningsvis presenterar denna studie en uppsättning tekniska och ekonomiskt genomförbara energisystemutvecklingsalternativ för Indonesien. Från modelleringsperspektivet identifierar denna studie sätt att implementera hanteringsåtgärder på efterfrågesidan i modelleringssystemet för energiförsörjning OSeMOSYS.

Preface - Biotechnology is generally accepted to be the next economical wave of the future. In order to attain the many benefits associated with this growing industry simulation modelling techniques have to be implemented successfully. One of the simulations that ne' ed to be performed is that of the human energy system. Pharmaceutical companies are currently pouring vast amounts of capital into research regarding simulation of bodily processes. Their aim is to develop cures, treatments, medication, etc. for major diseases. These diseases include epidemics like diabetes, cancer, cardiovascular diseases, obesity, stress, hypertension, etc. One of the most important driving forces behind these diseases is poor blood sugar control. The blood glucose system is one of the major subsystems of the complete human energy system. In this study a simulation model and procedure for simulating blood glucose response due to various external influences on the human body is presented. The study is presented in two parts. The first is the development of a novel concept for quantifying glucose energy flow into, within and out of the human energy system. The new quantification unit is called ets (equivalent teaspoons sugar). The second part of the study is the implementation of the ets concept in order to develop the simulation model. Development of the ets concept - In the first part of the study the ets concept, used for predicting glycaemic response, is developed and presented. The two current methods for predicting glycaemic response due to ingestion of food are discussed, namely carbohydrate counting and the glycaemic index. Furthermore, it is shown that it is currently incorrectly assumed that 100% of the chemical energy contained in food is available to the human energy system after consumption. The ets concept is derived to provide a better measure of available energy from food. In order to verify the ets concept, two links with ets are investigated. These are the links with insulin response prediction as well as with endurance energy expenditure. It is shown that with both these links linear relationships provide a good approximation of empirical data. It is also shown that individualised characterisation of different people is only dependent on a single measurable variable for each link. Lastly, two novel applications of the ets concept are considered. The first is a new method to use the ets values associated with food and energy expenditure in order to calculate both short-acting and long-acting insulin dosages for Type 1 diabetics. The second application entails a new quantification method for describing the effects of stress and illness in terms of ets. Development of the blood glucose simulation model - The second part of the study presents a literature study regarding human physiology, the development for the blood glucose simulation model as well as a verification study of the simulation model. Firstly, a brief overview is given for the need and motivation behind simulation is given. A discussion on the implementation of the techniques for construction of the model is also shown. The procedure for solving the model is then outlined. During the literature study regarding human physiology two detailed schematic layouts are presented and discussed. The first layout involves the complex flow pathways of energy through the human energy system. The second layout presents a detailed discussion on the control system involved with the glucose energy pathway. Following the literature review the model for predicting glycaemic response is proposed. The design of the component models used for the simulations of the internal processes are developed in detail as well as the control strategies implemented for the control system of the simulation model. Lastly, the simulation model is applied for glycaemic response prediction of actual test subjects and the quality of the predictions are evaluated. The verification of the model and the procedure is performed by comparing simulated results to measured data. Two evaluations were considered, namely long-term and short-term trials. The quality of both are determined according to certain evaluation criteria and it is found that the model is more than 70% accurate for long-term simulations and more than 80% accurate for short-term simulations. Conclusion - In conclusion, it is shown that simplified simulation of the human energy system is not only possible but also relatively accurate. However, in order to accomplish the simulations a simple quantification method is required and this is provided by the ets concept developed in the first part of this study. Some recommendations are also made for future research regarding both the ets concept and the simulation model. Finally, as an initial endeavour the simulation model and the ets concept proposed in this study may provide the necessary edge for groundbreaking biotechnological discoveries. / PhD (Mechanical Engineering) North-West University, Potchefstroom Campus, 2003

Preface - Biotechnology is generally accepted to be the next economical wave of the future. In order to attain the many benefits associated with this growing industry simulation modelling techniques have to be implemented successfully. One of the simulations that ne' ed to be performed is that of the human energy system. Pharmaceutical companies are currently pouring vast amounts of capital into research regarding simulation of bodily processes. Their aim is to develop cures, treatments, medication, etc. for major diseases. These diseases include epidemics like diabetes, cancer, cardiovascular diseases, obesity, stress, hypertension, etc. One of the most important driving forces behind these diseases is poor blood sugar control. The blood glucose system is one of the major subsystems of the complete human energy system. In this study a simulation model and procedure for simulating blood glucose response due to various external influences on the human body is presented. The study is presented in two parts. The first is the development of a novel concept for quantifying glucose energy flow into, within and out of the human energy system. The new quantification unit is called ets (equivalent teaspoons sugar). The second part of the study is the implementation of the ets concept in order to develop the simulation model. Development of the ets concept - In the first part of the study the ets concept, used for predicting glycaemic response, is developed and presented. The two current methods for predicting glycaemic response due to ingestion of food are discussed, namely carbohydrate counting and the glycaemic index. Furthermore, it is shown that it is currently incorrectly assumed that 100% of the chemical energy contained in food is available to the human energy system after consumption. The ets concept is derived to provide a better measure of available energy from food. In order to verify the ets concept, two links with ets are investigated. These are the links with insulin response prediction as well as with endurance energy expenditure. It is shown that with both these links linear relationships provide a good approximation of empirical data. It is also shown that individualised characterisation of different people is only dependent on a single measurable variable for each link. Lastly, two novel applications of the ets concept are considered. The first is a new method to use the ets values associated with food and energy expenditure in order to calculate both short-acting and long-acting insulin dosages for Type 1 diabetics. The second application entails a new quantification method for describing the effects of stress and illness in terms of ets. Development of the blood glucose simulation model - The second part of the study presents a literature study regarding human physiology, the development for the blood glucose simulation model as well as a verification study of the simulation model. Firstly, a brief overview is given for the need and motivation behind simulation is given. A discussion on the implementation of the techniques for construction of the model is also shown. The procedure for solving the model is then outlined. During the literature study regarding human physiology two detailed schematic layouts are presented and discussed. The first layout involves the complex flow pathways of energy through the human energy system. The second layout presents a detailed discussion on the control system involved with the glucose energy pathway. Following the literature review the model for predicting glycaemic response is proposed. The design of the component models used for the simulations of the internal processes are developed in detail as well as the control strategies implemented for the control system of the simulation model. Lastly, the simulation model is applied for glycaemic response prediction of actual test subjects and the quality of the predictions are evaluated. The verification of the model and the procedure is performed by comparing simulated results to measured data. Two evaluations were considered, namely long-term and short-term trials. The quality of both are determined according to certain evaluation criteria and it is found that the model is more than 70% accurate for long-term simulations and more than 80% accurate for short-term simulations. Conclusion - In conclusion, it is shown that simplified simulation of the human energy system is not only possible but also relatively accurate. However, in order to accomplish the simulations a simple quantification method is required and this is provided by the ets concept developed in the first part of this study. Some recommendations are also made for future research regarding both the ets concept and the simulation model. Finally, as an initial endeavour the simulation model and the ets concept proposed in this study may provide the necessary edge for groundbreaking biotechnological discoveries. / PhD (Mechanical Engineering) North-West University, Potchefstroom Campus, 2003

The rapid and sustained development of the rural regions of South Africa continues to pose an extraordinary challenge to the development community of the country. Policy makers continue to be overwhelmed by the lack of development in the rural areas in spite of the various efforts made to develop them. A review of the publications and development plans of the study region indicates that the planners have for long been pre-occupied with taking limited perspectives of the development planning problems. Development plans have been conceived and implemented in terms of individual sectors instead of looking at their relations with other sectors and regions. This study seeks to make a contribution to the solution of the development problems of the rural areas of the former homeland regions by demonstrating how an integrated approach to the research process and to development planning could make a difference to the lives of the rural communities. This theme is illustrated with reference to the rural energy sector and its relations with the broader regional development problems, challenges and plans of the Sekhukhune district municipality of the Limpopo Province. / GEOGRAPHY / MA (GEOGRAPHY)

Die Bundesregierung plant im Rahmen der Energiewende den Anteil von erneuerbaren Energien an der Stromerzeugung in Deutschland von heute rund 25% auf 80% bis zum Jahr 2050 auszubauen. Damit stehen auch dem Stromsektor in Sachsen grundlegende Veränderungen bevor. Derzeit leistet im Freistaat Sachsen die Braunkohle den größten Beitrag zur Elektrizitätsbereitstellung. Mit dem zunehmenden Ausbau an erneuerbaren Energien steigt der Anteil dargebotsabhängiger Energieträger. Daraus resultieren technische und wirtschaftliche Herausforderungen für das bestehende Energiesystem, wie z.B. die künftige Bereitstellung von Systemdienstleistungen. Mit diesen und weiteren Fragestellungen zur Transformation des Elektrizitätssystems haben sich Nachwuchswissenschaftler der TU Dresden in den vergangenen zwei Jahren im Rahmen des vom Europäischen Sozialfonds – ESF geförderten Projekts EnerSAX auseinander gesetzt. Neben der Erstellung einer Potenzialanalyse für Sachsen wurden sowohl technische Fragestellungen,wie z.B. die Auswirkungen der Integration erneuerbarer Energien auf die Übertragungs-, Verteilungs-und Niederspannungsnetze, als auch ökonomische Fragestellung, wie z.B. die künftige Ausgestaltung der Regelenergiemärkte, untersucht. Durch die Zusammenarbeit der Nachwuchsforscher aus den Bereichen der Elektrotechnik und Energiewirtschaft konnten so integrierte Lösungsansätze zur Ausgestaltung einer weitgehend auf erneuerbaren Energien beruhenden Energieversorgung mit dem Fokus auf Sachsen im transnationalen Kontext erarbeitet werden. Die wesentlichen Ergebnisse aus dem Projekt werden in diesem Buch vorgestellt.

Die Bundesregierung plant im Rahmen der Energiewende den Anteil von erneuerbaren Energien an der Stromerzeugung in Deutschland von heute rund 25% auf 80% bis zum Jahr 2050 auszubauen. Damit stehen auch dem Stromsektor in Sachsen grundlegende Veränderungen bevor. Derzeit leistet im Freistaat Sachsen die Braunkohle den größten Beitrag zur Elektrizitätsbereitstellung. Mit dem zunehmenden Ausbau an erneuerbaren Energien steigt der Anteil dargebotsabhängiger Energieträger. Daraus resultieren technische und wirtschaftliche Herausforderungen für das bestehende Energiesystem, wie z.B. die künftige Bereitstellung von Systemdienstleistungen. Mit diesen und weiteren Fragestellungen zur Transformation des Elektrizitätssystems haben sich Nachwuchswissenschaftler der TU Dresden in den vergangenen zwei Jahren im Rahmen des vom Europäischen Sozialfonds – ESF geförderten Projekts EnerSAX auseinander gesetzt. Neben der Erstellung einer Potenzialanalyse für Sachsen wurden sowohl technische Fragestellungen,wie z.B. die Auswirkungen der Integration erneuerbarer Energien auf die Übertragungs-, Verteilungs-und Niederspannungsnetze, als auch ökonomische Fragestellung, wie z.B. die künftige Ausgestaltung der Regelenergiemärkte, untersucht. Durch die Zusammenarbeit der Nachwuchsforscher aus den Bereichen der Elektrotechnik und Energiewirtschaft konnten so integrierte Lösungsansätze zur Ausgestaltung einer weitgehend auf erneuerbaren Energien beruhenden Energieversorgung mit dem Fokus auf Sachsen im transnationalen Kontext erarbeitet werden. Die wesentlichen Ergebnisse aus dem Projekt werden in diesem Buch vorgestellt.

科学研究費補助金 研究種目:基盤研究(C)(2) 課題番号:10680481 研究代表者:早川 直樹 研究期間:1998-1999年度