Sub-Saharan Africa is the region in the world that suffers the most from poverty and its worst effects: hunger, lack of water and diseases. And the problem is not even decreasing: in the past years there has been a peak in undernourishment in the continent. Furthermore, according to ongoing research, the area is expected to be one of the most affected by climate change. A solution that tackles at the same time water scarcity, diseases, hunger and greenhouse gas emissions is urgent. Luckily, with the development in the past years of the solar photovoltaic and battery technologies, these solutions can now compete head-to-head with fossil-fuelled pumps. Indeed, the photovoltaic water pump (PVWP) is becoming the preferred solution for locals and NGOs, enabling a cheaper, less pollutant and more self-sustainable growth vector. In this thesis, a PVWP system is pre-designed. This means that the effect of the different variables over the system are studied, without aiming to design any specific system. However, the calculations are done with the climatic conditions of Fada N’gourma (Burkina Faso) as an example. To start, the importance of water for basic supply, sanitation and agriculture is researched through reviewing existing literature. The specific advantages of an advanced method of irrigation such as drip irrigation are also investigated. To continue, the analysis of the influence of each parameter intervening in the system is undertaken. First, a method to calculate the watering needs of the plants (through the concept of evapotranspiration), and simultaneously the passive self-regulation of PVWP systems for irrigation purposes is analysed. Second, the possibility to calculate faithfully the optimal angle with only climatic values and the size of the orchard is demonstrated. Third, a model to obtain the optimal diameter of the pipes through the optimisation of the cost is elaborated. The specific influence of the pump efficiency in this process is also explored. Fourth, an analysis on the effect in the system resilience to weather changes depending on the different starting dates for planting the crops is done. To finish, some considerations and a preliminary design are made. The option of implementing a storage system is discussed, with advantages of the batteries and the water tank. A quick economical evaluation done, leading to the conclusion that a PVWP system of the characteristics studied is viable under most of the circumstances.

The need to make maximum use of renewable resources to the detriment of fossil fuels to achieve environmental goals with an increasing energy demand is driving research into the development of technologies to obtain energy from sources that are not currently being exploited, one of them being fusion energy. The aim of this report is to provide a general overview of fusion and to provide a critical opinion on whether fusion will become a commercial energy source in the future, and if so when. The followed methodology has been a literature review complemented by an interview to B Henric M Bergsåker, teacher and researcher at the KTH on fusion plasma physics and information person for the Swedish fusion research.In the results section the fusion physics and different technological approaches have been presented. Among the studied different projects, the ITER Tokamak magnetic reactor has been selected as the most promising of these projects, as a product of international collaboration, and it has been analyzed in more detail. The obtained results have been that fusion can be an inexhaustible, environmentally friendly and safe energy source. The first-generation fusion commercial reactors are expected to be part of the energy mix before 2100.

Gävle Energi har nyligen implementerat en ny prismodell till fjärrvärmen med en säsongsprismodell som kom 2018 och en kapacitetsprismodell som kommer 2019. Den nya prismodellen ska återspegla kostnaden för att producera fjärrvärmen samt belöna kunder som utför effektiviseringsåtgärder. Kapacitetsprismodellen, som denna studie fokuserar på, kommer att baseras på anläggningens energibehov vid -10 grader. Då kapacitetspriset är samma för samtliga kunder så kommer priset kunden betalar att återspegla hur stort energibehov byggnaden har vid -10 grader. I denna studie har det undersökts om en uppskattning kan utföras för att ta reda på hur stort energibehov en nyansluten kunds byggnad behöver vid -10 grader utifrån tidigare anslutna kunder. Signaturer för 115 tidigare anslutna kunder med byggnader byggda från 2000 – 2018 användes vid denna studie. Byggnaderna kategoriserades för att kunna jämföra energibehovet för varje kund med en liknande byggnad. Utifrån detta skapades uppvärmningssignaturer för varje enskild byggnad, vilka sammanställdes i diagram uppdelade på varje byggnadskategori. Med detta var tanken att en standardsignatur kunde skapas för varje kategori för att sedan kunna använda denna signatur vid kapacitetsberäkning av en ny kunds byggnad. Då resultatet inte blev som tänkt kunde dessa standardsignaturer dock inte skapas, utan en djupare analys för varje byggnad ser ut att behöva utföras. Hade en standardsignatur skapats utifrån befintliga resultat hade ett felaktigt energibehov tilldelats kunder med hög respektive låg energianvändning. Två olika metoder användes för att beräkna energibehovet bakom uppvärmningssignaturerna, dels med boarean för byggnaderna, dels med omslutande arean då tanken var att den omslutande arean skulle ge ett bättre resultat. Användningen av den omslutande arean vid framtagandet av signaturerna visade sig dock inte vara av bättre användning då resultaten varierade för mycket. / Gävle Energi have recently implemented a new price model for district heating with a seasonal depended price model that came in 2018 and a capacity pricing model that will be implemented 2019. The new price model is supposed to reflect the cost to produce the district heating and to reward customers who preform efficiency measures to their buildings. The capacity pricing model, on which this study is focused on, will be based on the buildings energy demand at -10 degrees. Since the capacity price is the same for all customers, the price the customer pays instead will reflect the amount of energy demand the building needs at -10 degrees. In this study it will be investigated whether an estimate can be made to find out how big of an energy demand a newly connected customer’s building needs at -10 degrees from previously connected customers. Signatures from 115 previously connected customers with buildings build from 2000 – 2018 were used in this study. The building was then categorized to compare the energy demand for each customer with a similar building. Based on this, signatures were created for each individual building and then put together in a common chart for each category. With this, the idea was that a standard signature could be created for each category to the use this signature when calculating the capacity for a customer’s building. As the result was not as intended, these standard signatures could not be created without preforming a deeper analysis of each building. If a standard signature had been created with these results, an unfair capacity had been awarded to customers with a high and low energy consumption. Different analyzes were used to calculate the different energy demands for the creation of the signatures, partly with the housing area of the buildings and the surrounding area with the thoughts that the surrounding area would provide the study with a better result. However, the use of the surrounding area in the development of the signatures did not provide to be of better use as the results varied too much.

The renewable energy sources increase the volatility on theelectricity market. To manage the quick variations battery energystorage systems (BESS), together with other storing solutions, willbe required in the future. Depending on which level in the grid thebattery is placed, it can serve different purposes. In this report amarket analysis is conducted, which examine the performance ofbattery storages installed in Sweden. Further on, a simulation, withPV-panels and a battery, was performed at Behrn Arena in Örebro. From the market analysis it was shown that the majority of therespondents had used, or will use, their battery for peak shaving.This function is particularly meaningful for customers with a powertariff, which is the case for Behrn Arena. The simulated systemdecreased their yearly cost due to the power tariff with 70 000 SEKand the total electricity bill decreased with 155 000 SEK. For the batteries to be more profitable in the future, the batteryprice needs to decrease or the number of revenue streams need toincrease. One revenue with great potential is frequency regulation,which has proven its efficiency in other countries.

The global community is facing great challenges as the energy system is transforming towards more reliable, effective, clean and renewable production. Small-scale and micro networks will play an important role in this changeover. Its advantages over today’s large conventional energy systems are their reliability and stability. In small-scale and micro networks, there is usually a variety of production units such as photovoltaic, wind power and micro-combined heat and power (micro-CHP). In this study, a small-scale network with an application of two different types of biogas fueled micro-CHPs is analyzed. The units are a micro gas engine (MGM) and a micro gas turbine (MGT). The application of micro-CHP is validated using a reference facility connected to a small-scale district heating network. The reference facility is a heat production plant at a horse race track outside Eskilstuna, Sweden consisting of an oil boiler, a pellet boiler and a heat storage tank. The potential in replacing the oil boiler with renewable micro-CHP is investigated. A simulation model is built in the software GAMS, using Mixed Integer Linear Programming (MILP) and the solver CPLEX, and the model is simulated using the heat demand from the horse race track. Results from the model validation shows that it is possible for both the MGM or the MGT together with the pellet boiler and the heat storage tank to fulfill the heat demand of the facility. The horse race track handles 4 000 m3 of horse manure annually, which is transported 124 km to a compost treatment facility. Therefore, a general analysis of biogas production from horse manure is conducted in order to investigate the possibilities for better horse manure treatment on site. A calculation for a biogas reactor with a capacity for the maximum biogas requirement of the micro-CHP is implemented. Horse manure is suggested to be co-digested with food waste, in order to provide a higher biogas exchange. The result of a Life Cycle Cost (LCC) analysis indicates difficulties in justifying an investment of a micro-CHP together with a biogas plant at current prices for heat and electricity. The results show that the payback period for the MGM is 7 years which is 2 years shorter than its lifetime and the MGT payback period is 12 year which also is it lifetime. The MGM shows the largest investment potential since it has an investment cost approximately 860 kSEK lower than for the MGT. The MGM also has a slightly higher electrical efficiency which results in higher revenues from produced electricity. The chosen MGM in this study is slightly smaller than the MGT, resulting in a lower biogas demand and a lower investment cost for a biogas plant. A sensitivity analysis shows great impact of the electricity price on the payback period for both types of micro-CHP. The results show that with an electricity price of 280 SEK/MWh, both the MGM and the MGT repays within their lifetime. But since MGM has a higher net present value at all electric prices, is the MGM considered to be a more economical feasible investment. What the authors think should be highlighted is also the environmental benefits of more efficient treatment of horse manure at the horse race track together with the possibility of local production of fuel resulting in reduced CO2 emissions by 47 tons/year.

Submitted by BEATRIZ HELENE XAVIER null (beatriz_helene@hotmail.com) on 2016-10-06T01:37:14Z No. of bitstreams: 1 BeatrizHelene - Dis. Mestrado 2016.pdf: 2378192 bytes, checksum: 45cf939c1d65cdb81c77d339bd66b279 (MD5) / Rejected by Ana Paula Grisoto (grisotoana@reitoria.unesp.br), reason: Solicitamos que realize uma nova submissão com o arquivo correto. Agradecemos a compreensão. on 2016-10-06T16:45:37Z (GMT) / Submitted by BEATRIZ HELENE XAVIER null (beatriz_helene@hotmail.com) on 2016-10-07T11:50:40Z No. of bitstreams: 1 BeatrizHelene - Dis. Mestrado 2016.pdf: 2378192 bytes, checksum: 45cf939c1d65cdb81c77d339bd66b279 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-10-07T13:59:03Z (GMT) No. of bitstreams: 1 xavier_bh_me_guara.pdf: 2378192 bytes, checksum: 45cf939c1d65cdb81c77d339bd66b279 (MD5) / Made available in DSpace on 2016-10-07T13:59:03Z (GMT). No. of bitstreams: 1 xavier_bh_me_guara.pdf: 2378192 bytes, checksum: 45cf939c1d65cdb81c77d339bd66b279 (MD5) Previous issue date: 2016-08-05 / Agência Nacional do Petróleo, Gás Natural e Biocombustíveis (ANP) / A preocupação com o meio ambiente e com a qualidade do ar têm sido crescente e objeto de diversos estudos. Quanto maior a densidade populacional, maior a necessidade de consumo de energia e consequentemente, maiores os índices de emissões de poluentes. Neste sentido, é essencial a procura por novas fontes e sistemas mais eficientes de geração de energia, a fim de reduzir os níveis de poluição, diminuir o efeito estufa sobre o planeta, e, principalmente, reduzir a dependência de petróleo na matriz energética mundial. Partindo deste conceito e considerando aspectos técnicos, econômicos e ecológicos, neste trabalho analisam-se três casos de cogeração utilizando motores de combustão interna (MCI) operando com gás natural em comparação com biogás e gás de síntese (syngas), ambos provenientes da biomassa. São aplicadas metodologias de pesquisadores renomados, com o objetivo de determinar a eficiência de geração de eletricidade, a eficiência de geração de calor e a eficiência global dos sistemas, e ainda como parte da análise técnica, determinam-se índices de correlação entre a produção térmica e a potência elétrica dos motores, tornando previsível a capacidade de produção de água quente, vapor e água gelada, dependendo da capacidade elétrica do motor a ser utilizado na implantação de sistemas de cogeração. São determinados os custos de geração de eletricidade e calor, período de retorno dos investimentos e posteriormente são estudadas as emissões de CO2, NOx, SOx, MP e o CO2 equivalente para a determinação do indicador de poluição e da eficiência ecológica dos sistemas de cogeração considerados nesta dissertação. Conclui-se com o estudo realizado que os biocombustíveis são uma importante fonte energética que vem ganhando espaço dia a dia. Na análise ambiental, o gás natural perdeu em eficiência ecológica tanto para o biogás como para o gás de síntese, e a análise energética comprovou que não há grandes perdas na utilização de biocombustíveis em substituição ao gás natural. No aspecto econômico, o biogás demonstrou-se como o mais rentável frente aos combustíveis estudados, apresentando rapidez no retorno dos investimentos e baixo custo de produção elétrica e térmica. / The concern with the environment and air quality has increased and subjected to several studies. The higher the population density, the greater the need for energy consumption and therefore higher pollutant emission rates. In this regard, the search for new sources and more efficient systems for power generation is essential in order to reduce pollution levels and the greenhouse effect on the planet, and, most importantly, reduce dependence on oil in the global energy matrix. Based on this concept and considering the technical, economic and ecological aspects, this paper analyzes three cases of cogeneration using internal combustion engines (ICEs) operating with natural gas in comparison with biogas and synthesis gas (syngas), both stemming from biomass. Methodologies from renowned researchers are applied, with the aim of determining the efficiency of electricity generation, heat generation efficiency and the overall efficiency of the systems; furthermore, as part of the technical analysis, we determine correlation coefficients between the thermal production and the power capacity of the engine, making it possible to predict hot, steam and cold water production capacities, depending on the engine power capacity used in the implementation of the cogeneration system. We determine the costs of generating electricity and heat, the payback period and then CO2, NOx, SOx, MP and equivalent CO2 emissions are studied in order to determine the pollution indicator and ecological efficiency of cogeneration systems considered in this thesis. From this study we conclude that the biofuels are an important energy source which is becoming increasingly popular. In the environmental analysis, the natural gas was less ecologically efficient than both the biogas and the syngas, and the technical analysis showed that there are not great losses when using biofuels in place of the natural gas. In the economic analysis, the biogas was the most feasible in comparison with the natural gas and the syngas, with a short payback period and low power and thermal production costs. / PRH/ANP: 2010.4698-0

Thesis submitted in fulfilment of the requirements for the degree Doctor of Technology: Electrical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology / This research focuses on the predictive current control of multilevel converters with the aim of providing an optimized system for three-phase, multilevel inverters (MLIs) so that the load current and the voltage of the capacitors can be controlled. A model predictive current control algorithm is proposed, specifically directed at the utilisation of power obtained from renewable energy systems (RESs). The model was developed for three-phase, multilevel voltage source inverters (MLVSIs), three-phase, three-level diode-clamped converters (DCCs) and flying capacitor converters (FCCs). In this study the renewable energy systems model is used to investigate system performance when power is supplied to a resistiveinductive load (RL-load). The proposed control method was split into two different control algorithms. Firstly, a finite set-model predictive current control (FS-MPCC) method was developed to control the output current of three-phase, MLIs. This control method was selected to reduce the calculation effort for model predictive control (MPC) and to increase the possible prediction horizon. Secondly, to solve the flying capacitor voltage balance problem in an FCC, as well as to solve the DC-link capacitor voltage balance problem in a DCC, a hysteresis-voltage alancing algorithm based on predictive control, was designed—this algorithm was used to keep the flying capacitor voltages and DC-link capacitor voltages within their hysteresis bands. Finally, for some classes of power converters, a performance evaluation of the FS-MPCC method for three-phase, three-level MLIs was investigated in terms of power quality and dynamic response. The improvement was assessed in terms of total harmonic distortion (THD) of the output voltage for the RL-load. The modelling and co-simulation were carried out using MATLAB/Simulink with PSIM software. The co-simulation results indicated that the proposed control algorithms achieved both high performance and a high degree of robustness in RESs applications.

The purpose of this degree project is to analyze and investigate how digitalization will affect business modeling in the district heating business. The chosen approach to this degree project was an iterative, abductive method, in order to always use a feedback-analysis and to keep the project open for new findings. The interviews were a mix of a structured method and a qualitative approach. With the structured method, the findings from the interviews were similar and regarding the research topic, and the qualitative approach in some open questions led to matters that otherwise would have been unnoticed. The interviews were performed via e-mail, phone and through personal interviews. This degree project concluded that digitalization has an impact on business modeling in district heating. Digitalization will affect some elements in a major way, for example key resources that will be characterized by digitalization. The findings from this work showed that a business model operating in district heating in a time of digitalization should focus on three main parts: economy, environment and easy visualization. An optimization tool should focus on delivering a value that consist of these three, and the remaining elements should together contribute to that value proposition. / Syftet med detta examensarbete är att analysera och undersöka hur digitaliseringen kommer att påverka affärsmodellering inom fjärrvärmebranschen. Det valda tillvägagångssättet för detta examensarbete är en iterativ, abduktiv metod för att hela tiden återkoppla och hålla studien öppen för nya intryck. Intervjuerna är en kombination av strukturerad metod blandad med en kvalitativ ansats. Med den strukturerade metoden blir svaren inom samma ram samtidigt som den kvalitativa aspekten lockar fram svar som annars skulle passera obemärkta. Intervjuerna genomfördes via mail, telefon samt genom personliga intervjuer. Detta examensarbete drar slutsatsen att digitaliseringen kommer påverka affärsmodeller inom fjärrvärme. Digitaliseringen kommer påverka vissa element i större utsträckning som till exempel nyckelresurserser som kommer präglas av digitaliseringen. Upptäckterna från studien visar att en affärsmodell verksam inom fjärrvärme i en tid präglad av digitaliseringen ska fokusera på tre delar: ekonomi, miljö och lättförstådd visualisering. Ett optimeringsverktyg ska fokusera på att leverera ett värde som innehåller dem tre delarna och resterande element ska tillsammans bidra till det värdeerbjudandet.

This thesis evaluates a local direct current grid (DC-grid) wherefour office buildings with photo-voltaic (PV) facilities has beenconnected. The power system has been analyzed and a model of the gridhas been developed to quantify the increased own consumption and thereduction of power peaks. The results has been used to evaluate thegrid from an economic point of view to answer if the installation ofthe grid was profitable. The grid has also been evaluated from atechnical standpoint and future possibilities has been identified.The study shows that an own consumption of solar power was increasedfrom 81,6 per cent in average to 99,2 per cent, which resulted in areduction of annual consumed power by 34 MWh. The power peaks wasreduced with 196 kW in total annually. The analysis also shows thatthe electrical contract can be changed for in one of the buildings.The annual operating costs was reduced by 13 kSEK along with thereduction in energy equating to roughly 34 kSEK in savings, resultingin approximately 47 kSEK of total annually savings. With aninvestment cost of 531 kSEK and a cost of capital set to 5 per cent,the installed DC-grid is profitable. Future possibilities identifiedwas to connect more buildings and PV systems to the grid, analyzeelectrical consumption for greater understanding, implementation ofenergy storage and fast electrical vehicle chargers.

Made available in DSpace on 2016-08-17T14:52:51Z (GMT). No. of bitstreams: 1 Alex Ricardo Arquinego Paz.pdf: 1215286 bytes, checksum: 346776688a2985bd55dd36d813b4e81a (MD5) Previous issue date: 2004-03-05 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The main objective of this research is to implement and evaluate the performance of a numerical solver known as DASSL, in a transient and long-term stability program, applied in the solution of differential and algebraic equations representing the network and its components. The solver is a computer code purely mathematic, ready to use, comprising numerical methods suitable to the analysis of interested phenomena. The user must develop an interface to the input and output data according to his personal interests, i.e., according to the problem being solved. The solver efficiency was tested in several steps. The beginning was over the solution of a first order ordinary differential equation, moving to computer tests with hypothetical power systems, increasing gradatively the computer simulation complexity. The obtained results revealed that this solver is very efficient in time domain transient and long-term stability studies, certifying that the power system dimension is either small- or medium-port. The resulting information from this work form the basis to the implementation of advanced solvers in a stability program. The goal is, independently of the power system size, provide a small processing time keeping the reliability of the numerical results. / O objetivo principal desta pesquisa é implementar e avaliar o desempenho numérico e computacional de um solver-numérico conhecido na literatura como DASSL, em um programa de estabilidade de fenômenos transitórios e de longo-termo, usado na resolução de sistemas de equações diferenciais e algébricas que representam a rede de energia elétrica e seus componentes. O solver-numérico é um programa computacional de caráter puramente matemático, já pronto para uso, contendo métodos numéricos que podem ser adequados às análises dos fenômenos de interesse. O usuário deve então desenvolver uma interface para a entrada e saída de dados de acordo com seu interesse, ou seja, de acordo com o problema a ser resolvido. A eficiência do solver foi testada em etapas. Começou-se por resolver uma simples equação diferencial ordinária de primeira ordem, passando-se para testes com modelos de energia elétrica hipotéticos, onde se aumentou gradativamente a complexidade das simulações computacionais. Os resultados obtidos revelaram que este solver-numérico é muito eficiente em estudos computacionais no domínio do tempo de fenômenos transitórios e de longo-termo, certificando-se que os sistemas elétricos sejam de pequeno-, ou de médio-porte. As informações decorrentes deste trabalho servirão de base para a implementação em um programa de estabilidade de solvers-numéricos mais avançados. A meta é, independentemente do tamanho do sistema simulado, ter um tempo de processamento pequeno sem perder a confiabilidade dos resultados numéricos.