This master thesis examines if a PV system in “norra Djurgårdsstaden” (Stockholm) can be optimized by the addition of a battery storage system. Both in terms of increasing the usage of the produced PV energy and also (partly as a consequence) becoming more efficient and environment friendly. Simulations were run in both MATLAB and PVsyst. The simulations were based on measured data - PV production and consumption - and different scenarios were examined. Though the central aspect was to maximize the amount of PV energy used, simulations for peak shaving and a combination of the two were also examined.  The major differences between simulation in MATLAB and PVsyst were firstly, the fact that the input for consumption was monthly in PVsyst and hourly measurement (given by Incoord) was used in MATLAB and secondly, that different types of battery types had to be used. The battery type used in the MATLAB simulation was a NiMH battery from a company called Nilar. This battery type has the ability to be rejuvenated and thereby extend its lifetime. This type of battery did not exist as an option in PVsyst. Due to this the result of the simulation was not exactly the same. They were however similar enough to be useful; they showed similar patterns even at points of divergence.  Although the real estate was planned and built to be very energy efficient and environmentally friendly, the integration of a battery storage system was definitely able to optimize the PV system. Of the different integration options examined the most optimal was determined to be when the battery system was fed by the surplus energy from the existing PV system; after it has met momentary consumption needs. At the largest, battery storage system (10 batteries) the primary energy number (EPpet) decreased with almost 8 kWh/m2 - i.e. from 48,2 to just above40 kWh/m2. Self - consumption and self - sufficient was also positively affected by the battery storage with the former going from 59 to 77 % and the latter from 31 to 41 %. Furthermore with around 4 batteries in the battery storage system the EPpet decreased such as the real estate entered a higher order of environmental classification.  The battery system will always be an expense, however this expense is lessened by utilizing as much as possible of the PV energy, i.e. when the momentary consumption is met by the PV system before the surplus PV energy is directed to the storage in order to maximize self - consumption.

In recent times the problems regarding global warming and climate change have become increasingly relevant in our society. Public attention is growing due to seemingly larger and more severe natural disasters each year and the search for solutions to these problems is greater than ever. Humanity is facing a lot of environmental challenges, but one could argue that the increasing rate of greenhouse gas emissions related to energy production and use is the main focus. This study focuses on how electricity generating and storage technologies can be installed for different types of buildings and businesses to maximize economic benefits and at the same time reduce dependency on grid bought electricity. The buildings in the analysis will have prior solar PV systems installed ranging from 35 kW to 254.8 kW in capacity. Three different buildings within this interval have been chosen and have the solar PV capacity of 35.84 kW, 143.36 kW and 254.8 kW. These buildings have been chosen to get three different load profiles that are as different as possible, given the available data. The study concludes that only using solar PV is the financially most profitable system configuration for all three buildings, rated by maximum IRR. Both wind power and batteries have a negative impact on IRR for all buildings. The building with the least changes in day-to-day peak demand benefited the most from solar PV. Wind power affects the demand in a similar way as solar PV, however batteries added more value to a building with a less consistent load curve. / På senare tid har problemen med global uppvärmning och klimatförändringar blivit alltmer relevanta i vårt samhälle. Allmänhetens uppmärksamhet växer på grund av till synes större och allvarligare naturkatastrofer varje år och sökandet efter lösningar på dessa problem är större än någonsin. Mänskligheten står inför många miljömässiga utmaningar, men det går att hävda att den ökande andelen växthusgasutsläpp relaterade till energiproduktion och användning är huvudfokus. Denna studie fokuserar på hur elproduktionens- och lagringsteknologier kan installeras för olika typer av byggnader och företag för att maximera ekonomiska fördelar och samtidigt minska beroendet av köpt el från elnätet. Byggnaderna i analysen har tidigare installerade solcellsanläggningar som sträcker sig från 35 kW till 254.8 kW. Tre olika byggnader inom detta intervall har valts och för dessa var solenergikapaciteten 35.84 kW, 143.36 kW och 254.8 kW. Dessa byggnader har valts för att få tre olika elförbrukningsprofiler som är så olika som möjligt med tanke på den tillgängliga datan. Studien drar slutsatsen att användningen av endast PV är den ekonomiskt est lönsamma systemkonfigurationen för alla tre byggnader, rankad efter maximal IRR. Både vindkraft och batterier påverkar IRR negativt för alla byggnaderna. Byggnaden med minst förändringar i det dagliga toppbehovet gynnades mest av solceller. Vindkraft påverkar elbehovet på liknande sätt som PV, men batterierna däremot gav mer värde till en byggnad med en förbrukningsprofil som var mindre konsekvent.

DC nano-grid system shows promising prospect and enjoys some advantages over AC micro-grid system. It enables easier integration of multiple renewable energy sources with multiple loads. Photovoltaic (PV) is essentially a typical renewable source that serves as main power source in DC nano-grid system. Traditional PV system includes centralized PV system, string PV system and micro-converter PV system. More recently, smart converter PV system has been introduced and shown great improvement in aspects of power generation achieved by distributed Maximum Power Point Tracking (MPPT). It is also advantageous over micro-converter PV system due to lower cost and flexibility. Detailed case study demonstrates that power generation efficiency can be easily compromised because of mismatch between different panels in centralized and string PV systems. In smart converter PV system, this problem can be solved due to distributed MPPT for each individual panel. The smart converter system has a very wide voltage range within which all panels can generate maximum power. The location and the width of this range are subject to change under different mismatch conditions. A second stage converter is needed to locate the array MPPT range. However, there is instability problem when doing second stage MPPT with traditional methods. Modified methods based on conductance control and resistance control are analyzed and compared. Both methods can solve the MPPT instability problem. However, in terms of steady state performance, resistance control MPPT is more promising in terms of higher utilization ratio and faster tracking speed. It is because both methods are of inherited variable operating point step size with constant conductance or resistance perturbation step size. However, the operating point change decreases with resistance perturbation but increases with conductance perturbation otherwise. Therefore, resistance control MPPT is chosen as a good candidate. Both simulation and experimental results verifies the concept. / Master of Science

Utbyggnationen av solceller ökar exponentiellt både i Sverige och internationellt. En anledning till detta är sjunkande priser, mer effektiv teknik, skattereduktioner och andra ekonomiska incitament samt ett ökande intresse från bland annat elbolag. I många fall behövs fortfarande ekonomiska hjälpmedel som just skattereduktioner eller investeringsstöd för att PV-system (solcellsanläggningar) ska bli förmånliga. I den här fallstudien undersöks möjligheten att installera solceller på Västerberg folkhögskola i Storvik. Fastigheterna ägs av Region Gävleborg. Bionär Närvärme AB som är ett dotterbolag till Gävle Energi AB tillhandahåller värme till fastigheterna via en pelletspanna. På sommaren används el till pannan då värmebehovet är lågt och det finns ett intresse att producera sin egen el med hjälp av solceller. El för uppvärmning tas från skolans elabonnemang och därför dimensioneras PV-systemet mot hela elbehovet. Syftet var att först identifiera lämpliga tak, för att sedan finna den mest kostnadsoptimala storleken på ett PV-system för skolan. Därefter utfördes en simulering för att ta reda på årlig elproduktion och med hjälp av dessa resultat kunde ekonomiska förutsättningar beräknas. Lämpliga takytor valdes ut med avseende på orientering, lutning, storlek och placering av elcentraler. Kvantitativa data gällande fastigheterna och elanvändning samlades in. Därefter testades olika dimensioner på anläggningen i Winsun för att finna den storlek som gav kortast rak återbetalningstid. Sedan utfördes simulering av vald systemstorlek i PVsyst där årligt elutbyte presenterades som resultat. Med hjälp av givna och beräknade värden för elanvändning, solcellsproducerad el, egenanvänd el och överproducerad el (som säljs ut på elnätet) kunde en ekonomisk analys utföras. Resultatet visar att den anläggningsstorlek som ger kortast återbetalningstid är strax under 100 kWp. Efter simulering av valda takytor i PVsyst uppnåddes en toppeffekt på 94,6 kWp. Detta gav en återbetalningstid på 7,8 år. / The advancement of photovoltaic systems is growing exponentially both in Sweden and internationally. Reasons for this include decreasing prices, more efficient techniques, reduction in taxes as well as the increasing interest. In many cases, financial incentives like tax reductions or investment incentives are still necessary for photovoltaic systems to become profitable. In this case study, the possibility of installing a photovoltaic system at Västerberg folkhögskola in Storvik is examined. The properties are owned by Region Gävleborg. Bionär Närvärme AB, which is a subsidiary of Gävle Energi AB, provides the properties with heat through a pellet boiler system. In the summer however, electricity is used for the boiler when the heating requirement is less demanding, and there is an interest in producing electricity using solar cells. Since there is only one electricity subscription the PV-system is dimensioned with regards to the whole of the school’s electricity use including heating. The main purpose was to first identify suitable rooftops and then find the most costeffective size of a photovoltaic system for the school. Then, a simulation was performed to find out the annual electricity production and with the help of these results, an economic calculation could be determined. Suitable rooftops were selected with respect to orientation, angle, size and placement of distribution boxes. Quantitative data regarding the properties and electricity use were collected from Region Gävleborg. Subsequently, different photovoltaic system sizes were tested in Winsun to find the system size that yielded the shortest straight repayment time. Next, simulation of the selected system size was performed in PVsyst, where annual electricity exchange was presented as a result. An economic analysis could be carried out with the help of the values of electricity usage, solar-produced electricity, self-used electricity, over-produced electricity (which is sold to the power grid). The result shows that the system size that gives the shortest repayment time is just under 100 kWp. After simulation of selected rooftops in PVsyst, a peak power of 94.6 kWp was achieved. This gave a payback period of 7,8 years.

Ethiopia has been facing problems regarding power generation, distribution, balancingbetween demand and supply and access to modern energy service. About 92.4% of energysupply is from biomass (mostly in traditional) 5.7% oil which is not friendly with theenvironment and about 1.6% of energy supply is from renewable energy resource,hydropower plants.Being dependent on hydropower plant causes the country to face many challenges indistribution and balancing demand and supply. This thesis provides another way ofconsidering and implementing renewable energy resource (solar energy resource) throughtechnologies like grid-connected roof mounted solar PV system and CSP plant with the helpof PVGIS, PVWatt and SAM software.This thesis aims to come up with an idea that will work out for current engineering, socialand political issue that is seen in the country. Considering new way in planting PV system onthe roof is strongly recommended and increasing the alternative sites for power generationalong with the appropriate technology is recommended as another way. The possibility andpower generating efficiency is checked through each application.Based on the demonstration in all software’s used, it is clearly visible that the country couldhave been satisfied the needed demand and become the hub of east Africa as mentioned inthe policy and strategy. However, this dependency causes the country to insufficiently supplythe need. Apart from the possibilities and estimation, ideas that might help the country tocome over these challenges are provided in recommendation section.

As the world is moving towards the renewable energy, there is increase in usage of the electric vehicles in transport sector. This has led to more consumption of electricity from the grid and thus affecting its stability. To overcome this issue many decentralized charging stations have come of which generating electricity from the solar energy is more popular. These solar carports act as a shelter for the vehicles from various climatic factors such as rain, snow, dust in addition to producing renewable electricity. The main aim of this thesis study is to design a solar carport with the reflector compared to the existing Solar carports. The roof selected for this thesis study is a “V” shaped roof with the PV modules installed on one side of the roof and a reflector installed on the other side of the roof. The objectives of this thesis study are creating a mathematical irradiation and yield model of the PV system with and without a reflector. In addition, find the optimum roof tilt angle for a PV system with the reflector. Finally, determine the optimum increase in the annual energy yield for a PV system with the reflector compared to the PV system without a reflector. Microsoft Excel is used to create the mathematical irradiation and yield model of the PV system. The simulation was done for three different locations by obtaining hourly irradiation and temperature data from the PVsyst software. As a case study four different reflective materials of different specular and diffuse reflectance were chosen for better understanding and comparison. The simulation results showed that there is significant increase in the annual energy yield for a PV system with the reflector for all the locations. The study also shows that the increase in energy yield, optimum roof tilt angle is dependent on the specular and diffuse nature of the reflector. The study has concluded that the increase in the annual energy yield for a PV system with the specular reflector is more compared to a PV system with the diffuse reflector for the lower roof tilt angles and vice versa. It is also clear that the increase in the energy yield is similar for all the three locations. Hence, based on the roof tilt angle the selection of the reflector material needs to be done for an optimum design of the solar carport.

The increasing global energy demand, which today is mainly supplied by energy sources with a fossil origin, is a severe threat to the environment and to the security of supply. In order to handle these problems, renewable energy sources are promoted globally as well as nationally in Sweden. Solar photovoltaic (PV) technology is one of the most mature and commercial renewable energy technologies and could play a vital role in phasing out fossil energy sources. In the emerging, promising concept of solar landfills, PV systems are installed on closed landfill sites in order to combine renewable electricity production with resource efficient use of land. In this study the legal, technical and financial aspects concerning a solar landfill project in a Swedish setting were investigated. Additionally, the potential of the concept on a regional level in Sweden was analysed. The methodology used in the study featured literature research, interviews, and a feasibility assessment of a solar landfill project on Visby landfill. Regarding the legal aspects linked to a solar landfill project, an inconsistency between Swedish municipalities concerning the need of a building permit for a ground mounted PV system was revealed in the study. While some municipalities demand a building permit, others do not. Additionally, the fact that a closed landfill usually is classified as an environmentally hazardous activity doesn’t result in any need for additional permissions for a PV system installation on a closed landfill. Therefore, such legal aspects are not likely to hinder a solar landfill project to any great extent. Considering the technical aspects, the choice of mounting system must be done carefully because of the special conditions which exist on a landfill site; such as ground penetration restrictions and risks of settlement. While a ballasted mounting system can avoid ground penetration, a driven pile mounting system generally features a lighter construction. Furthermore, a fixed tilt mounting system is preferred over a sun tracking mounting system due to the extra weight and sensitivity to settlement which comes with the latter choice. Regarding the choice of PV modules, thin film modules generally feature a lower weight and can therefore be advantageous in comparison with crystalline silicon modules. In the case of Visby landfill, where penetration was preferred to be avoided but where the risk of settlement was considered low, the PV system which was deemed most suitable for the site featured a ballasted fixed tilt mounting system with crystalline silicon PV modules. Considering the financial aspects, the study emphasises the importance of using the produced electricity to offset consumed electricity in order to enable a sound investment. This can be done by a wise choice of owning and financing structure where the produced electricity offsets consumed electricity for a large consumer, e.g. an industry or a grocery store, or for a number of residences in a community solar. The economic feasibility also heavily depends on the projects’ possibility to use policy incentives and tax exemptions. The feasibility assessment of Visby landfill showed that the most economically feasible investment was possible by founding a community solar which offsets the members’ consumed electricity. Such an investment would feature a 10 year payback time and an internal rate of return of 8.3 %. Finally, the potential of the solar landfill concept on a regional level was identified as significant. In a scenario where the PV system suggested for Visby landfill in the feasibility assessment is installed on all the suitable landfill sites on Gotland, the island has the possibility to produce 22 GWh of electricity from solar landfills, thereby meeting the regional energy goal set for 2020.

The use of solar photovoltaic systems has increased in the past years in an effort to move towards cleaner energy sources. Solar panels are however affected by negative factors such as dust deposition which hinder their performance. The negative effects that dust deposition has on solar panels depend on how much dust gets deposited on solar panels and how it spreads on the top surface. The spread of dust on solar panels can be uniform where all the solar panels in a entire solar photovoltaic array have the same amount of dust deposition. This is an ideal case and can be defined as uniform dust deposition. However, in real life operation, the spread of dust deposition can vary with one solar panel having a different quantity of dust deposition from another. This is defined as non-uniform dust deposition. Non-uniform dust deposition negatively affects the performance of solar panels by reducing the irradiance that reaches the solar cells thereby reducing the performance of the solar panels. The negative effects of non-uniform dust deposition are more significant over time and when there is no intervention to remove the dust. In practice, the negative effects of non-uniform dust deposition on photovoltaic modules has been addressed by periodically cleaning their top surfaces. Periodic cleaning can however increase the operational costs in terms of the cleaning frequency, time taken, cost of cleaning resources and effectiveness. In this study, we propose an optimal cleaning strategy for the solar power plants that are prone to the non-uniform dust deposition. To develop the optimal cleaning strategy, we first investigate the dust deposition process and develop a model to describe the relationship between the solar power generation and non-uniform dust deposition patterns. Then we formulate an optimization model to identify the most cost-effective solar panel cleaning plan. In the optimisation, the additional revenue due to cleaning the solar panels is formulated as the objective function. The decision variables are the number of photovoltaic strings cleaned at each cleaning interval. To highlight the effectiveness of the proposed solar panels cleaning strategy, the developed cleaning strategy is applied to a case study where analysis of the performances of other solar panel cleaning strategies, namely “full cleaning”, “no cleaning” and “random cleaning” is done. The results from the study show that the optimal cleaning strategy outperforms all the other cleaning strategies showing its effectiveness. The optimal cleaning strategy developed is useful to solar photovoltaic plants owners whose plants are located in dusty or polluted areas. It first provides them with an understanding of non-uniform dust deposition. It also provides a way of reducing the effects of non-uniform dust deposition through optimized cleaning which is cost effective and that allows the photovoltaic array to continuously give the desired output. / Dissertation (MEng)--University of Pretoria, 2020. / Electrical, Electronic and Computer Engineering / MEng / Unrestricted

The aim of this Master Thesis is to find the most suitable amount of photovoltaic (PV) panels to sustain an off-grid thermal energy storage (TES) system and to compare a maximum power point tracker (MPPT) with a pulse width modulator (PWM) in order to analyze which one of them that best suits the system. The purpose is to provide feedback on the design of the electrical part of the system in order to make it suitable for testing in a school in an Uganda refugee camp. This is done by developing a simulation model and by performing an economical analysis of the system. Additionally, visits to the considered refugee camps are done. The results are based on data from the camps and interviews at the Physics department at Makerere University and consider the number of meals cooked by the TES as well as economical profitability and payback time. The recommended amount of PV panels is nine and the recommended controller is an MPPT. The simulation shows that the system reaches a point where an increasing number of panels doesn't increase the number of cooked meals by much. The economic analysis shows that this small increase is not enough to make up for the extra costs of adding more PV panels. Having a lower cost, PWM is preferred in the early years by the economic analysis. However, having a low efficiency, it is less superior to the MPPT. The payback time and revenue are better for the MPPT in the investigated cases. It is important to consider that the model doesn't show reality to a full extent. Experiments are made where it is found that the model is inaccurate on an hourly level but can be considered valid over longer periods of time. When choosing the results, a trade-off is made between maximizing the revenue or shortening the payback time of the TES system. Considering rough circumstances and the uncertain future of the camps existence, short payback time is chosen. This results in nine panels being the optimum amount. However, if the aim is to maximize revenue, twelve panels are better than nine. The price of firewood is a factor of uncertainty which this study relays a lot on and it's thereby important to consider when reading the results. Suggestions for future studies are to investigate the price development of firewood further or to test the use of stones in the thermal storage tank to decrease costs. Additionally, possible utilization of surplus produced energy from the system could be investigated in order to find extra benefits from the installation.

Sverige har som mål att år 2040 ha helt förnybar elproduktion och därmed utredsalternativ som till exempel vind- och solenergi till elförsörjning där främstsolenergin har potential för mindre och medelstora system för privatpersoner ochföretag. Som en del i denna utveckling har bostadsrättsföreningen Stenbär i Gävlebörjat intresserat sig för att installera solcellssystem, vilket blev grunden för dettaprojekt. Målet med den här utredningen var att utreda områdets potential för ensolcellsanläggning samt hur många kilowattimmar denna skulle kunna genereraper år.Inledningsvis var intentionen att utföra simuleringarna i IDA ICE 4.8, men underförberedelserna inför arbetet uppmärksammades ett webinar på Youtube där IDAICE 5.0 beta presenterades. Equa Simulations AB, vilka har utvecklatprogrammet, förklarade där uppdateringar och styrkor med den nya versionen. Iden nya versionen finns nu möjlighet att upprätta och simulera mer komplexasolcellsystem samt få ut mer korrekta och mer detaljerade resultat. På så vis bleväven en mindre analys av IDA ICE 5.0 beta en del av det här examensarbetet.Mätningar av husens höjd och längd samt avstånd till omkringliggande skogutfördes på plats och takens lutning beräknades till 14,5°. Ritningar över områdettilldelades av uppdragsgivaren och klimatdata återfanns i mjukvaran. En kartbildfrån Google maps behandlades i Photoshop till grund för modellering i IDA ICE.Byggnaderna delades sedan upp i två kategorier, sydlig och öst/västlig riktning.Inga moduler placerade i nordlig riktning simulerades då det inte förväntades varalönsamt. Solcellerna placerades i två lutningar, 14,5° som är takens lutning och45° vilken är den lutning som används av Energimyndigheten vid deras tester avsolcellssystem. Jämförelsen av taklutningarna visade dock endast en skillnad på2,5 %. Då all information om byggnaderna ej varit tillgänglig har områdetsenergibehov, utifrån schablonvärden, beräknats till 64 kWh/m2 och totalt522 MWh/år. Detta för att kunna ställa den i proportion mot solcellsystemetspotentiella elproduktion, vilken i simuleringsresultaten uppgick till 554 MWh/år.Systemkostnaden för det fullstora modellerade systemet landade på 10 600 kronorper installerad kilowattpeak respektive 2 025 kronor per installerad kvadratmetersolpanel. Om återbetalningstiden sätts till 10 år ger det en systemkostnad på 1.17kronor per producerad kilowattimme. Undersökningen visar att potential finns attproducera en stor mängd solel i området. Då systemet producerar ett överskottunder sommarhalvåret finns även möjlighet att sälja el. / Sweden’s energy policy objectives aim to have strictly renewable energyproduction by the year 2040. Alternatives such as wind- and solar power aretherefore implemented as alternatives to fossil fuel where solar power has thebiggest potential for small and medium sized systems for private houses andsmaller companies. As a part of this development homeowner’s association BRFStenbär i Gävle have considered installing PV-systems in their residential areaand that became the foundation for this master thesis. The goal with this projectwas to investigate the residential areas potential for solar powered electricityproduction and how much energy it may produce per year.The simulations were initially meant to be made in IDA ICE 4.8, but during thepreparations a webinar on Youtube was found where the beta version of IDA ICE5.0 was presented. In the presentation Equa Simulations AB, who are thedevelopers of the programme, explained the updates and new features with thenew version. The new version includes possibilities to model and build morecomplex PV-systems and receive more correct and detailed results. Hence, asmaller analysis of IDA ICE 5.0 beta became a part of this master thesis.Measurements of the building’s height and length and the distance to thesurrounding trees were made on site. Drawings of the residential area wereprovided by the client and the climate data were already installed in the software.A map of the area was downloaded from Google maps, modified in a pictureediting programme and used as a base for the modelling in IDA ICE. Thebuildings were divided into two categories, south and east/west orientation. NoPV-systems were placed and simulated in northern orientation since it was notexpected to be profitable.The solar panels were placed in two different angles, 14.5° which is the angle ofthe roofs, and 45° which is the angle used by the Swedish energy agency for theirtesting of PV-systems. The comparisons only showed a deviation of 2.5 %. Allinformation about the building’s energy needs were not available, so fromstandard values their needs were calculated to be 64 kWh/m2 and in total522 MWh/year. This was made to enable comparisons of their needs with thepotential energy production, which amounted to 554 MWh/year. The system costof the total PV-system amounted to 10 600 SEK/installed kWp and 2 025 SEK/m2installed PV-panel. If the repayment period is set to 10 year the system costbecomes 1.17 SEK/kWh. As the system produces more electricity during summerthan needed there is also a possibility to sell the excess to the grid.