Energy consumption is on a permanent rise and it is becoming increasingly concentrated in cities. Hence, cities have to work on saving energy and being more efficient by finding sources with great potential to produce their own energy and implanting the correct policies. Photovoltaics is the renewable energy technology with the higher potential in the urban context and Sweden is highly committed on its investment since it is the less developed renewable source in the country. The aim of the thesis is to compare two methodologies and determine which one is better or gives more relevant information for this kind of studies in order to evaluate how good a solar map is. For doing this, the first step is to create a solar map to have a general idea about the solar potential and to know which roofs are more suitable to install PV systems. This is made with LiDAR data using ArcGIS and SEES software. After that, another study on the quantity of solar power that could be obtained from those roofs will be performed using PVsyst, where it is possible to develop an entire PV system installation and obtain more exhaust results on energy production and shadowing. Four buildings are going to be evaluated, two public ones located in Gävle city centre (Library and Concert House) and two residential ones located in Sätra. Factors such as the optimal tilt, the best azimuth angle and the distance between panel rows are dimensioned in order to reduce shading loss and improve the performance ratio of the system in PVsyst. The final system is defined with 10° tilt, south orientation (0° azimuth), 1.5meters distance between rows and modules in strings of 9 panels connected in series for the four buildings. The simulated production from the best alternative is compared with the solar map results. Since the solar map contains information about total yearly irradiation, the energy production is obtained by means of visual exploration of the results combined with simple calculations that include GCR and system efficiency. The results show that a solar map is a reliable tool to obtain a general estimation of the solar potential in buildings but it is necessary to first identify its limitations and be able to filter the results. On the other hand, PVsyst software allows making several simulations and eases to obtain a PV system in a building or structure with detailed results of the system components. It can be concluded that since the PVsyst only allows to work with specific buildings or structures, a solar map permits big amounts of data calculations. It can be said that a solar map takes part in the process of obtaining a pre-project and the PVsyst is used in the project when a real installation is sized. Nevertheless, both methods are found to be reliable and suitable for solar potential assessment works since the results obtained match.

With the growing popularity of solar cells in Sweden, real estate companies have become interested in the possibility of installing solar panels when constructing new apartment buildings. Riksbyggen is one of these companies that sees solar energy as an interesting alternative when constructing energy-efficient buildings with low energy consumption. The purpose of this study is to investigate optimal system solutions and the profitability of a PV-system in a newly produced apartment building containing 28 apartments in Västerås. This investigation is made possible by creating and simulating the PV-system in the simulation program PVSyst. The PV-system that will be installed on Brf. Sjökortet has an installed capacity of 54 kW. 40 kW will be placed on the roof with a tilt of 4° while 14 kW will be placed on the facade with a tilt of 90°. According the simulation results, the PV-system will produce 43,6 MWh per year, which means the specific electricity production becomes 807 kWh/kWp. Own use of solar electricity is estimated to be 61 %, which means that 26,7 MWh will be utilized directly by the housing association, while 16,9 MWh must be submitted for sale. Out of the solar electricity that can be used directly 9,9 MWh will cover the property electricity meanwhile the remaining 16,8 MWh covers the residents household electricity. The residents of the housing cooperative will thus gain access to a large portion of the produced solar electricity without having to pay for it. The PV-system will without investment aid become unprofitable with an annuity of – 16 304 SEK per year. When the investment aid covering 35 % of the investment cost is included, the PV-system becomes profitable with an annuity of 2 687 SEK per year. The own use of solar electricity is difficult to improve by only changing the tilt of the solar panels. However, the results shows that a greater amount of solar electricity can be utilized by the housing cooperative in the winter months by increasing the amount of solar panels on the facade while decreasing the amount of solar panels on the roof with the same amount. A higher amount of solar panels on the facade will though decrease the yearly solar electricity production, making it more difficult for the PV-system to show profitability. The determined distribution of solar modules on the roof and facade is optimally distributed if the goal for the housing association is to utilize as much solar electricity as possible directly.

During the recent years the popularity of solar power have increased tremendously. With the increased interest in solar power comes a development of more efficient and different types of technology to harvest the sun rays. Monofacial panels have been on the market for a long time and have rather developed simulation models. The bifacial technology on the other hand have been researched for years but just recently found its way to the market. Simulation models for the bifacial panels are continuously being developed and they are a key aspect to increase the knowledge about the bifacial technology. Most of the research that has been conducted until today is mainly about the bifacial gain, not about the bifacial simulation models.The purpose of this thesis was to evaluate and validate simulation models of bifacial solar panels in PVsyst with comparisons to measured data from six different bifacial installations in Sweden. The installations had different system configurations and varied in: tilt, azimuth, pitch, elevation, number of rows and albedo. Furthermore, the installation configuration parameters were analyzed to see how they affect the bifacial system and what an optimal configuration would be for a bifacial installation in Sweden.The results show that the main difficulties for an accurate simulation model is to determine the proper input data. The irradiance and albedo proved to be the most difficult parameters to determine. The irradiance was accurate looking at yearly level but already during monthly distribution the error is taking effect. One of the reasons for the errors is the difficulties to determine the diffuse irradiance fraction of the light, especially during cloudy days. The albedo was found to have a linear dependency on the yield, which meant that it is possible that the inaccuracy of the model are solely dependent on albedo.For tilted installations without optimizers the yearly error of the simulation ranged between -5,2% to +3,9% where the lower limit value is suspected to be caused by a wrong albedo value. For a tilted installation with optimizers the error was +9,1%. This could be caused by two reasons; the optimizers are even more dependent on the irradiance or that the software exaggerates the benefits of optimizers. The simulations of vertical installations had an error between -5,4% to -3% and are more accurate than the tilted simulations.Different parameters effect on the specific yield were studied using a simplified simulation model and stepwise change of each parameter. The results were that four of the six studied parameters have no characteristic change on each other and the optimal conditions was to maximize the pitch, elevation and albedo and minimize the number of rows. The remaining two parameters tilt and azimuth showed a dependence on the other parameters, where the optimal azimuth only was affected by tilt while the optimum tilt was affected by all the other parameters. This revelation lead to the conclusion that tilt is the most suitable parameter for optimization of installations because of its dependence on ambient conditions. The optimum tilt was found for the studied cases and in five of the six cases it would have an increased specific yield if the tilt was optimized. Note that for four of those five would lead to an increase of less than 0,5% while for the fifth an increase by 14,2%.

Idag utförs internationella standardtest på solcellspanelerna som speglar instrålningsförhållandenaen klar dag. Instrålningsförhållandena i norra Sverige skiljer sig från de på södra breddgrader. Solens bana är flackare sett till horisonten vilket medför högre luftmassförhållande,lägre instrålad effekt och större andel diffust ljus. Detta kan påverka vilken typ av modul som bäst lämpar sig för användning på norra breddgrader. En instrålningsanalys, produktionsanalys samt simulering av produktion i programmet PVsyst har utförts. Data till instrålningsanalysen är hämtad för Kiruna, Luleå, Norrköping,Visby och Piteå. Uppmätt data från SMHI och en lokal väderstation i Piteå jämfördes med resultat från instrålningsmodellen STRÅNG. Uppmätt data för olika orter jämfördes. Produktionsanalysen genomfördes för två trackingsystem, Kempersystemet och Degersystemet i Piteå 2017, där produktionen per modultyp ställdes mot varandra inom samma system. Trackingsystemens produktion simulerades för 2017 och jämfördes med dess uppmätta produktion. Resultatet från jämförelsen mellan orternas instrålning visade att Luleå, sett till andelen diffust ljus, liknar Norrköping mer än Kiruna, trots att Kiruna är närmre. STRÅNG tycks ofta underskatta instrålningen samt vara bättre på att modellera klara dagar. Den lokala väderstationens globala horisontella instrålning stämde bra överens med uppmätt instrålning från SMHI för Luleå 2017. Produktionsanalysen visade att tunnfilmsmodulen CIGS QSmart producerade mest, sett till Wh/Wp, under perioderna med högre total produktion medan monokristallina modulen Yingli Panda producerade lägst. För perioder med lägre total produktion var resultatet de motsatta. Sett till år 2017 producerade den texturerade multikristallina ITS ARC modulen mest. Bäst lämpad modul för användning på nordliga breddgrader tycks därför variera beroende på studerad period. Simulering av Kempersystemets produktion gav ca 1600kWh=kWp mer än den uppmätta produktionen medan Degersystemets gav ca 140kWh=kWp mer. Detta kan tyda på att Kempersystemets uppmätta produktion var lägre än väntat 2017. Modulens temperatur och verkningsgrad påverkas av instrålad effekt och shuntmotståndets storlek påverkar mängden energi som modulen kan leverera. Modulerna som installeras på nordliga breddgrader bör vara bra vid diffust ljus, ha låga temperaturkoefficienter och resultatet tyder på att en texturerad yta kan vara att föredra. Modulernas information bör finnas tillgänglig via databladen samt att producenter och återförsäljare borde kunna bistå med den. För att komplettera dagens standardtest bör ytterligare ett test införas som motsvarar en mulen dag med lägre instrålad effekt. / Today, international standard tests are performed on solar panels that represent the conditions of irradiation of a clear day. The irradiation conditions in the north of Sweden is different from more southern latitudes. At northern latitudes, the sun’s path is closer to the horizon, which results in a larger air mass ratio, less irradiation and a larger amount of diffuse light. This can affect the type of module that is best suited for use. At northen latitudes, additional tests might be needed that are not covered by the standard tests. An irradiation analysis, production analysis and a simulation in the photovoltaic system software PVsyst were performed. The data for the irradiation analysis were retrieved for Kiruna, Luleå, Norrköping, Visby and Piteå. Measured data from SMHI and a local weather station in Piteå were compared with results from the solar irradiation model STRÅNG. Measured data for the different locations were compared. The production analysis was preformed for two tracking systems, the Kempersystem and the Degersystem in Piteå 2017. The production per type of module was compared within each system. The trackingsystems production for 2017 was simulated and compared with the measured production. The result of the comparison between the irradiation of the different locations showed that the proportion of diffuse light in Luleå is more similar to Norrköping than Kiruna, even though Kiruna is located closer. STRÅNG often seems to underestimate the irradiation and appears to be better at modeling a clear day. The local weather station’s global horizontal irradiation matched well with measured irradiation from SMHI for Luleå 2017. The production analysis showed that the solar panel CIGS QSmart produced the most in Wh/Wp during periods with high total production, while the solar panel Yingli Panda produced the least. For periods with low total production, the result was the opposite. The textured ITS ARC module had the highest production during 2017. According to the results, most suitable module for use at northern latitudes seems to vary depending on period studied. The simulated production of the Kemper system was approximately 1600kWh/kWp more than the measured production, while the Deger system had around 140kWh/kWp more. This may indicate that the Kemper system’s measured production was lower than expected in 2017. The module’s temperature and efficiency are affected by the irradiation and the size of the shunt resistance that influences the amount of energy that the module can deliver. The modules installed at northern latitudes should be good at diffuse light, have low temperature coefficients and the result indicates that a textured surface may be preferable. The modules information should primarily be available in the data sheets, producers and retailers should be able to contribute with the information. To complement current standard test, another test should be introduced which corresponds to a cloudy day with less irradiation.

Re-powering solar PV plants is an upcoming discussion on the global stage. Although the respective component warranties indicate the time to change the system machinery, the methodology and justification for carrying this out are two aspects that need further study. The rooftop solar PV system on top of Dalarna University was re-positioned in 2014. Prior to installing the system in its new position, the system arrays were reconfigured and new inverters were installed. This thesis aimed to compare and analyze two sections of the solar power plant to understand which amongst them performs better. Graphs depicting energy, current, voltage and other parameters were formulated to ascertain the efficacy of the array configurations for this Nordic latitude. Thereafter, PVsyst and SAM were used to compare the simulated results with the actual output from the system. It was found that the measured energy output from one section of the solar power plant was higher than that of the other during 2014. On an annual basis, this difference was 21.5 kWh or 2%. On closer inspection, this contrast was attributed to a difference in yield early in the morning. Further, PVsyst simulated the annual energy with a deviation of less than 1% than what was measured, whereas SAM measured a deviation in energy measurement of 2.5% higher than the actual measured energy. These values were obtained using the detailed design options for both softwares. A point to keep in mind is that prior experience of working with both these softwares is recommended prior to carrying out the simulations on these softwares. An underlying point to note in this study is its limitations. This study is valid in the northern latitudes, such as the Nordic climates, since other regions would not have such low (sub-zero) temperatures to account for while sizing the inverter. In regions of high irradiance, a system re-powered in a way such as the system in this case would have higher clipping losses. Relevant previous studies and related topics have been visited, summarized and cited.

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

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The goal of this study is to evaluate Swedish photovoltaic systems regarding energy production from two different years and compare the gathered data with results from a model simulating optimal conditions. This is done to investigate how the energy production differs between each year, why there are differences, and also to evaluate the simulation tools compared to the real production data. A good way to measure performance is to calculate the specific yield, that is the energy produced per unit of installed power (kWh/kWp). In order to complete this study, a literature study was made to investigate reasons for potential variations in PV system yield. Besides that, the production data from 2373 PV systems in Sweden were collected from different databases, and the data were sorted and compiled in order to calculate specific yield (kWh/kWp). The total number of PV systems after sorting was 828 for the 2017-2018 data and 1380 systems for the 2018 data. Data from real PV system production was compared with calculations performed in two simulation tools, PVGIS and PVsyst. Differences in calculation methods were investigated for performance evaluations between the two programs, and also for comparison with the real plant data. The results showed that the average specific yield for Sweden as a whole, to be 798 kWh/kWp for 2017. For 2018 with the results where 890 kWh/kWp when looking at the exact same plants as for 2017. This is an increase of 11,5%. For the simulation tools the results where 974 kWh/kWp for PVGIS, and 978 for PVsyst for an optimized system. Larger variations in specific yield occurs between every of the 21 counties in Sweden. The solar irradiations show significant correlations to the variations of the 2017 and 2018 specific yield data. Differences between the production data from the two years and the simulation tools wereinvestigated further. Reasons for this was discussed to be because of orientations of the panels and shading of the panels. Real PV systemsdiffer in orientation and the amount of shadowing from the simulated calculations.

This thesis aimed for a better understanding of the Nordic weather conditions in terms of snow induced soiling on the performance and production of an established photovoltaic plant located on the roof of Økern nursing home, Oslo. In order to realize the main aim, several steps had to be done in preparation of the main analysis, these steps in fact are as important to this thesis as the main deliverable. The search for appropriate meteorological data proved to be not an easy task because of the scarcity of ground measurement stations, and the high inaccuracies in satellite observations. After analyzing all the sources with available data for the region of Oslo, three sources of data were chosen based on comparisons to an onsite set of reference measurements, these are the Blindern meteo station, the NASA SSE satellite derived observations, and the STRANG data base. A model of the actual system was created in PVsyst, exceptional attention to the level of detail was exercised in order to approach the case of eliminating any source of variation in the simulated models other than the required study parameter, the soiling. Simulations of many system variants ultimately resulted in the aggregation of a soiling loss profile to be used in conjunction with each of the meteo sources to predict the snow induced soiling consequences on the system. The soiling loss profiles were tested and the results compared to actual system production measurements, and it was successful in introducing the correction the model needed to simulate the system closely to reality. However, absolute change in production figures is relatively small, therefore, this study and any future continuation of it is oriented into research and improvement as it possess minimal impact on a commercial application.

Because of global warming and the Paris agreement from 2015, countries need to switch their energy sources into clean sources. For some countries, like Perú, electricity produced from renewable energy sources is still a new technology. Its electricity demand depends entirely on traditional hydropower and thermal plants. Despite the high solar radiation in the coast and Andes (mountain range that passes through the entire South American continent), solar electricity is not developed and it fairly reaches the 1% of the national electricity production. Sweden, similarly, also produces its highest share on electricity from hydropower. However, nuclear energy and renewables like biomass and wind cover the rest of the demand, compared to thermal plants for Perú. On the other hand, most of the poor citizens of Perú live in the Andes, especially in remote villages, disconnected from the national grid and suffering from the cold during winter. Because their energy demand is low, it is not profitable for the electrical companies to give them electricity. The Swedish population, however, has 100% access to electricity. Despite that, high prices on maintaining the connection to the electricity network, and constant failures because of bad weather (more common nowadays because of global warming), brings the idea to disconnect from the grid and produce one´s own electricity, with, for example, photovoltaic systems. These problems occur not exclusively in Sweden. The work done on this thesis consists on a design of an off-grid solar PV system using batteries for energy storage, both for a remote farmer village in the high Andes in Perú (Ungalluta 2) and for a rural, low populated village in the center of Sweden (Gåsborn). The design is done manually and by software (PVSyst), with real life components, analyzing costs and the possibility to live entirely on solar power. The priority when choosing the components is the lowest price. For Ungalluta 2, with a demand of 17.1kWh/d (11 people), 13 PV modules and 1600Ah of battery capacity (Lead Acid) are needed, with a payback in approximately 40 years, renewing the PV panels on year 25 because of degradation. The initial investment is 21540EUR. For Gåsborn, with a demand of 36.44kWh/d (average Swedish family with children), 42 PV modules and 2850Ah of battery capacity (Lithium) are needed, with a negative payback, even increasing the PV modules to cover the entire year (more than 400). This is because the solar irradiation is quite low during winter and the load demand needs to be satisfied with considerable amounts of Diesel with a backup generator. After analyzing the results, it is possible and viable to build PV systems for the villagers in the Andes of Perú, but they will need monetary help of the government (high initial cost). For Sweden, it is not profitable to depend entirely on PV power. Other renewable sources must complement it, such as wind, to compensate the low solar irradiation and reduce the diesel consumption. / På grund av global uppvärmning och Parisavtalet från 2015, måste länderna byta sina energikällor till förnybara alternativ. För vissa länder, som Perú, är el från förnybara källor fortfarande en ny teknik. Dess elbehov beror helt och hållet på traditionella vattenkraftverk och termiska anläggningar. Trots den höga solinstrålningen vid kusten och i Anderna (bergskedja som går genom hela den sydamerikanska kontinenten) är el från PV inte utvecklad och den täcker knappt 1 % av den nationella elproduktionen. Sverige producerar på motsvarande sätt sin högsta andel av el från vattenkraftverk. Den resterande delen av elbehoven täcks av kärnkraftverk och förnybar energi som biomassa och vindkraft jämfört med de termiska anläggningarna i Perú. De flesta fattiga invånarna i Perú bor i Anderna, särskilt i avlägsna byar, bortkopplade från det nationella elnätet och blir således lidande under de kalla vintrarna. På grund av deras låga energibehov är det inte lönsamt för elföretag att förse dem med elektricitet. I Sverige är det dock annorlunda. Befolkningen har 100 % tillgång till elektricitet. Trots det är priserna för underhåll av anslutning till elnäten höga och återkommande strömavbrott på grund av dåligt väder är vanligt, särskilt på landsbygden. Detta ger upphov till idén om att koppla bort från nätet och producera egen elektricitet med exempelvis solcellssystem. Arbetet i denna uppsats består av en konstruktion av ett off-Grid system med solceller som använder batterier för energilagring, både för en by högt upp i Anderna i Perú (Ungalluta 2) och för en mindre befolkad by på landsbygden i mitten av Sverige (Gåsborn). Systemen är beräknade både för hand och med mjukvara (PVSyst) med verkliga komponenter för att analysera kostnaden och möjligheten att helt och hållet leva på solenergi. Vid val av komponenterna har lägsta pris varit en prioritering. För Ungalluta 2, med ett behov på 17.1 kWh/d (11 personer), behövs 13 solcellsmoduler och en batterikapacitet på 1600Ah (Bly-syra). Den ursprungliga investeringen uppgår till 21540 EUR och återbetalningstiden till 40 år där modulerna byts ut efter 25 år på grund av degradation. För Gåsborn, med ett behov på 36.44 kWh/d (genomsnittet for en Svensk familj med barn), behövs 42 solcellsmoduler och en batterikapacitet på 2850Ah (Litium) vilket ger en negativ återbetalning även om solcellsarean ökas för att täcka hela året (mer än 400 solcellsmoduler). Detta beror på att solinstrålningen är låg under vintern och att behovet måste täckas med stora mängder diesel och med en backupgenerator. Efter att ha analyserat resultatet är det möjligt och genomförbart att bygga solcellssystem för de byborna i Anderna i Perú men de kommer att behöva kapital från regeringen (hög initial kostnad). För Sverige, är det varken lönsamt eller miljövänligt att vara helt beroende på solenergi utan andra förnybara källor så som vind måste komplettera den för att kompensera den låga solinstrålningen och för att reducera dieselförbrukningen.