The aim of this project is to nd the optimal size battery for an already installed PV system in a family house in Southern Sweden. First, the existing system is modelled and validated. Then a new model including a battery is built. In this model it is assumed that the aim of the battery is to maximize the self-consumption of the house. A sensitivity analysis is performed in order to study the inuence of the battery capacity on the electricity uxes between the house and the grid. The protability of the project is then investigated, considering the current tari schemes for thehouse and for the "average" Swedish house. Eventually the possibility of applying price-dependent control strategies to the battery is investigated. The primary conclusion is that a battery installation is not protable for the studied house whether the incentives provided by the Swedish government are considered or not. Yet a subsidized installation would be protable for a house subject to the average Swedish electricity price. Another conclusion is that the current hourly volatility in the electricity price is not high enough to make reasonable the use of price dependent battery control strategies. Their use would lead to better economical performance, with respect to the simplest battery control strategy, in case of increased volatility. / Malet av det har projektet ar att hitta batteri med den basta storleken for en existerande solcellssystem i en villa i Sodra Sverige. Forst, det existerande systemet modelleras och valideras. Sedan byggs en ny modell som innehaller ett batteri. I den har modellen antas att malet av batteriet ar att maximera sjalvkonsumption av villan. En kanslighetsanalys utfors for att studera inverkan av batteri kapacitet pa el ussmedel mellan villan och natet. Darefter, lonsamheten av projektetet unders oktes, med tanke pa den bentliga tarisystem for den utforskade villan och den "genomsnitt" Svenska villa. Slutligen, mojligheten att tillampa prisberoende batterikontrollstrategier undersoks. Den primara slutsats ar att en batteriinstallation ar inte lonsam for den studerade villa, med eller utan bidrag. Anda en subventionerad installation skulle vara lonsam for ett hus som utsatts for genomsnitt svenska elpriset. En annan slutsats ar att den nuvarande volatilitet i elpriset ar inte tillrackligt hog for att gora lamplig den anvandning av prisberoende batterikontrollstrategier. Deras anvandning skulle leda till battre ekonomisk prestanda, med avseende pa den enklaste batteristrategi, om prisvolatilet okningar.

Increases in electricity prices in Sweden during the second half of 2021 have created a great deal of concern among companies in Sweden. Some companies report that they have stopped their production temporarily when electricity prices have been high. Several of the companies also report that future investments have been stopped and some of the companies also state that they have or are planning to move their production abroad. One of the companies that has been affected by the increased electricity prices is an SME (Small Medium Enterprise) company located in electricity area 2 in Sweden. This has caused the company to evaluate different alternatives to be able to lower their costs linked to their electricity consumption. One of the options that is being evaluated is to invest in a solar (photo voltaic) cell, a technology that has become significantly cheaper over time and solar cells installations have increased a lot in Sweden recent years. The purpose of this study is to help the company evaluate whether it is a good option or not to install a solar cells system. The perception within the company is that the price for purchasing electricity is higher than what they would earn from selling the electricity. Therefore, the company wants to install a solar cells system which has a high proportion of self-consumption. But is that view true and, if so, to what extent and how could a solar cells system be designed to optimize self-consumption? The result shows that by tilting and turning the solar cell panels, it is possible to change the time for production and the amount of electricity produced from a solar power system. In the current case for this study, electrical consumption is at its highest during working hours 07.00-16.00. It is also during this time of the day the solar radiation is at its most intense and the solar cells system can produce as efficiently as possible. Results showed that it was not profitable to increase self-consumption by turning and tilting the solar panels so that they produced less during the holiday season and more during other parts of the year. The view that self-consumption would increase profitability proved correct and it turned out that a smaller solar plant system is more profitable until the point that the installed power per SEK increased. The conclusion of the work is based on the results of the best-designed solar cells system based on installation costs, previous electricity consumption, forecasted electricity prices and current STIBOR rate. The pay-off time for this solar cell system would be 8.6 years and 15.6 years discounted pay-off time. Which may certainly seem like a bad investment and therefore, one might wonder why so many solar cell plants are installed in Sweden. This can largely be explained that from 2020 there are no subsidies for the installation to apply for companies. The company is also not entitled to a tax reduction that gives 0.60 SEK for each kWh sold. This is because their main fuse exceeds the limit of 100A, which is above the limit according to one of the Swedish tax agency requirements for obtaining the tax reduction.

Photovoltaic technology is among the best tools our civilization has to reduce the emissions of greenhouse gas that are currently altering the atmosphere composition of our planet. The idea of using photovoltaic surfaces on the envelope of buildings is called with the acronym of BIPV (building integrated photovoltaics), it offers the advantage of producing energy in the same location of the demand for electricity. Furthermore, BIPV allows to save monetary and environmental costs by substituting building materials with photovoltaic collectors. As every technology,BIPV follows an adoption pattern that is bringing it from a very limited niche product to a pervasive one. Nevertheless, the adoption rate of BIPV appears to be slow, and the industry has offered little opportunities of business for its stakeholders over the last 20 years. There are multiple reasons for this sluggish growth, and a considerable body of scientific literature has offered potential solutions to the problem. The building industry is notoriously slow in picking up innovation, furthermore the BIPV material needs to compete with much more mature, versatile and often cheaper cladding technologies and materials. Numerous research endeavors are focusing on the development of new BIPV claddings to have diversified colors, dimensions, shapes and other properties. The argument is that the technology is not mature and thus cannot be adopted by the bulk of architects and designers. Unfortunately, the premium characteristics of these new materials often come with a higher price and a reduced efficiency, thus reducing their market potential. Other research endeavors, among which this thesis, are focusing on the design of buildings: trying to include the use of photovoltaics into the architectural practice through education and software development. Numerous software has been developed over the last 20 years with the aim of calculating the productivity or the economic outlook of a BIPV system. The main difference between the existing software and the method presented here lies in the following fact: previously, the capacity and positions of a BIPV system are required as input for the calculation of performance, in this method the capacity and positions of the BIPV system are given as the output of an optimization process. A designer whois skeptical or disengaged about the use of BIPV could be induced to avoid its use entirely by the discouraging simulation results given by the lack of a techno-economic optimal configuration. Conversely, a designer who opt for a premium architectural PV material would, thank to the methodology shown, be able to assess the impact its unitary cost has on the optimal BIPV capacity of the building. Ultimately, the method presented provides new knowledge to the designer regarding the use of BIPV on his building, hopefully this can facilitate the spread of BIPV technology. The method described was translated into a software tool to find the best positions and number of PV surfaces over the envelope of the building and the best associated battery capacity. The tool is based on the combined use of ray-tracing (for irradiation calculation) and optimization algorithms, its use led to the following conclusions: • BIPV is profitable under a wide range of assumptions if installedin the correct capacities • 20% of the residential electric demand can easily be covered by PV without the need for electric storage and in a profitable way • Despite an interesting rate of return of the investment, the payback time was generally found to be long (over 10 years) • More research is needed to assess the risk on the investment on BIPV: if found to be low, future financial mechanisms could increase its spread despite the long payback time • The optimal capacity in energy terms (i.e. the energy consumed on-site minus the energy used to produce a BIPV system) tends to be far higher than any techno-economic optimum • The specific equivalent CO2 emissions for an NPV optimal system have been found to be between 70 and 123 [kg CO2 eq/MWh] under the range of assumptions applied • The installation of optimal BIPV capacity could change the overall residential CO2 emission of -12%, +13%, -29% in England, France and Greece respectively • despite the non optimal placement of a BIPV system compared to a ground mounted, south oriented one, and despite the noncontemporaneity of production and consumption, the BIPV still easily outperforms the energy mix of most countries when optimized for maximum NPV. • The part of the building envelope that have the most annual irradiation (i.e. the roof) should not necessarily host the entirety of the system as other facades might have an advantage in terms of matching production and consumption times. • when different scenarios are made in terms of techno-economic input parameters (e.g. degradation of the system, future costs of maintenance, future variation of electricity price etc..) larger capacities are optimal for optimistic outlooks and vice-versa • the optimal capacity for the expected scenario (i.e. the 50 % ile) can be considered robust as it performs close to the optimum in optimistic and pessimistic scenarios alike. • a reduction in price for the electric storage appears to have a positive effect on the optimal capacity of PV installed for the case study considered. • when a group of households is optimized separately V.S. aggregated together, the aggregation have a huge positive effect on all KPIs of the resulting system: in the NPV optimal system of a case study examined the installed capacity ( +118%), the NPV ( +262.2%) and the self-sufficiency( +51%) improved thanks to aggregation.

In this thesis different methods of energy storage are evaluated for use in multifamily residential buildings in order to increase the self-consumption of self-generated photovoltaic electricity. The computational software MATLAB was used to simulate and study five different energy systems applied on two case studies. The five energy systems are; one reference system consisting of photovoltaics, one system with photovoltaics and a hydrogen storage system, and three systems consisting of photovoltaics and batteries using different management strategies. The different systems were compared based on their effect on the buildings self-consumption ratio and grid interaction as well as system costs and profitability. The battery systems successfully increased the self-consumption ratio and decreased grid interaction. Assuming a favourable development of market conditions, all systems containing batteries were paid back. The battery system that could reduce high consumption peaks during the entire year was the most profitable system as the buildings fixed grid fees could be lowered. The hydrogen storage system increased the self-consumption ratio to a small degree, as much of the electricity was lost in the conversion processes. Also, the components of the hydrogen system are very costly and the investment could therefore not be paid back within the 30 year life-time. Photovoltaics can be used to decrease variable electricity costs while energy storage can be used to decrease both variable and fixed electricity costs. The results suggest that focusing on handling power peaks and leveling grid interaction is more valuable than focusing on increasing self-consumption in multifamily residential buildings. The value of energy storage systems in multifamily residential buildings has been discussed with respect to technology development and changes in market conditions, the conclusion being that the value will most likely increase within the next decade and onward. It is believed that local energy storage systems have an important role to play in a power system with an increasing amount of renewable and intermittent power sources.

Technological improvements along with falling prices on photovoltaic (PV) panels and electric vehicles (EVs) suggest that they might become more common in the future. The introduction of distributed PV power production and EV charging has a considerable impact on the power system, in particular at the end-user in the electricity grid. In this PhD thesis PV power production, household electricity use and EV charging are investigated on different system levels. The methodologies used in this thesis are interdisciplinary but the main contributions are mathematical modeling, simulations and data analysis of these three components and their interactions. Models for estimating PV power production, household electricity use, EV charging and their combination are developed using data and stochastic modeling with Markov chains and probability distributions. Additionally, data on PV power production and EV charging from eight solar charging stations is analyzed. Results show that the clear-sky index for PV power production applications can be modeled via a bimodal Normal probability distribution, that household electricity use can be modeled via either Weibull or Log-normal probability distributions and that EV charging can be modeled by Bernoulli probability distributions. Complete models of PV power production, household electricity use and EV home-charging are developed with both Markov chain and probability distribution modeling. It is also shown that EV home-charging can be modeled as an extension to the Widén Markov chain model for generating synthetic household electricity use patterns. Analysis of measurements from solar charging stations show a wide variety of EV charging patterns. Additionally an alternative approach to modeling the clear-sky index is introduced and shown to give a generalized Ångström equation relating solar irradiation to the duration of bright sunshine. Analysis of the total power consumption/production patterns of PV power production, household electricity use and EV home-charging at the end-user in the grid highlights the dependency between the components, which quantifies the mismatch issue of distributed intermittent power production and consumption. At an aggregate level of households the level of mismatch is shown to be lower.

Solkraft kan täcka hela jordens energibehov många gånger utan att släppa ut växthusgaser eller andra giftiga ämnen vid drift och räknas därför till en hållbar och förnyelsebar energikälla. Solkraft är därför en lämplig kandidat till att ersätta dagens ej hållbara fossilbaserade energisystem. Priset för solceller har sjunkit mycket de senaste åren. Samtidigt som Sverige och EU har som mål att minska koldioxidutsläpp ges både skattereduktion för såld överskottsel från solkraft och ett investeringsstöd. Därför kan det eventuellt vara lönsamt att installera solceller i Sverige trots begränsad solinstrålning. Det krävs att återbetalningstiden är rimlig för att privatpersoner skall bestämma sig att investera i solceller. Miljövinster är inte alls motiverande för privatpersoner enligt undersökningar. Därför bör solcellsanläggningar optimera och dimensioneras för maximal ekonomisk lönsamhet för att öka chanserna att investeringen blir av. Det här arbetet undersöker hur ett optimalt solcellssystem ska se ut ur ett ekonomiskt perspektiv för en bostadsförening bestående av 25 lägenheter i Mellansverige under olika ekonomiska förutsättningar. Störst fokus ligger på att analysera hur lutningsvinkeln förändrar resultatet. Elproduktionen hos olika konfigurationer av solcellsanläggningar simulerades fram. Dessa resultat ställdes mot byggnadens elanvändning för att beräkna hur mycket el som används till för att spara inköpt el och hur mycket som säljs för att utifrån det beräkna lönsamheten. Mest el produceras vid lutningsvinkeln 40° vilket ger marginellt mer än 30° som taket lutar. Det visar sig att lutningsvinkeln kan justeras för att öka lönsamheten men det är endast ett fåtal procent som mest. Skillnaden är som störst för små anläggningar som precis täcker baslasten för fastigheten. Bästa vinkeln för dessa mindre system är 45°. Det är svårt att motivera det dyrare montaget för att vinkla upp modulerna då taket redan lutar nära optimalt. Skillnaden mellan köpt och sparad el är liten om skattereduktion ges. Det är dock oklart hur länge skattereduktionen varar så det är därför säkrare att dimensionera utifrån sitt eget elbehov. Ett solcellssystem dimensionerat för att sälja mycket överskottsel skulle kunna bli en stor förlustaffär. Om solkraft får större plats i Sveriges elproduktion kan den ge upphov till högre globala koldioxidutsläpp beroende på vilket energislag den ersätter. Samtidigt tar det längre tid i Sverige jämfört med andra länder innan en solcell kan beräknas koldioxidneutral då det redan är mycket låga koldioxidutsläpp i Sveriges elmix kombinerat med relativt låg solinstrålning. Det innebär att solkraft ur ett miljöperspektiv är tvivelaktigt i Sverige. / Solar power is estimated to be able to cover the whole earths energy demand many times without releasing greenhouse gases or other pollutants while they operate and is therefore considered a renewable energy source. Solar power is therefore a suitable replacement to today’s fossil based energy systems. The cost for solar cells have decreased a lot in recent years. At the same time Sweden and the European Union have goals set for reducing the amount of carbon dioxide released so a tax reduction is given to those who sells overproduced electricity from solar power to the grid. This means it could eventual be profitable even in Sweden for installing solar power even though the sun doesn’t shine as much that close to the poles. It is suitable to install solar panels at buildings since it is the building and service sector that uses the most electricity in Sweden. It must be profitable for private investors before they make the choice to invest in solar panels. Environmental benefits are not as attractive for private investors. Should the solar arrays be optimized in such way that the profit is maximized the investment is more likely to occur. This paper examines how an optimal solar cell system should look like from a profitable perspective for a building with 25 apartments in the middle of Sweden under different economic conditions. Most focus is directed towards how the tilt angle affects the results. The electricity production of different configurations of solar panels was simulated. These results were then compared to the electricity demand for the building so the amount used for self-consumption and how much is sold to the grid could be calculated and from that calculate how profitable that system is. Most electricity is produced at the tilt angle of 40°, but marginally more than 30° which the roof is tilted. The difference between tilt angles are just a few percent at most. The difference is most noticeable when the system is just big enough to cover the base electricity demand. The best tilt angle for those systems are 45°. It is hard to advocate for more expensive mounting for bigger systems since the roof already is close to the optimal tilt angle. The value for saved and sold electricity is very close to each other if tax reduction is given. It’s however uncertain for how long tax reduction will last. It is much safer to size a solar array to cover the building’s electricity demand. It could be very costly to size a solar array which relies upon selling electricity with today’s economic condition. However, solar power is questionable in Sweden in an environmental perspective.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The main objective of this work is to study the production systems of familiar livestock, analyzing which are the differences in the importance of the production for self-consumption and of the food produced by the families investigated. It is understood as self-consumption all the food (with vegetal or animal origin) produced and consumed by the families or yet, those food transformed by family agro-industry. This research has as basis methodological elements of the Analysis and Diagnosis of Agrarian Systems method (ADAS) which uses some principles of the systemic approach. The references for the analysis are the production systems of familiar livestock in Manoel Viana RS, that is, the production systems which present the beef or sheep cattle and the basis of familiar labor. The social, productive and economical aspects of the familiar livestock producers were studied, as well as how the production for self-consumption happens in these families. The logics of this group of producers is different and presents a great concern with the reproduction of the family, which in many cases, is more important than the productivity and economical profits. It is possible to notice differences of importance of the production for self-consumption among the families interviewed. The main differences in the production for self-consumption among the families researched are due to external revenues (pensions mainly) and health problems of the interviewed people which prevent them from working harder. The importance of the production for selfconsumption, specially the beef, allows the families to stand long periods (sometimes two years) without selling their production, because their monthly needs are financed by other revenues (pensions in many cases). And being the beef a product which is present every day in the meals and which has a high commercial value, the expenditures with alimentation decrease a lot and are reduced even more because of the production of other foods (other products of animal origin, subsistence farming, orchards, vegetable gardens and familiar agro-industry). If the value of the production for self-consumption is considered as revenue, it is observed that the familiar farms present high profits, because if they didn t produce anything, a significant amount of financial resources should be spent to buy products for alimentation. / O objetivo principal deste trabalho foi estudar os sistemas de produção de pecuária familiar, analisando quais são as diferenças na importância da produção para autoconsumo e dos alimentos produzidos entre as famílias investigadas. Entende-se por autoconsumo todos os alimentos (origem vegetal ou animal) produzidos e consumidos pelas famílias ou ainda aqueles transformados pela agroindústria caseira. A pesquisa teve como base determinados elementos da metodologia Análise e Diagnóstico de Sistemas Agrários (ADSA) que se utiliza de alguns princípios da abordagem sistêmica. A referência para a presente análise foram os sistemas de produção de pecuária familiar do município de Manoel Viana/RS, ou seja, os sistemas de produção que apresentam pecuária bovina de corte e/ou ovina e a base do trabalho familiar. Foram estudados os aspectos sociais, produtivos e econômicos dos pecuaristas familiares e como se dá a produção para o autoconsumo nesses estabelecimentos. A lógica deste grupo de produtores é diferenciada e apresenta uma preocupação grande com a reprodução da família, que em muitos casos é mais importante que a produtividade e os ganhos econômicos. Puderam-se observar diferenças de importância da produção para o autoconsumo entre as famílias entrevistadas. As principais diferenças entre a produção para o autoconsumo entre os estabelecimentos pesquisados devem-se às rendas externas (aposentadoria principalmente) e problemas de saúde dos entrevistados que os impedem de se dedicarem mais. A importância da produção para o autoconsumo, especialmente da carne, permite com que as famílias fiquem por longos períodos (às vezes dois anos) sem comercializar sua produção, pois as necessidades mensais são custeadas por outras rendas (aposentadoria em muitos casos). E, sendo a carne um produto presente diariamente nas refeições e de elevado valor no comércio, as despesas com alimentação diminuem bastante e reduzem mais ainda pela produção de outros alimentos (outros produtos de origem animal, plantas de cercado, horta, pomar e agroindústria caseira). Se o valor da produção para o autoconsumo for contabilizado como renda, observa-se que as propriedades apresentam uma alta rentabilidade, pois se não fosse produzido, uma quantidade significativa de recursos teria que ser gasta para a compra de produtos para a alimentação.

The purpose of this bachelor thesis is to assess whether it is possible to create a simplified model that estimates the hosting capacity of a low-voltage grid. The Simplified model is compared with a more elaborate model created by the Built Environment Energy Systems Group (BEESG) at Uppsala University. The Simplified model takes three easily obtainable variables into account. The model created by BEESG allows us to observe both the amount of photovoltaic (PV) power that is installed as well as the voltages in each bus in a grid. The hosting capacity is found by gradually increasing the amount of PV power installed in a low-voltage grid until overvoltage is reached. Simulations with BEESG’s model are done for a week in July when the PV generation has its peak and the load is generally low. The Simplified model is created using linear regression with the calculated values from the BEESG’s model as a reference. The report shows that the Simplified model will give an estimation of the low-voltage grid’s hosting capacity that is comparable to the value calculated with BEESG’s model. The results show that it is rarely the low-voltage grid that restricts the installation of PV facilities and that a high self-consumption is advantageous regarding to the grids hosting capacity.

Electric vehicles, which have both energy storage capability and mobility capability, can provide a new solution for electricity sharing between different building communities (i.e., a group of buildings connected with a microgrid). This comes to the community-to-community (C2C) energy sharing network. The C2C energy sharing networks have the potential to not only minimize the effects of electric vehicle integration into the energy grid, but also improve the electricity grid efficiency as a whole. In this thesis, a coordinated smart charging method of electric vehicles (EVs) is proposed for the C2C model. The proposed method considers the power regulation needs in both the present parking community and the next destination community. Then, based on the needs of both communities, the control method will decide the optimal amount of electricity that can be delivered by EV, so that the energy performances in both communities can be the best. The developed coordinated control has been compared with a base case (without any smart charging) and an uncoordinated control case under two control strategies: minimizing the peak energy exchanges with the grid and maximizing the renewable self-utilization. The genetic algorithm tools in MATLAB software are used for the optimization of the model. Meanwhile, to test the robustness of this C2C model, different combinations of building communities have been studied, namely residential-workplace, residential-university, and residential-workshop communities. The case study reveals that the C2C model is effective in improving energy performance under both control strategies. Peak reduction control strategies work most effectively for smaller systems with lower electricity demand and production. With C2C energy sharing, the annual mean peak reduction ranged from 39 % at the smallest community and 20 % at the largest community. Self-consumption maximization strategies work best for systems with a larger surplus of electricity production. With C2C energy sharing, the annual self-consumption increase ranged from 50 % at the community with the largest production surplus, to 7 % at the community with the smallest production surplus. The residential-workshop community studied in this thesis benefited the most from C2C charging control due to its production surplus and the relatively low electricity demands of the communities.

Electrical demand flexibility is a key component to enabling a low cost, low carbon grid. In this study, residential electricity demand and flexibility is explored from the lens of a virtual power plant operator. Individual and aggregate asset consumption is analysed using a pool of >10,000 household assets over 6 years. Key safety, comfort and availability limitations are identified per asset type. Pool flexibility is analysed using a combination of past data and principled calculations, with flexibility quantified for different products and methods of control. A machine learning model is built for a small pool of 200 assets, predicting consumption 24 hours in advance. Calculated flexibility and asset limitations are then used within an optimisation model, leveraging flexibility and combining the value of self consumption and day ahead price optimisation for a residential home. / Flexibilitet i efterfrågan av elektricitet är essentiellt för att möjliggöra ett elnät med låga kostnader och utsläpp. I denna studie undersöks elanvändning av en bostad samt flexibilitet i perspektiv från en virtuell kraftverksoperatör. Individuell och sammanlagd konsumtion analyseras genom tillgång av data från >10 000 bostäder över 6 år. Begränsningar av säkerhet, komfort och tillgänglighet identifieras per tillgångstyp. Sammanlagda flexibiliteten analyseras genom en kombination av tidigare data och principiella beräkningar, med flexibilitet kvantifierad för diverse produkter och kontrollmetoder. En modell för maskininlärning utvecklades för 200 bostäder och förutser konsumtion 24 timmar i förväg. Den beräknade flexibiliteten och tillgångsbegränsningar används sedan i en optimeringsmodell som utnyttjar flexibilitet och kombinerar värdet av självkonsumtion och optimerat pris för nästkommande dag för ett bostadshus.