The degree project was carried out in collaboration with Halmstad Fastighet AB. Two separate buildings with different uses of energy have been analyzed. The focus was on evaluating near-zero energy houses with solar power plants and associated battery storage to investigate profitability and dimensioning to form the basis for future constructions. Both properties are near-zero energy houses but differ in the use of electrical energy. It is currently unclear how the change in the dimensioning of the solar power plant and the battery storage will affect the profitability of two properties with different uses of energy. The method was quantitative. Simulation models in the Polysun software were created with the properties' reference house. Based on the simulations, profitability calculations were made to describe the difference in profit when changing the dimensioning. The work concludes that the total profitability increases with the size of the solar power plant, regardless of energy use, and battery storage is not profitable without price changes. / Examensarbetet gjordes i samarbete med Halmstad Fastighet AB. Två olika fastigheter med olika elanvändning har analyserats, där fokuset låg på att utvärdera nära-nollenergihus med solkraftsanläggningar och tillhörande batterilager för att undersöka lönsamhet och dimensionering som ska ligga till grund för framtida byggnationer.  Båda fastigheterna är nära-nollenergihus men skiljer sig åt i användning av elenergi. Det är idag oklart hur förändringen av dimensioneringen av solkraftsanläggningen och batterilagret påverkar lönsamheten i två fastigheter med skilda användning av elenergi. Metoden är av kvantitativ karaktär. Simuleringsmodeller i programvaran Polysun skapades med två fastigheter och dess solkraftsanläggningar med tillhörande batterilager som referens.Utifrån simuleringarna gjordes lönsamhetsberäkningar för att beskriva skillnad i vinst vid förändring av dimensionering. Slutsatserna av arbetet är att den totala lönsamheten ökar ju större solkraftsanläggningen är oavsett elenergianvändning och batterilagret är idag inte lönsamt utan prisförändringar.

To achieve the established environmental goals, a significant transformation is requiredin the Swedish transport sector. This includes a shift away from fossil fuels and a greateremphasis on electrifying a larger portion of the vehicle fleet. The goal of this study is toevaluate the impact on the local distribution grid when integrating a high power chargeradjacent to a mobile battery storage system. In addition an investigation of the energyflows was conducted to assess the continuous operations of charger, battery and electricitygrid. The introduction of high power loads leads to higher power peaks in the system,which may affect the stability with respect to the voltages, currents and harmonics in thegrid. This thesis was conducted in collaboration with Gävle Energi AB, which is a local energycompany that is active in the area around Gävle. In total two models were created inorder to simulate both the energy flows and grid stability. The first model was conductedin MATLAB and used to evaluate the energy flows for the scenarios of low and high load.The second model was conducted in OpenDSS to evaluate the grid stability for a total of6 scenarios. The scenarios are as follows: the initial electricity grid, the grid with a highpower charger integrated and the grid with both a high power charger and a solar parkintegrated, for both low and high load cases. The results of the study showed that high power loads affected the local electricity gridmost during low load since it entailed high load peaks during that period. The effect ofintegrating a high power charger in a grid with radial grid topology is that the voltageis reduced and harmonics increased in loads connected to the same node. The effect ofintegrating a solar park instead increases the voltage and reduces the harmonics in loadsconnected to the same node. The energy flow evaluation showed that the battery hadthe potential to be continuously used for both the low and high load cases. However,during low load the battery had the potential to provide frequency regulating services tomaximize the income.

The grid in the northern part of Sweden is characterized by long radial lines with just a few customers. To secure electricity supply it is necessary to have a redundant feeding alternative. A loop structured grid which is used in the more populated urban area is a poor solution in the rural areas both regarding economy and technology due to the long distances. To feed the northern grid in Sweden a battery energy storage system (BESS) is therefore a solution that could secure the power delivery. An important aspect to investigate is how the electric power quality changes with the new feeder, but more importantly to secure disconnection of supply at fault occurrence.   This thesis investigates how a battery storage system installed at the end of a mid-voltage line affects the electric power quality and the protection system compared to a reference case which represents the line today. The mid-voltage line is an existing line in the northern grid and is a good representation of the general northern grid.     The results obtained from this study show that the loop impedance does not necessarily have to deteriorate with the new feeder, which means that the voltage quality in this aspect does not change. This is only true for this particular grid when the impedance contribution from the mid-voltage grid is small and the contribution from the low-voltage grid is large because of long and weak distribution low-voltage lines.     The inverter is the limiting factor for the short circuit currents, and the short circuit power and current decrease with the new feeder. At fault occurrence in the low voltage grid the short circuit current does not affect the fuse blow. However the inverter will disconnect for all fault occurrences in the mid-voltage grid, and for faults with high short circuit power in the low voltage grid. This means that the selectivity will decrease, but the system will have a high security level.   For this particular grid the results show that the transformer can be isolated from the ground. A residual overvoltage relay is enough for disconnection of grounding faults. Directional ground fault protection is not necessary for this line with this particular characteristics. If the sensitivity for the disconnection of grounding faults with high transition impedances is adjusted according to ground fault currents in island operation, the sensitivity then decreases at the event of a fault during normal operations when the battery storage system is charging. The sensitivity might also be tuned according to normal operation, which then results in a higher sensitivity than necessary during island operation.

The electrification of the Swedish vehicle fleet is happening at a record pace and the proportion of rechargeable vehicles is increasing rapidly. An electric vehicle fleet will result in an extra demand of electrical power from an electricity grid that is already heavily strained. To achieve a successful electrification and enable a secure and stable power grid in the future, the design and development of the charging infrastructure must be carefully constructed. The aim of this thesis is to investigate how dynamic load balancing chargers and battery energy storage can be used to accomplish a sustainable charging infrastructure in parking garages. To achieve this, a simulation model has been generated in GNU Octave. Besides being applied in this project, the purpose of the model is also to be used further in upcoming projects to compare and evaluate the suitability of several power-reducing techniques. The simulations in this study are based on parking and charging behavior for two parking garages located in Gothenburg, where data over energy consumption, parking time and time of arrival have been used. The result indicates that charging with dynamic load balancing charger as well as battery energy storage can successfully be used to reduce the power demand in the buildings, where dynamic charging with prioritization proved to be the most beneficial technique. Results from the battery simulations concluded that only using the battery storage for peak shaving is not economically profitable. This could however be achieved when the battery also participates at the FCR-D upward market. Furthermore, the results from the battery simulations also demonstrate the importance of adjusting the technical settings regarding power limit for peak shaving and depth of discharge with respect to the consumption profile of the studied building. This to avoid occasions where peak shaving is desired but cannot be implemented due to capacity limitations in the battery.

This master thesis investigates the impact of battery energy storage utilization in the ancillary services market on a local electricity grid. Specifically, the study examines the technical impact of battery energy storage installations and how grid operators should handle these types of installations in the future. To achieve this goal, battery energy storage systems simulations using MatLab software based on historical frequency data have been conducted creating an operation scheme for the battery. The battery simulation was applied to the electrical systems consumption and production data, conducting a whole year power flow simulation investigating the effects on peak power demand both for the customer and local grid owner. The worst-case scenarios were also investigated to assure that the grid could withstand the change in production and consumption at any time. The results indicate that such an installation would increase the peak power demand for the local grid owner by a maximum of 12 kW for one week but in general, it would result in a smaller increment and some small decrement. For the customer, the maximum impact is greater both in absolute numbers and in proportion to the peak power demand before with an increment of 16 kW, but in general, there will not be any impact on the effect tariff at all. The results of the worst-case scenario simulations showed that during backup power supply at high load timestamps in combination with FCR-D down there would be contingencies in one cable connection between two nodes, causing the cable current to increase above the rated current. To allow such an installment the local grid owner would need to limit the battery capacity and increase their billings to the customer, expand the dimension of the system or even, increase their effect tariffs to always ensure a stable electricity supply and stable financial balance.

Uppsala is growing at a fast rate and todays powergrid cannot support the increase in population hence the power grid must be relieved. We can accomplish this through peak shaving.  The mobility house Dansmästaren in Rosendal was built with the purpose of serving as a test bed for technical systems that have the task of relieving the power grid. It does this by applying the peak shaving technique to reduce the energy use, which mainly comes from the electric car chargers that is in Dansmästaren. Uppsala Parkering AB (UPAB), which runs Dansmästren is currently building a second mobility house in Rosendal called Brandmästaren. This report presents a comprehensive analysis of what kind of energy storage system Brandmästaren should have to streamline it's peak shaving.  The results showed that there are many ways to improve the energy storage system. But a detailed cost estimate is needed to know which of the alternatives is the most cost-effective.

Energimarknaden förändras till följd av den alltmer aktuella klimatfrågan. En ökad efterfrågeflexibilitet är en förutsättning för omställningen till förnyelsebara energikällor. Energilagring i batterier ses som en nyckellösning i framtidens elförsörjning. Ett alternativ är implementering av batterilager i byggnader hos slutkonsumenten. Uppsatsen undersöker vilka incitament som finns för en bostadsrättsförening att investera i batterilager. Resultaten visar att ekonomiska aspekter är avgörande för beslutet. Potential till minskade elkostnader samt investeringsstöd är möjligheter som värderas högst. Även hållbarhetsaspekter och miljöperspektiv ger incitament. Störst hinder för investeringen i batterilager är brist på utrymme i byggnaderna. / The energy market is changing due to the current climate issue. Increased demand flexibility is a prerequisite for the transition to renewable energy sources. Energy storage in batteries is seen as a key solution in the ectricity supply of the future. An alterantive is the implementation of battery storage in buildings at the end consumer. The thesis examines the incentives for a Swedish tentant-owner association to invest in battery storage. The results show that financial aspects are crucial for the decision. Potential for reduced electricity costs and investment support are opportunities that are highly valued. Sustainability aspects and environmental perspectives also provide incentives. The biggest obstacle to the investment in battery storage is the lack of space in the buildings.

De senaste åren har en större mängd decentraliserad och variabel energiproduktion tagit plats inom elsystemet, mer specifikt vindkraft och solkraft, och etablering av mer distribuerad produktion kommer att fortsätta i enlighet med mål från nationer och världsorganisationer att fasa ut fossila bränslen och minska på växthusgasutsläpp. I takt med nedläggning av storskaliga kraftverk baserade på fossila bränslen påverkar detta möjligheterna att möta upp elbehovet med den tillgängliga produktionen. Mycket variabel produktion har samtidigt en negativ påverkan på elnätstabiliteten och kan skapa höga effekttoppar. Detta har skapat ett ökat behov av mer flexibilitet på kundsidan för att skapa balans på elnätet. Elektrokemiska batterilager kan lösa många av problemen som uppstår med intermittent förnybar energiproduktion. Batterilager har både utvecklats teknologiskt och minskats i pris avsevärt de senaste tio åren och kostnaderna kommer fortsätta att gå ned. För att batterilager på allvar ska bli intressant behöver aktörer som investerar i denna teknologi veta om det någon gång inom en snar framtid kommer att vara en positiv affär. Syftet med detta arbete har därför varit att undersöka lönsamheten med batterilager i kommersiella fastigheter idag och inom de närmsta 10 åren på den svenska marknaden. Studien har, med hjälp av blandad heltalsprogrammering (MILP) i MATLAB, tagit fram en modell som optimalt schemalägger energiflöden för en fastighet som har ett batterisystem och egen produktion installerat baserat på olika prisbilder. Modellen har i sin tur använts för att beräkna de ekonomiska möjligheterna som erbjuds på Sveriges elmarknad med ett batterisystem i en mängd olika scenarier både vad gäller pris på el, olika effektabonnemang, integration med solpaneler, olika batteristorlekar och systemlivslängd. Resultatet visar att det inte finns någon lönsamhet i att investera i batterier för de undersökta fastigheterna så som Sveriges elmarknad ser ut idag och någon hög lönsamhet kommer inte att ske även om pristrenden på batterier fortsätter nedåt. Ett mindre batterisystem på 28 kWh kan ge, beräknat med internräntan, en positiv avkastning på 1 % år 2020 men ju större batteriet är desto mindre blir avkastningen. Högst avkastningen som kan fås med dagens el- och nätpriser är 4-5 % om en investering görs med 2025-2030 års batteripriser. Om elnätsägarna går mot att endast erbjuda tidsdifferentierade nättariffer året om och det implementeras högre effektavgifter finns det möjligheter att avkastningen kan bli så hög som 15-18 % med 2025-2030 års batteripriser. Arbetet visar också att kapandet av effekttoppar med större batterilager än 28 kWh inte är kostnadseffektivt för de undersökta fastigheterna. / The world has seen a rapid deployment of distributed and time-varying renewable energy systems (RES) within the electricity grids for the past 20 years, especially from wind and solar power. The deployment RES is expected to increase even more as world organizations and nations will continue the phase-out of fossil fuels as the main source of energy for electricity production. As large scale power plants reliant on fossil fuels will shut down it will be harder for the system to balance production and demand. At the same time, time-varying production might have a negative effect on the grid stability which has spurred an increased interest in flexibility on the demand side and a call for technologies and strategies that can create balance on the grid. Energy storage, especially electrochemical battery storage, is seen as a part of a bigger solution to the problems that comes with intermittent energy production. Battery storage has had a fast technological development and a sharp downtrend in pricing the latest ten years and the costs are expected to keep on decreasing. For battery storage to be a serious contender on the electricity market there is a need to understand if and when an investment in this technology might give a positive outcome. The aim of this study has therefore been to analyse the profitability of battery storage within commercial real estate today, and in the oncoming 10-15 years on the Swedish electricity market. The study has, using mixed integer linear programming (MILP) within MATLAB, created a model which optimally schedules power flows for buildings that has a battery system and its own electricity production. The model has in turn been used to evaluate the economical possibilities that exist with a battery system within commercial real estate under various different scenarios that looks into pricing structures on electricity and demand, integration with and without solar panels, different battery sizes and system lifetimes. The results show that there is currently no profitability to invest in a battery system for the specific buildings analysed in this study. While break-even is possible just a couple of years from now, a high profitability will not be reached even with the future downtrend in battery prices under the current electricity market circumstances. A smaller battery system with a capacity of 28 kWh could give an internal rate of return (IRR) of 1 % year 2020. Larger battery systems are generally not cost-effective when compared to smaller battery systems when its primary purpose is utilized for demand reduction. Highest return with today’s electricity and utility pricing is 4-5 % somewhere between 2025 and 2030. However, if the market goes towards exclusively time-of-use billing structures on electricity and higher demand charges, the IRR can reach towards 15-18 % between 2025 and 2030.

Elnätet är ett komplext och viktigt system som konstruerats som en av de mest imponerande bedrifterna under ingenjörskonstens moderna tid. Det överför elektrisk energi till otaliga byggnader, industrier, skolor och hem. Och alltsammans sker konstant, varje minut av varje dag, året runt.  Grundbulten i systemet är den att en ständig balans måste råda mellan produktion och förbrukning av elektricitet. Vid obalans riskerar nämligen strömavbrott och andra oönskade företeelser att inträffa. Huruvida produktion och förbrukning av elektricitet är i nivå kan beskrivas av elnätets frekvens. Genom att övervaka elnätsfrekvensens beteende fås en överskådlig bild av elnätets status i realtid samtidigt som stödtjänster kan implementeras proaktivt för att motverka eventuella störningar. Tidigare har dessa stödtjänster främst representerats av stora aktörer såsom vattenkraftsanläggningar med enorma förutsättningar för att agera som reglerkraft. I takt med en omställning till en alltmer förnybar energipalett ökar dock behovet av ny reglerkraft. Samtidigt syns ett accelererande av installering av batterilager i bostadsrättsföreningar som energieffektiviserar. Eventuellt finns här en outforskad potential. Möjligen kan batterilager i flerbostadshus utnyttjas för frekvensreglering som en ytterligare balanskraft för elnätet. Projektarbetet syftade till att utreda potentialen kring batteristyrd mFRR-reglering från flerbostadshus. För att utvärdera den eventuella lönsamheten modellerades batteristyrningen i MATLAB. Modellen baserades främst på historiska data för upp- och nedregleringsbud från Nord Pool. I och med kravet på 1 MWh som minsta budstorlek på marknaden gjordes antagandet att vid varje regleringstillfälle reglerar batterilagret i aggregation med andra batterilager som tillsammans täcker den totala kapaciteten på 1 MWh. Modellen fungerar på så sätt att varje uppreglering föranleds av en uppladdning av batterilagret via antingen nedreglering eller spotpriser. Beroende på vilket alternativ som är mest lönsamt. Vidare gjordes antagandet att inga uppregleringsbud sker i två påföljande timmar.  Studiens mest lönsamma resultat genererades då batterilagret modellerades för att anta ett uppregleringsbud per dygn med det extra villkoret att samtliga bud som understiger 300 SEK/MWh förkastas. Vid dessa kriterium erhölls ett positivt årligt resultat om 149 100 kr från 306 battericykler.  Med endast frekvensreglering som användningsområde för batterilagret konkluderade dock studien att, det positiva resultatet till trots, ingen lönsamhet kunde uppnås. Investeringskostnaden är nämligen ännu för hög. Å andra sidan tyder teknologiska framsteg inom batterisektorn på en avtagande kostnadsutveckling. Vid år 2030 väntas nämligen priset för batterilager vara 225 USD/kWh, vilket skulle förbättra resultaten från denna rapport. / The electricity grid is a exceptionally sophisticated and crucial system which was created as one of the most impressive accomplishments in modern engineering. It transmits electrical energy to innumerable buildings, factories, schools and homes. And it can never stop. The system relies on the constant balance between generated and consumed electricity. Should an imbalance occur, it might give rise to power outages or failures in appliances on the grid. Whether or not generated and consumed electricity is at balance is determined by the grid frequency. By surveilling how the grid frequency behaves, an overview of the complete system can be obtained in real time. This is useful when it comes to deciding on whether or not to implement supporting mechanisms to counteract disturbances. The supporting mechanisms were historically represented by large facilities such as water power plants who possess great abilities of regulating the power balance on the grid. With the ongoing switch to renewables the need for more regulating power increases. At the same time installments of battery storage in energy efficient housing can be seen as accelerating. Here might be an untapped potential. What if battery storage in residential properties were utilized for frequency regulation as an additional balancing tool for the grid? The intent with this report was to outline the potential regarding power regulating via battery storages in multifamily residentials. In order to evaluate whether or not any profit could be redeemed, a battery control model was developed in MATLAB. The model was primarily based on historic data for regulating bids from Nord Pool. Since requirements on the market states that the lowest bid needs to be at least 1 MWh, the assumption was made that at every regulating occasion the battery regulates in aggregation with more batteries for a total capacity of 1 MWh. The objective of the model is to charge the battery using either spot price or down-regulating bids. Thereafter, an up-regulating bid is chosen. The assumption was made that no subsequent up-regulating bids were chosen. The most profitable optimization of the model was generated when 1 up-regulating bid was chosen per day with the additional condition that all bids under 300 SEK/MWh were rejected. At these criteria a yearly positive result of 149 100 kr was generated from 306 battery cycles. With frequency regulation as sole application for the battery storage, the study concluded that the model was not profitable. The cost of investment is yet too high. On the other hand, technological improvements will surely amount to declining prices. By year 2030 the price of battery storage may have fallen to 225 USD/kWh, which would improve the results in this study.

The use of lithium-ion batteries is something that is becoming more common in today’s society. They are found in a variety of electronic equipment such as mobile phones, laptops and tools. Several incidents have been reported due to lithium-ion batteries ending up in a state called thermal runaway. This in combination with the increasing demands for environmentally friendly and sustainable energy in the form of e.g. wind turbines and solar panels, can therefore lead to unforeseen consequences. Residual energy from wind or solar power can be stored in an energy storage, often a battery system of several interconnected lithium-ion batteries. In case of an incident in these storages where a large quantity of these batteries is located, there is a risk that an explosion will occur. This further leads to the interest if it’s possible to prevent an explosion with the help of mechanical ventilation.  The purpose of this report has been to investigate the reasons why these batteries are being able to cause an explosion, what gases are emitted in the event of a thermal runaway and how explosive they are. With the results given it’s possible to then perform calculations on ventilation capacity needed to maintain a non-explosive atmosphere. This was carried out through a literature study of currently available research combined with information from various authorities, hand calculations and calculations in Excel.  With the results of the literature study, it can be stated that the battery cell consisting of the cathode material lithium-nickel-manganese-cobalt oxide (NMC) is most reactive. The most common gases emitted from these cells during thermal runaway are hydrogen, carbon monoxide, carbon dioxide, methane, ethylene and ethane. These gases are also the most common gases during thermal runaway when the battery consists of a different cathode material, but the distribution may look different. All of these gases, with the exception of carbon dioxide, are flammable and can contribute to an explosive atmosphere.  Three different scenarios are developed where thermal runaway is assumed to take place at a battery cell inside battery storages of different sizes: two container-based energy storage and one battery storage for home use located in a garage space. In these respective scenarios, a certain number of cells are assumed to be in thermal runaway. The lower flammability limit for the ventilated gas mixture is determined to 8,53% based on the amount of emitted gas and the distribution of it due to thermal runaway. With the knowledge of the lower flammability limit of the emitted gas mixture, as well as other available data from each scenario, the desired capacity for ventilation is calculated at 0,23 m3/s for the two container-based battery storages and at 0,035 m3/s for the battery storage located in the garage space. If this capacity of the ventilation is present when thermal runaway occurs, it means that the concentration of combustible gases should remain below the lower flammability limit. It is worth noting that these calculations were performed to some extent based on assumptions and may therefore be judged more as approximate rather than exact.  The conclusions drawn by the performed calculations are that mechanical ventilation is a potential alternative to ensure that the atmosphere in a battery storage doesn’t become explosive if a thermal runaway occurs in the battery cells.