This report presents an overview of the engineering considerations involved in the design of grid-scale battery energy storage systems. Grid-scale is defined here as systems over 1 MW in rated power, typically operated by a utility, independent power producer, or Independent System Operator (ISO). The physical components of a BESS are presented and explained, including power electronics, an introduction to various commercially available battery technologies, necessary control systems, and balance of plant hardware. Also presented are a variety of real-world applications of battery energy storage systems, showing how the specific application determines what mix of technology will be selected when designing the system, as well as explaining the foundation for the control algorithms. / text

A critical requirement of any remote microgrid is its capability to control the balance between electric generation and load within the confines of the microgrid itself. The integration of significant amounts of “as available” renewable generation to any electric grid (macro or micro) makes it more difficult to maintain this balance and can result in large frequency deviations on a microgrid. Ancillary services provide the resources required to maintain the instantaneous and ongoing balance between generation and load. Battery energy storage systems (BESS) can provide regulating reserves, a type of ancillary service, by modulating active power for frequency control, referred to as load frequency control (LFC), to reduce frequency deviations caused by sudden changes in renewable generation. Historically, the most common methodology for reducing frequency disturbances exacerbated by wind plants with BESS systems is ramp rate control and more recently lead compensation. This thesis proposed a modified lead compensator for use in microgrid applications. A PSS®E microgrid model, based upon existing validated models, was developed to test the effectiveness of the LFC controllers used to dispatch the BESS as a regulating resource to allow increased wind energy penetration levels on remote microgrids. A model of the remote microgrid of the island of Maui, Hawaii was chosen as the basis for the designs. Daily wind power data from 2012 was classified and indexed on an hourly basis by severity of variation. The worst hour for power variation from the wind plants was identified from this indexing and used as the basis for simulating the LFC controllers. The results compared the effectiveness of droop, ramp rate, lead compensation, and modified lead compensation controllers in reducing the variability in the grid frequency caused by changes in wind power generation. An RMS of variation with respect to an average over different time windows was used as the comparison metric. The combined modified lead compensator with ramp rate control showed the best performance of the overall system behavior. / text

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

This thesis report provides a comprehensive analysis of the regulatory landscape governing Battery Energy Storage Systems (BESS) in Spain and offers insights into their operational optimization and economic viability. The study centers on a 40 MW BESS and explores three distinct case studies, each representing varying system durations (one, two, and four hours) and two different electricity price scenarios (2019 and 2022). A techno-economic analysis encompassing all scenarios concludes the investigation. The research findings reveal that BESS projects can be financially lucrative when operating under the 2022 scenario, particularly when participating in Spain's Wholesale and Secondary Regulation service (aFRR) markets. Notably, as the system duration increases, project profitability also rises, with Net Present Values (NPVs) amounting to 29.6 M€, 50.4 M€, and 80.6 M€ for one-hour, two-hour, and four-hour BESS durations, respectively. However, this trend is not consistent, as observed in the 2019 scenario, where the opposite holds true due to significantly lower prices in both Wholesale and Secondary Regulation service markets, resulting in negative NPVs that increase with longer BESS durations (specifically, -3.3 M€, -6.9 M€, and -17.7 M€ for one-hour, two-hour, and four-hour BESS durations, respectively). In terms of optimal dispatching strategy, the study identifies consistent patterns across all case studies and scenarios. The BESS prioritizes participation in the Secondary Regulation service due to its higher remuneration compared to arbitrage activities in the Wholesale market. Despite Spain's efforts to promote the adoption of BESS technologies, several barriers exist that could impede their deployment. Key challenges include the absence of Capacity Markets (CM), restrictions on BESS participation in technical constraints and black-start markets, and the lack of remunerated markets for Frequency Control Reserve (FCR) and voltage control. In summary, this study highlights the need for a more investor-friendly environment characterized by greater revenue stream certainty and streamlined administrative processes. / Denna avhandling ger en omfattande analys av den reglerande landskapskontexten som styr batterilagringssystem (BESS) i Spanien och ger insikter om deras drifts- och ekonomiska livskraft. Studien fokuserar på en 40 MW BESS och utforskar tre olika fallstudier, var och en representerar varierande systemtider (en, två och fyra timmar) och två olika elprisscenarier (2019 och 2022). En teknisk-ekonomisk analys som omfattar alla scenarier avslutar undersökningen. Forskningsresultaten visar att BESS-projekt kan vara ekonomiskt lönsamma när de verkar enligt 2022-scenariot, särskilt när de deltar i Spaniens grossist- och sekundärregleringstjänst (aFRR) marknader. Inte minst ökar lönsamheten i projektet när systemtiden förlängs, med nuvärdet (NPV) uppgår till 29,6 M€, 50,4 M€ och 80,6 M€ för BESS-varaktigheter på en timme, två timmar respektive fyra timmar. Denna trend är dock inte konsekvent, som observerats i 2019-scenariot, där motsatsen gäller på grund av betydligt lägre priser både på grossist- och sekundärregleringsmarknaderna, vilket resulterar i negativa NPV-värden som ökar med längre BESS-varaktigheter (specifikt -3,3 M€, -6,9 M€ och -17,7 M€ för BESS-varaktigheter på en timme, två timmar respektive fyra timmar). När det gäller optimal distributionsstrategi identifierar studien liknande mönster i alla fallstudier och scenarier. BESS prioriterar deltagande i sekundärregleringstjänsten på grund av dess högre ersättning jämfört med arbitrageaktiviteter på grossistmarknaden. Trots Spaniens ansträngningar att främja antagandet av BESS-teknologier finns det flera hinder som kan hämma deras utrullning. Viktiga utmaningar inkluderar frånvaron av kapacitetsmarknader (CM), begränsningar för BESS-deltagande i tekniska begränsningar och svartstartmarknader, samt avsaknaden av marknader med ersättning för frekvensreglering (FCR) och spänningsreglering. Sammanfattningsvis belyser denna studie behovet av en mer investerarvänlig miljö präglad av större säkerhet i intäktsströmmar och förenklade administrativa processer.

The demand for electricity is rising rapidly, with more power generated through re-newable energy sources. Renewable energy sources can fluctuate in their power output atshort notice, making it more difficult to maintain the balance between electricity consump-tion and production in the short term. A solution that has gained increased interest recentlyis to connect battery energy storage systems to the grid as a means of maintaining balance.However, such systems are often controlled remotely by a cloud control system, creatingtime-critical control loops over the internet that are partly responsible for the stability andcontinued function of the electrical grid. Cyberattacks against these closed-loop systemscould devastate the electrical grid and the apparatus connected to it.In this thesis, a reference model is designed for an electrical grid load-balancing cloudcontrol system connected to remote battery energy storage systems and remote grid fre-quency sensors (measuring the balance between production and consumption). The modelis evaluated from a cybersecurity perspective by implementing a simulator and applyingdifferent cyberattacks on the simulated system.The results show that some of the most critical attack methods that a threat actor couldutilize are: disrupting the connections over the internet that are part of the closed-loopsystem, abusing remote access links from the outside to gain access to subsystems (suchas seizing control of batteries), or disturbing external dependencies to the cloud such asdomain name system (DNS) and network time protocol (NTP) servers or the contractsrelated to electricity trading. The most important cyberattacks identified in the thesis are:time delay switch (delays of messages), denial of service (disturbing message availability),false data injection (modifying message contents), replay (replaying old messages), andload altering (affecting the grid balance through direct altering of electricity consumptionand production).The simulated cyberattacks differ in how they affect the grid frequency, i.e. the gridproduction-consumption balance. Large enough network packet delays caused oscilla-tions in the simulated frequency. Denial of service attacks caused unpredictable behavior,and a high enough packet drop rate caused oscillations. For false data injection, the re-sults depend on which internet link was attacked and what injection strategy was used;some attacks caused oscillations, while others caused a steady state error or even an in-creasingly deviating frequency. Replay attacks were able to cause a deviation during thereplay window when used effectively. Finally, large enough load altering caused oscilla-tions, especially when an attacker had control over at least 15% of the system’s balancingpower.Overall, attacks on the simulated system are serious and precautions must be carefullyconsidered before such a system is implemented in the real world.

The success of battery electric trucks in logistics depends on ef-ficient and cost-effective charging practices at logistic terminalsduring loading, unloading, and overnight parking. However, asfleets of electric trucks expand, the charging process at terminalscan become complex. Maintaining transport efficiency within theelectric grid’s limits and available chargers is crucial. Challengesarise from weak terminal grid connections, necessitating a needto manage peak power usage.The aim of this master’s thesis is to develop optimization algo-rithms for fleet charging at terminals. It involves modeling andevaluating algorithm(s) against strategies and exploring potentialimplementation within existing transport systems. Delving intovarious areas, such as energy integration (including photovoltaic& battery energy storage systems), system integration of charg-ing stations, terminal layout and implementation of algorithm(s).This thesis work will contribute to the innovation project "Local En-ergy Systems for Electrified Logistic Applications" (LEELA). Modeling will rely on empirical research, industry data and researchfrom companies involved within the project LEELA.The simulations from the algorithms showed the importance ofevaluating viable choices for implementation, such as integratedcharging systems, photovoltaic systems, battery energy storagesystems and megawatt charging systems.

Detta examensarbete utreder den tekniska och ekonomiska passbarheten av batterilagringssystem (BESS) inom den svenska el infrastrukturen. Syftet är att konstruera tre olika affärsfall för att representera den tekniska och den ekonomiska passbarheten av BESS inom den svenska el infrastrukturen, specifikt med uppkoppling mot distributionsnätverket på den regionala nivån, 6 kilovolt till 132 kilovolt (kV). Affärsfallen adresserar dem tekniska funktioner och kunder inom infrastrukturen som utifrån en litteraturstudie anses vara dem mest attraktiva att bygga ett affärsfall utifrån. Litteraturstudien utreder den svenska el infrastrukturens struktur samt dess existerande och uppkommande utmaningar. Studien utforskar även hela spektrumet energilagringssystem (ESS) för att rättfärdiga valet av litium-jon BESS. Litium-jon BESS är närmare undersökt, där systemets operativa parametrar samt komponenter är kartlagda. Vidare undersöks dem tekniska funktionernas tekniska krav och ekonomiska incitament i en marknadsanalys. Slutligen utforskas regler och lagar omkring BESS implementering i den svenska el infrastrukturen samt placeringen och de kostnader för att bygga en BESS anläggning. De tre affärfallen som är konstruerade i denna studie är: Kombinationen av frekvensrelaterade nätverksstödtjänster för en fristående BESS-tillgångsoperatör. Avbrottsfri strömtillförsel för ett datacenter. Skala effekttoppar och kombination av frekvensrelaterade nätverksstöddtjänster för en industri. Litium-jon BESS anses vara den mest tillämpliga tekniken på grund av dess snabba responstid, höga effekt- och energidensitet samt skalbarheten för att passa majoriteten av de tekniska funktioner som undersökts inom studien. Affärsfallens ekonomiska passbarhet utvärderas efter två ekonomiska indikatorer, nuvärdesberäkning (NPV) samt återbetalningstiden. Affärsfall nummer tvås tekniska funktion erbjuder ingen möjlighet att generera en inkomst vilket gör att den kommer bli utvärderad efter kostnad för service, där utgifterna är uppdelade utöver projektets livstid genom linjär amortering. Vidare används linjär amortering för att räkna ut kostnaden per kilo sparat CO2 utöver livstiden på projektet. Både affärsfall 1 (NPV= 231,0 MSEK, återbetalningstid= 7,8 år) samt affärsfall 3 (NPV= 17,3 MSEK, återbetalningstid= 8,8 år) visar en lönsamhet där affärsfall 2 ger en kostnad för service mellan 5,4 och 5,8 MSEK/år och där kostnaden per sparat kilo CO2 mellan 20,9 och 22,7 SEK/kg CO2. Denna studie fokuserar på de tre största distributionsnätverksoperatorerna (DNO) inom distributionsnätverket på en regional nivå: Vattenfall, Eon och Ellevio. Lönsamheten av de undersökta affärsfallen är starkt kopplade till placeringsområde inom nätverket, spänningsnivån och typ av DNO. Möjlighet att koppla upp BESS till en existerande transformatorstation på anläggningen för affärsfall två och tre minskar investeringskostnaden samt driftkostnaderna vilket vidare förbättrar dess lönsamhet. Affärsfall ett behöver gå igenom en noggrann bedömning för att försäkra sig om lönsamheten. NPV samt återbetalningstiden kan påverkas i affärsfall ett och tre på grund av den ständigt förändrande frekvensregleringsmarknaden där priserna är volatila på grund av nya marknadsinitiativ. Att konstruera ett BESS affärsfall medför att flertalet osäkerheter bör räknas in, såsom de ekonomiska incitamenten som inte visar någon garanti på att vara fortsatt lönsamt. Det höga priset på litium-jon batterier saktar ner attraktiviteten av affärsfallen och måste vidare sjunka för att främja ett lönsamt affärsfall. Andra ESS som flödesbatterier och vätgaslagringssystem visar god passbarhet att bli implementerad i den svenska el infrastrukturen men måste vidare utveckla sin tekniska och kommersiella mognadsgrad innan dem kan vara konkurrenskraftiga med litium-jon BESS.  Examensarbetet är utfört i samarbete med Omexom Infratek Sverige AB med målet att bidra till en större förståelse av BESS roll i den svenska el infrastrukturen och vidare bidra till att konstruera ett tekniskt erbjudande för Omexom Infratek Sverige AB. / This master thesis investigates the technical and economic feasibility of battery energy storage systems (BESS) in the Swedish electrical infrastructure. The aim is to construct three business cases to represent the technical and economic feasibility of BESS implementation in the Swedish electrical infrastructure in the distribution network on the regional level, 6 kilovolts to 132 kilovolts (kV). The business cases address the technical functions and customers within the infrastructure that is recognized through a literature study to build the most attractive and incentivized business cases from. The literature study investigates the Swedish electrical infrastructure’s structure and its existing and upcoming challenges. It investigates the spectrum of energy storage systems (ESS) to justify the choice of the lithium-ion (Li-ion) BESS. The Li-ion BESS is closer examined, where the systems operational parameters and components are mapped out. Furthermore, the technical functions technical requirements and economic incentives are investigated in a market analysis. Lastly, considerations regarding regulations and permits, the placement of BESS within the infrastructure and its surrounding costs is evaluated. The three business cases that are constructed within the thesis are:  Combination of frequency related grid support services for a standalone BESS asset operator. Uninterruptable power supply for a data center. Peak shaving and a combination of frequency related grid support services for an industrial plant.  The, Li-ion BESS is considered to most applicable technology due its fast response time, high power and energy density and scalability to suit the majority of technical functions investigated in the thesis. The business cases economic feasibility is evaluated after two economic indicators, the net present value (NPV) and the payback period. Business case two’s technical function offers no possible revenues and is evaluated as a cost for service where the expenses is divided throughout the project lifetime through linear amortization and the cost per saved kg CO2 is calculated over the lifetime of the BESS. Both business case 1 (NPV= 231.0 MSEK, payback period= 7.8 years) and case 3 (NPV=17.3 MSEK, payback period= 8.8 years) show profitability where business case 2 gives a cost per service between 5.4 and 5.8 MSEK/year and cost per saved kg CO2 between 20.9 and 22.7 SEK/kg CO2.  This thesis focuses on the three largest distribution network operators (DNO) in the distribution network on a regional level: Vattenfall, Eon, and Ellevio. The profitability of the business cases investigated are strongly connected to the location in the network, the voltage connection level, and the type of DNO. Being able to connect to an existing substation on site as for business cases 2 and 3 will lower the capital and operational costs and further improve the profitability. Business case 1 needs a thorough assessment of placement in the electrical infrastructure in Sweden to assure profitability. The NPV and payback period in business cases 1 and 3 could conflict with the interchanging frequency regulation market where prices are rather volatile due to new market initiatives. Therefore, looking forward, building a BESS business case to be implemented comes with lots of uncertainties as the economic incentives shows no guarantee to continuously be profitable. The high price of Li-ion batteries is slowing down the attractiveness of the business cases and need to further decrease to promote profitable business cases. Other ESS technologies as flow batteries and hydrogen storage systems show good applicability to be implemented in the Swedish electrical infrastructure but needs to develop its technical and commercial maturity until it can become competitive with Li-ion BESS.  The master thesis is performed in conjunction with Omexom Infratek Sverige AB with the aim to contribute to a broader understanding of the role of BESS in the Swedish electrical infrastructure and to help building BESS technical offers for Omexom Infratek Sverige AB.

In recent years, power systems are facing with various challenges arising from the increased share of renewable energy systems. Among all sections of power systems, distribution grids are affected the most since the majority of renewable energy sources are connected to distribution grids. As the penetration of Variable Energy Sources increases in electric grids, energy storage systems have become more influential. In this context, this thesis presents a new algorithm for the optimal operation of Battery Energy Storage Systems in distribution grids. The proposed algorithm aims to define the optimal operation of Battery Energy Storage Systems considering the network topology, the output power of Variable Energy Sources and the electricity prices from the one-day ahead electric market as well as real time control of the batteries through smart appliances. In order to do this, firstly a comprehensive study on the existing Optimal Power Flow methods is carried out. Then, AR-OPF which is a novel Optimal Power Flow method for radial distribution systems is presented and the required mathematical constraints, equations and parameters of Battery Energy Storage Systems for modelling in distribution systems are described. Then, the problem formulation and the proposed algorithm are discussed in detail. Further to energy storage as the main function of Battery Energy Storage Systems, the impact of the proposed method on other functions of Battery Energy Storage Systems such as voltage control, grid support and loss reduction will be investigated. In order to do so, the proposed algorithm is applied to the IEEE 34 node test system as a case study. This will be carried out through defining several different scenarios. Finally, a sensitivity analysis is performed on the size of the existing batteries and the electricity price. The thesis will be concluded by the findings and possible future works.

No description available.

Battery Energy Storage Systems (BESSs) have become an increasingly popular feature of the electrical grid in the California ISO (CAISO) as a means to address the challenges posed by renewable energy variability and escalating peak demand. Due to their ability to reduce peak load demand on traditional generators and extend the benefits of the merit order effect, they have been theorized and claimed to reduce peak electricity prices. The purpose of this study is to test these claims within CAISO and understand what effects BESSs have had on peak electricity prices. Our findings show that there has been a significant decrease in prices after the introduction of BESSs into the grid although we found no significant effects of an increasing utilization of BESSs on peak electricity prices. We conclude that BESS utilization in CAISO has had no effect on peak electricity prices. We are contributing to the literature on the tangible market impacts of BESSs, highlighting the need for further empirical research in this domain.