Due to the growing population and climate change, the world will see an increase in demand for food, freshwater and renewable energy supply. Agrivoltaics has the possibility to address all these problems, by producing food and renewable energy but also by reducing water usage in agriculture. This thesis aims to study if agrivoltaics including storage has the potential to enable sustainable greenhouses in Stockholm, Sweden by trying to create a near net zero energy consumption for greenhouses with Agrivoltaics (AV) implemented. Furthermore a techno-economic assessment will be made for the AV-systems where Key Performance Indicator (KPI)’s are compared to economic parameters. The selected KPI’s were a near net zero energy consumption and irradiance underneath the Photovoltaics (PV) technology. The selected PV-technology was standard PV-modules, Semi-Transparent Module (STM) and Organic Solar Cell (OSC) PV. These technologies were paired with li-ion batteries between 0-100 kWh and simulated in the software System Advisor Model (SAM) over a 25 year period. The AV system was applied to two load profiles, one for indoor plants and one for tomatoes. The economic parameters calculated was Net Present Value (NPV), Net Capital Cost (NCC), and Levelised Cost of Electricity (LCOE).  The results showed that the system is efficient in summertime where the PV reached maximum capacity in summer and the battery works as a complement. In wintertime, the AV-system is not very efficient and most of the electricity comes from the grid. It was not possible to create a near net zero energy consumption including storage in Stockholm Sweden. The irradiance beneath the panels were at a maximum for OSC, it was slightly reduced for the STM, and below 50% for the standard PV-module, depending on the size of the AV-system. Depending on the shade tolerance of the plant, the PV-technology should be selected.

Denna rapport undersöker implementeringen av batterienergilagringssystem (BESS) som en strategisk åtgärd för att hantera de återkommande instabiliteterna i elnätet i Ekerö kommun. Den lokala elkraftsinfrastrukturen drabbas ofta av frekventa och långvariga avbrott, huvudsakligen på grund av sitt beroende av sårbara luftledningar. Integrationen av BESS erbjuder en dubbel fördel: förbättrad nätstabilitet och tillhandahållande av nödvändiga stödtjänster under perioder med hög efterfrågan. Studien inleds med en analys av de nuvarande förhållandena i Ekerös elnät, där de ekonomiska och operativa utmaningarna med den befintliga infrastrukturen belyses. Luftledningarna är särskilt utsatta för miljöpåfrestningar, vilket resulterar i betydande tjänsteavbrott som påverkar både hushåll och kommersiella konsumenter. De ekonomiska konsekvenserna är betydligt viktiga, inte bara på grund av de direkta kostnaderna för reparationer, utan också på grund av de ersättningar som krävs enligt regulatoriska standarder vid tjänstefel. Som en lösning på dessa utmaningar föreslås en strategisk placering av BESS-enheter i kommunen. Dessa system kan lagra överskottsenergi som genereras under perioder med låg efterfrågan, såsom nattetid eller under perioder med låg belastning, och frigöra den under perioder med hög efterfrågan eller när nätet inte kan möta belastningskraven. Denna kapacitet bidrar inte bara till reservkraft och stabilisering av elnätet, utan säkerställer även en mer effektiv användning av genererad energi, vilket minskar spill och potentiellt sänker elkostnaderna för kommunen. För att besvara frågeställningarna kring den optimala kapaciteten och placeringen av BESS har HOMER Pro använts. HOMER Pro är en mjukvara för optimering av mikronät. Med HOMER Pro har olika scenarier simulerats för att hitta den mest effektiva lösningen baserat på Ekerös specifika energibehov och nätförhållanden. Simuleringarna har resulterat i en rekommendation om att implementera en total kapacitet av cirka 52 MWh batterilagring vid samtliga nätstationer för att tillgodose kommunens energibehov under avbrott och hög belastning. Vidare beskriver rapporten de tekniska specifikationerna och de operativa mekanismerna för BESS, inklusive de batterityper som övervägs (t.ex. litiumjon, bly-syra), deras förväntade livslängd, kapacitet och effektivitet. Den undersöker också potentiella platser för installation, bedömer deras inverkan på den övergripande nätstabiliteten och de logistiska övervägandena vid distribution och underhåll av dessa system. Slutligen förespråkar rapporten antagandet av BESS i Ekerö som ett kritiskt steg mot en mer motståndskraftig och ekonomiskt hållbar energiinfrastruktur. Genom att minska effekterna av strömavbrott och optimera användningen av elektrisk energi kan BESS avsevärt förbättra servicenivån för Ekerös invånare och företag, och sätta en standard för andra kommuner med liknande utmaningar. / This report investigates the implementation of Battery Energy Storage Systems (BESS) as a strategic measure to address the recurring electrical grid instabilities in the municipality of Ekerö. The local power infrastructure frequently experiences outages due to its reliance on vulnerable overhead power lines. The integration of BESS offers dual benefits: improved grid stability and the provision of essential support services during periods of high demand. The study begins with an analysis of the current conditions of the electrical grid of Ekerö, highlighting the economic and operational challenges posed by the existing infrastructure. Overhead lines are particularly susceptible to weather conditions, which lead to significant service interruptions that impact both residential and commercial consumers. The economic implications are substantial, not only due to direct repair costs but also due to compensations required by regulatory standards for service failures. In response to these challenges, the report proposes the strategic placement of BESS units throughout the municipality. These systems can store excess energy generated during periods of low demand, such as nighttime or off-peak hours, and release it during periods of high demand or when the grid cannot meet the load requirements. This capability not only stabilizes the grid but also ensures more efficient use of generated power, reducing wastage and potentially lowering electricity costs for the municipality. To address questions regarding the optimal capacity and placement of BESS, the report utilizes HOMER Pro software for microgrid optimization. Various scenarios were simulated using HOMER Pro to determine the most effective solution based on Ekerö’s specific energy needs and grid conditions. The simulations resulted in a recommendation to implement a total capacity of approximately 52 MWh of battery storage across all substations to meet the municipality’s energy needs during outages and periods of high demand. Furthermore, the report details the technical specifications and operational mechanisms of BESS, including the types of batteries considered (e.g., lithium-ion, lead-acid), their expected lifespan, capacity, and efficiency levels. It also examines potential installation sites, assessing their impact on overall grid stability and the logistical considerations involved in deploying and maintaining these systems. In conclusion, the report advocates for the adoption of BESS in Ekerö as a critical step towards a more resilient and economically sustainable energy framework. By mitigating the impact of power outages and optimizing the use of electrical energy, BESS can significantly enhance the quality of service provided to Ekerö’s residents and businesses, setting a precedent for other municipalities facing similar challenges.

<p dir="ltr">The need for reducing reliance on fossil fuels to meet ever-increasing energy demands and minimizing global climate change due to greenhouse gas emissions has led to an increase in investments in Variable Energy Resources (VREs), such as wind and solar. But due to the unreliable nature of VREs, an energy storage system must be coupled with it which drives up the investment cost.</p><p dir="ltr">Lithium-ion batteries are compact, modular, and have high cyclic efficiency, making them an ideal choice for energy storage systems. However, they are susceptible to capacity loss over the years, limiting the total life of the batteries to 15-18 years only, after which they must be safely discarded or recycled. Hence, designing a Battery Energy Storage System (BESS) should consider all aspects, such as battery life, investment cost, energy efficiency, etc.</p><p dir="ltr">Most of the available studies on cost and lifetime of BESS either consider a steady degradation rate over years, or do not account for it at all, they take constant charge/discharge cycles, and sometimes do not consider ambient temperature too. This may result in an error in estimation of the cost of energy storage. The location where the BESS is supposed to be installed can also impact its life, given that each location has its own power consumption trend and temperature profile. In this work, we attempt to simulate a BESS by considering the ambient temperature, degradation rate and energy usage. This will help in getting an insight of a more realistic estimate of levelized cost of storage and for estimating the thermal energy needed to keep them within a certain temperature range, so that they can last longer.</p>

Arbetet Tillämpning av batterilager som energitjänsten lastutjämnare är en litteraturstudie och en kvantitativ studie. I studien har driftkarakteristiken år 2015 hos en matvarubutik legat till grunden. Arbetet har syftat i att besvara frågan kring ett batterilagers lämplighet som agerade för lastutjämning. För att ta reda på det har batterilagersegenskaper kartlagts och dimensionering gjorts utifrån två olika driftfall. En ekonomisk besparingspotential har även beräknats utifrån de bägge driftfallen. Driftfallen har valts att kallas teknisk dimensionering och ekonomisk dimensionering. De tekniska dimensionerade lagerna har en lager storlek om 617 kWh och 555kWh vilket motsvarar 7,1% respektive 5,8% av den dagliga energianvändningen. För de ekonomiskt dimensionerade lagerna har en lager storlek om 597 kWh och 233kWh vilket motsvarar 6,8% respektive 2,8% av den dagliga energianvändningen. Den ekonomiska besparingspotentialen blir som störst för en blandad körning av de bägge driftfallen. Trotts att besparingspotentialen är uppskattade under ideala förhållanden med varken förluster eller degraderad prestanda lönar det inte sig att investera i ett batterilager för att enbart utföra tjänsten effektutjämning idag. Investering i ett batterilager för effektutjämning har potential att bli lönsam först när den kan tillgodose fler energitjänster eller när alternativkostnaden är förhöjd. / This thesis, is a study of battery energy storage and its use as energy source and smoothening of power fluctuation. Studies have been made as a systematic review and a quantitative study. The study has consisted of analysing the power characteristic from a supermarket in the city of Varberg during year 2015. The object has been to evaluate the energy storage and the power smoothing qualities. Therefore the battery energy storages characteristics have been evaluated in this systematic review. For the quantitative study, calculations of the energy storage sizes were made for two separate operation modes. The two different operation modes were named technical dimensioning and economic dimensioning. The function of the technical dimensioning was to smooth the power outlet from the grid, while the function of the economic dimensioning was to enable the supermarket to buy more energy during low-price hours. Based on monthly power characteristics, each dimensioning gave as a result two energy storage possibilities, one in medium and one in small size. The technical dimensioning resulted in battery energy storage of the sizes 617 kWh and 555kWh which is comparable to 7,1% and 5,8% of the daily energy usage of the supermarket. The economic dimensioning resulted in battery energy storage of the sizes 597 kWh and 233kWh which is comparable to 6,8% and 2,8% of the daily energy usage of the supermarket. For optimizing the economic savings, a variation of technical and economic operation mode are needed, depending on calculated power usage through the day and elspot prices. The study shows that a battery storage is difficult to finance. The calculated economic savings were estimated during ideal conditions and without power loss or loss in performance. As a conclusion from this study a battery storage may have a good payback if there are several energy services to be filled.

In this thesis, a simulation model developed in MATLAB® in consideration of system losses based on lithium ion-battery is presented. The purpose of the simulation model is to investigate peak shaving potential in the residential distribution network. In other word to determine an optimal threshold limit and battery capacity depending on if the battery system is placed at the transformer or household level. In the report there were economic calculations executed showing that profitability of investing in a battery system depends on the threshold limit and battery capacity. / I denna rapport presenteras analys av toppeffektreducering med ett simuleringsprogram baserad på litium-jon batteri med hänsyn till systemförlust. Simuleringsmodellen är uppbyggd i MATLAB® där metoder som Coulomb counting implementerades. Syftet med simuleringsprogrammet är att definiera en optimal tröskelgräns samt batterikapacitet på transformator- och hushållsnivån. I rapporten utfördes ekonomiska beräkningar som tyder på att lönsamheten för investering av ett batterisystem beror på tröskelgräns och batterikapacitet.

The main purpose of this thesis was to develop and evaluate Key Performance Indicators (KPIs) and battery usage associated with Lithium-ion Battery Energy Storage Systems (LiBESS) used as Frequency Containment Reserve (FCR). The investigation was based on three of Vattenfall´s LiBESS projects that use the same lithium-ion battery technology but vary in system rating and configuration. It was found that two of the most important KPIs are response time and energy efficiency. The response time describes how fast the system can respond to changes in grid frequency. Additionally, the energy efficiency describes how effectively the system can provide energy storage during service and it can be parametrized into the efficiency of the battery, converter and transformer. The results show that all the considered LiBESS can fulfill the response time requirements of 30 seconds for FCR provision. In the future stricter requirements for the response time in grid stabilization services will most likely be required. Nevertheless, the results showed that a well configured LiBESS can provide response times on the millisecond scale. The energy efficiency evaluation showed that the system energy efficiency decreased from 89% to 85% when the power increased from 50% to 100% of rated power. At 75% of rated power it was found that the converter had the lowest efficiency (92%) based on the analysis of the efficiency of all the system components. It was also found that the power consumed by auxiliary loads was nearly constant for the examined power rates and that it significantly reduced the energy efficiency. Lastly, the battery usage analysis showed that the battery often idles or operates at low power rates if the frequency dead-band of ±10 mHz is applied around the nominal value of 50 Hz. Moreover, the battery usage can be characterized by an average State of Charge of 50% and a maximum Depth of Discharge of 30% during both charge and discharge of the batteries.

Orientador: Dr. Alfeu J. Sguarezi Filho / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2015. / Neste trabalho apresenta-se uma configuração do sistema de armazenamento de energia com baterias aplicado a sistemas de geração de energia eólica empregando conversores de fonte Z conectados à rede elétrica. Os geradores de indução gaiola de esquilo, são frequentemente utilizados nos sistemas de geração de energia eólica, por sua robustez, simplicidade, peso menor e custo baixo. Este é conectado diretamente ao conversor de potência bidirecional back to back, pode fornecer potências ativa e reativa à rede elétrica. Além disso, é estudado o conversor de fonte Z aplicado nesta topologia. No entanto, a implantação de sistemas de armazenamento de energia com baterias nos sistemas de geração de energia eólica na atualidade é muito importante, devido à possibilidade de oscilações da tensão e corrente na rede elétrica, portanto, estes podem ajudar à estabilização das tensões, correntes e a frequência na rede elétrica. Este sistema é conectado ao conversor back to back por meio de um conversor elevador-abaixador de corrente contínua. Para controlar a velocidade no eixo do rotor no gerador de indução, a estratégia é baseada no controle direto de torque. Enquanto, para o conversor do lado da rede é empregada a técnica de controle orientado pela tensão. Para o banco de baterias é utilizado o controle da tensão no barramento de corrente contínua e do fluxo na corrente da bateria, utilizando controladores do tipo PI. Com os novos desenvolvimentos tecnológicos nas chaves de potência, são apresentadas topologias de conversores CC-CA como o conversor de fonte Z, este tipo de conversor corrige algumas limitações do conversor back to back, com as características de elevador/abaixador de tensão, sem o uso de dispositivos de comutação, são permitidos os curto-circuitos na chaves, empregando novas técnicas de modulação, e reduz a quantidade harmônica injetada na rede elétrica. Os estudos foram realizados por meio de técnicas de simulação computacional usando modelos matemáticos do sistema estudado para a validação das estratégias de controle empregadas em diferentes condições de operação. Para as simulações empregou-se a ferramenta computacional SimPowerSystems R do Matlab/Simulink R . / This paper presents a battery energy storage system applied to wind power generation based on Z-source inverter connected to the power grid. The squirrel cage induction generators, often used in wind power generation systems, for its robustness, simplicity, lower weight and low cost. This is connected directly to the bidirectional power converter back to back, therefore, and provides active and reactive powers to grid. In addition, it is studied the Z-source inverter applied in this topology. However, the implementation of battery energy storage systems in wind power generation systems, currently is very important, due to possibility of the voltage and current fluctuations in the power grid, so these may to stabilisation of current, voltage and frequency on the grid. This system is connected to back to back converter through a DC-DC converter (buck-boost). For the rotor speed control on induction generator, the strategy is based on direct torque control. While, for the grid side converter is employed the technique of voltage oriented control. For the battery bank voltage control is used on DC-link voltage and battery current flow, through PI type controllers. With the new technological developments in the keys of power, DC converters topologies are presented as the Z-source inverter, this type converter fixes some limitations of the converter back to back, with the characteristics of buck-boost voltage, without the use of switching devices, allowed short-circuits on converter, using new modulation techniques, and reduces the amount injected harmonic to power grid. The studies were performed by means of computer simulation techniques using mathematical models of studied system to validate the control strategies employed in different operating conditions. For the simulations was used the computational tool SimPowerSystems R do Matlab/Simulink R .

Sweden has experienced a significant increase in installed solar power capacity between 2010 and 2020, driven by decreasing installation costs, government subsidies and widespread public interest. However, Sweden's geographical distribution of electricity generation and consumption presents challenges for the national grid. Recent instability in the electricity supply due to the war in Ukraine has prompted increased interest in residential battery energy storage systems (BESS) as a means to enhance energy resilience and reduce electricity bills. The rapid growth of the European residential BESS market is expected to continue, driven by the need for flexibility and energy-shifting services in response to increasing renewable energy production. BESS can provide economic benefits to households with installed PV systems through peak shaving, allowing them to store excess electricity during periods of high production and use it during peak demand. This thesis investigates photovoltaic (PV) and BESS performance and profitability for Swedish households under various conditions. The study considers parameters such as system costs, energy prices, grid tariffs and dynamic battery management strategies to investigate the profitability of the systems. The research aims to provide guidelines for households to maximize the benefits of their PV and BESS installations and minimize their dependence on the grid. The effectiveness and practicality of the developed method are demonstrated through verification in two real-world installations. The study’s findings demonstrate that electricity prices, household consumption and roof orientation highly influence the profitability of PV systems. If future electricity prices align with present forecasts, installations on north-facing roofs will not be profitable under any circumstances investigated in this study. A distinct correlation is also discernible between larger loads and improved economic viability for PV and BESS installations, while a smaller battery capacity results in higher economic viability. This reveals that BESS profitability currently is limited due to high installation costs. However, the potential for future BESS profitability is shown if battery costs are reduced and more advanced battery dispatch strategies are developed. / Sverige har upplevt en betydande ökning av installerad solkraftskapacitet mellan åren 2010 och 2020, drivet av faktorer som minskande installationskostnader, statliga bidrag och ett brett folkligt intresse. Geografiska skillnader mellan elproduktion och konsumtion i Sverige innebär utmaningar för elnätet. Instabilitet i elförsörjningen till följd av kriget i Ukraina har ökat intresset för batterilagringssystem i bostäder som ett medel för hushåll att öka deras energiresiliens och minska elkostnaderna. Den snabba tillväxten på den europeiska marknaden för batterilagringssystem förväntas fortsätta, drivet av behovet av flexibilitet i elnätet och energiomställningstjänster till följd av ökad produktion av förnybar energi. Batterilagringssystem kan ge ekonomiska fördelar för hushåll med installerade PV-system genom utjämning av effekttoppar, vilket gör att överskottsenergi kan lagras under perioder av hög produktion och användas under toppbelastning. Denna rapport undersöker prestanda och lönsamhet för solcells- och batterisystem för svenska hushåll under olika förhållanden. Studien utforskar betydande parametrar såsom systemkostnader, energipriser, nättariffer och dynamiska batterihanteringsstrategier för att undersöka lönsamheten för systemen. Detta ämnar till att ge riktlinjer för hushåll att maximera fördelarna med solcells- och batteri-installationer och minimera dess beroende av elnätet. Effektiviteten och praktikaliteten av den utvecklade metoden demonstreras genom verifiering i två verkliga installationer. Resultaten visar atta elpriser, hushållsförbrukning och takorientering i hög grad påverkar lönsamheten hos solcellsanläggningar. Om framtida elpriser stämmer överens med nuvarande prognoser kommer installationer på tak mot norr inte att vara lönsamma under några omständigheter som undersökts i denna studie. En tydlig korrelation kan också urskiljas mellan större elkonsumtion och förbättrad ekonomisk lönsamhet för PV och batteri-installationer, medan en mindre batterikapacitet resulterar i högre ekonomisk lönsamhet. Detta visar att batteriers lönsamhet för närvarande är begränsad på grund av höga installationskostnader. Potentialen för framtida lönsamhet för batterier visas dock om batterikostnaderna sänks och mer avancerade batterihanteringsstrategier utvecklas.

Battery Storage Systems (BESS) installed Behind the Meter (BTM) can provide demand management services, reducing electricity costs and enhancing overall electricity system stability. BTM BESS can also imporve self-consumption obtained with distributed generation assets like solar photovoltaics. This study examines the influence on value creation from consumption patterns and utility tariffs. Using Swedish and UK tariffs and a set of consumption profiles, the study determines the optimal BESS configuration and conducts simulations to assess profability through Net Present Value. Comparative analysis reveals the impact of utility tariffs and consumption profiles on profitablility. Projected BESS cost levels for 2030 and 2050 are used to evaluate expected future profitability.  The findings indicate that utility tariff has a stronger influence on BTM BESS profitability than consumption profile. Energy arbitrage creates most of the value, depending more on tariff structure than consumption pattern. However, with higher demand charges, the consumtion profile becomes more important as the relative value of peak shaving increases. Two sensitivity analyses have been performed. The first shows that NPVs are affected by decreased electricity price variability, emphasising the need for accurate long-term price forcasts. The second shows that existing electricity consumption forecasting techniques prove sufficient for effective peak shaving.  In conclusion, this research inderscores the significance of utility tariffs and consumption profiles in determining BTM BESS profitability. Energy arbitrage dominates value creation, while peak shaving gains importance with higher demand charges. Accurate long-term price forecasts are crucial for assessing BTM BESS profitability, and existing consumption forecasting techniques are suitable for peak shaving. / Batterilagring installerad bakom elmätaren kan optimera en fastighets elkonsumtion för att reducera elkostnader samt förbättra stabiliteten i elsystemet som helhet. Den här studien undersöker faktorer som påverkar värdeskapande genom energiarbitrage och peak shaving, inklusive konsumtionsprofiler och eltariffer. Studien undersöker även om det går att uppnål önsamhet under nuvarande och framtida prisnivåer för batterilagring. Studien utgår ifrån svenska och brittiska eltariffer samt fem konsumtionsprofiler, och fastställer den mest optimala konfigurationen av batterilagring genom optimering. Därefter jämförs lönsamheten genom nettonuvärde-analys för att dra slutsatser om hur eltariff och konsumtionsprofil påverkar lönsamhet. Studien visar att lönsamhet för batterilagring bakom mätaren beror mer på eltariff än konsumtionsprofil. Detta eftersom mest värde skapas genom energiarbitrage som är mindre beroende av konsumtionsprofil men direkt beroende av variationer i elpriset. Med högre effektavgifter ökar lönsamhetens beroende av konsumtionsprofilen då det relativa värdet av peak shaving höjs. En känslighetsanalys visar på en stark korrelation mellan värdet av energiarbitrage och variationer i elpriset, vilket visar vikten av långsiktiga prognoser av elprisets volatilitet. Befintliga tekniker för prognostisering av elkonsumtion har tillräcklig noggrannhet för effektivpeak shaving. Sammanfattningsvis visar studien hur eltariff och konsumtionsprofil påverkar lönsamheten för batterilagring installerad bakom elmätaren. Majoriteten av värdet skapas genom energiarbitrage för svenska och brittiska tariffer. Med högre effektavgifter ökar betydelsen av peak shaving. Dessutom betonar studien vikten av långsiktiga prognoser av elprisvolatilitet vid utvärderingen av lönsamheten för investeringar i batterilagring bakom mätaren.

’Netto-noll utsläpp’ i EU vid 2050 är ett av målen för att påskynda övergången från fossila bränslen till mer förnyelsebara och hållbara alternativ. Detta har däremot introducerat mer turbulens på elnäten. Ett av verktygen för att reglera och förbättra eldistributionen är stor-skaliga batterier, där litium-jon är den mest förekommande kemin. Men på grund av oro kring resursutbud och hopp om teknologidiversifiering har det påbörjat en sökning efter alternativ som kan användas i stället eller tillsammans med litium-jon batterier. Från en lång lista så har tre alternativ med hög potential identifierats. Dessa är nickel-vätgasbatteri, zink-brom flödesbatteri och järn-luftbatteri. Deras lämplighet undersöktes och diskuterades för flertalet användningsområden och för ett speciellt användarfall av Vattenfall. Slutsatsen var att utav de tre, så är det endast nickel-vätgas som kan förväntas vara ett bra alternativ för specifika fall, att zink-brom har få möjligheter att konkurrera och att järn-luft har väldigt hög potential men också många oklarheter som gör det svårt att förutspå dess utveckling. / With net-zero emissions set to be achieved in the EU by 2050, the transition from fossil-based energy sources to more renewable and green options are ever expanding. This puts a strain on the electricity grids because of the intermittent nature from these energy sources. To mitigate this battery systems are used, of which the lithium-ion battery is the most prevalent, and expected to only increase in use. However, material resource concerns and possible danger of over-reliance on one technology has opened for a search to find other alternatives that could be used instead or in conjunction with the battery. Out of a long list of batteries, the nickel-hydrogen battery, zinc-bromide flow battery and iron-air battery are three alternatives that have been identified to have potential. Their suitability was researched and discussed for various grid-applications. The result show that out of the three, it is only believed that the nickel-hydrogen battery have a definitive competitiveness, that the zinc bromide flow battery has few things going for it, and that the iron-air battery has large potential but just as large uncertainty surrounding its future. Lastly, a specific off-shore wind park case was investigated to see the practicality and competitiveness of the nickel-hydrogen battery compared to a specific lithium-ion chemistry.