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Système inertiel de stockage d'énergie couplé au générateur photovoltaïque et piloté par un simulateur temps réel / Flywheel Energy Storage System coupled to a Photovoltaic power plant and managed by a real time simulatorAbbezzot, Cédric 15 December 2014 (has links)
Le sujet s'inscrit dans la stratégie d'augmentation de la pénétration des énergies renouvelables dans les réseaux électriques, en particulier ceux qui sont faiblement interconnectés, tels que les réseaux électriques insulaires. Une limite de pénétration des énergies intermittentes de 30% en puissance instantanée dans ces réseaux a été fixée par la loi française. Pour permettre de dépasser cette limite, une solution est de coupler les sources de production décentralisée et intermittente avec du stockage.Dans cette thèse, nous nous sommes intéressés au volant d’inertie, système de stockage permettant de convertir l’énergie électrique sous forme cinétique et vice versa. Celui-ci a en effet un nombre de cycles charge/décharge important en comparaison avec une batterie électrochimique et peut être utilisé pour lisser la production photovoltaïque. La fluctuation de l’énergie photovoltaïque est en effet faiblement prédictible au cours du temps et elle ne peut pas être contrôlée, notamment sa chute de production. La production photovoltaïque peut chuter jusqu’à 80 % de la puissance maximale en 30 secondes, et déstabiliser ainsi le réseau électrique. Le réseau électrique insulaire, tel que celui de la Corse, n’est pas interconnecté au réseau électrique continental. Les réseaux non – interconnectés sont plus fragiles et moins stables. Ainsi, le développement massif des centrales photovoltaïques peut faire fluctuer la fréquence et la tension du réseau. Le volant d’inertie a l’avantage de posséder un faible temps de réponse (quelques centaines de millisecondes). Cependant, il a une capacité énergétique moindre. Nous allons donc exploiter les avantages du volant d’inertie en le gérant en temps réel avec un calculateur approprié. Un volant d’inertie d’une puissance de 15 kVA et d’une capacité énergétique de 112 Wh a été caractérisé et testé à l’INES Chambéry en utilisant un simulateur réseau temps réel (RTLab®), un calculateur temps réel dSPACE® et une centrale PV. Le système de stockage est composé d’une machine électrique asynchrone et d’un volant d’inertie cylindrique en acier. Le logiciel Matlab/Simulink® est utilisé pour implémenter les lois de commande nécessaires à son pilotage. Dans cette thèse, le banc de test est présenté ainsi que les résultats sur les services système (lissage de puissance, régulation de la fréquence et de la tension). Trois méthodes de lissage de puissance sont présentées et évaluées (lissage avec une fonction de transfert, lissage avec limiteur de pente et lissage n’utilisant pas aucune fonction de lissage). La troisième méthode n’utilisant ni une fonction de transfert, ni une fonction limitant la pente des variations, nécessite moins de paramètres et s’avère plus optimale et plus robuste. Un volant d’inertie avec une autre technologie de machine électrique (la machine à réluctance variable) a été également caractérisé. C’est une Alimentation Sans Interruption (ASI), sur laquelle des paramètres tels que l’autodécharge et les rendements du système (en charge, en décharge et au repos) ont pu être mesurés. / The subject is part of the strategy to increase the penetration of renewable energy in power systems, particularly those that are poorly interconnected, such as island grids. A limit of penetration of intermittent energy by 30% in instantaneous power in these electrical grids was set by a French law. To help overcome this limitation, a solution is to couple the sources of decentralized and intermittent generation with energy storage systems. In this thesis, we are interested in flywheel energy storage systems (FESS) that converts electrical energy in kinetic energy form and vice versa. FESS have a number of cycles charge / discharge large compared with electrochemical batteries and can be used to smooth the photovoltaic power generation. The fluctuation of photovoltaic instantaneous power is indeed weakly predictable over time and it cannot be controlled, including its production fall. PV production can decrease up to 80% of its maximum power in 30 seconds, and so destabilize the grid. The island grids, such as that of Corsica, are not interconnected to the mainland power grid. The non - interconnected grids are more fragile and less stable. Thus, the massive development of photovoltaic power plants can cause fluctuations in the frequency and voltage. The flywheel has the advantage of having a low response time (a few hundred milliseconds). However, it has a lower energy capacity. The benefits of FESS are used by managing it in real time with an appropriate computer. A flywheel with a power of 15 kVA and an energy capacity of 112 Wh was characterized and tested at INES Chambery using a real time grid simulator (RTLab®), a real-time computer (dSPACE®) and a PV power plant. The storage system is composed by an asynchronous electrical machine and a cylindrical steel flywheel. The Matlab Simulink / software is used to implement the control laws necessary for its control. In this thesis, the test bench is presented and the results of ancillary services (power smoothing, frequency and voltage regulation). Three power smoothing methods are discussed and evaluated (smoothing with a transfer function, with a slope limiter function and a method not using any smoothing function). The third method uses neither a transfer function, nor a function that limits the slope variations, requires fewer parameters, and is more optimal and more robust. A flywheel with another electrical machine technology (the switched reluctance machine) has also been characterized. This is an Uninterruptible Power Supply (UPS) on which parameters such as self-discharge and efficiencies (charging mode, discharging mode and standby mode) were measured.
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Accounting for the Effects of Power System Controllers and Stability on Power Dispatch and Electricity Market PricesKodsi, Sameh January 2005 (has links)
Recently, the widespread use of power system controllers, such as PSS and FACTS controllers, has led to the analysis of their effect on the overall stability of power systems. Many studies have been conducted to allocate FACTS controllers so that they achieve optimal power flow conditions in the context of Optimal Power Flow (OPF) analysis. However, these studies usually do not examine the effect of these controllers on the voltage and angle stability of the entire system, considering that the types of these controllers and their control signals, such as reactive power, current, or voltage, have significant effect on the entire system stability. <br /><br /> Due to the recent transition from government controlled to deregulated electricity markets, the relationship between power system controllers and electricity markets has added a new dimension, as the effect of these controllers on the overall power system stability has to be seen from an economic point of view. Studying the effect of adding and tuning these controllers on the pricing of electricity within the context of electricity markets is a significant and novel research area. Specifically, the link among stability, FACTS controllers and electricity pricing should be appropriately studied and modelled. <br /><br /> Consequently, in this thesis, the focus is on proposing and describing of a novel OPF technique which includes a new stability constraint. This technique is compared with respect to existent OPF techniques, demonstrating that it provides an appropriate modelling of system controllers, and thus a better understanding of their effects on system stability and energy pricing. The proposed OPF technique offers a new methodology for pricing the dynamic services provided by the system's controllers. Moreover, the new OPF technique can be used to develop a novel tuning methodology for PSS and FACTS controllers to optimize power dispatch and price levels, as guaranteeing an adequate level of system security. All tests and comparisons are illustrated using 3-bus and 14-bus benchmark systems.
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Accounting for the Effects of Power System Controllers and Stability on Power Dispatch and Electricity Market PricesKodsi, Sameh January 2005 (has links)
Recently, the widespread use of power system controllers, such as PSS and FACTS controllers, has led to the analysis of their effect on the overall stability of power systems. Many studies have been conducted to allocate FACTS controllers so that they achieve optimal power flow conditions in the context of Optimal Power Flow (OPF) analysis. However, these studies usually do not examine the effect of these controllers on the voltage and angle stability of the entire system, considering that the types of these controllers and their control signals, such as reactive power, current, or voltage, have significant effect on the entire system stability. <br /><br /> Due to the recent transition from government controlled to deregulated electricity markets, the relationship between power system controllers and electricity markets has added a new dimension, as the effect of these controllers on the overall power system stability has to be seen from an economic point of view. Studying the effect of adding and tuning these controllers on the pricing of electricity within the context of electricity markets is a significant and novel research area. Specifically, the link among stability, FACTS controllers and electricity pricing should be appropriately studied and modelled. <br /><br /> Consequently, in this thesis, the focus is on proposing and describing of a novel OPF technique which includes a new stability constraint. This technique is compared with respect to existent OPF techniques, demonstrating that it provides an appropriate modelling of system controllers, and thus a better understanding of their effects on system stability and energy pricing. The proposed OPF technique offers a new methodology for pricing the dynamic services provided by the system's controllers. Moreover, the new OPF technique can be used to develop a novel tuning methodology for PSS and FACTS controllers to optimize power dispatch and price levels, as guaranteeing an adequate level of system security. All tests and comparisons are illustrated using 3-bus and 14-bus benchmark systems.
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Análise da viabilidade técnica e econômica do suporte de potência reativa a partir de geradores eólicos como prestadores de serviços ancilaresSouza, Flávio Santos de January 2016 (has links)
Orientador: Prof. Dr. Thales Sousa / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2016. / O crescimento da demanda por energia elétrica, ocasionada pelo desenvolvimento humano e o esgotamento e impactos ambientais causados pelas fontes tradicionais de geração de
eletricidade têm feito com que novas fontes energéticas sejam não só cada vez mais
importantes, mas necessárias, chamando a atenção de governos e entidades do setor elétrico no mundo inteiro. Tendo este cenário como base, este trabalho avalia a viabilidade técnica e
econômica da utilização de aerogeradores também para o provimento do serviço ancilar de
suporte de potência reativa, visto que algumas máquinas utilizadas na aerogeração tais como os DFIG (Double Fed Induction Generator), possuem a capacidade de operarem com fator de
potência diferente do unitário. Para tanto, utiliza-se o software AMPL (Modeling Language for Mathematical Programming), em conjunto com o solver Knitro, com o intuito de modelar e
analisar a operação de sistemas de transmissão com a inserção de geradores eólicos com a
tecnologia DFIG. Para atender ao objetivo proposto é modelado um FPO (Fluxo de Potência
Ótimo) de maneira a permitir a análise dos resultados sobre a contribuição dos aerogeradores
para o sistema, considerando a potência reativa produzida pelos geradores eólicos para
minimizar as perdas técnicas na transmissão. Para validar o modelo proposto são realizadas
simulações em sistemas elétricos conhecidos (benchmarks do IEEE). / The growth in demand for electricity, caused by human development and depletion and
environmental impacts caused by traditional sources of electricity generation, have caused new energy sources are not only increasingly important, but necessary, drawing attention to
governments and the electricity sector entities worldwide. Taking this scenario as a basis, this
study evaluates the technical and economic feasibility of using wind generators also for the
provision of reactive power ancillary service, as some machines used in wind-generation such
as DFIG (Double Fed Induction Generator) have the ability it operates with different power
factor of the unit. To do so, it uses the software AMPL (Modeling Language for Mathematical
Programming), together with the solver Knitro in order to model and analyze the transmission
system operating with the insertion of wind generators with the DFIG technology. Therefore, it is modeled the OPF (Optimal Power Flow) and subsequent analysis of the results on the
contribution of wind turbines for the system, considering the reactive power produced by the
wind farms to minimize technical losses in transmission. In order to validate the model,
simulations are performed in known electrical systems (IEEE benchmarks).
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Marginaler för morgondagen : En kvantitativ analys av flexibiliteten hos aggregerade laddande elbilar / Margins for tomorrow : A quantitative analysis of the flexibility from aggregated electric vehiclesKarlén, Albin, Genas, Sebastian January 2021 (has links)
Elektrifieringen av bilflottan sker i rasande takt. Även andra samhällssektorers efterfrågan på el väntas öka drastiskt under kommande decennier, vilket i kombination med en växande andel intermittenta energikällor trappar upp påfrestningarna på elnätet och ställer krav på anpassningar. En föreslagen dellösning till kraftsystemets kommande utmaningar är att utnyttja efterfrågeflexibiliteten i laddande elbilar genom att en aggregator styr ett stort antal elbilsladdare och säljer den sammanlagda kapaciteten på till exempel Svenska kraftnäts stödtjänstmarknader. För att avgöra hur mycket flexibilitet som elbilsladdning kan bidra med behöver aggregatorn upprätta prognoser över hur mycket effekt som mest sannolikt finns tillgänglig vid en viss tidpunkt – en punktprognos – men också en uppskattning av vilken effektnivå man kan vara nästan säker på att utfallet överstiger – en kvantilprognos. I den här studien har en undersökning gjorts av hur prognosfelet förändras om gruppen av aggregerade elbilsladdare ökas, och hur mycket en aggregator på så sätt kan sänka sina marginaler vid försäljning av efterfrågeflexibiliteten för att med säkerhet kunna uppfylla sitt bud. Det gjordes genom att kvantifiera flexibiliteten för 1 000 destinationsladdare belägna vid huvudsakligen arbetsplatser, och genom att skala upp och ner datamängden genom slumpmässiga urval. För dessa grupper gjordes sedan probabilistiska prognoser av flexibiliteten med en rullande medelvärdes- och en ARIMA-modell. Utifrån prognoserna simulerades slutligen potentiella intäkter om aggregatorn skulle använda den flexibla kapaciteten för uppreglering till stödtjänsten FCR-D upp, vilket är en frekvensreserv som aktiveras vid störningar av nätfrekvensen. Resultaten visar att en tiodubbling av antalet aggregerade elbilsladdare mer än halverar det relativa prognosfelet. De båda prognosmodellerna visade sig ha jämförbar precision, vilket talar för att använda sig av den rullande medelvärdesmetoden på grund av dess lägre komplexitet. Den ökade säkerheten i prognosen resulterade dessutom i högre intäkter per laddare. De genomsnittliga intäkterna av att leverera flexibilitet från 1 000 aggregerade elbilsladdare till FCR-D uppgick till 6 900 kr per månad, eller 0,8 kr per session – siffror som troligen hade varit högre utan coronapandemins ökade hemarbete. En 99-procentig konfidensgrad för kvantilprognosen resulterade i en säkerhetsmarginal med varierande storlek, som i genomsnitt var runt 90 procent för 100 laddpunkter, 60 procent för 1 000 laddpunkter samt 30 procent för 10 000 laddpunkter. Mest flexibilitet fanns tillgänglig under vardagsförmiddagar då ungefär 600 kW fanns tillgängligt som mest för 1 000 laddpunkter. Att döma av tio års nätfrekvensdata är den sammanlagda sannolikheten för att över 50 procent aktivering av FCR-D-budet skulle sammanfalla med att utfallet för den tillgängliga kapaciteten är en-på-hundra-låg i princip obefintlig – en gång på drygt 511 år. Att aggregatorn lägger sina bud utifrån en 99-procentig konfidensgrad kan alltså anses säkert. / The electrification of the car fleet is taking place at a frenetic pace. Additionally, demand for electricity from other sectors of the Swedish society is expected to grow considerably in the coming decades, which in combination with an increasing proportion of intermittent energy sources puts increasing pressure on the electrical grid and prompts a need to adapt to these changes. A proposed solution to part of the power system's upcoming challenges is to utilize the flexibility available from charging electric vehicles (EVs) by letting an aggregator control a large number of EV chargers and sell the extra capacity to, for example, Svenska kraftnät's balancing markets. To quantify how much flexibility charging EVs can contribute with, the aggregator needs to make forecasts of how much power that is most likely available at a given time – a point forecast – but also an estimate of what power level the aggregator almost certainly will exceed – a quantile forecast. In this study, an investigation has been made of how the forecast error changes if the amount of aggregated EV chargers is increased, and how much an aggregator can lower their margins when selling the flexibility to be able to deliver according to the bid with certainty. This was done by quantifying the flexibility of 1000 EV chargers located at mainly workplaces, and by scaling up and down the data through random sampling. For these groups, probabilistic forecasts of the flexibility were then made with a moving average forecast as well as an ARIMA model. Based on the forecasts, potential revenues were finally simulated for the case where the aggregator uses the available flexibility for up-regulation to the balancing market FCR-D up, which is a frequency containment reserve that is activated in the event of disturbances. The results show that a tenfold increase in the number of aggregated EV chargers more than halves the forecast error. The two forecast models proved to have comparable precision, which suggests that the moving average forecast is recommended due to its lower complexity compared to the ARIMA model. The increased precision in the forecasts also resulted in higher revenues per charger. The average income from delivering flexibility from 1000 aggregated electric car chargers to FCR-D amounted to SEK 6900 per month, or SEK 0.8 per session – figures that would probably have been higher without the corona pandemic's increased share of work done from home. A 99 percent confidence level for the quantile forecast resulted in a safety margin of varying size, which on average was around 90 percent for 100 chargers, 60 percent for 1000 chargers and 30 percent for 10,000 chargers. Most flexibility was shown to be available on weekday mornings when approximately 600 kW was available at most for 1000 chargers. By examining frequency data for the Nordic power grid from the past ten years, the joint probability that a more than 50 percent activation of the FCR-D bid would coincide with the outcome for the available capacity being one-in-a-hundred-low, was concluded to be nearly non-existent – likely only once in about 511 years. For the aggregator to place bids based on a 99 percent confidence level can thus be considered safe.
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Potenciál nefrekvenčních podpůrných služeb pro provozovatele distribuční sítě / Potential of non-frequency ancillary services for a distribution system operatorReiskup, Filip January 2020 (has links)
This thesis provides a basic overview of the ancillary services in a transmission system. It summarizes changes regarding the implementation of European directives SOGL and EBGL. It describes in detail a portfolio of non-frequency ancillary services used in the distribution systems. It evaluates the demand of E.ON distribution system potential for those services in particular locations. Practical part is focused on a potential of reactive power management in this distribution area. It evaluates reactive power flow into transmission system and indicates the most critical substations. This thesis also covers analysis of existing resources in this distribution area and assign their possible potential in reactive power management.
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Framtidens vätgassystem : En fallstudie om vätgasproduktion mot en industriell marknad med el från havsbaserad vindkraft / Hydrogen systems in the future : A case study regarding hydrogen production for an industrial market utilizing offshore wind powerNedar, Herman, Celsing, Alexander January 2023 (has links)
Vätgas producerad från förnybar el har en stor potential att minska utsläppen från flera olika branscher. Detta genom att införa nya innovativa ändamål och även genom storskalig ersättning av vätgas som idagproduceras med fossila bränslen. Men för en storskalig förändring behöver kostnaden för förnybar vätgasproduktionsjunka. Förutom den generella teknikutveckling och storskalighetsfördelar finns det effektivasätt att bättre nyttja existerade teknik för att sänka kostnaden för vätgas mot slutkund. Exempel på detär försäljning av spillvärme från systemet till lokala fjärrvärmesystem samt nyttjandet av vätgassystemetför att agera på balansmarknader. Denna studie undersökte hur ett vätgassystem innehållandes elektrolysörer, lager, kompressor och gasturbinerkan utformaras och driftas för att på ett effektivt sätt agera på marknader för el och vätgas. Det gjordes genom att studera hur en anläggning kopplat till vindkraftsproduktion genom ett Power purchaseagreement (PPA) kan utformas och driftas för att tillgodose ett industriellt vätgasbehov. Stort fokus ladespå hur ett sådant system kunde nyttjas för att agera på balansmarknader genom att sälja stödtjänsteroch hur erbjudandet av stödtjänster påverkade resten av vätgassystemet. Fallstudien som genomfördes utgick från ett potentiellt vätgassystem i Helsingborg med två stora industriellakunder som ville skifta från nyttjandet av vätgas producerad genom ångreforming till vätgasproducerad genom elektrolys med förnybar el. Då mycket fokus i studien var på balansmarknader ochflexibilitet ansågs PEM-elektrolsyören var den bäst lämpade. Vidare valdes komprimerad vätgaslagringoch ett antal alternativ för vätgasturbiner. Då produktionen var kopplad till en intermittent energikällagjordes bedömningen att systemet skulle vara assisterat med möjligheten att handla el på dagenföre- ochintradagsmarknaden. Om all eltillförsel skulle ske från vindkraften hade lagret behövt vara orimligt stortför att säkerställa förmågan att klara leveranskrav under perioder med låg elproduktion. För att analyseradet valda systemet modellerades ett vätgassystem i Energy Optima 3, en programvara som nyttjar linjärprogrammering för totaloptimering av energisystem. För att undersöka hur dem olika komponenternaskulle dimensioneras gjordes ett antal helårsoptimeringar med tidsupplösning om en timme för att se hursystemet presterade med olika kombinationer av storlek på elektrolysör, lager samt typ av gasturbin. Vid värdering av vilken konfiguration som var mest lämpad användes den utjämnade vätgaskostnaden.Den konfiguration som bedömdes vara mest lämpad för det studerade fallet var en PEM-elektrolysör på 55MW, ett komprimerat lager som motsvarade 12 timmars behov från kunderna och en gasturbin på 24 MW.Den konfigurationen kunde under den studerade tidsperioden producera vätgas till en utjämnad kostnadpå 4,7 EUR/kg. Allmänt kan sägas att studien visade att agerande på balansmarknaden gav stor intäkterför systemet och hade en betydande påverkan på systemets lönsamhet. Försäljning av spillvärme hade idet studerade fallet inte en lika kritiskt påverkan på systemet då intäkter var betydligt lägre. En viktigtinsikt från studien var att värdet av att agera på dem olika marknaderna ofta ställdes mot varandradå deltagande på balansmarknaden ibland innebar att elektrolysören inte kunde nyttja all kapacitet.Samtidigt innebar uppbunden kapacitet på balansmarknaden att flexibiliteten i systemet inte kundenyttjas för att agera på intradagsmarkanden och/eller hantering av prognosfel från vindkraftsproduktion. Studien visade allmänt att utformning och prissättning av PPA har en avgörande roll i ett vätgassystemsgångbarhet. I studien användes ett pay-as-produced-avtal, vilket resulterade i att elektrolysören vid vissatillfällen hade underskott på el (och el från intradagsmarknaden behövde köpas in för att kompensera)och vid vissa tillfällen var det överskott på el (och el behövde säljas vidare på dagenföre- eller intradagsmarknaden.)Vidare bedömdes försäljning av vätgas med långsiktiga kontrakt vara det mest lämpadealternativet då det säkrar intäkter för vätgas producenter och tillgången på vätgas till för industrierna. / Hydrogen produced from renewable electricity has significant potential to reduce emissions in variousindustries, both through new innovative applications and as a large-scale replacement for hydrogen currentlyproduced using fossil fuels as a feed stock. However, in order for large scale adaptation of renewablehydrogen the costs associated with it must decrease. In addition to technological advancements and economiesof scale, there are effective ways to better utilize existing technology to lower the cost of hydrogenfor end user. Examples include selling excess heat from the system to local district heating networks ifthe location of the electrolyzer allows for it, as well as utilizing the hydrogen system to participate inbalancing markets. This study investigated how hydrogen systems containing electrolyzers, storage, compressors, and gasturbines can be designed and operated to effectively participate in electricity and hydrogen markets. Itwas done by studying how a facility connected to wind power production through a Power PurchaseAgreement (PPA) can be designed and operated to meet an industrial hydrogen demand. A major focuswas placed on how such a system could be utilized to participate in balancing markets by providingancillary services and how offering these services affected the rest of the hydrogen system. The case study was focused on a potential hydrogen system in Helsingborg with two large industrialcustomers interested in transitioning from steam reforming hydrogen production to electrolysis using renewableelectricity. As the study heavily emphasized balancing markets and flexibility, a PEM electrolyzerwas chosen over other technologies. Additionally, compressed hydrogen storage and several options forhydrogen gas turbines were selected. Since the production was linked to an intermittent energy source,it was assessed that the system would need to be supported by trading electricity on the day-ahead andintraday markets. If all electricity supply were to come from wind power, the hydrogen storage wouldhave to be unreasonably large to ensure the ability to meet delivery requirements during periods of lowelectricity production. To analyze the selected system, a hydrogen system was modeled using EnergyOptima 3, a software that utilizes linear programming for total optimization of energy systems. Severalyear-long optimizations with 1-hour resolution were performed to examine how the system performedwith different combinations of electrolyzer and storage sizes, as well as types of gas turbines. When evaluating which configuration was most suitable, the levelized cost of hydrogen (LCOH) was used.The configuration deemed most suitable for the studied case consisted of a 55 MW PEM electrolyzer,compressed storage equivalent to 12 hours of customer demand, and a 24 MW gas turbine. This configurationcould produce hydrogen at a levelized cost of 4.7 EUR/kg during the studied period. Overall,the study demonstrated that participating in the balancing market generated significant revenue for thesystem and had a substantial impact on its profitability. The sale of waste heat had a less critical effecton the system in the studied case, as the revenues were considerably lower. An important insight fromthe study was that the value of participating in different markets was often weighed against each other,as participating in the balancing market some times meant that the electrolyzer could not utilize itsfull capacity, while having tied-up capacity in the balancing market limited the system’s flexibility toparticipate in the intraday market and/or manage forecast errors related to wind power production. The study generally showed that the design and pricing of Power Purchase Agreements (PPAs) plays acrucial role in the viability of a hydrogen system. In the study, a pay-as-produced design was used, whichresulted in both electricity deficits and surpluses at certain times. Furthermore, selling hydrogen throughlong-term contracts was deemed the most suitable option for large industrial producers, as it ensuresrevenue for hydrogen producers and a stable supply of hydrogen for the industries.
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Short-term Forecasting of EV Charging Stations Power Consumption at Distribution Scale / Korttidsprognoser för elbils laddstationer Strömförbrukning i distributionsskalaClerc, Milan January 2022 (has links)
Due to the intermittent nature of renewable energy production, maintaining the stability of the power supply system is becoming a significant challenge of the energy transition. Besides, the penetration of Electric Vehicles (EVs) and the development of a large network of charging stations will inevitably increase the pressure on the electrical grid. However, this network and the batteries that are connected to it also constitute a significant resource to provide ancillary services and therefore a new opportunity to stabilize the power grid. This requires to be able to produce accurate short term forecasts of the power consumption of charging stations at distribution scale. This work proposes a full forecasting framework, from the transformation of discrete charging sessions logs into a continuous aggregated load profile, to the pre-processing of the time series and the generation of predictions. This framework is used to identify the most appropriate model to provide two days ahead predictions of the hourly load profile of large charging stations networks. Using three years of data collected at Amsterdam’s public stations, the performance of several state-of-the-art forecasting models, including Gradient Boosted Trees (GBTs) and Recurrent Neural Networks (RNNs) is evaluated and compared to a classical time series model (Auto Regressive Integrated Moving Average (ARIMA)). The best performances are obtained with an Extreme Gradient Boosting (XGBoost) model using harmonic terms, past consumption values, calendar information and temperature forecasts as prediction features. This study also highlights periodical patterns in charging behaviors, as well as strong calendar effects and an influence of temperature on EV usage. / På grund av den intermittenta karaktären av förnybar energiproduktion, blir upprätthållandet av elnäts stabilitet en betydande utmaning. Dessutom kommer penetrationen av elbilar och utvecklingen av ett stort nät av laddstationer att öka trycket på elnätet. Men detta laddnät och batterierna som är anslutna till det utgör också en betydande resurs för att tillhandahålla kompletterande tjänster och därför en ny möjlighet att stabilisera elnätet. För att göra sådant bör man kunna producera korrekta kortsiktiga prognoser för laddstationens strömförbrukning i distributions skala. Detta arbete föreslår ett fullständigt prognos protokoll, från omvandlingen av diskreta laddnings sessioner till en kontinuerlig förbrukningsprofil, till förbehandling av tidsserier och generering av förutsägelser. Protokollet används för att identifiera den mest lämpliga metoden för att ge två dagars förutsägelser av timförbrukning profilen för ett stort laddstation nät. Med hjälp av tre års data som samlats in på Amsterdams publika stationer utvärderas prestanda för flera avancerade prognosmodeller som är gradient boosting och återkommande neurala nätverk, och jämförs med en klassisk tidsseriemodell (ARIMA). De bästa resultaten uppnås med en XGBoost modell med harmoniska termer, tidigare förbrukningsvärden, kalenderinformation och temperatur prognoser som förutsägelse funktioner. Denna studie belyser också periodiska mönster i laddningsbeteenden, liksom starka kalendereffekter och temperaturpåverkan på elbilar-användning.
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Electric cars for grid services : A system perspective study of V2G in a future energy system of Sweden and a local perspective study of a commercial car fleetSøgaard Vallinder, Isak, Carlsson, Matilda January 2022 (has links)
One of the biggest challenges of today is to mitigate climate change and adjust our way of living in accordance with sustainability. To reduce the climate impact of the transport sector the electrification of the road transport sector is commonly seen as having a key role to play. The rate of increase in number of electric cars has increased dramatically the recent years. Substantial electrification of the transport sector highlights the need of efficient integration of EVs with the electricity grid in order to handle the extra electricity demand. A potentia lway of efficiently integrating EVs to the grid could be to apply the concept of vehicle to grid (V2G). V2G simply means that the battery within an EV is seen as a storage component of the electricity grid that can be charged and discharged. Hence, in this thesis, the potential of V2G is explored. This thesis comprises of two parts. The first part investigates this potential impact of V2G in a future Swedish energy system. The second part investigates the optimized economic value, a car sharing company can achieve using different charging modes as well as the potential for participation in Swedish ancillary service markets. For the first part, the dispatch model EnergyPLAN was used to simulate a future energy system in Sweden in 2045. For the second part, an optimization model was designed using Python Optimization Modeling Objects (PYOMO) to optimize the charging and V2G usage of a car sharing fleet. Additionally, the battery degradation cost due to V2G was calculated as well as the potential income from participation in the FCR-D up and FCR-D down market. For both parts of the thesis different scenarios were developed. Scenarios with different electrification rate of the transport sector, V2G compatibility as well as different electricity production mix were considered for energy systems model of Sweden. For participation of shared cars in ancillary services market, scenarios related to different charging modes, rated charging power and the impact of including or excluding tax on sold electricity were created. While analysing the impact of V2G on Swedish energy system in future, it was observed that V2G has a marginal system impact on an annual basis, regardless of transport electrification rate, V2G compatibility and energy mix. The analysis of optimization algorithm for participation of shared pool of 255 cars resulted in economic savings when implementing smart charging and V2G. Due to battery degradation, the savings from integrating V2G in the system were marginal compared to the smart charging annual cost. For both the FCR-D up market and FCR-D down market, the revenue for participation was higher than electricity arbitrage through V2G. Both parts of the methodology, highlight the need for in centives inorder to make V2G an attractive business model and for electric cars to be able to provide flexibility services in a future Swedish energy system. / En av dagens största utmaningar är att begränsa klimatförändringarna och anpassa vårt sätt att leva i enlighet med hållbarhet. För att minska transportsektorns klimatpåverkan anses elektrifieringen av vägtransportsektorn allmänt ha en nyckelroll att spela. ökningstakten i antalet elbilar har ökat dramatiskt de senaste åren. En betydande elektrifiering av transportsektorn belyser behovet av en effektiv integrering av elfordon med elnätet för att hantera den extra efterfrågan på el. Ett potentiellt sätt att effektivt integrera elfordon i nätet skulle kunna vara att tillämpa begreppet fordon till nät (V2G). V2G innebär helt enkelt att batteriet i en elbil ses som en lagringskomponent i elnätet som kan laddas och laddas ur. Därför undersöks potentialen för V2G i detta examensarbete. Detta examensarbete består av två delar. Den första delen undersöker den potentiella påverkan av V2G i ett framtida svenskt energisystem. Den andra delen undersöker det optimerade ekonomiska värde som ett bildelningsföretag kan uppnå med olika laddningslägen samt potentialen för deltagande på svenska stödtjänstmarknader. För den första delen användes modeller-ingsverktyget EnergyPLAN för att simulera ett framtida energisystem i Sverige 2045. För den andra delen gjordes en optimeringsmodell med hjälp av Python Optimization Modeling Objects (PYOMO) för att optimera laddningen och V2G-användningen av en bildelningsflotta. Dessutom beräknades batterinedbrytningskostnaden på grund av V2G samt de potentiella intäkterna från deltagande på FCR-D upp och FCR-D ned-marknaden. För båda delarna av examensarbetet utvecklades olika scenarier. I den första delen jämförs scenarier med olika elektrifieringstakter inom transportsektorn, V2G-kompatibilitet samt olika elproduktionsmixar. För deltagande av bildelningsbilar på stödtjänstemarknader, skapades scenarion kopplat till olika laddningslägen, nominell laddningseffekt och effekterna av att inkludera eller exkludera skatt på såld el. Vid analys av V2G:s inverkan på det svenska energisystemet i framtiden observerades det att V2G har en marginell systempåverkan på årsbasis, oavsett transporteltrifikationshastighet, V2G-kompatibilitet och energimix. Analysen av optimeringsalgoritm för deltagande av delad bilpool med 255 bilar resulterade i ekonomiska besparingar vid implementering av smart laddning och V2G. På grund av batteriförsämring, blev besparingarna frĂĽn att integrera V2G i systemet marginella jämfört med den årliga kostnaden för smart laddning. För både FCR-D upp och FCR-D ned marknaderna var intäkterna för deltagande högre än el arbitrage genom V2G. Båda delarna av metodiken belyser behovet av incitament i för att göra V2G till en attraktiv affärsmodell och för att elbilar ska kunna tillhandahålla flexibilitetstjänster i ett framtida svenskt energisystem.
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Modelagem de inversores em fluxo de potência considerando suporte de potência reativa como serviço ancilar na distribuição / Modeling inverters in power flow considering reative power support as ancillary service on distributionSarmiento, Jonattan Emanuel 23 June 2016 (has links)
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Previous issue date: 2016-06-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In recent years there has been a great increase in the use of distributed generators. This occurred
not only by advances in production technologies of small generators and frequency inverters,
but also by the benefits that brings to the distribution systems and the incentive policies. In the
analysis of these systems is essential to calculate the power flow and properly solve it and the
modeling of the inverter should be reviewed together with its implementation in the method
employed, attempting to the fact that the inverters are beginning to use advanced functions that
can to provide ancillary services. In this work the modelling of inverter with advanced functions
such as Basic Intelligent Volt-Var Control (BIVV) and Intelligent Volt-Var With Hysteresis
(IVVH) are reviewed, therefore it is propose methods the implements this models in the method
sweep. In proposal implementation it is use of elements of the sensitivity matrix of nodes PV
defined in the compensation method. In the analyzed cases, the implementations were
effectiveness achieving solutions in convergent values and in accordance to the control
strategies. In the results of simulations there were differences in the operating points of the
inverter acting on a node of the distribution system comparing the different modeling analyzed
in different system load conditions and different levels of active power supply. When
comparing the voltage profiles of the various modeling, in general notice that there is a greater
variation when it has large reactive power capacity. If in the future of distributed generation
evolve to provide reactive support as the ancillary service, it shall be careful properly modelling
the inverter avoiding mistaken results that will affect the plans of the concessionaires. / Nos últimos anos verificou-se um grande aumento no uso de geradores distribuídos. Isso
ocorreu não apenas pelos avanços nas tecnologias de produção de pequenos geradores e
inversores de frequência, mas também pelos benefícios que estes trazem aos sistemas de
distribuição e pelas políticas de incentivos. Nas análises desses sistemas é fundamental calcular
o fluxo de potência e, para resolvê-lo adequadamente, deve-se revisar a modelagem do inversor
e sua implementação no método empregado, atentando-se ao fato de que os inversores estão
começando a utilizar funções avançadas passíveis de fornecer serviços ancilares. Neste trabalho
são revisadas as modelagens dos inversores com funções avançadas, tais como o controle Basic
Intelligent Volt-Var (BIVV) e Intelligent Volt-Var With Hysteresis (IVVH), além de propor
métodos de implementação para o método da varredura. Nas implementações propostas se faz
uso de elementos da matriz de sensibilidade dos nós PV definida no método da compensação.
Nos casos analisados, as implementações tiveram eficácia, conseguindo atingir soluções em
valores convergentes e em concordância às estratégias de controle. Já nos resultados das
simulações, ilustram-se as diferenças dos pontos operativos do inversor atuando em um nó do
sistema de distribuição comparando-se as diferentes modelagens analisadas em distintas
condições de carga do sistema e diversos níveis de fornecimento de potência ativa. Ao
comparar-se os perfis de tensão das diversas modelagens, em geral, nota-se que há uma variação
maior quando se tem maior capacidade de potência reativa. Se no futuro a geração distribuída
evoluir para prestar suporte de potência reativa como um serviço ancilar, é necessário tomar
precauções para modelar adequadamente o inversor, de modo a evitar obter resultados
equivocados que afetarão os planejamentos das concessionárias.
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