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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Previsão de cargas elétricas a curto prazo por combinação de previsões via regressão simbólica

Braga, Douglas de Oliveira Matos 31 August 2017 (has links)
Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-01-12T11:44:53Z No. of bitstreams: 1 douglasdeoliveiramatosbraga.pdf: 1221207 bytes, checksum: 2e8c8b8de9aa188f87fe5670354d478c (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-01-23T13:56:44Z (GMT) No. of bitstreams: 1 douglasdeoliveiramatosbraga.pdf: 1221207 bytes, checksum: 2e8c8b8de9aa188f87fe5670354d478c (MD5) / Made available in DSpace on 2018-01-23T13:56:44Z (GMT). No. of bitstreams: 1 douglasdeoliveiramatosbraga.pdf: 1221207 bytes, checksum: 2e8c8b8de9aa188f87fe5670354d478c (MD5) Previous issue date: 2017-08-31 / O planejamento energético é base para as tomadas de decisões nas companhias de energia elétrica e, para isto, depende fortemente da disponibilidade de previsões acuradas para as cargas. Devido á inviabilidade de armazenamentos em larga-escala e o custo elevado de compras de energia a curto prazo, além da possibilidade de multas e sanções de órgãos governamentais, previsões em curto prazo são importantes para a otimização da alocação de recursos e da geração de energia. Neste trabalho utilizamos nove métodos univariados de séries temporais para a previsão de cargas a curto prazo, com horizontes de 1 a 24 horas a frente. Buscando melhorar a acurácia das previsões, propomos um método de combinação de previsões através de Regressão Simbólica, que combina de forma não-linear as previsões obtidas pelos nove métodos de séries temporais utilizados. Diferente de outros métodos não-lineares de regressão, a Regressão Simbólica não precisa de uma especificação previa da forma funcional. O método proposto é aplicado em uma série real da cidade do Rio de Janeiro (RJ), que contém cargas horárias de 104 semanas dos anos de 1996 e 1997. Comparamos, através de critérios indicados na literatura, os resultados obtidos pelo método proposto com os resultados obtidos por métodos tradicionais de combinação de previsões e ao resultado de simulações de redes neurais artificiais aplicados ao mesmo conjunto de dados. O método proposto obteve melhores resultados, que indicam que a não-linearidade pode ser aspecto importante para combinação de previsões no problema de previsão de carga a curto prazo / Decision-making in energy companies relies heavily on the availability of accurate load forecasts. Because storing electricity on a large scale is not viable, the cost of short-term energy purchasing is high, and there are government fines and sanctions for failing to supply energy on demand, short-term load forecasts are important for the optimization of resource allocation and energy production. In this work we used nine univariate time series methods for short-term load forecasts, with forecast horizons ranging from 1 to 24 hours ahead. In order to improve the accuracy of forecasts, we propose a method of combining forecasts through Symbolic Regression, which combines in a non-linear way the forecasts obtained by the nine methods of the time series used. Unlike other non-linear regression methods, Symbolic Regression does not need a previous specification of the function structure. We applied the proposed method to a real time series of the city of Rio de Janeiro (RJ), which contains data on hourly loads of 104 weeks in the years 1996 and 1997. We compare, through the criteria indicated in the literature, the results obtained by the proposed method with the results obtained by traditional methods of forecasts combination and the result obtained by artificial neural networks applied to the same dataset. The method has yielded better results, indicating that non-linearity may be important in combining predictions in short term load forecasts.
72

Previsão do consumo de energia elétrica a curto prazo, usando combinações de métodos univariados

Carneiro, Anna Cláudia Mancini da Silva 26 September 2014 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-03-02T12:24:39Z No. of bitstreams: 1 annaclaudiamancinidasilvacarneiro.pdf: 1333903 bytes, checksum: a7b3819bb5b0e1adb8efd07bca0f9aa2 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-03-06T19:35:55Z (GMT) No. of bitstreams: 1 annaclaudiamancinidasilvacarneiro.pdf: 1333903 bytes, checksum: a7b3819bb5b0e1adb8efd07bca0f9aa2 (MD5) / Made available in DSpace on 2017-03-06T19:35:55Z (GMT). No. of bitstreams: 1 annaclaudiamancinidasilvacarneiro.pdf: 1333903 bytes, checksum: a7b3819bb5b0e1adb8efd07bca0f9aa2 (MD5) Previous issue date: 2014-09-26 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A previsão de cargas elétricas é fundamental para o planejamento das empresas de energia. O foco deste estudo são as previsões a curto prazo; assim, aplicamos métodos univariados de previsão de séries temporais a uma série real de cargas elétricas de 104 semanas no Rio de Janeiro, nos anos de 1996 e 1997, e experimentamos várias combinações dos métodos de melhor desempenho. As combinações foram feitas pelo método outperformance, uma combinação linear simples, com pesos fixos. Os resultados das combinações foram comparados ao de simulações de redes neurais artificiais que solucionam o mesmo problema, e ao resultado de um método de amortecimento de dupla sazonalidade aditiva. No geral, este método de amortecimento obteve os melhores resultados, e talvez seja o mais adequado e confiável para aplicações práticas, embora necessite de melhorias para garantir a extração completa da informação contida nos dados. / Forecasting the demand for electric power is crucial for the production planning in energy utilities. The focus of this study are the short-term forecasts. We apply univariate time series methods to the forecasting of a series containing observations of the energy consumption of 104 weeks in Rio de Janeiro, in 1996 and 1997, and experiment with several combinations of the methods which have the best performance. These combinations are done by the outperformance method, a simple linear combination with fixed weights. The results were compared to those obtained by neural networks on the same problem, and with the results of a exponential smoothing method for dual additive seasonality. Overall, the exponential smoothing method achieved the best results, and was shown to be perhaps the most reliable and suitable for practical applications, even though it needs improvements to ensure complete extraction of the information contained in the data.
73

Avaliação do algoritmo Gradient Boosting em aplicações de previsão de carga elétrica a curto prazo

Mayrink, Victor Teixeira de Melo 31 August 2016 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-03-07T14:25:21Z No. of bitstreams: 1 victorteixeirademelomayrink.pdf: 2587774 bytes, checksum: 1319cc37a15480796050b618b4d7e5f7 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-03-07T15:06:57Z (GMT) No. of bitstreams: 1 victorteixeirademelomayrink.pdf: 2587774 bytes, checksum: 1319cc37a15480796050b618b4d7e5f7 (MD5) / Made available in DSpace on 2017-03-07T15:06:57Z (GMT). No. of bitstreams: 1 victorteixeirademelomayrink.pdf: 2587774 bytes, checksum: 1319cc37a15480796050b618b4d7e5f7 (MD5) Previous issue date: 2016-08-31 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / O armazenamento de energia elétrica em larga escala ainda não é viável devido a restrições técnicas e econômicas. Portanto, toda energia consumida deve ser produzida instantaneamente; não é possível armazenar o excesso de produção, ou tampouco cobrir eventuais faltas de oferta com estoques de segurança, mesmo que por um curto período de tempo. Consequentemente, um dos principais desafios do planejamento energético consiste em realizar previsões acuradas para as demandas futuras. Neste trabalho, apresentamos um modelo de previsão para o consumo de energia elétrica a curto prazo. A metodologia utilizada compreende a construção de um comitê de previsão, por meio da aplicação do algoritmo Gradient Boosting em combinação com modelos de árvores de decisão e a técnica de amortecimento exponencial. Esta estratégia compreende um método de aprendizado supervisionado que ajusta o modelo de previsão com base em dados históricos do consumo de energia, das temperaturas registradas e de variáveis de calendário. Os modelos propostos foram testados em duas bases de dados distintas e demonstraram um ótimo desempenho quando comparados com resultados publicados em outros trabalhos recentes. / The storage of electrical energy is still not feasible on a large scale due to technical and economic issues. Therefore, all energy to be consumed must be produced instantly; it is not possible to store the production leftover, or either to cover any supply shortages with safety stocks, even for a short period of time. Thus, one of the main challenges of energy planning consists in computing accurate forecasts for the future demand. In this paper, we present a model for short-term load forecasting. The methodology consists in composing a prediction comitee by applying the Gradient Boosting algorithm in combination with decision tree models and the exponential smoothing technique. This strategy comprises a supervised learning method that adjusts the forecasting model based on historical energy consumption data, the recorded temperatures and calendar variables. The proposed models were tested in two di erent datasets and showed a good performance when compared with results published in recent papers.
74

Développement de modèles de bâtiment pour la prévision de charge de climatisation et l’élaboration de stratégies d’optimisation énergétique et d’effacement / Development of building models for load curve forecast and design of energy optimization and load shedding strategies

Berthou, Thomas 16 December 2013 (has links)
Pour atteindre les objectifs de réduction de consommation et augmenter la flexibilité de la demande des bâtiments, il est nécessaire de disposer de modèles de prévision de charge de climatisation facilement diffusables sur site et performants qui permettent la mise en place de stratégies d’optimisation énergétique et d’effacement. Cette thèse compare plusieurs architectures de modèles inverses (« boite noire », « boite grise »). Un modèle semi-physique d’ordre 2 (R6C2) a été retenu pour prévoir la puissance de climatisation et la température intérieure moyenne en chauffage et en refroidissement. Il permet aussi d’interpréter des situations inédites (effacement), absentes de la phase d’apprentissage. Trois stratégies d’optimisation énergétique et d’effacement adaptées aux contraintes d’exploitation sont étudiées. La première permet d’optimiser la relance en chauffage afin de réduire la consommation et d’atteindre effectivement la température de confort le matin. La seconde stratégie optimise les températures de consigne sur une journée dans un contexte de prix variable de l’énergie, ceci afin de réduire la facture énergétique. Enfin, la troisième stratégie permet au bâtiment de s’effacer en limitant la charge tout en respectant des critères de confort spécifiés. Le modèle R6C2 et les stratégies ont été confrontés à un bâtiment réel (une école élémentaire). L’étude montre qu’il est possible de prévoir la puissance électrique et la température moyenne d’un bâtiment complexe avec un modèle mono-zone ; elle permet d’évaluer les stratégies développées et d’identifier les limites du modèle. / To reach the objectives of reducing the energy consumption and increasing the flexibility of buildings energy demand, it is necessary to have load forecast models easy to adapt on site and efficient for the implementation of energy optimization and load shedding strategies. This thesis compares several inverse model architectures ("black box", "grey box"). A 2nd order semi-physical model (R6C2) has been selected to forecast load curves and the average indoor temperature for heating and cooling. It is also able to simulate unknown situations (load shedding), absent from the learning phase. Three energy optimization and load shedding strategies adapted to operational constraints are studied. The first one optimizes the night set-back to reduce consumption and to reach the comfort temperature in the morning. The second strategy optimizes the set-point temperatures during a day in the context of variable energy prices, thus reducing the energy bill. The third strategy allows load curtailment in buildings by limiting load while meeting specified comfort criteria. The R6C2 model and strategies have been faced with a real building (elementary school). The study shows that it is possible to forecast the electrical power and the average temperature of a complex building with a single-zone model; the developed strategies are assessed and the limitations of the model are identified.
75

[en] VERY SHORT TERM LOAD FORECASTING IN THE NEW BRAZILIAN ELECTRICAL SCENARIO / [es] PREVISIÓN DE CARGA A CORTÍSIMO PLAZO EN EL NUEVO ESCENARIO ELÉCTRICO BRASILERO / [pt] PREVISÃO DE CARGA DE CURTÍSSIMO PRAZO NO NOVO CENÁRIO ELÉTRICO BRASILEIRO

GUILHERME MARTINS RIZZO 19 July 2001 (has links)
[pt] Nesta dissertação é proposto um modelo híbrido para previsão de carga de curtíssimo prazo, combinando amortecimento exponencial simples e redes neurais artificiais do topo feed-forward. O modelo fornece previsões pontuais e limites superiores e inferiores para um horizonte de quinze dias. Estes limites formam um intervalo ao qual pode ser associado um nível de confiança empírico, estimado através de um teste fora da amostra. O desempenho do modelo é avaliado ao longo de uma simulação realizada com dados reais de duas concessionárias de energia elétrica brasileiras. / [en] This thesis presents an hibrid short term load forecasting model that mixes simple exponential smoothing with feed- forward neural networks. The model gives point predictions with upper and lower limits for 15-day-ahead horizon. These limits yields an interval with associated empirical confidence level, estimated by an out of sample test. The model's performance is evaluated through a simulation with real data obtained from two Brazilian utilities. / [es] En esta disertación se propone un modelo híbrido para previsión de carga de cortísimo plazo, combinando amortecimiento exponencial simple y redes neurales artificiales tipo feed-forward. EL modelo nos da las previsiones puntuales y los límites superiores e inferiores para un horizonte de quince días. Estos límites forman un intervalo al cual se le puede asociar un nível de confianza empírico, estimado a través de un test out of sample. EL desempeño del modelo se evalúa utilizando datos reales de dos concesionarias de energía eléctrica brasileras.
76

Estimation et sélection pour les modèles additifs et application à la prévision de la consommation électrique / Estimation and selection in additive models and application to load demand forecasting

Thouvenot, Vincent 17 December 2015 (has links)
L'électricité ne se stockant pas aisément, EDF a besoin d'outils de prévision de consommation et de production efficaces. Le développement de nouvelles méthodes automatiques de sélection et d'estimation de modèles de prévision est nécessaire. En effet, grâce au développement de nouvelles technologies, EDF peut étudier les mailles locales du réseau électrique, ce qui amène à un nombre important de séries chronologiques à étudier. De plus, avec les changements d'habitude de consommation et la crise économique, la consommation électrique en France évolue. Pour cette prévision, nous adoptons ici une méthode semi-paramétrique à base de modèles additifs. L'objectif de ce travail est de présenter des procédures automatiques de sélection et d'estimation de composantes d'un modèle additif avec des estimateurs en plusieurs étapes. Nous utilisons du Group LASSO, qui est, sous certaines conditions, consistant en sélection, et des P-Splines, qui sont consistantes en estimation. Nos résultats théoriques de consistance en sélection et en estimation sont obtenus sans nécessiter l'hypothèse classique que les normes des composantes non nulles du modèle additif soient bornées par une constante non nulle. En effet, nous autorisons cette norme à pouvoir converger vers 0 à une certaine vitesse. Les procédures sont illustrées sur des applications pratiques de prévision de consommation électrique nationale et locale.Mots-clés: Group LASSO, Estimateurs en plusieurs étapes, Modèle Additif, Prévision de charge électrique, P-Splines, Sélection de variables / French electricity load forecasting encounters major changes since the past decade. These changes are, among others things, due to the opening of electricity market (and economical crisis), which asks development of new automatic time adaptive prediction methods. The advent of innovating technologies also needs the development of some automatic methods, because we have to study thousands or tens of thousands time series. We adopt for time prediction a semi-parametric approach based on additive models. We present an automatic procedure for covariate selection in a additive model. We combine Group LASSO, which is selection consistent, with P-Splines, which are estimation consistent. Our estimation and model selection results are valid without assuming that the norm of each of the true non-zero components is bounded away from zero and need only that the norms of non-zero components converge to zero at a certain rate. Real applications on local and agregate load forecasting are provided.Keywords: Additive Model, Group LASSO, Load Forecasting, Multi-stage estimator, P-Splines, Variables selection
77

Capacity demand and climate in Ekerö : Development of tool to predict capacity demand underuncertainty of climate effects

Tong, Fan January 2007 (has links)
The load forecasting has become an important role in the operation of power system, and several models by using different techniques have been applied to solve these problems. In the literature, the linear regression models are considered as a traditional approach to predict power consumption, and more recently, the artificial neural network (ANN) models have received more attention for a great number of successful and practical applications. This report introduces both linear regression and ANN models to predict the power consumption for Fortum in Ekerö. The characteristics of power consumption of different kinds of consumers are analyzed, together with the effects of weather parameters to power consumption. Further, based on the gained information, the numerical models of load forecasting are built and tested by the historical data. The predictions of power consumption are focus on three cases separately: total power consumption in one year, daily peak power consumption during winter and hourly power consumption. The processes of development of the models will be described, such as the choice of the variables, the transformations of the variables, the structure of the models and the training cases of ANN model. In addition, two linear regression models will be built according to the number of input variables. They are simple linear regression with one input variable and multiple linear regression with several input variables. Comparison between the linear regression and ANN models will be carried out. In the end, it finds out that the linear regression obtains better results for all the cases in Ekerö. Especially, the simple linear regression outperforms in prediction of total power consumption in one year, and the multiple linear regression is better in prediction of daily peak load during the winter.
78

Load Hindcasting: A Retrospective Regional Load Prediction Method Using Reanalysis Weather Data

Black, Jonathan D 01 January 2011 (has links) (PDF)
The capacity value (CV) of a power generation unit indicates the extent to which it contributes to the generation system adequacy of a region’s bulk power system. Given the capricious nature of the wind resource, determining wind generation’s CV is nontrivial, but can be understood simply as how well its power output temporally correlates with a region’s electricity load during times of system need. Both wind generation and load are governed by weather phenomena that exhibit variability across all timescales, including low frequency weather cycles that span decades. Thus, a data-driven determination of wind’s CV should involve the use of long-term (i.e., multiple decades) coincident load and wind data. In addition to the challenge of finding high-quality, long-term wind data, existing load data more than several years old is of limited utility due to shifting end usage patterns that alter a region’s electricity load profile. Due to a lack of long-term data, current industry practice does not adequately account for the effects of weather variability in CV calculations. To that end, the objective of this thesis is to develop a model to “hindcast” what the historic regional load in New England would have been if governed by the conjoined influence of historic weather and a more current load profile. Modeling focuses exclusively on summer weekdays since this period is typically the most influential on CV. The summer weekday model is developed using multiple linear regression (MLR), and features a separate hour-based model for eight sub-regions within New England. A total of eighty-four candidate weather predictors are made available to the model, including lagged temperature, humidity, and solar insolation variables. A reanalysis weather dataset produced by the National Aeronautics and Space Administration (NASA) – the Modern Era Retrospective-Analysis for Research and Applications (MERRA) dataset – is used since it offers data homogeneity throughout New England over multiple decades, and includes atmospheric fields that may be used for long-term wind resource characterization. Weather regressors are selected using both stepwise regression and a genetic algorithm(GA) based method, and the resulting models and their performance are compared. To avoid a tendency for overfitting, the GA-based method employs triple cross-validation as a fitness function. Results indicate a regional mean absolute percent error (MAPE) of less than 3% over all hours of the summer weekday period, suggesting that the modeling approach developed as part of this research has merit and that further development of the hindcasting model is warranted.
79

[en] ELECTRIC LOAD FORECASTING MODEL CONSIDERING THE INFLUENCE OF DISTRIBUTED GENERATION ON THE LOAD CURVE PROFILE / [pt] MODELO DE PREVISÃO DE CARGA ELÉTRICA CONSIDERANDO A INFLUÊNCIA DA MINI E MICROGERAÇÃO DISTRIBUÍDA NO PERFIL DA CURVA DE CARGA

RAFAEL GAIA DUARTE 28 June 2021 (has links)
[pt] O Brasil vem registrando a cada ano um crescimento expressivo no número de conexões de geração distribuída na rede de distribuição devido à concessão de incentivos governamentais que permitiu a difusão do uso de placas solares fotovoltaicas, fonte de geração de energia mais usada na geração distribuída no Brasil. Em sistemas elétricos com alta penetração de fontes intermitentes a previsão do comportamento da curva de carga tende a representar um grande desafio para os operadores do sistema devido à imprevisibilidade associada à geração de energia, podendo impactar diretamente no planejamento e operação da rede elétrica. Para lidar com esse desafio, este trabalho propõe uma metodologia de previsão de carga usando redes neurais recorrentes com arquitetura LSTM, considerando o impacto da mini e microgeração distribuída solar fotovoltaica conectada à rede de distribuição brasileira. São feitas previsões de carga do Sistema Interligado Nacional brasileiro e dos subsistemas que o integram, levando em conta um horizonte de curto prazo, de 24 horas, em intervalos horários, e um horizonte de médio prazo, de 60 meses, em intervalos mensais. Os resultados indicam que a metodologia pode ser uma ferramenta eficiente para a obtenção de previsões de carga podendo ser utilizada também para horizontes de previsão distintos dos apresentados neste trabalho. O MAPE encontrado para as previsões de curto prazo não passam de 2 por cento e para as previsões de médio prazo não passam de 3,5 por cento. / [en] Every year, Brazil has been registering a significant growth in the number of distributed generation connections in the distribution grid due to the granting of government incentives that allowed the use of solar photovoltaic panels to spread, the most used source of energy in distributed generation in Brazil. In electrical systems with high penetration of intermittent sources, the prediction of the behavior of the load curve tends to represent a great challenge for system operators due to the unpredictability associated with power generation, which can directly impact the planning and operation of the electrical grid. To deal with this challenge, this work proposes a load forecasting methodology using recurrent neural networks with LSTM architecture, considering the impact of the distributed photovoltaic solar generation connected to the Brazilian distribution grid. Load forecasts are made for the Brazilian National Interconnected System and for the subsystems that integrate it, taking into account a short-term horizon, of 24 hours, in hourly intervals, and a medium-term horizon, of 60 months, in monthly intervals. The results indicate that the methodology can be an efficient tool for obtaining load forecasts and can also be used for different forecast horizons than those presented in this work. The MAPE found for short-term forecasts is no more than 2 percent and for medium-term forecasts, no more than 3.5 percent.
80

What would be the highestelectrical loads with -20°C inStockholm in 2022 ? : A study of the sensitivity of electrical loads to outdoor temperature in Stockholm region.

Mellon, Magali January 2022 (has links)
In the last 10 years, no significant increase in the peak electricity consumption of the region of Stockholm has been observed, despite new customers being connected to the grid. But, as urbanization continues and with electrification being a decisive step of decarbonization pathways, more growth is expected in the future. However, the Swedish Transmission System Operator (TSO), Svenska Kraftnat, can only supply a limited power to Stockholm region. Distribution System Operators (DSOs) such as Vattenfall Eldistribution, which operates two thirds Stockholm region's distribution grid, need to find solutions to satisfy an increasing demand with a limited power supply. In these times, forecasting the worst-case scenarios, i.e., the highest possible loads, becomes a critical question. In Sweden, peak loads are usually triggered by the coldest temperatures, but the recent winters have been mild: this brings uncertainty about a possible underlying temperature adjusted growth that would be masked by relatively warm winters. Answering the question 'What would be the highest loads in 2022 with -20°C in Stockholm region ?' could help Vattenfall Eldistribution estimating the flexibility needed nowadays and designing the future grid with the necessary grid reinforcements. This master thesis uses a data-driven approach based on eleven years of hourly data on the period 2010-2021 to investigate the temperature sensitivity of aggregated electricity load in Stockholm region. First, an exploratory analysis aims at quantifying how large the growth has been in the past ten years and at understanding how and when peak loads occur. The insights obtained help design two innovative regression techniques that investigate the evolution of the loads across years and provide first estimates of peak loads. Then, a Seasonal Autoregressive Integrated Moving Average with eXogenous regressors (SARIMAX) process is used to model a full winter of load as a function of temperatures. This third method provides new and more reliable estimates of peak loads in 2022 at e.g. -20°C. Eventually, the SARIMAX estimates are kept and a synthesis of the global outlooks of the three methods and possible extensions of the SARIMAX method is presented in a final section. The results conclude on a significant increase in the load levels in southern Stockholm ('Stockholm Sodra') between 2010 and 2015 and stable evolution onwards, while the electric consumption in Northern Stockholm remained stable during the period 2010-2021. During a very cold winter, the electricity demand is expected to exceed the subscription levels during about 300h in Stockholm Sodra and 200h in Stockholm Norra. However, this will be a rare occurrence, which suggests that short-term solutions could be privileged rather than costly grid extension work. Many questions arise, and the capability of local heat & power production and electricity prices signals to regulate today's demand are yet to investigate. Additional work exploring future demand scenarios at a smaller scale could also be contemplated. / Under den senaste årtionden har Stockholms toppkonsumtion av el inte ökat markant trots nya elkunder som ansluter till elnätet. Med en snabb urbanisering, är ökad elektrifiering en huvudlösning för att uppnå ett fossilfritt samhälle och denna trend förväntas fortsätta under kommande årtionden. Samtidigt börjar den svenska transmissionsnätoperatören (TSO) Svenska kraftnät få problem med att leverera elkraft till Stockholmsregionen, på grund av en begränsad överföringskapacitet. Därför måste lokala eldistributörer (DSO), liksom Vattenfall Eldistribution, som är Sveriges största DSO med systemansvar för distributionssystem, undersöka nya lösningar för att uppfylla den ökande efterfrågan på el. Det blir dessutom mycket viktigt att identifiera de värsta tänkbara scenario, som att göra prognos av högsta möjliga elförbrukning. Stockholm konsumerar exempelvis mest el när det är som kallast – men de senaste vintrarna har varit milda jämfört med till exempel vintrarna 2010 – 2011 eller 2012 – 2013 då temperaturer i Stockholmsregion mättes till under -20°C grader för flera dagar i sträck. Detta resulterar i en relevant frågeställning: ” Vad skulle Stockholms elkonsumtion vid -20°C bli 2021 eller 2022?”. Att kvantitativt kunna besvara denna fråga skulle hjälpa Vattenfall med att designa framtidens elnät samt se till att det finns rätt mängd flexibilitet i reserv i nuvarande Stockholm Flex elmarknad. Detta examensarbete utgår från att kvantitativt analysera denna frågeställning. Utgångsläget är ett datadrivet tillvägagångssätt baserat på tio års tidseriedata för att undersöka temperaturkänsligheten för det aggregerade elbehovet i Stockholmsregionen, och dra slutsatser om dess utveckling genom åren. I första hand, utförs en explorativ analys för att förstå när och hur toppbelastning kan hända. Då hjälper dessa insikter till att utforma två innovativa regressionsmetoder för att undersöka utvecklingen av elförbrukning under det senaste decenniet och uppskatta värdet på toppbelastningen. Därefter används ett säsongmässigt autoregressivt integrerat rörligt genomsnitt med exogena faktorer (SARIMAX) för att modellera en vinter som en funktion av temperaturerna. Denna tredje metod behandlar nya och mer tillförlitliga beräkningar av toppbelastning värden i 2022 på -20°C. Huvudslutsatser från examensarbetet är att elförbrukningen skulle öka i området Stockholm Södra speciellt mellan 2010 och 2015, medan elförbrukningen skulle vara stabil under hela perioden i området Stockholm Norra. Det finns en risk för att under ett antal timmar vid riktigt kall vinter, ha ett elbehov högre än Vattenfall Eldistributions summa av abonnemang. Dock är det väldigt låg sannolikhet att detta händer, vilket innebär att det förmodligen finns andra sätt att hantera denna efterfråga på el än att öka överföringskapaciteten i elnätet. Examensarbetet resulterar i flera frågor. Exempelvis att utreda möjligheter i att utnyttja lokala el och värmekraftverk och använda elprissignaler. Ytterligare arbete kan också undersöka scenarier av den framtida elförbrukning i en mindre skala.

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