Πολυ-κριτηριακή βελτιστοποίηση συστημάτων διεσπαρμένης παραγωγής ενέργειας με έμφαση στην ευστάθεια των λύσεων

A solution towards economically attractive and environmentally friendly energy systemsl is the development of Distributed Energy Systems (DES). DES have many advantages, with the most significant one being the local energy generation which minimizes energy losses. DES can offer better integration between conventional energy systems and renewables and can satisfy the energy demand at a single building, a complex of buildings or even up to a whole city with a varied degree of decentralization. A DES can be designed to satisfy local energy needs in electricity, heating, and cooling. Also, they can lead to a reduction of total annual cost (TAC) and CO2 emissions. This thesis aims to provide a methodology for the optimal design of DES using multi-objective mixed-integer linear programming (MILP), with TAC and CO2 emissions as the objective functions. The candidate technologies are: (a) cogeneration units, (b) heat pumps, (c) absorption chillers, (d) boilers, (e) solar thermal collectors, (f) solar photovoltaics, (g) wind turbines, (h) thermal energy storage, (i) electric energy storage, (j) district heating network (DHN) and (k) microgrid. The results offer as outputs the selected technologies and their respective sizes at each building, the layout of the DHN (if formed), the operational profile of the installed technologies, and the electricity exchange through the microgrid (if selected) and the national grid. Additionally, in literature all the developed methods can be broadly separated into two categories, namely: (a) “Method A” in which a simultaneous selection and sizing of candidate technologies and (b) “Method B” in which the sizes of the candidate technologies are predefined. This thesis presents some innovative aspects in the field of optimal design of DES. Particularly, two approaches for the modelling of technologies are developed, expanding previous relevant work in literature. In addition, mathematical models for all available candidate technologies are presented. Those approaches are compared as they offer different solutions, and their advantages and disadvantages are assessed. Furthermore, this thesis aims to examine the optimal design of DES under uncertainty. Changes in the values of several parameters can affect the optimal design of a DES, and the scope of this thesis is to provide a decision-maker (DM) with robust solutions. In this thesis uncertainty is assumed to exist in energy prices (electricity and natural gas), interest rate, energy loads (electricity, heating, and cooling), solar radiation, and wind speed. To examine uncertainty and identify robust solutions four techniques are used, which are in the fields of robust optimization (RO) and stochastic optimization (SO), namely: (a) objective-wise worst case, (b) minimax regret criterion (MMR), (c) minimax expected regret (MER) and (d) Monte Carlo simulations. Overall, these techniques provide solutions that are notably different of the results of the deterministic approach and can be characterized as robust, highlighting the importance of considering uncertainty for the design process. This thesis concludes that considering uncertainty in designing a DES is necessary as the optimal solutions change significantly, which is very important for the optimal design of the system, its financial viability and operational stability. Finally, it is noted that the developed methodologies are generic and can be easily adopted and applied according to the preferences of a DM.Μια λύση προς την κατεύθυνση των οικονομικά ελκυστικών και περιβαλλοντικά φιλικών ενεργειακών συστημάτων είναι η ανάπτυξη των συστημάτων διεσπαρμένης παραγωγής ενέργειας (ΣΔΠΕ). Τα ΣΔΠΕ έχουν πολλά πλεονεκτήματα με το σημαντικότερο να είναι η παραγωγή ενέργειας σε τοπικό επίπεδο, ελαχιστοποιώντας έτσι τις απώλειες. Τα ΣΔΠΕ μπορούν να προσφέρουν καλύτερη ενσωμάτωση μεταξύ των συμβατικών ενεργειακών συστημάτων και των ΑΠΕ, και μπορούν να καλύψουν τις ενεργειακές ανάγκες είτε πρόκειται για ένα κτήριο, ένα σύμπλεγμα κτηρίων ή ακόμη και μια πόλη, με το βαθμό αποκέντρωσης να διαφέρει. Ένα ΣΔΠΕ μπορεί να σχεδιαστεί για να καλύπτει τις ενεργειακές ανάγκες σε ηλεκτρισμό, θερμότητα και ψύξη. Επίσης, τα συστήματα αυτά μπορούν να προσφέρουν λύσεις με χαμηλό ετήσιο κόστος και χαμηλές εκπομπές CO2. Ο σχεδιασμός ενός ΣΔΠΕ είναι ένα περίπλοκο πρόβλημα στο οποίο πολλές πτυχές πρέπει να λαμβάνονται υπόψη. Αυτή η διατριβή έχει σκοπό να παρουσιάσει μια μεθοδολογία για τον βέλτιστο σχεδιασμό ΣΠΔΕ χρησιμοποιώντας πολυ-κριτηριακό μικτό-ακέραιο γραμμικό προγραμματισμό (ΜΑΓΠ) με αντικειμενικές συναρτήσεις το συνολικό ετήσιο κόστος και τις εκπομπές CO2. Οι υποψήφιες τεχνολογίες είναι: (α) μονάδες συμπαραγωγής ηλεκτρισμού και θερμότητας, (β) αντλίες θερμότητας, (γ) μονάδες ψύξεις με απορρόφηση, (δ) λέβητες, (ε) ηλιακοί συλλέκτες, (στ) φωτοβολταϊκά, (ζ) ανεμογεννήτριες, (η) μονάδες αποθήκευσης θερμότητας, (θ) μονάδες αποθήκευσης ηλεκτρισμού, (ι) δίκτυο διανομής θερμότητας και (κ) μικροδίκτυο. Τα αποτελέσματα δίνουν ως λύσεις τις τεχνολογίες που επιλέγονται να εγκατασταθούν σε κάθε κτήριο και την αντίστοιχη ισχύ τους, τη διάταξη του δικτύου διανομής θερμότητας (αν σχηματιστεί), το επιχειρησιακό προφίλ των τεχνολογιών, και την ανταλλαγή ηλεκτρισμού διαμέσου του μικροδικτύου καθώς και μεταξύ των κτηρίων και του εθνικού δικτύου ηλεκτρισμού. Επιπλέον, οι αντίστοιχες μελέτες που υπάρχουν στη βιβλιογραφία διαχωρίζονται σε δύο γενικές κατηγορίες, (α) στη «Μέθοδο Α» όπου γίνεται ταυτόχρονη επιλογή και διαστασιολόγηση των υποψήφιων τεχνολογιών, και (β) στη «Μέθοδο Β» όπου οι διαστάσεις των τεχνολογιών είναι προκαθορισμένες. Αυτή η διατριβή παρουσιάζει αρκετά καινοτομικά στοιχεία αναφορικά με τον βέλτιστο σχεδιασμό ΣΔΠΕ. Συγκεκριμένα, παρουσιάζονται δύο προσεγγίσεις για την μοντελοποίηση τεχνολογιών, επεκτείνοντας την σχετική βιβλιογραφία. Επιπλέον, παρουσιάζονται μαθηματικά μοντέλα για όλες οι διαθέσιμες τεχνολογίες. Αυτές οι προσεγγίσεις συγκρίνονται καθώς προσφέρουν διαφορετικές λύσεις, και εξετάζονται πλεονεκτήματα και μειονεκτήματα που έχουν. Πέρα απ’ αυτά, η διατριβή έχει ως σκοπό τον βέλτιστο σχεδιασμό ΣΔΠΕ υπό συνθήκες αβεβαιότητας. Οι αλλαγές στις τιμές των παραμέτρων σχεδιασμού μπορούν να επηρεάσουν τον βέλτιστο σχεδιασμό και αυτή η διατριβή σκοπεύει να προσφέρει στον αποφασίζων εύρωστες λύσεις. Στο πλαίσιο της διατριβής υποτίθεται ότι οι παράμετροι που είναι υπό αβεβαιότητα είναι οι τιμές ενέργειας (ηλεκτρισμού και φυσικού αερίου), το επιτόκιο αναγωγής, τα ενεργειακά φορτία, η ηλιακή ακτινοβολία και η ταχύτητα του ανέμου. Για την αντιμετώπιση της αβεβαιότητας και τον εντοπισμό των εύρωστων λύσεων χρησιμοποιούνται τέσσερις τεχνικές που ανήκουν στο πεδίο της «εύρωστης βελτιστοποίησης» ή της «στοχαστικής βελτιστοποίησης»: (α) objective-wise worst case, (β) minimax regret criterion (MMR), (γ) minimax expected regret (MER) και (δ) ανάλυση Monte Carlo. Συνολικά, αυτές οι τεχνικές προσφέρουν λύσεις πολύ διαφορετικές σε σχέση με την ντετερμινιστική προσέγγιση του προβλήματος, οι οποίες μπορούν να χαρακτηριστούν ως εύρωστες, υπογραμμίζοντας τη σημασία της θεώρησης της αβεβαιότητας κατά τη διαδικασία σχεδιασμού. Η διατριβή καταλήγει ότι η αντιμετώπιση της αβεβαιότητας κατά τον σχεδιασμό ενός ΣΔΠΕ είναι πολύ σημαντική καθώς οι λύσεις αλλάζουν σημαντικά, και αυτό έχει ιδιαίτερη σημασία για τον βέλτιστο σχεδιασμό του συστήματος, την οικονομική του βιωσιμότητα καθώς και την επιχειρησιακή του σταθερότητα. Εν τέλει, σημειώνεται ότι οι μεθοδολογίες που έχουν αναπτυχθεί είναι γενικές και μπορούν εύκολα να προσαρμοστούν και να εφαρμοστούν σύμφωνα με τις προτιμήσεις του αποφασίζων

Multi-objective optimization of distributed energy systems with focus on robust solutions

Primary energy consumption has increased exponentially in the last decades due to global economic growth. Energy is necessary for all aspects of modern life and is used in many sectors, such as electricity, heating and cooling generation, transportation and industry. However, energy consumption comes at a cost. Conventional energy systems rely on fossil fuels which have high carbon dioxide (CO2) emissions. As a result, the environment is affected due to the contribution of CO2 emissions to the greenhouse effect and by extension to climate change. Providing clean energy and tackling climate change are two of the most important challenges our planet faces. In the last years, the international community took measures to reduce CO2 emissions, such as the Kyoto protocol and more recently the Paris Agreement. European Union (EU) is implementing an ambitious set of policies in the fields of energy efficiency, promotion of renewable energy sources (RES) and reduction of CO2. Greece has also released an ambitious national energy plan recently based on European energy policies. Moreover, in the last decades global population has increased dramatically, which leads to increased consumption of resources, including energy. Additionally, it has been calculated that about 52% of the global population live in cities, with the number expected to rise in the following decades. Urban areas account to a large share of energy demand, which leads to several challenges in order to satisfy it. In this context, urban energy systems are expected to play a significant role. The future urban energy systems need to be redesigned and offer sustainable solutions. A solution towards this goal is the development of Distributed Energy Systems (DES). DES have many advantages, with the most significant one being the local energy generation which minimizes energy losses. DES can offer better integration between conventional energy systems and renewables and can satisfy the energy demand at a single building, a complex of buildings or even up to a whole city with a varied degree of decentralization. A DES can be designed to satisfy local energy needs in electricity, heating, and cooling. Also, they can lead to a reduction of total annual cost (TAC) and CO2 emissions. In the last years, several models have been proposed for the design of DES, based on mathematical programming. Those models applied either single- or multi- objective optimization problems with the most common objective functions being the minimization of TAC (which includes capital, operational and maintenance costs) and CO2 emissions. Designing a DES is a complex problem in which many aspects need to be considered. This thesis aims to provide a methodology for the optimal design of DES using multi-objective mixed-integer linear programming (MILP), with TAC and CO2 emissions as the objective functions. The candidate technologies are: (a) cogeneration units, (b) heat pumps, (c) absorption chillers, (d) boilers, (e) solar thermal collectors, (f) solar photovoltaics, (g) wind turbines, (h) thermal energy storage, (i) electric energy storage, (j) district heating network (DHN) and (k) microgrid. The results offer as outputs the selected technologies and their respective sizes at each building, the layout of the DHN (if formed), the operational profile of the installed technologies, and the electricity exchange through the microgrid (if selected) and the national grid. Additionally, in literature all the developed methods can be broadly separated into two categories, namely: (a) “Method A” in which a simultaneous selection and sizing of candidate technologies and (b) “Method B” in which the sizes of the candidate technologies are predefined. This thesis presents some innovative aspects in the field of optimal design of DES. Particularly, two approaches for the modelling of technologies are developed, expanding previous relevant work in literature. In addition, mathematical models for all available candidate technologies are presented. Those approaches are compared as they offer different solutions, and their advantages and disadvantages are assessed. Moreover, this thesis examines the robustness of solutions and it combines multi-objective mathematical programming with several techniques for optimization under uncertainty. To examine the benefits of DES and to compare these two methods, a case study was carried out for a neighbourhood of six buildings in an area in Attica and three scenarios are depicted, with Scenario 1 being business-as-usual, Scenario 2 – Renewables and Scenario 3 – Green. The results show that between these three scenarios, Scenario 3 offers the most attractive solutions. In addition, the comparison between “Method A” and “Method B” shows that “Method A” offers better results at each solution, specifically between 3% and 11% for TAC, which was expected due to the higher degrees of freedom it has. Regarding carbon emissions both methods show similar results. Moreover, several differences exist between each solution at each method regarding system’s structure, operational profiles of technologies, formation of DHN and electricity exchange with microgrid and national grid. A recommended strategy for designing a DES it is suggested to apply “Method A” at first to get a first approximation of the capacities of technologies, and afterwards, when the capacity bounds become constrained (which means less combinations and therefore lower computational complexity) apply “Method B” which will offer more accurate results. Furthermore, this thesis aims to examine the optimal design of DES under uncertainty. Changes in the values of several parameters can affect the optimal design of a DES, and the scope of this thesis is to provide a decision-maker (DM) with robust solutions. In this thesis uncertainty is assumed to exist in energy prices (electricity and natural gas), interest rate, energy loads (electricity, heating, and cooling), solar radiation, and wind speed. To examine uncertainty and identify robust solutions four techniques are used, which are in the fields of robust optimization (RO) and stochastic optimization (SO), namely: (a) objective-wise worst case, (b) minimax regret criterion (MMR), (c) minimax expected regret (MER) and (d) Monte Carlo simulations. Those techniques are applied to “Method A” either as multi-objective optimization problem (objective-wise method) or as single-objective optimization problems (MMR, MER and Monte Carlo simulations). For the transformation of the multi-objective deterministic problem to a single-objective one it is assumed that the TAC is the objective function and carbon emissions becoming a constraint with an upper bound of 100,000 kg/year. For the application of MMR and MER it is assumed that uncertainty exists only in economic parameters (interest rate and energy prices) and five scenarios are depicted, namely Scenario R1 to Scenario R5, where parameters take a high and low value respectively. Regarding the application of MER, it is assumed that each Scenario R1 to R5 has a specific probability to occur, which leads to less conservative results. As for the application of objective-wise worst case and Monte Carlo simulations, two scenarios are depicted for each method, Scenarios OW1 and OW2 and Scenarios MC1 and MC2, respectively. Scenarios OW1 and MC1 assume that uncertainty exists in economic parameters, while Scenarios OW2 and MC2 assume uncertainty in all parameters. Each method generates different solutions, with the worst results occurring at objective-wise worst-case method as it considers the worst value of the uncertain parameters. MMR and MER show solutions with small values of regret, indicating that uncertainty in economic parameters does not affect results significantly. Finally, at the application of Monte Carlo simulations each parameter is assigned a specific probability distribution and the results show the range of TAC values at each scenario. It is noted that for each method the results of system’s configuration and operation profile of technologies are different. Overall, these techniques provide solutions that are notably different of the results of the deterministic approach and can be characterized as robust, highlighting the importance of considering uncertainty for the design process. This thesis concludes that considering uncertainty in designing a DES is necessary as the optimal solutions change significantly, which is very important for the optimal design of the system, its financial viability and operational stability. Finally, it is noted that the developed methodologies are generic and can be easily adopted and applied according to the preferences of a DM

Ανάλυση προσδιοριστικών παραγόντων της εξέλιξης των εκπομπών διοξειδίου του άνθρακα του τομέα ηλεκτροπαραγωγής στην Ευρωπαϊκή Ένωση

88 σ.Οι εκπομπές διοξειδίου του άνθρακα (CO2) συμβάλλουν ιδιαίτερα στο φαινόμενο του θερμοκηπίου που θεωρείται υπεύθυνο για την κλιματική αλλαγή. Ο τομέας της ηλεκτροπαραγωγής έχει μεγάλο μερίδιο ευθύνης για τις εκπομπές αυτές. Ο σκοπός αυτής της εργασίας είναι η μελέτη των προσδιοριστικών παραγόντων που επηρεάζουν τις εκπομπές CO2 στον τομέα της ηλεκτροπαραγωγής στην Ευρωπαϊκή Ένωση (ΕΕ) την περίοδο 2001 – 2010. Η μελέτη αφορά όλες τις χώρες της ΕΕ, όπου εξετάζονται οι ομοιότητες και διαφορές στην εξέλιξη των εκπομπών CO2 καθώς και στη συμβολή των προσδιοριστικών παραγόντων. Με τη μεθοδολογία της ανάλυσης προσδιοριστικών παραγόντων και συγκεκριμένα της μεθόδου Divisia αναπτύχθηκε ένα υπολογιστικό μοντέλο για τον υπολογισμό της συνεισφοράς των προσδιοριστικών παραγόντων στις εκπομπές CO2. Οι προσδιοριστικοί παράγοντες που επηρεάζουν τις εκπομπές CO2, είναι το επίπεδο παραγωγής ηλεκτρικής ενέργειας, η διάρθρωση της ηλεκτροπαραγωγής, η τεχνολογία παραγωγής ηλεκτρικής ενέργειας, η ειδική ενεργειακή κατανάλωση καυσίμου του συστήματος και ο συντελεστής εκπομπής CO2. Από τα αποτελέσματα της ανάλυσης, φαίνεται ότι οι προσδιοριστικοί παράγοντες που επηρεάζουν περισσότερο τις εκπομπές CO2 από τον τομέα ηλεκτροπαραγωγής είναι το επίπεδο παραγωγής και η διάρθρωση της ηλεκτροπαραγωγής. Η ειδική ενεργειακή κατανάλωση καυσίμου και η τεχνολογία παραγωγής επηρεάζουν επίσης σημαντικά τις εκπομπές CO2. Για τη χρονική περίοδο 2001 - 2010, εμφανίζεται μείωση των εκπομπών CO2 στο σύνολο της ΕΕ, λόγω της αλλαγής της διάρθρωσης της ηλεκτροπαραγωγής, της βελτίωσης της ειδικής ενεργειακής κατανάλωσης και την αύξηση χρήσης τεχνολογιών όπως συμπαραγωγή ηλεκτρισμού – θερμότητας (ΣΗΘ) και παραγωγή ηλεκτρικής ενέργειας από Ανανεώσιμες Πηγές Ενέργειας (ΑΠΕ). Η πτωτική πορεία των εκπομπών CO2 θα μπορούσε να συνεχιστεί εφαρμόζοντας διάφορα μέτρα ενεργειακής αποδοτικότητας και εξοικονόμησης για τη μείωση της παραγωγής ηλεκτρικής ενέργειας, καθώς και με τη βελτίωση της διάρθρωσης ηλεκτροπαραγωγής κάνοντας χρήση καυσίμων με χαμηλό συντελεστή CO2 όπως το φυσικό αέριο. Ακόμη, η περαιτέρω βελτίωση της ειδικής ενεργειακής κατανάλωσης των καυσίμων και η αύξηση της χρήσης ΣΗΘ και παραγωγής ηλεκτρικής ενέργειας από ΑΠΕ θα συνεισφέρει σημαντικά στο σκοπό αυτό.The Greenhouse Effect is considered to be responsible for the climate change in the planet and the carbon dioxide emissions (CO2) have a major contribution in this effect. The electricity generation sector contributes significantly in these emissions. The purpose of this project is to identify the factors that are responsible for the CO2 emissions of the electricity generation sector in the European Union (EU) during the years 2001 – 2010. A mathematical model for the calculation of the factors that are responsible for CO2 emissions was developed using decomposition analysis and the Divisia method specifically. The factors that affect the CO2 emissions are the electricity production, the electricity generation structure, the technology used for electricity generation, the specific energy consumption of the fuels and the CO2 emission factor. The results of this analysis showed the factors that contribute the most in the CO2 emissions are the electricity production and the electricity generation structure. Also, the specific energy consumption and the technology used for electricity generation have a significant effect in CO2 emissions. During the 2001 – 2010 period CO2 emissions were reduced due to the change of the electricity generation structure, the improvement of the specific energy consumption of fuels and increasing use of other technologies, such as cogeneration of electricity and heat (CHP) and electricity generation from Renewable Energy Sources (RES). The further reduction of CO2 emissions could be continued with further development of energy efficiency and reduction of energy use that would lead to reduction of electricity generation. Also, the further improvement of electricity generation structure by use of fuels with lower emission factor such as natural gas and the further improvement of specific energyΜάριος Ι. Καρμέλλο

Enhancing decarbonization of power generation through electricity trade in the Eastern Mediterranean and Middle East Region

The region of the Eastern Mediterranean and Middle East (EMME) is one with highly diverse socioeconomic conditions. It is split between countries with rich fossil fuel reserves, which are net energy exporters, and countries that rely to a large extent on energy imports to satisfy their domestic demand. Despite the abundant renewable energy resources, especially for wind and solar, in 2019 renewable energy accounted for merely 12% of the total electricity generation across the region. The present effort aims to highlight the potential benefits offered by a future enhancement in electricity trade between EMME countries; this could unlock the currently unexploited renewable energy resources of the region. A model representing the national electricity supply system of seventeen EMME countries is developed in a cost-optimisation modelling framework (OSeMOSYS). This is then used to project cost-optimal development pathways for the respective energy systems, by assessing alternative scenarios where regional trade is limited or enhanced. Comparison of a set of scenarios is conducted to quantify implications in terms of renewable energy deployment, greenhouse gas emissions and overall system costs. Results from the analysis indicate that in the absence of climate neutrality ambition across the region, electricity trade is limited to existing levels. However, the need for electricity trade increases when countries strive to decarbonise their electricity supply cost-effectively

Estimating the economy-wide impacts of energy policies in Cyprus

Decarbonisation of the global economy is necessary to achieve the climate targets set by the Paris Agreement at COP21. Significant investments are required in low-carbon technologies on the supply and demand side of energy systems; the scale of these may pose challenges to national economies. In this paper, an energy forecast model, a cost-optimisation model and an input-output model are combined to conduct an economy-wide assessment of policy pathways for energy transition in Cyprus. The results of the study indicate that a scenario with additional energy efficiency measures and a modal shift in the transport sector can reduce final energy consumption by 10% as compared to a reference case in 2030. The macroeconomic assessment shows that the measures have a moderate but positive effect on economic growth. The construction, metal products and transportation sectors are those mainly benefiting in terms of economic output generation, while the largest negative effects are observed in the energy sector. Our findings highlight the importance of targeted investments to ensure a positive impact of energy policies on the broader economy

Environmental and Economic Impacts of the National Energy and Climate Plan of Cyprus

This paper provides a summary of the Impact Assessment of the National Energy and Climate Plan of Cyprus, which was submitted by the Cypriot government to the European Commission in January 2020. The analysis is based on detailed modelling of the national energy system in combination with simulations by macroeconomic and household demand models. The study has produced numerous results describing the energy, environmental and economic impacts of different scenarios. This paper focuses on some key findings and recommendations that are of interest to economic policy makers. Results show that the planned energy and climate policies of the Cypriot government, while contributing to compliance of Cyprus with its legally binding energy and environmental obligations, can also yield economic benefits to society. However, they require strong political will to implement, and this especially applies to measures promoting sustainable transport. As further decarbonisation measures will be needed in the coming years, the country can exploit business and investment opportunities arising from the global energy transition

Environmental and Economic Impacts of the National Energy and Climate Plan of Cyprus

This paper provides a summary of the Impact Assessment of the National Energy and Climate Plan of Cyprus, which was submitted by the Cypriot government to the European Commission in January 2020. The analysis is based on detailed modelling of the national energy system in combination with simulations by macroeconomic and household demand models. The study has produced numerous results describing the energy, environmental and economic impacts of different scenarios. This paper focuses on some key findings and recommendations that are of interest to economic policy makers. Results show that the planned energy and climate policies of the Cypriot government, while contributing to compliance of Cyprus with its legally binding energy and environmental obligations, can also yield economic benefits to society. However, they require strong political will to implement, and this especially applies to measures promoting sustainable transport. As further decarbonisation measures will be needed in the coming years, the country can exploit business and investment opportunities arising from the global energy transition

A decomposition and decoupling analysis of carbon dioxide emissions from electricity generation: Evidence from the EU-27 and the UK

In this paper the driving factors of carbon dioxide emissions from electricity generation in the European Union are examined for the years 2000–2018, separated into three time periods using decomposition analysis, and particularly LMDI-I. Seven driving factors are examined, namely the economic activity effect, the population effect, the electricity intensity effect, the electricity trade effect, the energy intensity effect, the generation structure effect, and the emissions factor effect. The results showed that the main driving factor leading to increased carbon dioxide emissions is the economic activity effect counterbalanced mainly by the contribution of the generation structure effect. Moreover, a decoupling analysis between economic growth and carbon dioxide emissions was carried out aiming to identify the state of each country for each period. In the third examined period (2013–2018) most countries in the EU-27 are in a state of strong decoupling