Clustering EU Member States by Energy Security Level Using Kohonen Maps

Abstract

The topic of energy security is relevant for EU countries that pay great attention to new renewable energy sources and sustainable environmental development. The purpose of the article is to analyze and group EU countries by their level of energy security. To achieve this goal, general scientific methods and Kohonen maps (Deductor Studio package) were used. This article analyzes the state of energy security in EU countries, energy imports, the development of renewable energy sources, energy consumption, and energy security challenges. As a result of grouping EU countries according to Kohonen maps, three clusters were identified: countries with high, medium, and relatively low levels of energy security. The approach demonstrated the effectiveness of neural network-based clustering in revealing structural differences in national energy systems. The findings indicate that to strengthen energy security across the European Union, it is important to adopt differentiated approaches tailored to the specific needs of each cluster. The practical significance of the article lies in clustering EU countries by their energy security potential, which provides a basis for developing and implementing appropriate policies to enhance energy security. Recommendations for strengthening energy security were proposed for each cluster.

1. Introduction

Energy security, defined as the uninterrupted availability of energy sources at affordable prices, has become a critical factor for economic stability in the European Union. The concept goes beyond the simple security of supply to encompass the diversification of energy sources, the geopolitical stability of suppliers, and the ability to adapt to climate-related disruptions. After 2022 the European energy system faced unprecedented challenges. The EU was forced to urgently review its energy supply sources, strengthen internal resilience, and accelerate the development of renewable energy sources. In this context, the need for an in-depth comparative analysis of the energy sustainability of EU member states has become more pressing.

Despite the existence of various indices and approaches to measuring energy security (such as the Energy Trilemma Index, the 4A model, etc.), most of them are based on aggregate indicators and do not reflect internal patterns and cluster structures within the European Union. Existing classifications rarely use machine learning methods to identify hidden sustainability profiles, which makes it difficult to develop targeted policies. In addition, the literature does not pay enough attention to comparing energy security levels with comprehensive metrics of sustainable development, equal access, and technological modernization.

The aim of this article is to identify the typology of energy security in EU countries using Kohonen self-organizing maps based on multidimensional indicators. This study answers the following question: Are there stable groups of EU countries with similar energy characteristics, and what features distinguish these groups in terms of sustainability, import dependence, share of renewable sources, and social justice?

This study’s research hypothesis is as follows: if EU countries are grouped using clustering methods based on multidimensional energy security indicators (including sustainability, equal access, share of RES, and share of nuclear and alternative energy), then substantively different clusters of countries will emerge, demonstrating different vulnerabilities and strengths in energy policy, which will allow for the development of targeted recommendations to improve their energy sustainability.

The scientific novelty of the article lies in the fact that for the first time a comprehensive classification of EU countries by the level of energy security is proposed, which combines global indicators (Energy Security Score, Energy Equity Score, Environmental Sustainability Score) with indicators of renewable energy development, which distinguishes it from previous approaches focused on only one aspect. This study proposes a new typology of EU countries based on cluster analysis, which demonstrates that energy security has persistent structural differences within the Union. The novelty lies in the integration of multidimensional indicators, the interpretation of clusters in the context of sustainability, and the development of targeted recommendations.

Previous studies lack a comprehensive approach to classifying EU countries that integrates modern global energy security indicators with an analysis of renewable energy dynamics. This gap underscores the relevance of the present article, which introduces a refined research concept involving the clustering of EU countries into three groups based on their energy security levels. So, the practical significance of the article lies in clustering the EU countries and grouping them according to their energy security potential. From a practical point of view, this will allow the development and implementation of appropriate policies to improve energy security.

The article is structured as follows. First, the article provides an overview of current scientific approaches to measuring energy security and a description of the main energy security trends in the EU (Section 2), followed by a description of the methodologies and data sources used (Section 3). Section 4 presents the results of clustering EU countries using Kohonen maps and their interpretation. Section 5 includes a discussion of the clusters obtained in the context of geopolitics, sustainability, and practical applicability. The conclusion (Section 6) presents the main findings and directions for further research.

2. Literature Review

2.1. Concept and Definition of Energy Security

The concept of the energy security of EU countries was studied by authors such as Pokhodenko B. [1]; Konopelko A.; Kostecka-Tomaszewska L.; Czerewacz-Filipowicz K. [2]. The economic aspects of energy security were considered by scientists Bogachov S.; Kirizleyeva A.; Mandroshchenko O.; Shahoian S.; Vlasenko Y. [3]. The authors Man O.R.; Radu R.I.; Mihai I.O, De Rosa, Mattia, Kenneth Gainsford, and others have proposed a new model of the energy security of the EU countries in their scientific articles [4,5].

The researcher E. Cox developed the 4A model, emphasizing that energy security should be ensured not only in the short term, but also in the long-term perspective and this implies increased attention to the reliability of energy systems, as well as the economic and environmental performance of their operation [6]. Willrich M. defined energy security as: “The assurance of sufficient energy supplies so that the national economy can function in a politically acceptable manner”. This definition focuses on economics, politics, and supply [7]. Later, Deese D. introduced the concept that energy security is a condition, situation, or status, not a policy or attitude.

In this article, energy security is understood as a multidimensional concept encompassing the availability, accessibility, affordability, and sustainability of energy resources, ensuring the uninterrupted supply of energy at acceptable economic and environmental costs. This definition combines both short-term stability (protection against sudden disruptions or price shocks) and long-term resilience through the diversification of energy sources, the integration of renewables, and infrastructure modernization. Thus, energy security in the EU context reflects the ability of national energy systems to adapt to global challenges such as supply chain volatility, geopolitical risks, and climate commitments.

2.2. Measurement Approaches and Indicators

Eurostat provides static data on the energy security of EU countries, which presents energy sources, energy production, energy exports and imports, energy transit, energy consumption structure, and energy dependence [8]. These datasets are widely used in baseline assessments of national energy profiles but are limited to descriptive statistical indicators rather than multidimensional risk analysis. In addition to this study, Jarosław Brodny and Magdalena Tutak classify the EU countries by energy security levels for 2010–2020 into the following four groups: high level, safe level, warning level, dangerous level. The authors also continue to classify EU countries by sustainable energy security into four groups. The authors calculate these indices using energy security indicators [9]. The same authors have also worked on assessing sustainable energy security by integrating environmental and social aspects, using a similar four-tier grouping system based on composite indices.

Another widely recognized method is the Energy Trilemma Index, developed by the World Energy Council, which evaluates national energy systems across three fundamental dimensions: energy security (reliability and resilience of supply), energy equity (accessibility and affordability), and environmental sustainability (impact on ecosystems and climate). The underlying logic of this method is to capture the trade-offs between these interrelated but often conflicting goals, providing a composite score that facilitates cross-country comparisons [10].

2.3. Research Gap and Contribution

Having analyzed the literature, it should be noted that the authors did not classify the EU countries by the level of energy security using global energy security indicators and indicators of the use of alternative energy sources, which necessitates further research. Thus, there is a gap in previous studies, as there has been no comprehensive approach to the classification of EU countries based on modern global energy security indicators combined with an analysis of the dynamics of renewable energy sources. This demonstrates the relevance of this article, which will propose a refined research concept that will include clustering EU countries into three groups by energy levels.

2.4. Background

In recent years, the European Union has undergone profound shifts in its approach to energy security, driven by geopolitical tensions, climate commitments, and structural market changes. These evolving trends reflect the EU’s efforts to balance sustainability, affordability, and resilience across its energy systems.

According to the Energy Security Index for 2023, Finland became the leader among the European Union countries, receiving the highest score of 75.9 points. Romania, Sweden, the Czech Republic, and Germany also demonstrated high scores, indicating the effective diversification of energy sources, infrastructure stability, and adaptability to crisis situations. While northern and central European countries generally demonstrate a high level of energy security, southern and island states such as Cyprus (39.7) and Malta (49.9) remain more vulnerable due to limited access to energy resources and the dependence on imports [10]. These disparities highlight structural challenges in the EU’s energy system, particularly in the face of recent global energy shocks, price surges, and supply chain disruptions following Russia’s invasion of Ukraine.

However, the EU’s energy security system faces systemic risks, including cyberattacks on critical infrastructure and climate-related disruptions. The introduction of anomaly detection systems based on artificial intelligence can help identify potential threats before they escalate into crises. In addition, blockchain technology can improve network decentralization and increase supply chain transparency. At the same time, extreme weather events, such as droughts that impair hydropower operations or hurricanes that damage offshore wind farms, require adaptive strategies, such as the Dutch Energy Islands, which combine flood-resistant structures with renewable energy [11].

Thus, energy security in the EU is inextricably linked to economic stability due to its impact on industrial competitiveness, price volatility, and geopolitical autonomy. As the IMF notes, the energy security benefits of climate action are immediate and profound, confirming the EU’s integrated approach to resilience and security [12]. However, the way forward requires continued investment in innovation, infrastructure strengthening, and equitable policies to address the twin challenges of decarbonization and geopolitical uncertainty. In the words of the World Energy Council, “the cost of inaction far outweighs the cost of transition”—a rule that underscores the urgency of the EU’s energy agenda to secure its economic future [11].

Over the past decade, the energy landscape of European countries has undergone a significant structural transformation driven by climate imperatives, geopolitical upheaval, and technological advances. In 2023, the energy mix in the EU, meaning the range of available energy sources, was mainly composed of five different sources: crude oil and petroleum products, natural gas, renewable energy, solid fuels, and nuclear energy [13].

2.5. Renewable Energy

Renewable energy has become a cornerstone of structural change in the EU, with its share of gross final energy consumption increasing from 9.6% in 2004 to 24.5% in 2023, driven by wind, solar, and hydroelectric power. Countries such as Sweden, Finland, and Denmark are now leading the way in renewable energy deployment, with Sweden achieving 66.4% of its energy from renewables—mainly biofuels, hydropower, and wind—while Malta, Belgium, and Luxembourg lag due to geographic and infrastructure constraints [14]. The EU’s energy transformation is also driven by changes on the demand side. Final energy consumption in the EU in 2023 amounted to 1211 Mtoe, which is 16.6% less than in 2006 (the peak primary consumption was 1511.4 Mtoe), but still higher than the 2030 target (763 Mtoe) (Figure 1) [15].

Despite challenges such as energy availability and raw material supply, the EU’s integrated policy—which combines market mechanisms, incentives for innovation, and solidarity mechanisms—creates the conditions for combining energy security with economic and environmental sustainability [16].

2.6. Import Dependence and Geopolitical Vulnerabilities

The European Union’s energy dependence on imports remains a critical vulnerability: as of 2023, 58% of gross domestic energy consumption came from external suppliers, highlighting the bloc’s strategic sensitivity to fluctuations in global markets and geopolitical risks. This dependence is unevenly distributed across different types of energy: petroleum products account for the bulk of imports (65% of total energy imports), followed by natural gas (25%) and solid fossil fuels (5%), electricity (3%), and renewable energy (2%) [15].

Despite targeted efforts to diversify suppliers after 2022, the EU’s energy security still largely depends on a limited number of countries. In 2024, 55.5% of the EU’s imports of oil and oil products came from five countries: The United States, Norway, Kazakhstan, Libya, and Saudi Arabia [17].

The EU’s diversification strategies, including REPowerEU and the mandate to reduce gas demand by 15%, have yielded tangible results. Between 2022 and 2024, the utilization of LNG regasification capacity increased to 96% in Poland and 93% in Croatia, reflecting infrastructure investments to accommodate non-Russian supplies. However, the level of reserves remains unstable: in March 2025, European reserves were only 34% full, and Ukrainian storage facilities are at a critically low level of only 3% [18].

Europe’s energy dependence on imports, although reduced since 2022, remains structurally entrenched. The bloc’s dependence on Norway and the United States for gas supplies, as well as the continued receipt of gas revenues from Russia, emphasize the difficulty of separating from geopolitical adversaries. The EU’s success in balancing these imperatives will determine its resilience in an increasingly fragmented global energy order [15].

2.7. Decarbonization Progress and Emission Reductions

The EU’s net greenhouse gas emissions decreased every year from 2012 to 2014, then increased slightly until 2017, after which they fell again every year (except for 2021, as the outbreak of the COVID-19 pandemic in 2020 reduced several activities, such as transportation and travel, that generate greenhouse gas emissions). The largest decreases were recorded in Romania, Sweden, and Lithuania, and the largest increases were recorded in Cyprus, Latvia, and Ireland (Figure 2) [15].

Overall, renewables are indispensable for Europe’s energy security, offering a path to decarbonization, price stability, and geopolitical resilience. The EU’s progress—as exemplified by the dominance of wind energy in Denmark and the rapid growth of solar energy—confirms the effectiveness of policies such as REPowerEU. According to the International Renewable Energy Agency (IRENA), doubling the share of renewables to 34% by 2030 is both economically viable and critical to achieving the goals of the Paris Agreement. The bloc’s ability to harmonize these elements will determine its success in transforming energy security from a reactive strategy to a basis for sustainable prosperity [19].

3. Materials and Methods

This research draws upon a combination of secondary data sources, including scholarly articles, monographs, and statistical databases from Eurostat, the World Bank, and the European Commission, supplemented by curated internet resources and the author’s empirical findings. This study focuses on EU energy consumption (2006–2023) and greenhouse gas emissions (2012–2022), ensuring a comprehensive temporal scope for trend analysis.

The object of this study is the countries of the European Union, and the subject of this study is their energy security, considered as a multidimensional category that includes the stability of energy systems, equal access, as well as the dependence on external supplies and the share of alternative energy sources.

To achieve the purpose of the article, the author used general scientific methods of information analysis and synthesis, systematization, and comparison. A Kohonen network was used to group the EU countries by their energy security potential. A Kohonen network consists of neurons organized in a two-dimensional grid. Each node is represented by a vector with weights, the number of which corresponds to the number of indicators that characterize the objects under study. During training, these weights are adapted so that the network can effectively reflect the structure of the input data. Once trained, the network can be used to cluster new data by placing it in the appropriate clusters according to its similarity.

The choice of Kohonen maps as a methodological tool is based on their advantages in analyzing high-dimensional, nonlinear data and identifying latent patterns without imposing predefined assumptions. As an unsupervised machine learning technique, Kohonen maps enable the clustering of countries according to multiple energy security indicators, providing an intuitive visual representation of the similarities and differences among the analyzed objects. This makes them particularly suitable for tasks where the relationships between variables are complex and not strictly linear. Additionally, Kohonen maps allow for simultaneous data reduction and classification, which simplifies the interpretation in comparative energy security analysis.

Compared with traditional approaches such as multifactorial regression, autoregressive models, or panel analysis, Kohonen maps offer greater flexibility for exploratory analysis. While those methods are effective for estimating linear relationships or temporal dynamics, they are less suitable for uncovering hidden structures in multidimensional datasets without strong parametric assumptions.

The Deductor Studio Academic package (free version) was used to conduct a study of the global intellectual and technological landscape of the development of the countries of the world using the Kohonen algorithm.

The following indicators were used to model Kohonen’s maps: Energy Security Score, Energy Equity Score, Environmental Sustainability Score, Share Of Energy From Renewable Sources, Alternative and Nuclear Energy in 2022–2023.

The Energy Security Score is an indicator that reflects the ability of a country to ensure a stable, reliable, and sufficient supply of energy at present and in the future. The Energy Equity Score assesses the accessibility and affordability of energy for all consumers, including households and industries. The Environmental Sustainability Score evaluates the extent to which a country’s energy system aligns with environmental goals, such as reducing greenhouse gas emissions and limiting ecological impacts. The Share of Energy from Renewable Sources represents the percentage of a country’s total final energy consumption derived from renewable sources, including wind, solar, hydro, and bioenergy. It demonstrates the progress toward reducing the reliance on fossil fuels and enhancing sustainability. Alternative and Nuclear Energy measures the share of energy generated from alternative low-carbon sources, including nuclear power and certain non-traditional energy technologies. It reflects a country’s strategy for diversifying its energy mix and lowering carbon intensity while maintaining supply security.

These indicators were chosen for their alignment with EU policy frameworks, such as the European Green Deal, and their ability to capture multidimensional aspects of energy transitions.

Expected outcome: meaningful groups with substantive differences between them.

Value: the ability to propose targeted policy measures.

One iteration was performed to group countries into three clusters, which corresponds to the research hypothesis.

The number of clusters was chosen by the authors because SOM does not cluster data directly, but projects it into a lower space with a certain structure of neurons (e.g., 3 × 3, 4 × 4, etc.). Once trained, each neuron on the map can be viewed as a cluster centroid. You can then use all neurons as separate clusters; or combine neighboring/similar neurons into fewer clusters (in our case, three clusters).

The stability and reliability of the clustering results were verified through multiple training runs of the Kohonen network, which produced consistent topological structures and cluster assignments. This robustness ensures that the identified clusters are not arbitrary but represent real structural differences among EU countries in terms of energy security.

4. Results

To better understand the diverse energy security profiles across the European Union, a cluster analysis was conducted using Kohonen maps based on key indicators of energy security, sustainability, and energy mix diversity. This method provides a visual and analytical representation of how EU member states group together according to their energy resilience and capacity to respond to current challenges such as energy transitions, climate change, and geopolitical tensions. The Kohonen map was constructed using the Deductor Studio package based on the indicators listed in

Table A1. Indicators of energy security of EU.

EU Countries	Energy Security Score	Energy Equity Score	Environmental Sustainability Score	Share of Energy from Renewable Sources, %	Alternative and Nuclear Energy, %
Austria	71.8	95.3	78.6	40.8	16.2
Belgium	61.7	95.2	76.8	14.7	22.5
Bulgaria	72.6	67.1	73.2	22.5	26.1
Croatia	68.4	90.9	75.5	28.1	8.7
Republic of Cyprus	39.7	92.3	68	20.2	6.6
Czech Republic	73	93.2	71.6	18.6	22.2
Denmark	72.2	95.8	83.5	44.4	13.9
Estonia	69.9	94.8	78.5	41	2.9
Finland	82.7	75.9	92.3	50.8	35.3
France	69.4	93.7	83.2	22.3	46.7
Germany	72.9	94.4	76.6	21.6	9
Greece	53.6	88.7	75.4	25.3	12.3
Hungary	72.7	90.2	73.1	17.4	21.3
Ireland	54.2	98.7	76.8	15.3	8.6
Italy	66.4	89.3	73.6	19.6	9.8
Latvia	72.1	86.5	74.8	43.2	8.3
Lithuania	63.4	89.6	74.6	31.9	4.7
Luxembourg	52.5	98.2	79.2	14.4	2.6
Malta	49.9	95.5	66.7	15.1	3.6
Netherlands	64.4	95.2	74.6	17.1	9.1
Poland	65.1	85.5	65.3	16.6	3.4
Portugal	65.4	88.2	81.2	35.2	14.9
Romania	73.7	82.8	75.1	25.8	15.5
Slovakia	72.3	87.4	75.8	17	30.4
Slovenia	69.1	93.8	77	25.1	32.8
Spain	67.3	91.4	79.9	24.9	25.1
Sweden	73.4	93.4	85	66.4	49.2

Developed by authors according to [10,14,25].

(Figure 3).

According to the modeling, we obtained the following three groups of clusters:

Cluster 0—Finland, France, Slovakia, Slovenia, and Sweden. It is a cluster with a high energy security level. The main characteristics of Cluster 0 are as follows:

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High energy security. Finland (82.7) and Sweden (73.4) lead in energy security due to diversified energy mixes and stable infrastructure;

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Strong nuclear/alternative energy: France (46.7% nuclear) and Slovenia (32.8% alternative/nuclear) rely heavily on low-carbon sources;

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High environmental sustainability: Sweden (85) and Finland (92.3) excel in sustainability, driven by renewables and efficient policies.

Cluster 1—Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Hungary, Portugal, Romania, and Spain. It is a cluster with a moderate energy security level. The main characteristics of the cluster are as follows:

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Moderate-to-high equity: Denmark (95.8) and Austria (95.3) ensure affordable energy access;

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Mixed renewable adoption: Denmark (44.4%) and Portugal (35.2%) lead in renewables, while others lag (e.g., Bulgaria: 22.5%);

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Moderate sustainability: Most scores range between 71 and 81, indicating room for improvement.

Cluster 2—Croatia, the Republic of Cyprus, Estonia, Germany, Greece, Ireland, Italy, Latvia, Lithuania, Luxemburg, Malta, the Netherlands, and Poland. It is a cluster with a low energy security level (among EU countries). Its characteristics are as follows:

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Lower energy security: Poland (65.1) and Cyprus (39.7) face vulnerabilities due to fossil fuel reliance;

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Low nuclear/alternative energy: Germany (9%) and Malta (3.6%) depend on imports or traditional sources;

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Variable sustainability: Estonia (78.5) performs well, but Poland (65.3) and Malta (66.7) lag.

The clustering of EU countries reflects underlying similarities in their energy systems, policy frameworks, and resource dependencies. Countries in Cluster 0 demonstrate high energy security due to diversified energy mixes, strong investments in nuclear and renewable energy, and advanced sustainability policies. These nations have consistently prioritized low-carbon strategies and infrastructure reliability, placing them ahead in resilience and environmental performance.

Cluster 1 includes countries which have moderate energy security. These states exhibit a balanced performance across equity, sustainability, and renewable energy adoption. However, the uneven pace of transition and varying reliance on traditional energy sources among cluster members result in a mid-range security profile.

Cluster 2 brings together countries facing greater energy security challenges, such as Poland, Malta, and Cyprus. These nations are more dependent on fossil fuels and have limited nuclear or alternative energy capacity. Their inclusion in the same cluster reflects shared vulnerabilities, such as a reliance on imports and slower progress in clean energy transformation.

Overall, the clusters illustrate how structural energy choices, geographic constraints, and national policies shape the current state of energy security across the EU.

All clusters should prioritize the digitalization of energy systems and EU-wide collaboration to address shared challenges like supply chain disruptions and climate change.

The grouping of countries by Kohonen maps allows us to recommend certain areas for strengthening energy security in countries.

5. Discussion

To effectively strengthen energy security across the European Union, it is essential to develop cluster-specific policy approaches that reflect the distinct characteristics and challenges of each group of countries identified through the Kohonen map analysis.

For countries in Cluster 0, which already demonstrate high levels of energy security and environmental sustainability, the priority should shift toward enhancing system resilience and technological leadership. These countries can benefit from investing in advanced digital infrastructure, such as AI-driven grid management, and expanding cross-border interconnections to support broader EU energy stability. Additionally, they are well positioned to lead in the development of the hydrogen economy and to export clean energy technologies to support the transition in other regions.

In Cluster 1, where countries enjoy a strong performance in energy equity but show uneven progress in renewable energy adoption, the focus should be on accelerating the decarbonization of key sectors, particularly transport and heating. This can be achieved through greater electrification, the expansion of bioenergy solutions, and increased investment in renewables in the countries that are currently lagging. Regional collaboration on energy innovation and storage infrastructure will further enhance the collective resilience of this group.

Countries in Cluster 2 face the most significant challenges, with lower energy security and vulnerabilities related to affordability and fossil fuel dependence. For these nations, a strategic shift toward decentralized energy solutions is critical. Implementing localized renewable generation, such as community solar and small-scale wind, along with smart grids and local storage systems, can enhance flexibility and reduce the reliance on imports. At the same time, targeted subsidies and support for vulnerable households are necessary to improve energy equity. These countries should also prioritize phasing out fossil fuels through industrial transition strategies and policy frameworks that encourage clean energy adoption.

The proposed classification of the EU countries into three clusters (high, medium, and low energy security) is mainly based on macro-level indicators (such as the Energy Security Index, the share of renewable energy, and the use of nuclear/alternative energy) and meso-level factors (e.g., infrastructure resilience, import diversification). However, recent studies have emphasized the growing importance of micro-level determinants—such as corporate sustainability practices, decentralized energy systems, and adaptability at the individual company level—in shaping energy security [20].

Micro-level factors could improve the cluster analysis by taking into account their impact. For example, decentralized energy systems in countries such as Germany and Denmark show significant corporate investment in renewable energy, which can serve as a buffer against systemic risks. On the other hand, the lack of micro-level resilience in Malta, where SMEs are not well engaged in the energy transition, reinforces its low position in the clustering. Adaptability at the company level also plays an important role: in Sweden (Cluster 0), companies such as Vattenfall are integrating circular economy principles, which are consistent with a high environmental sustainability performance. At the same time, in Poland (Cluster 2), the resistance of coal companies to the transition to clean technologies may slow down progress. In addition, micro-level digitalization, such as AI-based grid monitoring systems, could improve cluster-specific recommendations, especially on cybersecurity.

Despite the importance of micro-level determinants, their exclusion from this study is justified. Firstly, macro-level datasets (from Eurostat, World Bank) provide standardized indicators for all EU countries, while company- or community-level data are fragmented and not sufficiently comparable. Secondly, this study focuses on policy interventions at the national level (e.g., REPowerEU initiative, cross-border infrastructure) that prioritize systemic analysis over detailed analysis. Thirdly, methodological limitations (the use of Kohonen maps) require homogeneous input variables; incorporating qualitative micro-level data (e.g., company ESG reports) would require mixed methods beyond the quantitative design of this study.

To bridge this gap, future research could use hierarchical clustering to embed micro-level data in macro-level clusters, use case studies (e.g., SMEs in the German Energiewende) to contextualize classification exceptions, or use the textual analysis of corporate reports to quantify the micro-level contribution to national energy security.

To summarize, micro-level determinants undoubtedly influence energy security, but they were excluded in this study due to methodological limitations and the research focus. Future work should integrate them to refine cluster-specific policies—for example, those aimed at supporting SMEs in Cluster 2 or corporate partnerships in Cluster 0. This would align the EU’s top-down policy framework with bottom-up resilience mechanisms, contributing to a more holistic energy security strategy.

It is also important to pay attention to geopolitical factors when clustering EU countries.

The geopolitical challenges that threaten the European Union’s energy security are deeply rooted in historical dependence, the changing global balance of power, and the urgent need to transition to sustainable energy systems. These dependencies are closely linked to broader geopolitical risks, including fragile supply chains, competition for critical resources, and the need for strategic rethinking in the context of the global energy transition [21].

To counter these threats, the EU has adopted a multifaceted strategy that focuses on diversification, resilience, and systemic transformation. The REPowerEU initiative aims to reduce Russian gas imports by 66% by 2030 by accelerating the deployment of renewable energy sources, developing hydrogen infrastructure, and diversifying liquefied natural gas (LNG) supplies [11].

Energy diplomacy has once again become a key element of the EU’s strategy, combining industrial policy with geopolitical pragmatism. Long-term liquefied natural gas (LNG) supply contracts with Qatar and the United States, which will be in effect after 2050, ensure supply stability during the transition period. At the same time, the return of the production of critical minerals and wind turbines to Europe is aimed at reducing the dependence on China [22].

However, serious challenges remain with public opposition to extractive projects, delays in the construction of nuclear power plants, and the so-called “energy trilemma”, which implies the need to simultaneously ensure energy affordability, sustainability, and security, which all make it difficult to achieve full energy autonomy [23,24].

Europe’s energy security depends on its ability to manage interdependence in a balanced way while accelerating systemic decarbonization [25]. While diversification and strengthening infrastructure reduce short-term risks, long-term sustainability requires the deeper integration of energy networks, circular supply chains for critical materials, and the democratization of energy access to avoid socioeconomic inequalities.

Recent research also highlights the role of market-based mechanisms in supporting this transition. For example, Cheng and Jiang [26] demonstrate that carbon markets can effectively stimulate investment in renewable energy by creating financial incentives for low-carbon technologies and reducing the relative cost of green energy compared with fossil fuels. Such instruments, if adapted to the EU context, could complement regulatory measures and accelerate progress toward energy security and decarbonization goals.

This is particularly relevant considering the increasing frequency of hybrid threats, where energy systems are both a target and a tool of geopolitical coercion.

Although hydrogen plays a central role in the EU’s energy transition narrative, its deployment faces substantial economic, technical, and geopolitical constraints that warrant critical scrutiny. Recent analyses have revealed that only a small fraction of planned green hydrogen projects is likely to materialize by 2030, owing to high production costs, weak demand, and project delays. Moreover, the stringent additionality requirements of EU regulations designed to ensure that hydrogen production stimulates new renewable capacity raise overall system costs by billions of EUR and could hinder hydrogen’s cost competitiveness [27]. On the geopolitical front, hydrogen import strategies may replicate past dependencies; the reliance on a handful of hydrogen exporters and electrolyzer suppliers, especially those dominated by non-EU actors, creates new strategic vulnerabilities. These limitations underscore the need for a more nuanced assessment of hydrogen’s role within EU energy security strategies, balancing ambition with realism and ensuring policies are sustainable both economically and geopolitically.

Additionally, broader macroeconomic dynamics further complicate hydrogen deployment. Scholars Li, Li, and Liao [28] emphasize that energy intensity in emerging economies tends to fluctuate with business cycles, highlighting the vulnerability of energy transition strategies to global economic volatility. Similar risks apply to the EU, where economic downturns or supply shocks can disrupt investment flows into capital-intensive technologies such as green hydrogen, delaying infrastructure rollouts and undermining decarbonization targets. This reinforces the argument that EU hydrogen policies must incorporate counter-cyclical mechanisms such as targeted subsidies or flexible financing instruments to maintain momentum during periods of economic contraction.

6. Conclusions

Thus, the energy security of EU countries was analyzed and the Kohonen scores were constructed to group EU countries by the level of energy security. EU countries were then grouped into three clusters, which made it possible to develop recommendations for each cluster to strengthen energy security.

To strengthen energy security across the European Union, it is important to adopt differentiated approaches tailored to the specific needs of each cluster. Countries in Cluster 0, which already demonstrate high energy security, should focus on political leadership within the EU by promoting the integration of national energy systems and advancing common climate and nuclear policies. Economically, they should invest in innovation through increased funding for hydrogen technologies, long-duration energy storage, and carbon capture, as well as support cross-border clean energy initiatives that generate mutual economic benefits. From a managerial perspective, the focus should be on enhancing the efficiency and cybersecurity of energy systems by implementing AI-based tools for predictive maintenance, infrastructure monitoring, and demand forecasting.

Cluster 1 countries, with moderate energy security, require policies that harmonize national renewable energy targets with EU goals. Political dialog and engagement at both national and local levels will help accelerate the energy transition. Economically, these countries should prioritize investments in renewable energy, particularly where adoption remains low, and implement financial mechanisms such as tax incentives and feed-in tariffs to support clean energy and efficiency upgrades. On the management side, institutional capacities for energy planning, monitoring, and evaluation should be strengthened. Establishing regional hubs for technical support and knowledge sharing can also contribute to the more effective implementation of new energy solutions.

Cluster 2 countries face more significant challenges and require political strategies focused on reducing fossil fuel dependence and improving energy autonomy. These strategies should also include support for a just transition and the protection of vulnerable groups. Economically, the introduction of decentralized subsidy schemes for residential solar power, energy-efficient housing, and local energy production is key. Targeted public funding should be directed toward the modernization of aging infrastructure. Managerial improvements should concentrate on implementing smart grid technologies and digital monitoring systems at the local level, while encouraging community-based energy models that empower municipalities and households to take part in managing and producing energy.

Through these differentiated political, economic, and managerial measures, each cluster can address its specific vulnerabilities and strengths, contributing to a more resilient, integrated, and sustainable European energy system.

Overall, the recommendations across the three clusters reflect a comprehensive approach to strengthening the EU’s energy resilience, equity, and sustainability. While the specific priorities vary by region—ranging from technological innovation and infrastructure modernization to social support and geopolitical diversification—they collectively emphasize the need for coordinated action at both national and EU levels. By aligning investment strategies, enhancing regional cooperation, and prioritizing both energy security and climate goals, the EU can accelerate its transition toward a more integrated, decentralized, and just energy system.

The limitation of this study is connected to micro-level determinants. Despite their importance, their exclusion from this study is justified for several reasons. First, the analysis relies on macro-level datasets from sources such as Eurostat and the World Bank, which provide standardized and comparable indicators for all EU countries. In contrast, company- or community-level data are fragmented and lack consistency, making cross-country comparisons challenging. Second, this study focuses on policy interventions at the national level, such as the REPowerEU initiative and cross-border infrastructure projects, where systemic, macro-level insights are more relevant than localized assessments. Third, the chosen methodological approach of Kohonen maps requires homogeneous quantitative input variables to ensure clustering accuracy.

Future research directions will focus on global energy security, building on the framework developed in this study for the EU. This will involve analyzing macro-level indicators across countries worldwide, while also exploring the dynamics of renewable and alternative energy adoption in diverse geopolitical and economic contexts.