The European Union (EU) countries, as one of the most economically developed regions in the world, are taking increasingly decisive actions to reduce the emission of harmful substances into the natural environment. This can be exemplified by a new climate strategy referred to as “The European Green Deal”. Its basic assumption is that the EU countries will have achieved climate neutrality by 2050. To do so, it is necessary to make an energy transition involving the widest possible use of renewable energy sources (RES) for energy production. However, activities in this area should be preceded by analyses due to the large diversity of the EU countries in terms of economic development, the number of inhabitants and their wealth as well as geographical location and area. The results of such analyses should support the implementation of adopted strategies. In order to assess the current state of the energy sector in the EU and indicate future directions of activities, research was carried out to analyze the structure and volume of energy production from RES in the EU countries. The aim of the study was to divide the EU countries into similar groups by the structure and volume of energy production from RES. This production was compared with the number of inhabitants of each EU country, its area and the value of Gross Domestic Product (GDP). This approach allows a new and broader view of the structure of energy production from RES and creates an opportunity to take into account additional factors when developing and implementing new climate strategies. The k-means algorithm was used for the analysis. The presented analyses and obtained results constitute a new approach to studying the diversified energy market in the EU. The results should be used for the development of a common energy and climate policy and economic integration of the EU countries.

Successful implementation of digital solutions in a given region or country significantly depends on the implementation of this process by Small and Medium-Sized Enterprises (SMEs). This problem is very well understood in the European Union, where actions are being taken to accelerate this process and build a sustainable and competitive knowledge-based economy. This article addresses this issue by conducting a study of the digital maturity of SMEs among the EU-27 countries. The aim of the study was to determine the level of digital maturity of SMEs in the EU-27 countries as well as whether and how the economic parameters of individual EU countries affect the process of SME digitalization. The adopted objectives determined the developed research methodology and the applied methods. The research was based on data from the Eurostat database, on the basis of which 11 indicators characterizing technologies and digital solutions identified with the Industry 4.0 concept were specified and adopted for the study. The entropy-based Evaluation based on distance from average solution (EDAS) method was used to assess the EU countries in terms of the level of digital maturity of SMEs, and the Principal Component Analysis (PCA) method was used to analyze similarities between these countries in terms of technologies implemented in SMEs. On the other hand, to determine a relationship between the digital maturity index (digitalization) and the basic economic parameters of the economy, two nonparametric tests (Spearman and Tau Kendall) were utilized. Based on the determined digital maturity index, the EU-27 countries were evaluated in terms of the level of digital maturity of SMEs, dividing them into four groups. The results showed large discrepancies between individual EU-27 countries and between the old (EU-14) and the new (EU-13) EU countries in terms of SMEs digitalization. These results should be widely used to develop a digitalization strategy for the EU economy and policies to improve the degree of digitalization, especially in countries lagging in this area. The universality of the developed methodology creates wide opportunities for its use to study other countries and regions worldwide.

The concept of sustainable development integrates activities in the economic, environmental and social areas. Energy policy, which is very closely linked to climate protection, is of key importance for achieving the goals of the concept in question. All these elements are connected by the European Green Deal strategy and Agenda 2030. Their implementation requires the evaluation of previous actions undertaken within the framework of sustainable development and the diagnosis of the current state. Therefore, this article presents the results of such research in relation to the key industry connected with this process, which is the energy sector. The research methodology was based on the analysis of 14 indicators that characterize four basic areas (dimensions) related to energy and climate sustainability. These indicators concern energy and climate as well as social and economic issues. This approach makes it possible to comprehensively assess the actions taken so far in the implementation of sustainable economic development in the energy and climate area in the European Union (EU) countries. The entropy-complex-proportional-assessment (COPRAS) methodologies, which belong to the group of multiple criteria decision-making methods, were used for this study. The conducted research allowed for the assessment of the changes in the EU countries in terms of energy and climate sustainability between 2009–2018. In addition, the effects of the introduced changes in individual years and in relation to the studied areas (dimensions) were also evaluated. Based on the results, considering the adopted criteria, the EU countries were divided into groups similar to the level of energy and climate sustainability. The results constitute a valuable set of data, which allows for a wide and in-depth multicriteria analysis. This allows for a very objective and broad assessment of the effects of sustainable development policies in the EU countries and the current state in the context of the European Green Deal strategy and Agenda 2030.

The dynamic development of information and communication technology (ICT) reported in recent years has caused significant changes in almost all areas of social and economic life. The digitalization process resulting from this development is now becoming a determinant of both progress and modernity. This issue has been addressed in this paper, and thereby we present a methodology developed to study the level of digitalization and the use of innovative technologies among the enterprises of the EU-27 countries. The research was conducted using selected indicators—determinants (10) characterizing the main digital technologies and infrastructure associated with their implementation in the enterprises under study. Based on these indicators, the Entropy-Multi-Objective Optimization on the basis of Ratio Analysis (MOORA) method was used to determine the index (level) of digitalization among the companies of the EU-27. The level of use of digital technologies and infrastructure for Industry 4.0 was also determined. Another important goal of the study was to determine a relationship between the values of the digitalization index for the EU-27 countries and the economic parameters characterizing their economies. For this analysis, non-parametric tests such as the Kendall’s Tau and Spearman’s rank correlation coefficients were applied. The results significantly enrich the knowledge of methodology for studying the level of digitalization and its status among the enterprises of the EU-27. These findings provide great opportunities for interpretation and practical application, especially in terms of building an innovative knowledge-based economy. They show great diversity of the EU-27 countries in the field of digitalization and poor results reported in this area by the so-called “new EU” countries. Among the many interesting findings, it is worth pointing out the positive impact of spending on research and development on the process of digitalization of enterprises. The results should be used when creating a digitalization strategy for individual countries and their groups.

The concept of sustainable economic development takes into account economic, social and environmental aspects and strives to achieve balance between them. One of the basic areas where it is required to revalue the current views on sustainable development is energy. The growing public awareness of environmental protection forces changes in this industry. Despite the global nature of this problem, its solution is perceived differently in various regions of the world. The unquestionable leader in introducing the idea of sustainable development economy is the European Union, where the energy sector is of key importance for the effectiveness of this process. In order to assess the sustainable energy development of the European Union countries, studies were conducted based on 13 selected indicators characterizing this sector in terms of energy, economy and environment. In order to assess the specificity of the European Union countries, these indicators were additionally compared to the gross domestic product value and the number of inhabitants of individual countries. For these cases, multi-criteria analyses were carried out using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method. It allowed the authors to rank the European Union countries in terms of their adaptation to a sustainable energy economy. Based on the determined values of indicators versus the gross domestic product and the number of inhabitants of the countries in question, these countries were also divided into similar groups with the use of the Kohonen artificial neural networks. These groups can pursue a common energy policy in the field of sustainable development. The aim of the research was to present a new approach to the assessment of sustainable energy development of the European Union countries. The extensive ratio analysis (13 indicators of the sustainable energy development), including the economic and demographic potential of individual countries, and the use of modern tools made it possible to acquire new knowledge in the field of sustainable energy development in the European Union countries. The results should be utilized for more effective sustainable energy development of the European Union countries.

The global economic development is, to a great extent, dependent on access to large amounts of cheap energy sources. The growing social awareness of ecology and the enormous damage to the Earth’s ecosystem due to the production of energy from conventional sources have forced fundamental changes in the energy sector. Renewable energy is considered to be an opportunity for such changes. The current state of the art allows such changes to be made without restricting economic development. Therefore, activities related to the energy transition are being taken all over the world. The European Union has definitely managed to achieve the most tangible effects in this regard. This article presents the findings of the research aimed at presenting the current state of renewable energy in the European Union and analyzing the changes reported in this sector in the last decade. The research was carried out using a selected set of 11 indicators characterizing renewable energy in individual countries. These indicators were selected on the basis of literature review and own studies of the state of renewable energy and its development prospects. Based on these indicators, changes in the energy structure of individual European Union countries between 2008–2018 were determined. The study is divided into two main stages. The principal components analysis (PCA) was used for the first analysis. In turn, the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was adopted to assess the level of renewable energy development in the European Union countries. Both these methods and the extended statistical analysis were applied to determine the state of renewable energy development in the European Union countries in the studied period and to divide the Member States into classes with different levels of development. The results of the study showed that the EU countries are characterized by significant differences in the development of RES during the period in question. The unquestionable leaders in this respect are Sweden, Austria, Finland, and Latvia. Based on the findings, it is possible to evaluate the effects of activities related to renewable energy development and to prepare assumptions for future activities. Additionally, both the research and its findings broaden the knowledge of the directions of renewable energy development in individual European Union countries. This is particularly important in the context of changes related to the need to reduce harmful substance emissions and the implementation of the European Green Deal idea.