The policy related to the use of renewable sources is a key element of the energy policy executed in the European Union (EU). One of the targets set for 2050 is to increase the share of electricity in energy consumption to 50%, and 80% of electricity is to be generated from low-carbon sources. In recent years, the EU economies have significantly modified their electricity production, which raises the question of the scale of these changes. The aim of the presented analysis is to assess changes in the use of renewable sources for electricity production in the EU countries in 2005–2019. Gini coefficient and k-mean are applied in the analysis. The conducted research shows that EU countries, in line with the energy policy assumptions, have both increased the share of renewable sources in energy production, especially in electricity production, as well as increased the diversity of used renewable sources. The results also indicate a vast diversity in terms of the use of such sources for the production of renewable electricity in the EU. This indicates that the energy transition is being implemented by EU countries with individual country-level approaches. Nonetheless, a variety of the EU’s both support and restrictive measures are of considerable importance for the ongoing energy transition.

Energy plays a crucial role in the modern world. The acquisition and consumption of energy is unfortunately associated not only with economic development or the facilitation of everyday life, but also with a negative impact on the environment. To prevent these, measures are being taken which are part of a broad programme referred to as sustainable energy development (SED). A special place among energy consumers is occupied by households, as access to energy is a fundamental factor affecting the quality of life. The aim of this paper is to look at and assess the current situation of the household sector in the EU energy market in the context of SED and to point out similarities and differences between EU countries. The analysis considers factors based on SED indicators: final energy consumption per capita, energy prices offered to households, and the share of renewable energy in household energy consumption. The k-means method was used as a research tool. The results obtained indicate first of all that the EU countries are highly differentiated in terms of the analysed factors. It can be said that these differences result not only from the wealth of a given country, geographical location, or natural possibilities to use renewable energy sources, but mainly from the energy policies implemented in individual countries.

Private households are an important group of energy consumers. Based on Eurostat data, their energy consumption constituted 30% of the final consumption of energy use across the European Union in 2021. The cost of energy is one of the main components of household budgets; thus, the prices provided by energy carriers have a significant impact on energy consumption. The price offered to the final consumer consists of three components: the price of energy and its supply, network costs, and taxes and levies. The values of the three components, however, depend on several factors, among which the structure of the energy markets and energy policies in individual EU countries play a key role. This work aimed to analyze and assess the structure of electricity prices offered to households across EU countries in the years 2019–2021. The differences and similarities between the pricing policies of selected products in the EU and their impacts on households’ purchasing capacity were captured and a non-pattern classification method (k-means) was applied as a research tool. The results indicated that the heterogeneity of the electricity price structure increased significantly over the period analyzed. This may be a consequence of the use of strongly differentiated tools to mitigate electricity price increases and the steps being taken towards low-carbon economies.

Purpose: The study checks relations between different developed and Visegrad stock markets and mainly concentrates on the analysis of the American market influence (reflected by S&P500) on other stock markets. It examines the influence of crisis situations such as Covid-19 pandemic and Russia-Ukraine war on the strength of the linkage between markets. Methodology/approach: The study of changes in the dependence of stock market indices over 2018 – 2023 is conducted using rolling windows for the Pearson correlation coefficient. The similarity strength of indices is indicated using the DTW measure. The influence of the S&P500 index on other stock indices is examined by the Granger causality. Findings: We show that both the Covid-19 pandemic and the war increased the linkage between stock markets, although for the latter this rule refers only to markets that are geographically close to the conflict zone. The research also shows that the American stock exchanges are the most strongly interconnected. Another important notice is that crises decrease the similarity of shapes between stock exchanges represented by market indices. Moreover, greater similarity between stock exchanges leads to lower volatility in correlations over time. Originality/value: The paper adds value in three aspects. The first one is that it examines changes in relations between indices, both in their correlations and their similarities strength during Covid-19 pandemic and Russia-Ukraine war – recent crisis situations. Contrary to the previous literature which is rather concentrated on the Covid-19 pandemic and its influence on stock markets, we show that such events that are not global also influence relations between stock markets close to the conflict zone. The second one is combining in one paper connections between both different indices from developed countries and Visegrad countries. The third one is using DTW method rarely used for financial time series analysis to examine shapes similarity between S&P500 index and so many stock markets, both from developed and Visegrad countries in one paper.

Capital markets react almost immediately to crises. Such relationships can be both international and local. The research focuses on the stock markets of two countries: Spain and Poland. These countries are often compared in terms of various economic and social criteria. The research covers the period from March 3, 2019, to March 31, 2021. The aim is to identify sectors and indices similar to each other at the local level and to identify, among pairs of similar indices, those that provide a boost to another sector. The research uses the hierarchical cluster analysis method (Ward’s method) and the Granger causality test. This work presents a novel approach to sectoral comparison at the local level.