Europe's energy security is a very relevant and debatable topic today, especially since the Russia Ukraine conflict energy security is becoming a challenge for Europe. Many countries in the European Union do not have sufficient fossil energy resources and are dependent on neighboring, energy-rich countries. Such dependence on other countries in the EU is useless and even dangerous, both economically and politically or in terms of energy security. The EU faces serious energy security challenges due to its high dependence on external energy exporters. Countries that export energy resources can manipulate them and exert both economic and political pressure. The main problem is how to assess the energy transformation opportunities while strengthening energy security. Currently, there is a lack of research that would propose solutions to increase energy security on a national scale. Renewable energy solutions would allow achieving these goals, thus creating synergy with economic benefits. During the study, energy business representatives were interviewed in order to understand market trends and attitudes. When processing the data using the factor analysis method, results were obtained that reveal a clear connection between renewable energy and energy security. Research shows that geopolitical security becomes an important aspect when the volume of renewable energy deployment increases.

Clay paving blocks made of natural, environmentally friendly materials have their own originality and colorful authenticity, but due to the complex technological production process, they are also relatively expensive products; therefore, their environmental resistance properties are strictly defined and controlled by the standards. The physical and mechanical properties of clay paving blocks are the key factors aiming to ensure the longevity of products and their long-term success in the market. Therefore, ensuring high physical and mechanical properties of clay paving blocks have become a most crucial challenge for the manufactures. This article considers the parameters of the technological production process of clay paving blocks manufacturing and evaluates the influence of the chemical composition of three different types of clay on the physical and mechanical properties of the paving blocks. Water absorption, linear shrinkage, freeze/thaw, acid resistance, and transverse breaking load of clay paving blocks are investigated. This study reveals the importance of raw material selection in the production process of clay paving blocks and provides the concept of main quality factors of clay.

The shadow economy is a significant factor in impoverishing the economies of countries and unequal operating and competitive conditions distort the market economy system, as opaque parallel activities impoverish socially responsible business units. The biomass energy sector faces this risk because the biomass supply chain is not yet fully secure and balanced. The study conducted by the authors showed that the manifestations of the shadow economy in the biomass energy sector are possible in the biomass production and transportation sub‐sectors. Lack of digitization and poor resource management can lead to the problem of misuse of resources, which has non‐transparent economic activities. The evaluation methodology developed by the authors allows to investigate the directions of shadow economy in the biomass energy sector and to measure the possible extent of such activities. The measurements were made in order to compare the official activities of enterprises with the factors attributable to the shadow economy. This is also due to the lack of innovation and digital solutions. The application of innovative solutions would help to reduce the size of the shadow economy, which would increase the income of regions and the state, and reduce the level of poverty.