This study delves into the structure of primary energy consumption in European countries, utilizing data from the Eurostat database, and focuses on the years 1990 and 2021. Through cluster analysis, countries were categorized based on their consumption patterns, revealing significant insights into energy security. The findings indicate a discernible shift away from solid fossil fuels, with renewable energy sources witnessing the most substantial growth. Natural gas, serving as a transitional fuel, has seen a rise in consumption, while nuclear energy’s development remained relatively stagnant. Oil, despite its declining share, remains a crucial component in the European energy mix. The study also highlights the challenges and implications of over-reliance on a single energy source, emphasizing the need for a diversified energy strategy. The analysis underscores the importance of diversifying primary energy sources to ensure energy security. While renewable sources are environmentally favorable, their inherent instability necessitates backup from other energy sources. Solid fossil fuels, despite their availability, face challenges due to environmental concerns. Natural gas, while flexible, requires extensive infrastructure and is highly politicized. Nuclear energy, despite its potential as an ideal complement to renewables, faces barriers in terms of investment and public perception. Oil, though convenient, is a fossil source with associated CO₂ emissions and largely needs to be imported. In conclusion, the study advocates for a well-diversified set of energy sources tailored to individual country-specific situations, emphasizing the importance of strategic planning in energy consumption to ensure long-term energy security.

Hydrocarbon production from a gas condensate reservoir has a major concern to the petroleum industry around the world. Due to pressure decline in a reservoir, liquid drops out of solution and cause a significant reduction of well productivity. As a result, huge amount of valuable oil stays underground. The proper production management for a gas condensate reservoir minimizes or eliminates the blocking problems. Optimization of condensate recovery can be achieved through appropriate selection of production and injection rates. However, determination of the optimal rates is a complex problem, involving many factors including geological uncertainty, rock petrophysical characteristics, fluid properties, economic costs, and technical ability. In this research, nature-inspired optimization algorithms are employed to evaluate the potential of production boost. Numerical testing and comparative study revealed that investigated natural-inspired algorithms outperform widely reported in the literature optimization methods and provide a higher quality solutions. The primary concern of this research is to develop an optimal gas condensate production strategy in terms of economic efficiency by utilization of nature-inspired optimization algorithm and providing their ability to generate better quality solution than engineering approach as well as gradient optimization.

Energy security, as one of the most important components of state security, is a permanent element of academic debates and political discussions. Owing to the multidimensional and multifaceted nature of energy security, defining it is a complex process, requiring the consideration of a wide range of factors straddling economics, geology, ecology and geopolitics which decide whether we are dealing with the state of energy security or the lack of it. Energy security is usually equated with the security of supply. Another group of definitions of energy security focuses on the concept of security of services. A different approach to energy security issues is presented by energy exporting countries, whose objective is to ensure sufficiently high and stable income from sales of energy resource exports (security of demand). The subject of this paper is an analysis of the energy security of hydropower-producing countries—Tajikistan and Kyrgyzstan. Energy security has been analyzed in the context of security of supply, services, and demand on the basis of the approach proposed by Llamosas and Sovacool. So far, no work has been carried out to analyse the hydropower sectors of Kyrgyzstan and Tajikistan in the context of the energy security comparison of both countries. It is worth emphasising that their energy security and mutual relations are important from the point of view of the stability of the entire Central Asian region. Kyrgyzstan and Tajikistan have large hydropower potential, which, if properly used, could cover their domestic electricity demand and the surplus can be exported to neighbouring countries. Unfortunately, both countries are not utilising this potential for the time being. The main difficulty in the area of security of supply and services is the seasonality and low reliability of electricity supplies. Among the reasons for this are the poor technical and economic conditions of energy companies as a result of maintaining low tariffs, the irrecoverability of consumers’ energy bills, electricity theft, significant transmission loses and a high level of corruption. Although both countries aspire to the role of an energy exporters, they are themselves forced to import electricity from neighboring countries.