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.