The transition to low-carbon energy systems is a central objective of the European Union and a key requirement for sustainable economic and environmental development. Portugal has historically shown a high dependence on imported fossil fuels, which has affected energy security, carbon emissions, and economic stability. European climate policy has promoted renewable energy expansion, electrification, and efficiency improvements, but significant structural differences remain among member states in the effectiveness of decarbonization strategies.
This study applies a quantitative panel data approach to analyse the evolution of the Portuguese energy system in comparison with selected European Union countries over the period 1990–2025. The empirical framework is based on official energy and environmental indicators, including greenhouse gas emissions, carbon intensity, energy intensity of GDP, renewable energy shares, and external energy dependence. Data were obtained from national emission inventories, European statistical databases, and energy policy reports. Time-series analysis, cross-country benchmarking, and fixed-effects panel estimation were used to evaluate the relationship between renewable energy expansion, efficiency improvements, and emission reduction, while controlling for structural shocks related to economic crises and energy market volatility.
The results indicate that increases in renewable energy shares and improvements in energy efficiency are associated with significant reductions in carbon intensity. Portugal shows substantial progress in emission reduction and renewable electricity generation, but still presents higher external energy dependence compared with more efficient European economies. Countries with stronger policy integration and technological development demonstrate better environmental performance and greater resilience to energy shocks.
The findings confirm that the effectiveness of decarbonization policies depends on the combined effect of renewable energy expansion, efficiency improvements, and technological modernization. Strengthening these factors is essential for achieving long-term sustainability goals and for building resilient economic and urban systems in the European Union.
