© 2021, Emerald Publishing Limited.Purpose: In spite of the drive toward environmental sustainability and the attainment of sustainable development goals (SDGs), coal, oil and natural gas energy utilization has remained the Turkey's largest energy mix. In view of this concern, this study examined the role of coal and oil energy utilization in environmental sustainability drive of Turkey from the framework of sustainable development vis-à-vis income expansion over an extended period of 1965–2017. Design/methodology/approach: In this regard, the authors employ carbon emission as an environmental and dependent variable while the Gross Domestic Product per capita (GDPC), coal and oil energy consumption are the explanatory variables employed in the study. Findings: The study found that both energy mixes (coal and oil) have a detrimental impact on the environment in both the short and long run, but oil consumption exerts a less severe impact as compared to coal energy. In addition, sustainable development via income growth is not feasible because the income–environmental degradation relationship follows a U-shaped pattern (invalidating the Environmental Kuznets curve, EKC hypothesis) especially when coal and oil remained the major source of lubrication to the economy. At least the EKC hypothesis is unattainable in Turkey as long as the country's major energy mix or primary energy (coal and oil) is in use, thus the application of other socioeconomic, macroeconomic policies might be essential. Research limitations/implications: Considering the lingering energy challenge associated with Turkey, this novel insight further presented useful policy perspectives to the government and stakeholders in the country's energy sector. Originality/value: This evidence (the U-shaped relationship) is further ascertained when the aggregate primary energy is employed. Thus, this study provides a novel insight that attaining a sustainable economic growth in Turkey remained a herculean task as long as a more aggressive energy transition approach is not encouraged.