This study examines how transport diplomacy can serve as a mechanism for energy policy convergence between Türkiye and the European Union. Specifically, it investigates the following research question: To what extent and under which conditions can transport infrastructure projects function as instruments of transport diplomacy to promote regulatory alignment, enhance energy security, and facilitate decarbonized energy cooperation between Türkiye and the EU? The study employs a qualitative comparative case-study design grounded in George and Bennett’s (2005) structured-focused comparison. Two cases were selected using a "most-similar systems" approach, emphasizing shared features such as direct physical linkages to EU markets, the need for multilateral coordination, and post-2021 operational relevance: the Trans-Anatolian Natural Gas Pipeline (TANAP) within the Southern Gas Corridor (SGC) and the Baku–Tbilisi–Kars (BTK) railway as the land backbone of the Middle Corridor (TITR). Drawing on process-tracing and thematic content analysis, the research analyzes primary sources including intergovernmental agreements, EU–Türkiye High-Level Dialogue communiqués (2022–2025), European Commission regulations on PCI/PMI lists and TEN-E/TEN-T guidelines, and official project reports, supplemented by secondary sources from the IEA, World Bank, OECD, and EBRD (2022–2025). The findings reveal that transport diplomacy has enabled partial regulatory convergence and improved supply diversification, but its impact is limited by geopolitical tensions and incomplete market liberalization. This contributes to the literature by refining transport diplomacy as a tool for selective policy integration in non-accession contexts, offering empirical insights into Türkiye-EU energy relations and actionable strategies for sustainable cooperation amid decarbonization challenges.
Çağlar Özer (2026) studied this question.