A Review of Evolving Challenges in Transmission Expansion Planning Problems

Transmission Expansion Planning (TEP) is a well-established field in power systems, focused on identifying the best timing and location for new transmission lines and related infrastructure. Its main goals are to meet growing electricity demand, ensure system reliability, and maintain economic efficiency. However, recent changes in the energy sector-such as the rapid growth of renewable energy, the push for decarbonisation, and the rise of electric vehicles-have introduced new challenges and uncertainties for TEP. This paper reviews more than 150 research articles to explore how these trends are reshaping TEP. We identify key insights, emerging challenges, and research gaps, emphasizing the need for improved tools and approaches to address the complexities of modern power systems. Finally, we discuss the need for research in TEP to incorporate uncertainties like energy storage systems (ESS), electric vehicle adoption, and high renewable energy integration, using advanced algorithms and real-world data to enhance accuracy and relevance.