Edeh, UELie, TTMahmud, MA2025-06-092025-06-092025-04-29Energies, ISSN: 1996-1073 (Print); 1996-1073 (Online), MDPI AG, 18(9), 2267-2267. doi: 10.3390/en180922671996-10731996-1073http://hdl.handle.net/10292/19287The integration of renewable energy sources (RESs), such as wind and solar, introduces significant uncertainties into power system operations, complicating Available Transfer Capability (ATC) assessment. A key factor in ATC determination, the Transmission Reliability Margin (TRM), accounts for uncertainties like load variations, generation fluctuations, and network dynamics. The traditional deterministic TRM methods often fail to capture the stochastic nature of modern grids, leading to inaccurate estimations. This paper reviews the TRM assessment methodologies, emphasizing probabilistic approaches that enhance accuracy in high-RES environments. It explores adaptive statistical techniques, such as rolling window analysis, for dynamic TRM computation. Key challenges, emerging trends, and potential solutions are discussed to support the development of robust ATC modeling frameworks for secure and efficient renewable energy integration.All articles published by MDPI are made immediately available worldwide under an open access license. No special permission is required to reuse all or part of the article published by MDPI, including figures and tables. For articles published under an open access Creative Common CC BY license, any part of the article may be reused without permission provided that the original article is clearly cited. For more information, please refer to https://www.mdpi.com/openaccess.40 Engineering4009 Electronics, Sensors and Digital Hardware7 Affordable and Clean Energy13 Climate Action02 Physical Sciences09 Engineering33 Built environment and design40 Engineering51 Physical sciencesrenewable energy sourcesavailable transfer capabilitytransmission reliability marginJournal ArticleOpenAccess10.3390/en18092267