This report is written and prepared by all the members of the Urban Synergy Thinkers, in fulfilment of the "(Re)Think the Energy Transition Planning of a Metropolis" module challenge hosted by The Institut National des Sciences Appliquées de Rouen Normandie (INSA Rouen Normandie). The hybrid course took place from January to April 2024. A one-week in-person session was held at the INSA Rouen Normandie Campus from the 4th to the 8th of March 2024. This challenge is made possible by The European Consortium of Innovative Universities (ECIU University). In this paper, the Urban Synergy Thinkers team presents a proposed solution that can potentially help accelerate the achievement of the environmental objectives set for the coming years: utilizing the Delphi Technique in energy transition planning. This methodological tool centralizes communication and consultation among all stakeholders involved in the planning process, ensuring the effective coordination of various needs per player to produce more sustainable, inclusive, and feasible planning and implementation. This proposed solution has been a product of lessons gathered in this challenge, both from the various experts' perspectives and physical observations during the study visit to the Metropolis of Rouen in Normandie, France, and the discussion on environmental policy planning in the team members' respective home countries.