In order to manage an energy system responsibly and maintain its benefits indefinitely, science-based decision-making should be valued during energy policy making and energy management. This research presents a framework for developing a scientific tool with the long-range energy alternatives planning (LEAP) system for evaluating energy consumption and greenhouse gas (GHG) emission mitigation pathways for a national energy system. The framework developed is applied to create a bottom-up (technology-explicit), data-intensive (over 2 million data points), multi-regional (13 integrated regions) energy model of Canada, one of the world's most energy and emission intensive nations. Model accuracy was validated with historical data showing emissions varied 0-1.2% proving the framework can provide accurate assessments. The model was used to generate baseline Canadian energy-emissions outlooks to 2050 that do not currently exist in literature. The developed framework provides robust capabilities that are helpful for energy efficiency analysis, energy planning, and GHG mitigation assessment. M. Davis et al.