Abstract
To reach net zero climate goals, existing fossil fuel-based energy consumption - such as heating and transportation - is proposed to be transferred to a clean power system. These plans for massive system expansion prompt us to reconsider traditional technical, economic, and regulatory frameworks and assumptions to ensure they still work in the context of deep electrification. This study examines the interaction between transmission and distribution systems during the accelerated expansion required for decarbonization. Transmission and distribution options, together with their connected sources, are modeled both together and separately to recognize optimal outcomes at a societal level. Essential future multidisciplinary research topics involving accelerated transmission and distribution expansions are identified. To ensure a responsible transition to net-zero, additional research is needed in: coordination between transmission and distribution expansions, a greatly expanded role of distribution, supply feasibility, demand elasticity and social implications, planning philosophy and methods, and future uncertainty.