South Korea's electricity sector is at a crossroads. A transition to a safer and more ecologically friendly electricity system, one that would reduce dependence on coal and nuclear power plants and produce more electricity from new and renewable energy, is being suggested and actively discussed. Changes to these two pillars of the electricity sector, which have enabled a reliable and affordable electricity supply, present environmental and economic concerns. Will this shift adversely affect the electricity sector's greenhouse gas emissions? Will this change be economically feasible? To answer these questions, this study explored the environmental and economic implications of changes in the South Korean electricity sector using the Long-range Energy Alternative Planning model. Despite using very conservative assumptions about the generation of new and renewable energy, the study found an economically feasible path that would yield less greenhouse gas emissions than the reference scenario. This path, which involved closing old coal-fired power plants, phasing out nuclear power, and reducing demand, shed light on the green shift in the electricity sector. Decreasing electricity demands should be discussed and considered along with this change. The study's implications could apply to other countries as they investigate the economic and environmental implications of various policy options for transitioning to safer and more ecologically friendly sources of electricity.