As climate change and various environmental pollution issues are becoming more serious, many countries are actively promoting energy transition. The Paris Agreement, adopted in 2015, is aimed at curbing the rise in global average temperatures to within 2℃ above pre-industrial levels and limiting temperature rises to 1.5℃ above pre-industrial levels. Taiwan is accelerating its path of energy transition to a "nuclear-free homeland" and “low-carbon economy” by phasing out all nuclear power generation in 2025 and imposing a legally binding goal of reducing coal-fired power generation from 47 percent to 26 percent. This paper investigates the impact of nuclear and coal power regulations on fuel mix CO2 emissions in the power sector by 2050 in Taiwan. Analysis is a future technology shift in the power sector called “Future Technology Transformations; FTT” for the power sector; Consider using the E3ME model linked to FTT: Power sub-model.