On November 24, 2018, Taiwan held referendums on ten topics. All three referendums related to energy issues passed. The results of these referendums reflect the discontent among citizens stemming from a nation-wide electricity blackout on August 15, 2017, deteriorating air pollution in recent years and other concerns regarding the government’s energy transformation policy, such as electricity price surge, energy insecurity and grid risks. Considering the operating characteristics of the various power plants, this chapter proposes an optimal electricity mix by 2025 from an economic and environmental perspective by applying cost minimisation principle. The electricity mix proposed is 32.5% from coal-fired power generation, 40% from gas-fired power generation, 10% from renewable energy power generation and 17.5% from nuclear power generation by 2025. Such an electricity mix could significantly lessen the impact of the five major problems caused by the government’s energy transformation policy. And most importantly, the optimal electricity mix could comply with the three referendums. Consequently, it might serve as an alternative strategy for the government to reformulate its energy policy.