The power generation sector is one of the largest sources of greenhouse gas emissions in South Korea. Reducing greenhouse gas emissions in this sector is therefore of crucial importance. The government has recently released its core energy policy objectives: elimination of coal-fired power generation, phase-out of nuclear plants, and promotion of renewable energy sources. This energy policy should be consistent with the national climate change response policy. This paper analyzed the optimum power generation structure based on the South Korean government's energy policy and climate change policy and then analyzed the optimum power generation structure if the greenhouse gas reduction and renewable energy targets were different. Seven scenarios with different 2030 greenhouse gas reduction and renewable energy generation targets were investigated. The scenario analysis shows that it is difficult to reduce dependence on coal power generation if the South Korean government's current energy and climate change policies are maintained. The current greenhouse gas reduction target level is insufficient to be a driving force for energy transition, but dependence on coal power generation can be reduced by applying a deeper level of greenhouse gas reduction (e.g. 50% reduction compared to BAU). To achieve the energy transition planned by the South Korean government, it would be necessary to set a target for greenhouse gas reduction that is deeper than the current plan. The results of this study analyzing the optimal power configuration for 2030 in light of South Korea's energy and climate change policies are expected to contribute to the South Korean government's establishment of policies in the future.