According to the Paris Agreement at the 21st Conference of the Parties, 196 member states are obliged to submit their Intended Nationally Determined Contributions (INDC) for every 5 years. As a member, South Korea has already proposed the reduction target and need to submit the achievement as a result of the policies and endeavors in the near future. In this paper, a Korean bottom-up energy system model to support the low-carbon national energy R&D roadmap will be introduced and through the modeling of various scenarios, the mid-to long-term impact on energy consumptions and CO2 emissions will be analyzed as well. The results of the analysis showed that, assuming R&D investments for the 11 types of technologies, savings of 13.7% with regards to final energy consumptions compared to the baseline scenario would be feasible by 2050. Furthermore, in the field of power generation, the generation proportion of new and renewable energy is expected to increase from 3.0% as of 2011 to 19.4% by 2050. This research also suggested that the analysis on the Energy Technology R&D Roadmap based on the model can be used not only for overall impact analysis and R&D portfolio establishment, but also for the development of detailed R&D strategies.