Development of a CO₂ emission benchmark for achieving the national CO₂ emission reduction target by 2030

To achieve the national CO₂ emission reduction target (CERT) in the building sector established together with the launching of POST-2020, various countries are introducing the emission trading scheme (ETS), which is considered to have a considerable effect on CO₂ emission reduction. Towards this end, it is important to establish a reasonable CO₂ emission benchmark for the effective allocation of CO₂ emission allowances. As the previous CO₂ emission benchmark, however, was focused on the industry sector (e.g., power generation sector, manufacturing sector, etc.), it is difficult to apply to the building sector. To solve this problem, this study aimed to develop a CO₂ emission benchmark for allocating CO₂ emission allowances in multi-family housing complexes (MFHCs). This study was conducted in three steps: (i) establishment of the database; (ii) formation of clusters using a decision tree (DT); and (iii) development of the CO₂ emission benchmark for MFHCs. The nine CO₂ emission benchmarks (i.e., 0.03116-0.06667 tCO₂/m² year) for MFHCs were developed using a DT based on the heating type and the elapsed years, and were validated using the Kruskal-Wallis test and t-test. It was shown that using the developed CO₂ emission benchmark for MFHCs to calculate the national CO₂ emission reduction in MFHCs satisfied the national CERT (18.1%). On the other hand, when the CO₂ emission benchmarks for MFHCs calculated based on the South Korean ETS and the EU ETS, which were applied to the industry sector, were used, the national CO₂ emission reduction was −5.29 and 45.55%, respectively. The proposed CO₂ emission benchmark for MFHCs may be useful for policymaking for determining the allocation of CO₂ emission allowances for achieving the national CERT.