Decarbonizing the high-rise office building: A life cycle carbon assessment to green building rating systems in a tropical country

Abstract

The construction sector contributes a considerable share of global carbon emissions, with high-rise buildings having high emission density. Green Building Rating System (GBRS) certifications aim to reduce building emissions and improve occupant comfort. Most studies focus on low-to-mid-rise buildings, neglecting GBRS’ impact on commercial high-rises. Studies on the feasibility of adapting international GBRS to local high-rise buildings from a life cycle perspective are also scarce in tropical countries. Hence, taking Malaysia as a case study, this research quantifies the embodied and operational carbon reduction of GreenRE (local) and LEED (international) certifications on a high-rise office building using Life Cycle Assessment, where various certification tiers and scenarios are analyzed. LEED Platinum comprises 25.1% embodied (EC) and 74.9% operational carbon (OC) emissions, whereas GreenRE Platinum is 13.4% and 86.6%, respectively. Combining EC and OC emissions, LEED scenarios achieve reductions up to 61.1% with high OC reduction targets, while GreenRE offers up to 28.7% reduction with more stringent EC requirements. The LEED Max scenario, obtaining all available credits, achieves the highest carbon reduction of 65.1%. Unlike GreenRE, which specifies reductions from individual building components, LEED lacks specific requirements for components like lighting or cooling, potentially resulting in uneven emission reduction. Unconventional designs incorporating building-integrated photovoltaics, radiant cooling slabs, and other green features reduce carbon emissions by 62.7%. Recommendations to improve GBRS criteria towards achieving low-carbon buildings include relaxing the energy-related credit limit for GreenRE to reduce emissions by an additional 12.5% and incentivizing stakeholders to reduce EC in both LEED and GreenRE.