An investigation into implementing net zero carbon new buildings: a case of the eThekwini Municipality, Kwazulu-Natal, South Africa.

Abstract

Better design practices, energy efficiency, and green building materials will enable the building sector to unlock emissions savings into the future, because what is constructed today will be the future of our buildings and its associated emissions.¹ Buildings are integral to the growth of our economy and provides a scaled opportunity to influence our environment and health positively. Buildings have relatively long lifespans and contribute significantly to energy consumption and greenhouse gas (GHG) emissions. It is vital that the development of sustainable buildings is encouraged. The role of the building sector toward reducing GHG emissions is now better understood, resulting in various initiatives globally, to move toward being a net-zero carbon sector. While low-carbon buildings are gaining momentum in the realm of sustainable development, this study provides decision-makers with quantifiable information on the cost of reducing GHGs to aid in their prioritisation of climate actions. The eThekwini Municipality (Durban) in South Africa has a long history of developing early climate change interventions and is therefore selected as a case study. This study analyses high emitting sectors within the eThekwini Municipality to verify global findings that the building sector is indeed the sector to offer high abatement potential at the lowest cost, and then offers an evidence-based pathway of implementation of climate actions. Specifically, as the city has committed to a zero-carbon building sector, this study presents the associated cost implications of such a commitment through the approach of determining Marginal Abatement Cost Curves (MACC) using the Climate Action Plan mitigation potential assessment for the municipality. Technical interventions to reduce GHG emissions within the MACC employed a bottom-up approach for each sector and are based on the availability and feasibility of the interventions with some engagement being conducted with Municipal stakeholders and from industry experts. The MACC presents timeframes of 2030, 2040, 2050 across key sectors and highlights that the building sector offers significant GHG reductions at the lowest cost when compared to other high emitting sectors in the eThekwini Municipality. Further to this, this study deep-dives into the most financially feasible sub-sectors within the building sector using a tool specifically developed for this study, namely, the Net-Zero Carbon Energy Efficiency Cost Model. This model explores sub-sectors within the building sector to narrow down the selection of climate change mitigation projects within the building sector. The cost model accounts for differences in lifecycle costs for buildings with enhanced energy efficiency and buildings with standard energy efficiency requirements contained within existing building regulations. It is established that shopping centres and school blocks should be prioritised within the building sector for emissions reductions. These findings should serve as a tool to assist decision-makers in prioritising climate actions that will provide a high abatement potential at the least cost. While this study focuses on the bottom-line economics of climate mitigation interventions, it is important that a more holistic cost-benefit analysis be undertaken, to consider broader opportunity costs, risk mitigation, and savings that is associated with reducing GHGs.