Mitigating climate change by minimising the carbon footprint and embodied energy of construction materials: A comparative analysis of three South African Bus Rapid Transit (BRT) stations

Abstract

This article investigates the role that architecture can play in mitigating climate change by comparing the environmental impact of construction material use in two existing South African Bus Rapid Transit (BRT) stations in Johannesburg and Cape Town and a proposed BRT station for Tshwane. The article will generate guidelines to improve the resource efficiency of future BRT trunk-route stations. The climate change mitigation potential of BRT stations has been determined by analysing their carbon footprint and embodied energy over the cradle to gate1 period. The quantity of construction material used in each station was calculated, while the carbon footprint intensity and embodied energy intensity were determined by means of the Inventory of Carbon & Energy (ICE) carbon and embodied energy calculator. Calculations of embodied energy of structural systems and material use reveal that the Cape Town station is 36.5% more efficient in terms of carbon footprint intensity and embodied energy intensity than the Johannesburg station and 23.2% more efficient than the Tshwane station. The station base is the most energy-intensive component, contributing an average of 38% to the total embodied energy. It was concluded that steel contributes more than 50% to the total carbon footprint and embodied energy of each station. The analysis determines that lower scaled, spatially economical structures using low embodied energy materials will positively contribute to reduced carbon footprints and thus climate change mitigation strategies. The outcomes of the article also set a benchmark for prospective life-cycle assessments (LCA) and establish design guidelines for the design of future BRT stations.