Embodied energy and carbon analysis of urban residential buildings in Malawi

Abstract

The rising demand for bricks baked in wood-fuelled kilns in Malawi is raising concerns due to its contribution to fluctuations of climatic conditions locally and globally. This paper presents findings of a study to evaluate the global warming potential of urban houses built of three different building materials. The International Organization for Standardization life-cycle environmental impact assessment approach was used. To obtain lifecycle inventory, process inventory analysis was used, focusing on energy inputs and carbon outputs at the initial construction stage. A functional unit of a 1m2 wall was used for calculating energy and carbon emissions. The results demonstrate that, for individual blocks, kiln burnt bricks (KBBs) consume 0.531 GJ/m2 compared to 0.138 GJ/m2 and 0.106 GJ/m2 for stabilized soil-cement blocks (SSBs) and solid cement blocks (SCBs) respectively. Similarly, KBBs have a higher global warming potential than the SCBs and SSBs. When cement or lime joint and plaster mortars are included, the KBBs contain the highest values for the energy consumed and CO2 emitted. The results suggest the need to switch from KBBs to other energy and carbon efficient materials, as well as a call to sound sectoral policy to tackle the effects of climate change in Malawi and beyond.