Life cycle assessment of solar home system informal waste management practices in Malawi

This study performs the first life cycle assessment of solar home systems (SHSs) to use data quantifying lead pollution from informal lead-acid battery recycling. The typical life cycle of SHSs in off-grid communities surrounding Malawi’s capital of Lilongwe is assessed, considering affordable components imported from China,
lead-acid battery lifetimes of one year, the collection of materials through the informal scrap market, the open dumping and burning of waste, and informal lead-acid battery recycling (remanufacturing). Lead-acid batteries are highlighted as the most damaging SHS component, occupying 54–99% of each impact category, caused by the burdens of lead mining and the high assembly energy of batteries, amplified by short battery lifetimes – subject to detrimental user practices. The amount of electricity delivered to users is significantly restricted by the low efficiency of affordable SHS components. Meanwhile, the informal remanufacturing of a single lead-acid battery is recorded to release over 100 times the lethal oral dose of lead for an adult into densely populated communities, resulting in a terrestrial ecotoxicity potential of 200–386 kg 1,4-DCB eq. per kWh delivered. Proposed formal recycling solutions are found to successfully mitigate the toxicity of informal waste management but incur significant burdens: substituting toxic but resource-efficient informal remanufacture with safe but energy-intensive formal battery production. Furthermore, the short one-year lifetimes of lead-acid batteries can cause the environmental impacts of SHS to exceed the impacts of diesel generators in most impact categories, resulting in a global warming potential of up to 1.4 kg CO2/kWh. Hence, both extended battery lifetimes of three years and formal recycling are found to be necessary for SHSs to be considered as a safe and low-carbon technology – requiring holistic interventions.