A life cycle sustainability assessment of biomethane versus biohydrogen-For application in electricity or vehicle fuel? Case studies for African context

This study employed a life cycle sustainability assessment (LCSA) to compare the biomethane with biohydrogen produced from organic waste streams in various African settings, such as agro-industrial, urban, and rural settings. It also used biomethane and biohydrogen in cogeneration unit systems to generate electricity, and as a transportation fuel for motor vehicles. In the agro-industrial setting, applying biohydrogen in the electricity generation system records a higher sustainability performance compared to the vehicles' operation. The electricity generation system records a sustainability performance index (SPI) value of 2.20; the vehicles' operation records a value of 1.15. In urban settings, applying biohydrogen in the vehicles' operation records higher sustainability performance outcomes compared to the electricity generation system, which recorded SPI values of 1.95 and 1.80, respectively. In rural settings, applying biohydrogen in the vehicle operation records higher sustainability performance outcomes compared to the electricity generation system, which recorded SPI values of 1.55 and 0.80, respectively. Agro-industrial settings are well suited for biohydrogen production. There is no compelling case for admitting biohydrogen technology in both urban and rural settings. Biomethane technology remains an all-round preferred technology due to higher production rates, whilst yielding, compared to the biohydrogen technology. Biomethane infrastructural development could be a precursor for biohydrogen technology installation.

Automated summary

The study showed that in agro-industrial settings, biohydrogen performs better in electricity generation systems than in vehicles' operation; in urban settings, biohydrogen used in vehicles' operation also has higher sustainability performance; and in rural settings, biohydrogen used in vehicle operation shows better sustainability performance as well.