Valorization of Maize Stover into Biogas for Heat and Power Generation: A South African Perspective

Maize (Zea mays) is one of the most cultivated crops in South Africa, serving as a staple food, stock feed, and a key element in several industrial applications. It contributes significantly to the growth of the South African agricultural economy. The cultivation of maize generates a large amount of agricultural waste, mainly in the form of maize stover (MS), which encapsulates leaves, stalks, cobs, and husks. Approximately 5.15 metric tons (Mt) yr−1 of MS are generated in South Africa. This corresponds to an energy potential of 94 PJ. There is immense potential to surpass the annual yield of MS by 126% up to about 11.66 Mt yr−1 through practices such as zero tillage and improved agricultural production systems. MS may pose a serious threat to the environment if not managed in a sustainable and eco-friendly manner. Valorization of MS into biogas presents an excellent opportunity to effectively control biomass waste while contributing to renewable energy production and mitigating dependence on depleting fossil fuels. However, MS continues to be overlooked as a sustainable bioenergy resource due to its lignocellulosic structure. This study explores the potential of converting MS into biogas for heat and power generation, addressing both energy needs and waste management in South Africa. The purpose is to provide knowledge that will inform researchers, innovators, industrialists, policy makers, investors, and other key stakeholders interested in renewable energy systems. Collaborative efforts among multiple stakeholders are vital to leverage biogas as a technology to promote socio-economic development in South Africa.