A study commissioned by the South African National Energy Development Institute (SANEDI) has found that the micro-digester sector has significant opportunities to grow through strengthening partnerships within the sector and with stakeholders in allied sectors ahead of the South African Waste to Energy Roadmap in 2022.

The University of Johannesburg Process, Energy, Environmental and Technology Station (UJ Peets) requested SANEDI to raise anaerobic micro-biogas awareness; grow a mindset/culture regarding the information by conducting workshops and training to boost this largely untapped sector. 

“Biogas technologies like micro-digesters possess potential for scaling and promoting a green circular economy. It is the only fully closed circular renewable energy system that produces near-zero waste. The study shows that the technology capitalises shy of the regulatory, policy, and market financial support extended to other popular forms of renewable energy like solar PV and wind,” said Dr Karen Surridge, Renewable Energy Manager at SANEDI.

When organic waste is collected and digested in this small system to create methane gas for fuel, it also creates beneficial byproducts like a rich soil fertiliser. The technology has multiple benefits for managing waste decomposition, reducing the volume of organic waste sent to landfills, and thus reducing methane emissions at landfill sites.

The study also indicated that South Africa’s uptake of this technology is low compared with other African countries. SA’s total number of small-scale biogas digesters installed is estimated to be only 350 compared to Kenya with over 14,000, Uganda with 11,000 and Ethiopia with 10,000.

The study also predicts that the domestic potential size of the sector is initially estimated to be 21,000 units, followed by a maximum yearly demand potential of 50,400 units. Assuming a continuous market penetration rate of 1%, this equates to 5,400 units a year until 2030.

Micro-digesters for biogas production at present are reportedly concentrated in public sector programmes in rural areas where the primary source of waste is cow dung and food waste to provide clean cooking gas, but there is little uptake in urban areas where the technology is a sustainable solution for some municipal waste. These sites are small-scale and are defined by the Working Group as an anaerobic biogas digester producing less than 0.5 kW of power or less than 2 kW of biogas a day. 

The Sector Development Plan (SDP) recommends that the narrative about micro-biogas production exceed energy and cooking to encompass the benefits from other value additions available from using a micro-digester, especially waste management and fertiliser from digestate. In addition, micro-digesters are valuable to people through community-based installment (or pay-as-you-go) schemes that secure gas for generators, battery charging, lights, and clean cooking. 

The development of the SDP for micro-biogas forms part of the SANEDI Strategic Plan 2020-2025, focused on enhancing energy access with an emphasis on clean renewable energies, transforming waste to energy, and upskilling women and youth to assist in the commercialisation and embracing of renewable energy technologies.