A study, commissioned by the South African National Energy Development Institute (SANEDI), has uncovered the untapped potential for a micro-digester sector to aid in climate mitigation and the green circular economy, and showed that the sector has significant opportunity to grow if it can strengthen partnerships within the sector and with stakeholders in allied sectors.

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

The study estimates the potential size of the domestic sector at an initial 21 000 micro-digester 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.

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, SANEDI says.

Micro-digesters for biogas production, at present, are 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. These sites are small-scale anaerobic biogas digesters producing less than 0.5 kW of power or less than 2 kW of biogas a day.

However, there is little uptake in urban areas where the technology is a sustainable solution for some municipal waste.

“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 which produces near-zero waste.

“Further, the study shows that the technology does not have the regulatory, policy and market financial support extended to other popular forms of renewable energy, like solar photovoltaic and wind,” says SANEDI renewable energy manager Dr Karen Surridge.

The University of Johannesburg (UJ) Trilateral Research Chair in Transformative Innovation, Fourth Industrial Revolution and Sustainable Development conducted a feasibility study and action dialogue to develop the sector development plan.

UJ Process, Energy, Environmental and Technology Station researchers have recommended that the right policies and possible subsidies be urgently introduced to support uptake of biogas technologies.

The sector development plan recommends, firstly, that the narrative about micro-biogas production be moved beyond energy and cooking to encompass the benefits from other value additions available from using a micro-digester, especially waste management and fertiliser from digestate.

Additionally, micro-digesters can bring value to people through community-based installment, or pay-as-you-go, schemes that secures gas for generators, battery charging, lights and clean cooking.

Field researchers worked at existing micro-digester sites in South Africa, and noted challenges like access to cow dung for people in rural areas, lack of maintenance and available technical skills, as well as access to water.

Further, at Emmanuel Primary School System, in Gauteng, researchers re-introduced the school kitchen to the technology and infrastructure through the development of a multi-disciplinary manual on the creation of a green circular economy, which is a beneficial tool for academics, local government bodies, community members, industry, tradesmen and those interested in micro-digester technology.

One of the pathways set out in the sector development plan focuses on building up economic opportunities for youth and women’s groups and more formal capacitation of new and established small, medium-sized and microenterprises.

The plan's pathways will, however, need enhanced financial incentive schemes to drive demand while innovation competitions are among the ways to start stimulating private sector interest and public-private partnerships, the researchers said.

Further, more market segment analysis is also necessary to understand the potential opportunities, especially in urban environments, and possible models for community-sized systems.

"The development of the sector development plan for micro-biogas forms part of the SANEDI Strategic Plan 2020-2025, which is 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.

"Further, the 2019 Integrated Resource Plan also recognises biomass and biogas as energy sources with huge potential to provide electricity and heat for the country, including from small-scale systems," Surridge says.

The sector development plan aims to support the sector for the next five years based on a broader set of market pathways, which are a series of final stakeholder engagements that are being undertaken.