Bioenergy – the renewable energy derived from plant and animal waste products – is largely ignored in South Africa. Solar energy, wind power, and green hydrogen attract the most investment in renewable energy.
Sugarcane trash (the discarded leaves and tops of the plant) is a good example of plant waste that could be turned into energy. But it’s overlooked.
South Africa is a major sugarcane producer, producing about 2.2 million tonnes of refined sugar per season. This generates an estimated average direct income of over R20 billion (more than US$1 billion) per year.
The country has about 20,200 registered small-scale sugarcane growers producing about 2.09 million tonnes of cane every year. This is about 11% of the total sugarcane production in the country.
But many small-scale sugarcane farmers are not prosperous. The problems they face include drought and poor harvests, small farm sizes, the high costs of inputs such as fertiliser and chemicals and little access to finance.
Sugarcane trash makes up 13% to 30% of sugarcane. More than 90% of the sugarcane trash in the country, or an estimated 2.7 million tonnes per year, is burnt. This has huge environmental implications with greenhouse gas emissions being released into the atmosphere.
If this was turned into bioenergy instead, assuming a 50% recovery efficiency, about 180.1MW of electricity could be produced in each 200-day production season. This is enough electricity to power more than 100,000 homes in South Africa (1MW of electricity can power about 650 homes).
Bioenergy from sugarcane trash presents the potential for smallholder farmers to improve their profitability. At the same time, they’d be contributing to alternative energy generation and reducing the greenhouse gas emissions that come from burning sugarcane trash in the fields.
We are agricultural economists who research bioenergy and climate change. Research on using sugarcane trash for energy generation in South Africa has been limited, and most existing studies are more than 10 years old. Changes in knowledge and technology for harvesting and producing energy from sugarcane trash since then highlight the need for updated research to address current opportunities and challenges.
We looked into the environmental damage caused by burning sugarcane trash, and explored whether small-scale sugarcane farmers could turn this plant waste into bioenergy instead.
Our research found that sugarcane trash could be used to produce bioenergy. Rural green energy production would not only reduce energy insecurity in South Africa, but also play a huge part in improving the environment.
Sugarcane trash is damaging the environment
We studied 330 small-scale sugarcane farmers in rural parts of South Africa’s sugarcane-producing provinces – KwaZulu-Natal and Mpumalanga. We found that almost half the farmers regularly burnt sugarcane leaves and tops. Only 44% left the sugarcane trash on the ground, or turned it into compost to nourish the soil.
We also found that small-scale sugarcane growers generally don’t know enough about how sugarcane trash can be used to create bioenergy. Most of the farmers we surveyed said they didn’t collect sugarcane trash because there was no market for it. Only 20.7% knew that sugarcane tops and leaves could be harvested and sold.
The burning of sugarcane leaves and tops emits approximately 0.08 tCO2-e (tonnes of CO₂ equivalents) per hectare. This is the equivalent of 9.16kg of burned coal or of driving 74.4km in an average petrol car. This practice significantly contributes to global warming.
In total, the estimated greenhouse gas emissions from sugarcane burning of all small-scale growers in the two provinces are 725 tCO2-e per annum. This is the same as burning 368 tonnes of coal or consuming 244,568 litres of diesel.
A green market for bioenergy could solve the problem
Several things need to happen to stop the greenhouse gas emissions caused by burning sugar cane trash:
Incentives: Small-scale farmers will need financial support to stop burning sugarcane trash. Hiring baling machines (green harvesting) to bundle up the sugarcane tops and leaves is expensive. The South African government should give small-scale farmers incentives for green harvesting. This would include subsidies for buying mechanical harvesting equipment. Currently, there are few incentives for farmers to stop burning sugar cane trash.
New policies: Pollution-deterring policies to stop the practice of burning of sugarcane should be introduced. Policies around energy production and technology transfer for small-scale production of bioenergy are also needed. A grid feed-in tariff should be set up to allow small independent power producers to sell their surplus electricity to the state-owned electricity provider, Eskom.
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Creating bioenergy awareness: Different government departments and Eskom must work as a collective and communicate with small-scale farmers and communities about the potential of bioenergy. They need to set up a process where the farmers can say how they want bioenergy developments to happen and what their priorities are.
Developing the science on the ground: The University of South Africa’s Rural Bioenergy Programme and the Agricultural Sector Education and Training Authority are working on a plan to promote the participation of small-scale sugarcane farmers in the bioenergy energy sector in South Africa. More support is needed.
Support for a rural bioenergy industry: The South African government must mobilise support to set up a rural industry. This includes helping develop sugarcane value chain alternatives to using the plant for sugar only, and bringing small-scale farmers into this new bioenergy value chain.
Involve small-scale farmers in the green transition
If the government does not include small-scale farmers in the transition to renewable energy, it will not be a just transition. Instead, it will be a missed opportunity for transformation at the grassroots level. This is because energy will become more expensive for impoverished rural people in the future. Inequality will deepen.
The future will always demand energy for development. With global shifts towards green energy consumption, green markets (people who will buy bioenergy and other forms of renewable energy) are guaranteed. And if small-scale farmers who are mainly situated in rural areas are brought into the renewable energy value chain, their livelihoods will improve. This will reduce poverty and inequality in South Africa’s rural areas.
- is an Associate Professor of Agricultural Economics, University of South Africa
- is a Postdoctoral Fellow, University of South Africa
- This article first appeared in The Conversation
