Upcycling sugar cane trash: the role of small-scale farmers

Involving small-scale farmers in the conversion of sugar cane trash to bioenergy has many benefits, write Prof Aluwani Maiwashe-Tagwi and postdoctoral fellow Unity Chipfupa, from the University of South Africa.

- Aluwani Maiwashe-Tagwi and Unity Chipfupa

"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 most of the investment in renewable energy.

Sugar cane trash – the discarded leaves and tops of the plant – is a good example of plant waste that could be turned into energy. But it is overlooked.

South Africa is a major sugar cane producer, producing about 2,2 million tons of refined sugar per season. This generates an estimated average direct income of over R20 billion per year.

The country has about 20 200 registered small-scale sugar cane growers producing about 2,09 million tons of cane every year. This is about 11% of the total sugar cane production in the country. But many small-scale sugar cane 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.

Sugar cane trash makes up 13% to 30% of sugar cane. More than 90% of the sugar cane trash in the country, or an estimated 2,7 million tons per year, is burnt.

This has huge environmental implications with greenhouse gas (GHG) 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 sugar cane 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 GHG emissions that come from burning sugar cane trash in the fields.