A more circular system than you think
Sugar production is water-intensive, but it is also surprisingly good at reusing what would otherwise be waste. Bagasse becomes electricity, molasses becomes fuel, and filter cake goes back to the field as fertiliser.
Water usage
Sugarcane is a water-intensive crop, requiring approximately 1,500 millimetres of water per year (rainfall plus irrigation). Zimbabwe's Lowveld operations rely heavily on irrigation infrastructure, particularly the Tokwe-Mukorsi Dam and a network of supporting canals.
Efficient drip and sprinkler irrigation systems help manage water use. Water is also consumed in the milling process for juice extraction (imbibition) and for steam generation, though much of this is recycled within the mill.
Energy and cogeneration
Sugar mills burn bagasse, the fibrous residue from crushed cane, to generate steam and electricity. This makes them largely energy self-sufficient during the crushing season. Zimbabwe's mills generate up to 30 megawatts from bagasse cogeneration.
An electricity swap agreement with the Zimbabwe Power Company allows mills to supply surplus power to the national grid during peak production and draw electricity during off-peak periods. This biomass energy is considered carbon-neutral because the carbon dioxide released during burning was absorbed by the same sugarcane during its growth.
Carbon footprint
- Sugarcane is an efficient carbon fixer through photosynthesis, sequestering large volumes of CO2 during its growth cycle.
- The production cycle has natural carbon offsets through bagasse energy and filter cake recycling.
- Transportation of cane from field to mill, which must happen within 24 to 48 hours, is the most carbon-intensive step.
- Compared to sugar beet production in temperate climates, tropical cane sugar generally has a lower carbon footprint per tonne thanks to higher yields and bagasse cogeneration.
The circular economy of a sugar mill
- Bagasse: burned for energy. Not wasted.
- Molasses: used for animal feed and ethanol production.
- Filter cake (mudcake): returned to fields as organic fertiliser.
- Boiler ash: can be used as a soil amendment.
Very little of the sugarcane plant is truly wasted in a modern mill. Read the full breakdown on by-products and sustainability.
Biodiversity and land use
- Sugar estates in the Lowveld coexist with game reserves and wildlife areas. Hippo Valley Estates maintains extensive game reserves alongside its plantations.
- The balance between agricultural expansion and conservation is an ongoing consideration, particularly as the AFSRTS-2 strategy targets higher cane output.
- Outgrower schemes help distribute land use across many smallholder farmers rather than concentrating it in single estates.
Ethanol as a renewable fuel
- Triangle's distillery produces up to 30 million litres of ethanol annually from molasses.
- Ethanol can be blended with petrol as a renewable fuel component, displacing imported fossil fuels.
- The Zimbabwe government has explored ethanol blending mandates as part of broader energy and currency strategy.
Connect the threads
Read the full by-products breakdown on by-products and sustainability, the conditions that make Lowveld cane so productive on sugarcane growing, or the headline figures behind the industry on production statistics.