Biofuels such as ethanol and biodiesel have been touted as the future of energy. Cleaner, home-grown and potentially cheaper than petroleum, countries such as Brazil and Britain have already made biofuels a major part of their energy consumption with many others expected to follow.
For South Africa to integrate bio-fuels into its economy, the country will have to dramatically expand the production of the crops from which they are derived. The government is expected to roll out a plan for integrating ethanol into the economy by the end of the year, which will determine which feedstocks get used and in what quantities.
Several factors determine what makes a good biofuel feedstock, including the crop’s content of starch (for ethanol production) or vegetable oil (for biodiesel), its potential for agricultural expansion, its suitability to the South African climate and its cost.
Maize: Maize and grain sorghum may have the best potential as ethanol feedstocks, according to some experts. Both have a high content of starch. Maize is also among the most efficient potential feedstocks in terms of crop yield. But production has been slashed to 1920s levels in the past few decades, said Fanie Brink, manager of industry services for Grain SA. Production, expected to reach about six million tonnes this year according to the Department of Agriculture, would have to be expanded considerably.
Grain sorghum: Grain sorghum has a starch content of about 75%, which is very high. The crop is suited to the climates of the Free State and Mpumalanga, where hundreds of thousands of tonnes are already produced for food. There is a great deal of room for expansion of the crop’s production in North West province, Brink said.
Wheat: About 1,9-million tonnes of wheat are expected to be harvested this year, according to the agriculture department. But the starch content is too low and the cost too high to make it economical for agriculture production, Brink said. ‘Wheat is for bread, and I think farmers are going to find the prices a bit too high on wheat.”
Triticale: This wheat-rye hybrid is still in its experi-mental phases. Potentially more drought-resistant than wheat, its starch content is uncertain when produced on a larger scale. It is produced in small quantities in the Western Cape, and varieties are being grown and tested at the University of Stellenbosch.
Sugarcane has highest yield and could be the cheapest of all potential ethanol feedstocks, said Adrian Wynne, deputy director of industrial affairs at SA Cane Growers, at a bio-fuels conference last month. South Africa is among the top 10 producers of sugarcane, Wynne said, but half of the crop is exported. A fuel with a 4% ethanol blend could be developed right away if the exports were diverted to ethanol production, he said.
Soyabeans: Several experts believe that soya-beans and sunflower seeds hold the most promise as feedstocks for biodiesel in South Africa. While soyabean oil content — about 18% — is lower than in other feedstocks, it has potential for expansion in South Africa, especially in the wetter provinces. In addition, its biggest byproduct, protein, can be sold by farmers.
Sunflower seeds: Already a major crop in South Africa, sunflower seeds have an oil content of about 40%, making it well-suited for biodiesel production. In addition, both soyabeans and sunflowers can be rotated on farms with maize. About 600 000 tonnes are expected to be harvested this year, but this figure could be doubled depending on government policy, Brink said.
Jatropha: There is debate about whether jatropha, a tree alien to South Africa whose seeds are toxic to humans, will be useful as a feedstock. While jatropha can grow on otherwise unfavourable land and may require less water than other feedstocks, according to Brian Tait, manager of the alternative energy group at Sasol, its environmental impact assessments are pending and it may not be suitable for growth in South Africa.