Bioethanol Potential and Production in Africa: Sweet Sorghum as a Complementary Feedstock

Abstract

This chapter presents an overview of bioethanol potential and production in Africa with specific emphasis on sweet sorghum as a complementary feedstock to sugarcane. Bioethanol feedstock types in Africa include sugarcane, sweet sorghum, maize and cassava. The bioethanol potential in selected African countries for different feedstocks is estimated at 35 EJ, with the Democratic Republic of Congo having the largest potential, followed by Angola, Sudan, Zambia and Tanzania. Bioethanol production in Africa was 637 million litres in 2007, with largest production in South Africa, followed by Egypt and Nigeria. Potential ethanol markets in southern African countries based on E5 and E10 are estimated at 0.8 and 1.5 billion litres per year. The biggest challenge for the development of biofuel markets in southern Africa is that although potential markets exist, and conventional technologies are available, feedstock is not available in sufficient quantities. The main feedstock for ethanol production in Africa is sugarcane, but in the recent past the continent has seen an increasing interest in new feedstock types such as sweet sorghum. In this chapter results for yields and sugar brix for eight exotic sweet sorghum varieties (TS1, Madhura, Praj-1, GE2, GE3, Wray, Cowley, and Keller) are presented and compared to a local sweet sorghum variety (Sima). The results show encouraging yields averaging at 30 tons per hectare under rain-fed conditions. Sugar content in Brix% averaged at about 18% for medium maturing varieties (Keller, GE3, and Sima). The highest values of sugar content of sweet sorghum varieties are similar to those of sugarcane (18%).