Bio-Fuel Feedstock Production and its Implications for Agricultural Water Use in Zambia

Abstract

This research assessed the implications of introducing bio-fuel feedstock production for agricultural water use in Zambia so as to advise whether Zambia should go for the production of bio-fuels given the limited available water resources for competing agricultural uses and the urban, industrial and mining requirements. The background to the research was the contemporary debates surrounding the global development of bio-energy systems. The general belief is that whilst contributing to energy security, economic development and climate change mitigation, bio-fuels can increase competition for land and water resources. The study sought to fulfill the need for site-specific studies to support decision-making with regards to the limited availability of freshwater resources against the emerging drivers of water use. Agricultural water use was conceptualised in terms of green, blue and virtual water, which are management-oriented concepts of water flows. Literature review focused on the global development of bio-energy systems for the purpose of understanding the link between bio-energy and water. It was established that the basis of a bio-energy system is biomass production in the process of photosynthesis of which one of the basic inputs is water. The methodology involved estimating crop water requirements for the identified energy crops using the FAO CROPWAT Model 8.0 of 2009, and quantifying the water demand for the projected bio-fuel production using Water Footprint Analysis. The study showed that the crop water requirements were higher for the selected energy crops than for the major food crops. Quantitatively, a minimum of 550 litres of water would be required to produce 1 litre of bioethanol, from sweet sorghum. As regards bio-diesel, a minimum of 2,720 litres of water would be needed to produce 1 litre of bio-diesel from oil palm. Further evaluation of the energy crops using Multi-Criteria Analysis showed that sweet sorghum and jatropha were the most viable energy crops followed by sugar cane and oil palm. The conclusion of the study is that Zambia can undertake the production of liquid bio-fuels given the available water resources, but should consider that an aggressive bio-fuel strategy will increase the level of agricultural water use with a potentially high degree of stress on the limited available water resources.