Economic and energy balances of jatropha production in Tanzania: a case of Monduli and Mpanda districts

The increase in the use of fossil fuels has led to an increase in Green House Gas (GHG) emissions which are believed to be the main reason for global warming. The world is now encouraged to use bioenergy as a solution in reducing GHG emission from fossil fuels. Jatropha has received much interest as a feedstock for biofuel production because of its minimal adverse effects on the environment and food supply. This crop is now cultivated and processed at both Engaruka and Mpanda study sites as alternative source of energy and income. Jatropha cultivation has economic and environmental impact due to its various products such as seeds and its effects on land use change. Despite the production of the crop in the country, there are no studies which have examined in details its economic and environmental impacts. This makes the assessment of the economic and energy balances of jatropha production in Tanzania using Life Cycle Assessment approach necessary. The objectives understudy include describing jatropha based products, to assess economic benefit of jatropha production to small scale farmers, to assess the energy balance of jatropha production and finally to assess impact of the use of jatropha based products on GHG emissions in the study sites. The findings show that farmers get profit for high yield scenario 135 TZS/kg per metre. Also oil processing using hand press and oil expeller show positive economic return of 1 200 and 1 421 TZS/litre respectively. The environmental performance of jatropha is high due to low input application in the cultivation stage. The ratio of biodiesel energy output to fossil energy input is 4.7. Also results show that production and use of jatropha base products is associated with GHG emission contributes 0.59 kg CO 2 eq, 0.014 kg CO 2 eq and 0.45 kg CO 2 equivalent for cultivation, electricity and charcoal production respectively.