Energy and Carbon Impact of Sweet Sorghum

In light of increased discussions regarding the competition between bioenergy and food, Sweet Sorghum (“Zuckerhirse”) has emerged as a promising energy crop. Due to the fact that it can be used for the production of food, first and second generation biofuels as well as for fertilizer, its cultivation is to be encouraged. However, to date neither a consistent picture nor sufficiently reliable scientific documentation exists regarding the crop’s sustainability. Consequently, the FAO commissioned the IFEU to investigate the environmental impact of different Sweet Sorghum production systems. These production systems include the production of first and second generation bioethanol from different crop parts as well as a combined use for both biofuels and food.

The study focuses on three main topics:

The energy and greenhouse gas balances of different Sweet Sorghum pathways are examined by means of a quantitative analysis. For this purpose a so-called screening assessment is conducted which analyses the energy and greenhouse gas impacts along the entire life cycle of Sweet Sorghum for each examined production and use system. The results are compared to the environmental impacts of equivalent fossil fuels.
Additional environmental impacts from the cultivation of Sweet Sorghum are examined qualitatively.
Sweet Sorghum is compared to other crops available for biofuel production regarding selected technical aspects.

Based on the findings of the screening assessment and the qualitative evaluation, recommendations regarding the need for further research as well as regarding further FAO steps have been derived.

Further information
Susanne Köppen, Guido Reinhardt, Sven Gärtner, 2009: Assessment of energy and greenhouse gas inventories of Sweet Sorghum for first and second generation bioethanol. Report to the FAO: Executive Summary and Final Report (PDF-documents)

Contact
Guido A. Reinhardt
E-Mail: guido.reinhardt@ifeu.de