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Report, 1999

Energy and exergy analyses of bioenergy crops and rapeseed oil methyl ester production

Hovelius, Karolina

Abstract

Energy crops are a non-fossil fuel that can provide solid, liquid and gaseous fuels which may be stored and transported. In Sweden winter wheat, rapeseed and Salix are crops which are very suitable for energy use, since they suit the climatic conditions and are grown using well-established technology. However, it is important that the production of bioenergy supplies more energy than that required for production. Besides this, it is important to know how the energy quality, exergy, is affected during production and by using both energy and exergy analysis it is possible to determine not only the quantity of the energy used, but also its quality. The objective for this study was to analyse the rapeseed oil methyl ester (RME) production chain and the cultivation of winter wheat, summer turnip rape, winter rape and Salix with respect to their energy use and exergy consumption. The objective was also to identify the stages in the production chain that accounted for the largest energy use and exergy consumption and to see how the production chain would be affected by introducing different production strategies. The energy and exergy analyses were performed using process analysis methodology. Energy and exergy ratios and net outputs were calculated and the links in the production chain accounting for the largest energy use and exergy consumption were identified. Different production strategies were studied in order to make the production process more energy and exergy effective. The study showed that the cultivation of winter wheat, rapeseed and Salix yielded more energy and exergy than they required during production. The whole RME production chain also had larger energy and exergy outputs than inputs. The study further showed that fertilisers accounted for a large part of the total energy use and exergy consumption. However, this energy use and exergy consumption due to use of fertilisers could be markedly decreased by using alternative fertilisers, such as furnace ash, different types of sludges and human urine, in cultivation.

Keywords

energy

Published in

Rapport - Sveriges lantbruksuniversitet, Institutionen för lantbruksteknik
1999,
Publisher: Institutionen för lantbruksteknik, Sveriges lantbruksuniversitet

Permanent link to this page (URI)

https://res.slu.se/id/publ/125810