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Sustainability, overall and process efficiency of energy crops

Schäfer, Winfried (2008) Sustainability, overall and process efficiency of energy crops. In: Lehocka, Zuzana; Klimekova, Marta and Sukkel, Wijnand (Eds.) ECOMIT: proceedings of the 5th International Scientific Conference on Sustainable Farming systems, CD-ROM: Slovak Association for Sustainable Agriculture, c/o Slovak Agricultural Research Centre – Research Institute of Plant Production, Piešťany, pp. 82-87.

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A method to calculate efficiency of energy crop production including sun energy,
direct and indirect energy for cultivation, processing, and conversion into fuel is
demonstrated using rape and derived fuels as an example. Every production and
conversion step is a process and calculated separately. The overall efficiency
includes energy input and output of all processes. The process efficiency of rape
cultivation reaches in Finland up to 1100 %. However, the overall energy efficiency of
rape methyl ester (RME) is 1 to 2 ‰ only. The production of biogas from manure of
dairy fed by rape meal results in a process energy efficiency of 33 to 41 %, but the
overall energy efficiency of RME and biogas together is only 1.2 to 2.5 ‰. In
contrast, thermal or photovoltaic solar collectors improve overall efficiency 1 to 3
orders of magnitude compared to fuel production from rape. Competition for
cultivation area and the low photosynthetic efficiency limit the feasibility of fuel
production from energy crops. As a measure for sustainability of renewable fuel
production, the energy surplus of energy conversion from insolation to fuel per
resident and square meter is proposed.

EPrint Type:Conference paper, poster, etc.
Type of presentation:Paper
Keywords:Energy crops, renewable energy, efficiency, sustainability
Subjects: Food systems > Recycling, balancing and resource management
Research affiliation: Finland > Luke Natural Resources Institute
Deposited By: Schäfer, Dr. Winfried Christian
ID Code:15164
Deposited On:16 Jan 2009
Last Modified:12 Apr 2010 07:38
Document Language:English
Refereed:Peer-reviewed and accepted
Additional Publishing Information:Distribution: Paper copies may be ordered from the Slovak Association for
Sustainable Agriculture, Považany 124, 916 26 Považany, Slovakia,

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