Co-production of ethanol, biogas, protein fodder and natural fertilizer in organic farming – evaluation of a concept for a farm-scale biorefinery

Summary

The organic farming community has long been recognized for its environmental awareness and has been seeking ways to reduce greenhouse gas emissions and become energy independent. In that regard, ethanol can substitute a fraction of the gasoline used by farming equipment, whereas biogas can fuel the production of heat and electricity for the farm. We investigated the addition of a biorefinery to an organic farm, where ethanol was produced from germinated rye grains and whey and the effluent was separated into two streams: the protein-rich solid fraction, to be used as animal feed, and the liquid fraction, which can be co-digested with clover grass silage to produce biogas. The effluent from the anaerobic digestion process was assumed to serve as natural fertilizer.
We also performed a technoeconomic analysis based on results from laboratory experiments, assuming that four products were generated in a 1000 ha farm: ethanol, biogas, animal feed, and natural fertilizer. Total capital investment was estimated to be approximately 4M USD. Setting a methane selling price according to available incentives for “green electricity” (0.72 USD/m3) leads to a minimum ethanol selling price of 1.89 USD/L. Furthermore, the possibility of using these results to design an energetically self-sufficient farm was discussed.

Available Versions of this Item

• Co-production of ethanol, biogas, protein fodder and natural fertilizer in organic farming – evaluation of a concept for a farm-scale biorefinery. (deposited 30 Jun 2011 10:39) [Currently Displayed]
  • Co-production of ethanol, biogas, protein fodder and natural fertilizer in organic farming – evaluation of a concept for a farm-scale biorefinery. (deposited 01 Jun 2012 09:15)