Evaluation of Biofuel Production Using Energy and Exergy Analyses—Introduction of a System Design Concept for Achieving Final Benefits—

Abstract

Evaluation functions for minimizing the disparity between energy supply and demand and reducing the fi eld area for biomass production, which are based on energy benefi ts, were proposed in a system design for biofuel production. An Exergy Profi t Ratio (ExPR) and an extended the Energy Profi t Ratio (EPR) were also proposed to measure the quality and availability of energy for the biofuel plant in Utsunomiya City in Tochigi Prefecture, Japan. In the calculation of minimum fi eld area of biomass production based on societal demand in household of Utsunomiya City, 17,500 ha was the minimum value by the evaluation function by energy (E ((system E) and 29,500 ha was the minimum value by the evaluation function by exergy (E ((system E EX) under the case of lighting: 100% electricity; heating: 89% electricity and 11% of vapor. On the other hand, 17,000 ha was the minimum value by E system E and 29,000 ha was the minimum value by E system E EX under the case of lighting: 100% electricity; heating: 100% electricity and 100% of vapor. Thus, if EPR and E system E of bio-ethanol & electricity production were underestimated for a minimum fi eld area, then ExPR and E system E EX could be used to maintain the results of introducing biofuel production to prevent fi eld area shortages for biofuel production.