The Scientific World Journal / 2013 / Article / Tab 4

Research Article

Emergy Analysis of Biogas Systems Based on Different Raw Materials

Table 4

The comparative table of energy index.

Item Evaluation indexBPCBPF

Ecological-economy benefit Purchased emergy ratio (PER)0.38 0.12
Natural emergy/purchased emergy1.627.26
Emergy investment rate (EIR)0.62 0.14
Emergy yield ratio (EYR)8.8613.95
Emergy self-sufficiency ratio (ESR)0.62 0.88

Environmental benefitWaste processing ratio (%W)61.30 87.89
Environmental load ratio (ELR)0.530.13

Sustainable developmentFeedback yield ratio (FYR)2.595.08
Renewable ratio (%R)65.1588.70
Sustainability index (ESI)16.57109.50