Table 4 Energy demand of inputs, process heat and electricity per tonne of straw (dry matter (DM) basis) and per tonne of oil (allocated), and mass balance for biomethane and yeast oil production in the base scenario (not allocated)
Inputs | Per tonne DM straw | Per tonne of oil produced (allocated) | Units |
|---|---|---|---|
Straw | |||
 Straw farming | 270 | 2000 | MJ |
 Transport | 66 | 490 | MJ |
Pre-treatment | |||
 Electricity | 73 | 540 | MJ |
 Heat | 2270 | 16,910 | MJ |
 Sulphuric acid | 69 | 510 | MJ |
Hydrolysis | |||
 Electricity | 33 | 250 | MJ |
 Heat | 0 | 0 | MJ |
 Enzymes | 176 | 1310 | MJ |
Fermentation | |||
 Electricity | 1200 | 9000 | MJ |
 Heat | 0 | 0 | MJ |
 Ammonia | 590 | 4400 | MJ |
 Acid and base for pH adjustment | 170 | 1240 | MJ |
Lipid extraction | |||
 Electricity | 130 | 950 | MJ |
 Heat | 620 | 4630 | MJ |
 Hexane | 270 | 1970 | MJ |
Anaerobic digestion | |||
 Electricity | 150 | 1150 | MJ |
 Heat | 98 | 730 | MJ |
Wastewater treatment | |||
 Electricity | 18 | 130 | MJ |
 Heat | 0 | 0 | MJ |
 Total electricity demand | 1610 | 11,960 | MJ |
 Total heat demand | 2990 | 22,270 | MJ |
 Total heat demand with recovery | 1450 | 10,780 | MJ |
 Primary energy demand | 1.6 | 11.9 | GJ |
Outputs | Â | Not allocated | Â |
|---|---|---|---|
Yeast oil | 109 | 1 | kg |
Gross electricity | 2270 | 20,810 | MJ |
Gross heat | 3290 | 30,180 | MJ |
Biomethane | 2350 | 21,500 | MJ |
Excess electricity | 660 | 6030 | MJ |
Excess heat | 1840 | 16,880 | MJ |