Table 3 System I: Ecological footprint (SPI [m2/ha]) of s-cc (for biogas or mulched) with wheat as the main crop
From: Ecological evaluation of biogas from catch crops with Sustainable Process Index (SPI)
V0 without cc | V1 cc mulched | V2 cc biogas, ploughing | V3 cc biogas no ploughing | V4 cc biogas no ploughing, biomethane | |
|---|---|---|---|---|---|
Wheat (t/ha) with 12% residual moisture | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 |
Cc yield (t DM/ha) | 0 | 2.5 | 4.5 | 4.5 | 4.5 |
Wheat, technique, fuel, maintenance resource | 244,000 | 208,000 | 185,000 | 160,000 | 150,000 |
Cc technique. fuel | 0 | 3,000 | 28,000 | 29,000 | 29,000 |
NO3, H2O, erosion, humus | 162,000 | 119,000 | 21,000 | 19,000 | 19,000 |
Sum wheat/biomass production | 406,000 | 330,000 | 234,000 | 209,000 | 198,000 |
SPI change in relation to V0 (%) | 100 | 81 | 58 | 51 | 49 |
SPI change in relation to V1 (%) | 100 | 71 | 63 | 60 | |
Biomethane/natural gas (m3) | 1260 | 1260 | 1260 | 1260 | 1260 |
Natural gas demand or biogas fermentation, cleaning, compression (m2 SPI/ha) | 675,000 | 675,000 | 275,000 | 275,000 | 275,000 |
SPI Sum incl. natural gas substitution or biomethane supply | 1,081,000 | 1,005,000 | 509,000 | 484,000 | 473,000 |
SPI change in relation to V0 (%) | 100 | 93 | 47 | 45 | 44 |
SPI change in relation to V1 (%) | 100 | 51 | 48 | 47 |