Environmental and Economic Impact Assessment of Syngas Supply Chains from Residual Biomass in Central Italy: An LCA and LCC Scenario Analysis

Environmental and economic assessments of syngas chains from residual woody biomass are rarely integrated in Mediterranean regions. Attributional life cycle assessment and life cycle costing were combined for three prospective configurations in the Lazio Region, central Italy: a regional feedstock mix (S1), residues from widespread coppicing (S2) and a pruning hub (S3). Impacts were characterized with Environmental Footprint 3.1; costs were discounted over 15 years at a pre-tax rate of 6.75%. In deterministic terms, S2 was lowest in fifteen of sixteen midpoint categories; its single score (an illustrative aggregate) was 0.47 µPt MJ−1, 18% below S1. Quicklime for syngas cleaning was the largest contributor among the inventoried flows (65–80%). The advantage of S2 rests on cut-off allocation and, on the single score, passes to S3 once more than 18% of upstream forest burdens are attributed to residues. With delivered heat valued at 0.20 € kWh−1 and a conversion efficiency of 0.90, S2 and S3 were profitable, and S1 was not (break-even 0.221, 0.171 and 0.182 € kWh−1). Profitability was sensitive to both: S3 became unprofitable at an efficiency of 0.80 or with feedstock-specific conversion. Forest-residue chains required at least 100 kg h−1 and the pruning hub 250 kg h−1, and procurement cost outweighed transport distance almost fourfold.