Bio-SNG - CNG Services

BIO-SNG FEASIBILITY STUDY – ESTABLISHMENT OF A REGIONAL PROJECT6 Economic AssessmentUsing best available information, the economic profile of bio-SNG projects is considered. Evaluation ofprocess economics is critically dependent on input assumptions. This builds on the technical review,along with a perspective on costs and impact of existing, and proposed incentives. Plant economics forsuch capital intensive processes are dependent on the state of the market, and costs associated with risktransfer for equipment supplied under EPC contract structures. Similarly, the emergent state of thebiomass market supply chain, along with competitive uses, means that biomass fuel resources will bevolatile. Therefore appropriate sensitivity analyses are undertaken. Against these scenarios, the potentialproject returns are evaluated. This review also compares (at a high level) the returns for a gasificationfacility producing power.This analysis assesses the cost of carbon abatement via this route, when compared with alternative directuses of biomass for heat and electricity as well as other carbon abatement approaches.6.1.1 Scale and operational assumptionsTwo representative scales have been assessed; a small, demonstration scale facility requiring ~100,000te pa of feedstock and a larger commercial facility of requiring ~600,000 te pa . These are outlined inTable 6-1. It is assumed that the process operates at a pressure which matches grid injection such thatdownstream compression requirements are limited. Here it is assumed this would be 20bar, so would besuitable for intermediate or high pressure distribution level injection but not NTS without furthercompression. This assumes therefore that the gasifier operates at the appropriate pressure to account forpressure drops in the gas processing train (typically ~20% from gasifier to exit of methanation reactor, iegasification at ~26bar)Whilst the facility does generate electricity recovered from the high grade heat, at the assumed SNGefficiency, the heat suitable for power production is assumed to compensate for the parasitic loads,including the ASU load (separation, oxygen compression) and sufficient CO2 compression for lockhopperinert blanket. In the event that an indirect gasification configuration is used, there would be noASU load, although it is likely that the system would operate at low or atmospheric pressure, thereforeimpose syngas compression loads. Therefore it is assumed in either case there is no excess electricity forexport.44