Integration of Biomass Gasification and CO₂ Capture in the LCA Model for the Energy, Water and Food Nexus

The energy, water and food (EWF) Nexus tool developed by the authors is used to evaluate the different pathways for a hypothetical 40 % food self-sufficiency target in Qatar. The EWF systems are represented by sub-systems described in detail. With emphasis on the inter-linkages between EWF resources, the tool quantifies material flows, natural resource and energy consumption at component unit process level. In this paper, the EWF Nexus tool detailed previously in Al-Ansari et al. (2014; 2015) is expanded to include waste management techniques, in which the objective is to reduce the reported life cycle scores. The sub-systems consist of a biomass integrated gasification combined cycle (BIGCC) which recycles solid waste into useful forms of energy that can be re-used within the nexus. In addition, a carbon capture (CC) sub-system is integrated to capture and recycle CO₂ from both the CCGT and the BIGCC. The integration of CC with the BIGCC transforms the carbon neutral BIGCC process to a negative GHG emission technology (BECCS). For the different scenarios and sub-system configurations considered, the global warming potential can be theoretically balanced (reduced by ~ 98 %) through the integration of photovoltaic (PV), BIGCC and CC technologies. The peak GWP, i.e. a fully fossil fuel dependent system, is recorded at 1.73 × 10⁹ kg CO₂ eq. /year whilst the lowest achievable GWP is 2.18 × 10⁷ kg CO₂ eq. /year when utilising a combination of PV, CC integrated with CCGT in addition to BECCS technology. The natural gas consumption is reduced by 7.8 × 10⁷ kg/year in the best case configuration achieving a credit. In the same scenario, the PV land footprint required is calculated to a maximum of 660 ha. The maximum theoretically achievable negative emission is 1.09 × 10⁹ kg CO₂/year.