Optimal Combination of Net-Zero Pathways for Minimum Energy, Land, and Water Consumption in Chemical Production

Abstract

Net-zero chemical production can be achieved through electrification, biomass-based processes, and carbon capture, utilization, and storage. However, these net-zero pathways require more resources than business-as-usual processes. One possibility to produce net-zero chemicals at a lower resource consumption is the combination of net-zero pathways based on locally available resources. This study determines the optimal combinations of netzero pathways for producing chemicals with net-zero emissions that minimize the use of renewable energy, land, and water while complying with local waste biomass and CO 2 storage availability. Waste biomass is defined as residue biomass that does not compete for land and water with other sectors. The analysis is performed worldwide at the country level and considers the production of ammonia, methanol, and plastics, which, when combined, account for ∼5% of the global CO 2 emissions. Findings show that, when considering net-zero pathways individually, waste biomass is preferably used for producing ammonia and methanol, whereas carbon capture and storage is preferably deployed for plastics production. At the same time, a mixed strategy using carbon capture, utilization, and storage, and waste biomass, allows one to achieve a net-zero chemical industry with a nearly 60% reduction in energy consumption and 90% reduction in land and water consumption, with respect to single-pathway strategies. Finally, we find that adopting a net-zero portfolio that minimizes water allows water consumption to be reduced by more than 90% and land consumption to be reduced by more than 70% at the cost of an energy increase of only 5%, when compared to the minimum-energy portfolio.