Fig. 3: Technology pathways for high value chemicals (HVCs), ammonia and methanol.

HVC production is illustrated in three approaches, being (a) technology split, (b) technology typology and (c) carbon source. In the legend box for plot a, colours relate to the feedstocks used as inputs: grey: fossil-based; red: CCU (i.e., CO₂ captured from bio-based or process emissions sources as well as from Direct Air Capture) or fossil-based; green: bio-based. Demands for ethylene, propylene, butadiene, and Benzene, Toluene, and Xylenes (BTX) are static, but ethylene can be used as an intermediate for propylene and butadiene via Metathesis and Catadiene (Supplementary Method 2), thus explaining different production levels across scenarios. d Technology split for hydrogen in ammonia production. Ammonia demand is static. e Methanol production (only non-energy). Methanol long-term demand is composed of both a static demand and an ancillary demand as an intermediate for ethylene, propylene and BTX via MTO and MTA. This explains the increased demand after mid-century. EJ exajoules, NPi implemented National Policies; 1.5C: carbon budget consistent with limiting global warming to 1.5 °C; gCCS: a 1.5C scenario with restrictions on global CCS deployment; PBIO: a 1.5C scenario with constraints on global primary biomass use; MNEToff: a 1.5C scenario that turns off the assumption of biogenic carbon storage in materials; all: a comprehensive 1.5C sensitivity scenario incorporating all the abovementioned restrictions; FCC: fluidised catalytic cracking; FS feedstock, CCU carbon capture and utilisation, CCS carbon capture and storage. Source data are provided as a Source Data file.