Net-zero emissions chemical industry in a world of limited resources

Abstract

The chemical industry is responsible for about 5% of global CO2 emissions and is key to achieving net-zero targets. Decarbonizing this industry, nevertheless, faces particular challenges given the widespread use of carbon-rich raw materials, the need for high-temperature heat, and the complex global value chains. Multiple technology routes are now available for producing chemicals with net-zero CO2 emissions based on biomass, recycling, and carbon capture, utilization, and storage. However, the extent to which these routes are viable with respect to local availability of energy and natural resources remains unclear. In this review, we compare net-zero routes by quantifying their energy, land, and water requirements and the corresponding induced resource scarcity at the country level and further discuss the technical and environmental viability of a net-zero chemical industry. We find that a net-zero chemical industry will require location-specific integrated solutions that combine net-zero routes with circular approaches and demand-side measures and might result in a reshaping of the global chemicals trade. The chemical industry is responsible for about 5% of global CO2 emissions and is key to achieving net-zero targets. Decarbonizing this industry, nevertheless, faces particular challenges given the widespread use of carbon-rich raw materials, the need for high-temperature heat, and the complex global value chains. Multiple technology routes are now available for producing chemicals with net-zero CO2 emissions based on biomass, recycling, and carbon capture, utilization, and storage. However, the extent to which these routes are viable with respect to local availability of energy and natural resources remains unclear. In this review, we compare net-zero routes by quantifying their energy, land, and water requirements and the corresponding induced resource scarcity at the country level and further discuss the technical and environmental viability of a net-zero chemical industry. We find that a net-zero chemical industry will require location-specific integrated solutions that combine net-zero routes with circular approaches and demand-side measures and might result in a reshaping of the global chemicals trade. To keep global warming below the 1.5°C threshold stipulated by the Paris Agreement, all anthropogenic CO2 emissions will have to reach net zero by around mid-century, with all greenhouse gas (GHG) emissions achieving net zero soon after.1Rogelj J. Popp A. Calvin K.V. Luderer G. Emmerling J. Gernaat D. Fujimori S. Strefler J. Hasegawa T. Marangoni G. et al.Scenarios towards limiting global mean temperature increase below 1.5 °C.Nat. Clim. Change. 2018; 8: 325-332https://doi.org/10.1038/s41558-018-0091-3Crossref Scopus (613) Google Scholar,2Guardian T. The 1977 White House Climate Memo that Should Have Changed the World.2022Google Scholar In a world of net-zero CO2 emissions (hereafter simply referred to as net-zero) at steady state, any carbon atom extracted from the subsurface will have to be permanently returned to it, lest it is sooner or later emitted to the atmosphere. Any carbon atom released into the atmosphere will have to be pulled back out of it to avoid the rise of carbon concentration in the atmosphere and, hence, the global average temperature.3IPCCSummary for policymakers.in: Masson-Delmotte V. Zhai P. Pirani A. Connors S.L. Péan C. Berger S. Caud N. Chen Y. Goldfarb L. Gomis M.I. Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, 2021: 3-32https://doi.org/10.1017/9781009157896.001Google Scholar Some energy services such as electricity, residential heating and cooling, and light-duty transport may be relatively easy to decarbonize by electrifying and generating carbon-free (C-free) electricity. However, electrification is insufficient for so-called hard-to-abate industries, such as the chemical, aviation, cement, iron, and steel industries, responsible for nearly one-third of global carbon emissions.4Davis S.J. Lewis N.S. Shaner M. Aggarwal S. Arent D. Azevedo I.L. Benson S.M. Bradley T. Brouwer J. Chiang Y.-M. et al.Net-zero emissions energy systems.Science. 2018; 360: eaas9793https://doi.org/10.1126/science.aas9793Crossref PubMed Scopus (840) Google Scholar In hard-to-abate industries, carbon emissions are mainly due to the need for high-temperature heat and carbon as a material feedstock, e.g., in chemical products, such as plastics. Thus, achieving net-zero emissions requires combining C-free energy supply with CO2-neutral carbon feedstock. Within hard-to-abate industries, the chemical industry is vital in climate discussions.5Woodall C.M. Fan Z. Lou Y. Bhardwaj A. Khatri A. Agrawal M. McCormick C.F. Friedmann S.J. Technology options and policy design to facilitate decarbonization of chemical manufacturing.Joule. 2022; 6: 2474-2499https://doi.org/10.1016/j.joule.2022.10.006Abstract Full Text Full Text PDF Scopus (1) Google Scholar,6Financial Time Chemicals: Core to a Net Zero Future.2022Google Scholar First, chemical production is very energy- and CO2-intensive. Moreover, chemical products are ubiquitous and integrated across multiple supply chains, with around 96% of all manufactured goods being touched by chemistry.7Brudermüller M. How to Build a More Climate-Friendly Chemical Industry.2020Google Scholar,8World Economic ForumTowards Net-Zero Emissions: Policy Priorities for Deployment of Low-Carbon Emitting Technologies in the Chemical Industry.2021Google Scholar Today the chemical industry emits about 2 billion metric tons of CO2 (GtCO2) per year (direct and energy emissions), accounting for about 5% of global GHG emissions. Furthermore, the chemical industry faces a particular challenge, as most chemical products contain carbon and it is, therefore, virtually impossible to decarbonize. Yet multiple technology routes are available for producing chemicals with net-zero CO2 emissions based on biomass, CO2 use, recycling, and carbon capture and storage. However, all these routes are potentially limited by the local availability of energy and natural resources, such as land and water. Whereas multiple studies assess the viability of a net-zero chemical industry concerning global resources,9Meng F. Wagner A. Kremer A.B. Kanazawa D. Leung J.J. Goult P. Guan M. Herrmann S. Speelman E. Sauter P. et al.Planet-compatible pathways for transitioning the chemical industry.Proc. Natl. Acad. Sci. USA. 2023; 120 (e2218294120)https://doi.org/10.1073/pnas.2218294120Crossref Scopus (2) Google Scholar,10Bachmann M. Zibunas C. Hartmann J. Tulus V. Suh S. Guillén-Gosálbez G. Bardow A. Towards circular plastics within planetary boundaries.Nat. Sustain. 2023; https://doi.org/10.1038/s41893-022-01054-9Crossref Scopus (2) Google Scholar,11D’Angelo S.C. Cobo S. Tulus V. Nabera A. Martín A.J. Pérez-Ramírez J. Guillén-Gosálbez G. Planetary boundaries analysis of low-carbon ammonia production routes.ACS Sustain. Chem. Eng. 2021; 9: 9740-9749https://doi.org/10.1021/acssuschemeng.1c01915Crossref Scopus (18) Google Scholar,12Galán-Martín Á. Tulus V. Díaz I. Pozo C. Pérez-Ramírez J. Guillén-Gosálbez G. Sustainability footprints of a renewable carbon transition for the petrochemical sector within planetary boundaries.One Earth. 2021; 4: 565-583https://doi.org/10.1016/j.oneear.2021.04.001Abstract Full Text Full Text PDF Scopus (52) Google Scholar,13Ioannou I. Galán-Martín Á. Pérez-Ramírez J. Guillén-Gosálbez G. Trade-offs between sustainable development goals in carbon capture and utilisation.Energy Environ. Sci. 2022; https://doi.org/10.1039/D2EE01153KCrossref PubMed Google Scholar geographical differences are unresolved. Thus, the net-zero chemical industry’s technical, environmental, and biophysical viability remains less clear for different countries based on local requirements and resources. In this review, we examine the feasibility of the technology routes to attain net-zero CO2 emissions in the production of chemicals, accounting for geographical specificities. In the presence of existing knowledge, we assess and compare available technology routes to achieve net-zero CO2 emissions in the production of all primary chemicals, namely ammonia, methanol, and plastics. The assessment is performed on a country level and coupled with geospatial analysis to determine the land and water scarcity induced by a net-zero chemical industry worldwide. Findings show that a net-zero chemical industry will require integrated solutions that combine net-zero routes with circularity and demand-side measures; such integrated solutions will have to differ regionally based on available resources regarding renewable energy, land, and water availability. Also, our results suggest a potential reshaping of the international trading of chemicals, with the production of chemicals moving from countries with fossil resources to countries with renewable energy, land, and water resources. When counting the biorefineries across the forests and lakes of south-east Finland, it almost feels as if we are on the right track for a post-fossil chemical industry: the pulp and paper industry and the wood industry provide a sustainable carbon-neutral feedstock for the synthesis of many valuable chemicals. One such example is the UPM biorefinery in Lappeenranta, where black liquor waste from pulp and paper manufacture is converted into renewable diesel. This speaks for the ambitious climate goals of the Finnish chemical industry: to be carbon neutral by 2045.14CEFICFinland.2021https://cefic.org/a-pillar-of-the-european-economy/landscape-of-the-european-chemical-industry/finland/Google Scholar However, when looking at global trends in the chemical industry, it is evident that the world is heading in a different direction: the demand for chemicals is rising and so are the associated CO2 emissions15IEAChemicals.2021Google Scholar (Figure 1). The demand for chemicals is related to a vast array of products that are produced on the basis of so-called primary chemicals (Box 1). These include methanol, ammonia, and high-value chemicals (ethylene, propylene, benzene, toluene, xylenes), which are the key precursors to plastics.15IEAChemicals.2021Google Scholar Methanol and high-value chemicals (and plastics) are carbon-based (C-based), while ammonia is C-free. Primary chemicals can either be used directly, e.g., ammonia and methanol as fuels, or to produce other products, e.g., high-value chemicals are mainly used to produce plastics.20Levi P.G. Cullen J.M. Mapping global flows of chemicals: from fossil fuel feedstocks to chemical products.Environ. Sci. Technol. 2018; 52: 1725-1734https://doi.org/10.1021/acs.est.7b04573Crossref PubMed Scopus (135) Google ScholarBox 1Primary chemicalsMethanol(CH3OH). Methanol production is currently the fastest rising of all primary chemicals, with a 21% increase from 2015 to 2020 and a global production of about 91 Mt/year in 2020 (decline from 98 Mt/year in 2019 due to the Covid-19 pandemic).15IEAChemicals.2021Google Scholar Methanol is mostly used for producing other chemicals such as formaldehyde, which is employed to manufacture several specialized plastics, coatings, and acetic acid. Methanol is also used for fuel applications (the main driver of its above-average demand growth) and as an intermediary to produce high-value chemicals (ethylene, propylene, benzene, toluene, xylenes), hence plastics (Figure 1B).15IEAChemicals.2021Google Scholar,18IRENAInnovation Outlook. Renewable Methanol, 2021Google Scholar Methanol demand and production capacity are highly concentrated in the Asia-Pacific region, due to the rise in petrochemical production in the region. China is the global leader in methanol consumption owing to a sharp rise in the use of methanol in fuel products (Figure 1C).15IEAChemicals.2021Google ScholarAmmonia(NH3). Ammonia is the precursor to most nitrogen fertilizers and makes an important contribution to global food security.21Rosa L. Gabrielli P. Energy and food security implications of transitioning synthetic nitrogen fertilizers to net-zero emissions.Environ. Res. Lett. 2023; 18014008https://doi.org/10.1088/1748-9326/aca815Crossref Scopus (3) Google Scholar,22Smil V. Nitrogen and food production: proteins for human diets.Ambio. 2002; 31: 126-131https://doi.org/10.1579/0044-7447-31.2.126Crossref PubMed Scopus (337) Google Scholar It is estimated that the food provision for half of the world population depends on synthetically produced ammonia fertilizers.21Rosa L. Gabrielli P. Energy and food security implications of transitioning synthetic nitrogen fertilizers to net-zero emissions.Environ. Res. Lett. 2023; 18014008https://doi.org/10.1088/1748-9326/aca815Crossref Scopus (3) Google Scholar,22Smil V. Nitrogen and food production: proteins for human diets.Ambio. 2002; 31: 126-131https://doi.org/10.1579/0044-7447-31.2.126Crossref PubMed Scopus (337) Google Scholar,23Erisman J.W. Sutton M.A. Galloway J. Klimont Z. Winiwarter W. How a century of ammonia synthesis changed the world.Nat. Geosci. 2008; 1: 636-639https://doi.org/10.1038/ngeo325Crossref Scopus (2345) Google Scholar About 70% (131 Mt/year) of ammonia is used to make fertilizers, with the remainder being mostly used to produce plastics, explosives, and synthetic fibers (Figure 1B).17IEAAmmonia Technology Roadmap.2021Google Scholar With food demand expected to double by 2050, demand for ammonia is expected to increase by 40% (Figure 1B).17IEAAmmonia Technology Roadmap.2021Google Scholar,24Bodirsky B.L. Popp A. Lotze-Campen H. Dietrich J.P. Rolinski S. Weindl I. Schmitz C. Müller C. Bonsch M. Humpenöder F. et al.Reactive nitrogen requirements to feed the world in 2050 and potential to mitigate nitrogen pollution.Nat. Commun. 2014; 5: 3858https://doi.org/10.1038/ncomms4858Crossref PubMed Scopus (310) Google Scholar The greatest contribution to ammonia’s demand comes from the Asia-pacific region (Figure 1C), due to the large-scale agricultural activities in the region, mostly in India and China.25Zhao F. Fan Y. Zhang S. Eichhammer W. Haendel M. Yu S. Exploring pathways to deep de-carbonization and the associated environmental impact in China’s ammonia industry.Environ. Res. Lett. 2022; 17045029https://doi.org/10.1088/1748-9326/ac614aCrossref Scopus (4) Google ScholarPlasticsDemand for plastics drives demand for high-value chemicals, which are the key precursors to most plastics. Between 1950 and 2020, plastics production increased from 2 to 420 Mt/year,26Geyer R. Jambeck J.R. Law K.L. Production, use, and fate of all plastics ever made.Sci. Adv. 2017; 3: e1700782https://doi.org/10.1126/sciadv.1700782Crossref PubMed Scopus (6314) Google Scholar with a 12% increase from 2015 to 2020.15IEAChemicals.2021Google Scholar Plastics production is projected to achieve 1100 Mt/year in 2050, resulting in a carbon footprint (direct and energy CO2 emissions) of about 3.5 GtCO2/year in a BAU scenario (Figure 1). It is worth mentioning that the carbon footprint of plastics is significantly higher than that of high-value chemicals (1.4 GtCO2/year versus 250 MtCO2/year in 2020), due to the high carbon intensity of the processes transforming high-value chemicals into plastics.16Cabernard L. Pfister S. Oberschelp C. Hellweg S. Growing environmental footprint of plastics driven by coal combustion.Nat. Sustain. 2021; 5: 139-148https://doi.org/10.1038/s41893-021-00807-2Crossref Scopus (66) Google Scholar Major plastic end-use sectors are packaging, building and construction, textiles, and transport applications (Figure 1B). Similar to methanol and ammonia, the greatest contribution to plastics demand comes from the Asia-Pacific region, although Europe and North America play a greater role (Figure 1C). (CH3OH). Methanol production is currently the fastest rising of all primary chemicals, with a 21% increase from 2015 to 2020 and a global production of about 91 Mt/year in 2020 (decline from 98 Mt/year in 2019 due to the Covid-19 pandemic).15IEAChemicals.2021Google Scholar Methanol is mostly used for producing other chemicals such as formaldehyde, which is employed to manufacture several specialized plastics, coatings, and acetic acid. Methanol is also used for fuel applications (the main driver of its above-average demand growth) and as an intermediary to produce high-value chemicals (ethylene, propylene, benzene, toluene, xylenes), hence plastics (Figure 1B).15IEAChemicals.2021Google Scholar,18IRENAInnovation Outlook. Renewable Methanol, 2021Google Scholar Methanol demand and production capacity are highly concentrated in the Asia-Pacific region, due to the rise in petrochemical production in the region. China is the global leader in methanol consumption owing to a sharp rise in the use of methanol in fuel products (Figure 1C).15IEAChemicals.2021Google Scholar (NH3). Ammonia is the precursor to most nitrogen fertilizers and makes an important contribution to global food security.21Rosa L. Gabrielli P. Energy and food security implications of transitioning synthetic nitrogen fertilizers to net-zero emissions.Environ. Res. Lett. 2023; 18014008https://doi.org/10.1088/1748-9326/aca815Crossref Scopus (3) Google Scholar,22Smil V. Nitrogen and food production: proteins for human diets.Ambio. 2002; 31: 126-131https://doi.org/10.1579/0044-7447-31.2.126Crossref PubMed Scopus (337) Google Scholar It is estimated that the food provision for half of the world population depends on synthetically produced ammonia fertilizers.21Rosa L. Gabrielli P. Energy and food security implications of transitioning synthetic nitrogen fertilizers to net-zero emissions.Environ. Res. Lett. 2023; 18014008https://doi.org/10.1088/1748-9326/aca815Crossref Scopus (3) Google Scholar,22Smil V. Nitrogen and food production: proteins for human diets.Ambio. 2002; 31: 126-131https://doi.org/10.1579/0044-7447-31.2.126Crossref PubMed Scopus (337) Google Scholar,23Erisman J.W. Sutton M.A. Galloway J. Klimont Z. Winiwarter W. How a century of ammonia synthesis changed the world.Nat. Geosci. 2008; 1: 636-639https://doi.org/10.1038/ngeo325Crossref Scopus (2345) Google Scholar About 70% (131 Mt/year) of ammonia is used to make fertilizers, with the remainder being mostly used to produce plastics, explosives, and synthetic fibers (Figure 1B).17IEAAmmonia Technology Roadmap.2021Google Scholar With food demand expected to double by 2050, demand for ammonia is expected to increase by 40% (Figure 1B).17IEAAmmonia Technology Roadmap.2021Google Scholar,24Bodirsky B.L. Popp A. Lotze-Campen H. Dietrich J.P. Rolinski S. Weindl I. Schmitz C. Müller C. Bonsch M. Humpenöder F. et al.Reactive nitrogen requirements to feed the world in 2050 and potential to mitigate nitrogen pollution.Nat. Commun. 2014; 5: 3858https://doi.org/10.1038/ncomms4858Crossref PubMed Scopus (310) Google Scholar The greatest contribution to ammonia’s demand comes from the Asia-pacific region (Figure 1C), due to the large-scale agricultural activities in the region, mostly in India and China.25Zhao F. Fan Y. Zhang S. Eichhammer W. Haendel M. Yu S. Exploring pathways to deep de-carbonization and the associated environmental impact in China’s ammonia industry.Environ. Res. Lett. 2022; 17045029https://doi.org/10.1088/1748-9326/ac614aCrossref Scopus (4) Google Scholar Demand for plastics drives demand for high-value chemicals, which are the key precursors to most plastics. Between 1950 and 2020, plastics production increased from 2 to 420 Mt/year,26Geyer R. Jambeck J.R. Law K.L. Production, use, and fate of all plastics ever made.Sci. Adv. 2017; 3: e1700782https://doi.org/10.1126/sciadv.1700782Crossref PubMed Scopus (6314) Google Scholar with a 12% increase from 2015 to 2020.15IEAChemicals.2021Google Scholar Plastics production is projected to achieve 1100 Mt/year in 2050, resulting in a carbon footprint (direct and energy CO2 emissions) of about 3.5 GtCO2/year in a BAU scenario (Figure 1). It is worth mentioning that the carbon footprint of plastics is significantly higher than that of high-value chemicals (1.4 GtCO2/year versus 250 MtCO2/year in 2020), due to the high carbon intensity of the processes transforming high-value chemicals into plastics.16Cabernard L. Pfister S. Oberschelp C. Hellweg S. Growing environmental footprint of plastics driven by coal combustion.Nat. Sustain. 2021; 5: 139-148https://doi.org/10.1038/s41893-021-00807-2Crossref Scopus (66) Google Scholar Major plastic end-use sectors are packaging, building and construction, textiles, and transport applications (Figure 1B). Similar to methanol and ammonia, the greatest contribution to plastics demand comes from the Asia-Pacific region, although Europe and North America play a greater role (Figure 1C). Figure 1 provides an overview of the global production and CO2 emissions associated with the primary chemicals in 2020 and 2050. Ammonia is the only primary chemical for which projected CO2 emissions in 2050 are lower than current CO2 emissions, since its production can be decarbonized by electrifying hydrogen production.17IEAAmmonia Technology Roadmap.2021Google Scholar Plastics production alone is responsible for about 1.4 GtCO2 per year (Figure 1A).15IEAChemicals.2021Google Scholar,27Ritchie H. Roser M. CO2 and Greenhouse Gas Emissions.2020Google Scholar,16Cabernard L. Pfister S. Oberschelp C. Hellweg S. Growing environmental footprint of plastics driven by coal combustion.Nat. Sustain. 2021; 5: 139-148https://doi.org/10.1038/s41893-021-00807-2Crossref Scopus (66) Google Scholar Under business-as-usual (BAU) scenarios where the industry follows current trends, such as the Stated Policies Scenario defined by the International Energy Agency,28IEAWorld Energy Model.2021Google Scholar the emissions related to the chemical industry are projected to be about 4.5 GtCO2 per year in 2050 (Figure 1A).17IEAAmmonia Technology Roadmap.2021Google Scholar,18IRENAInnovation Outlook. Renewable Methanol, 2021Google Scholar As most chemical end-products contain carbon, it is difficult to envision a chemical industry without C-based feedstock and primary chemicals.7Brudermüller M. How to Build a More Climate-Friendly Chemical Industry.2020Google Scholar Thus, in the case of the chemical industry one should not talk about decarbonization but rather focus on how it could achieve net-zero emissions. In fact, the chemical industry uses fossil fuels primarily as raw materials to provide carbon and/or hydrogen to the final products, with about 50% of the energy input to the chemical industry being required as feedstock.15IEAChemicals.2021Google Scholar While both carbon and hydrogen are largely available in nature, they are constituent parts of more complex molecules, e.g., water, CO2, fossil fuels, and biomass. The chemical industry has historically favored the use of fossil fuels above other abundant molecules, as they embed the energy required for product synthesis rather than requiring it. In many plausible future scenarios, where fossil fuels are phased out from other sectors, the chemical industry is expected to become the largest driver of global oil consumption by 2050, going from about 10 to 15 million barrels of oil from today to 2050, hence nearly doubling its contribution from 12% today to 25% in 2050.29IEAThe Future of Petrochemicals.2018Google Scholar,30Lange J.-P. Towards circular carbo-chemicals – the metamorphosis of petrochemicals.Energy Environ. Sci. 2021; 14: 4358-4376https://doi.org/10.1039/D1EE00532DCrossref Google Scholar However, with more than 60 countries worldwide having pledged to become carbon neutral by 2050,31Höhne N. Gidden M.J. den Elzen M. Hans F. Fyson C. Geiges A. Jeffery M.L. Gonzales-Zuñiga S. Mooldijk S. Hare W. Rogelj J. Wave of net zero emission targets opens window to meeting the Paris Agreement.Nat. Clim. Change. 2021; 11: 820-822https://doi.org/10.1038/s41558-021-01142-2Crossref Scopus (65) Google Scholar,32Net Zero TrackerNet Zero Stocktake 2022: Assessing the Status and Trends of Net Zero Target Setting across Countries, Sub-national Governments and Companies. New Clim. Institute, Oxford Net zero, energy clim. Intell. Unit data-driven EnviroLab, 2022https://www.zerotracker.net/analysis/net-zero-stocktake-2022/Google Scholar the emissions of the chemical sector will need to peak in the next few years and decline around 2030.15IEAChemicals.2021Google Scholar The chemical industry can continue to deliver its service while complying with net-zero targets through multiple production routes.33Schlögl R. Abanades C. Aresta M. Azapagic A. Blekkan E.A. Cantat T. Centi G. Duic N. El Khamlichi A. Hutchings G. Mazzotti M. Novel Carbon Capture and Utilisation technologies: research and climate aspects.2018https://doi.org/10.26356/CARBONCAPTURECrossref Google Scholar,34Gabrielli P. Gazzani M. Mazzotti M. The role of carbon capture and utilization, carbon capture and storage, and biomass to enable a net-zero-CO2 emissions chemical industry.Ind. Eng. Chem. Res. 2020; 59: 7033-7045https://doi.org/10.1021/acs.iecr.9b06579Crossref Scopus (184) Google Scholar These are illustrated in Figure 2, together with the current BAU route. A fossil fuel provides the carbon atoms, the hydrogen atoms, and most of the energy required for the product synthesis. Such fossil-based industry yields net-positive CO2 emissions into the atmosphere over the product lifetime, which is typically significantly shorter than any climate-relevant timescale. The bulk CO2 emissions are due to the product synthesis and, for C-based chemicals, to the end-of-life of the carbon content (e.g., via combustion or decomposition). Additional CO2 emissions are due to fossil fuel extraction and preparation, as well as leakages along the supply chain, which can contribute up to about 20% of the total emissions.16Cabernard L. Pfister S. Oberschelp C. Hellweg S. Growing environmental footprint of plastics driven by coal combustion.Nat. Sustain. 2021; 5: 139-148https://doi.org/10.1038/s41893-021-00807-2Crossref Scopus (66) Google Scholar,35IPCCShukla R. Skea J. Slade R. Al Khourdajie A. van Diemen R. McCollum D. Pathak M. Some S. Vyas P. Fradera R. Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change P. 2022https://doi.org/10.1017/9781009157926Crossref Google Scholar Within BAU, improvements to efficiency and carbon intensity are underway by reducing the use of coal, recovery of waste heat, electrification (e.g., of steam crackers), and switching from steam boilers to steam/power co-generation.30Lange J.-P. Towards circular carbo-chemicals – the metamorphosis of petrochemicals.Energy Environ. Sci. 2021; 14: 4358-4376https://doi.org/10.1039/D1EE00532DCrossref Google Scholar For example, the European chemical industry recorded a 58% reduction in CO2 emissions from 1990 to 2017, despite the growth of the sector.7Brudermüller M. How to Build a More Climate-Friendly Chemical Industry.2020Google Scholar Therefore, further efficiency gains in chemical production are expected to have a relatively modest impact in terms of energy and emissions savings, and more transformative measures will be required.36Jones N. Net-zero Goals in Chemical Industry Could Shift Energy Demand.2022https://insight.factset.com/net-zero-goals-in-chemical-industry-could-shift-energy-demandGoogle Scholar In the carbon capture and storage (CCS) route, chemicals are still synthesized from fossil fuels using the current organic chemistry (the same as BAU). However, all CO2 emissions generated along the chain (i.e., product synthesis, end-of-life, and other CO2-positive processes) are captured and permanently stored in suitable underground geological structures or in building materials. CO2 can be captured exclusively from the air via direct air capture (DAC) or via a combination of point-source capture (PSC) and DAC. PSC is more favorable costs- and energy-wise, but might not always be viable.37Bui M. Adjiman C.S. Bardow A. Anthony E.J. Boston A. Brown S. Fennell P.S. Fuss S. Galindo A. Hackett L.A. et al.Carbon capture and storage (CCS): the way forward.Energy Environ. Sci. 2018; 11: 1062-1176https://doi.org/10.1039/C7EE02342ACrossref Google Scholar Overall, CCS routes are available today at a commercial scale, with costs that range from a few tens of US dollars per tCO2 for capture from concentrated sources to a few hundred for capture from air.37Bui M. Adjiman C.S. Bardow A. Anthony E.J. Boston A. Brown S. Fennell P.S. Fuss S. Galindo A. Hackett L.A. et al.Carbon capture and storage (CCS): the way forward.Energy Environ. Sci. 2018; 11: 1062-1176https://doi.org/10.1039/C7EE02342ACrossref Google Scholar,38Kearns D. Liu H. Consoli C. Technology Readiness and Costs of CCS.2021Google Scholar,39Wang X. Song C. Carbon capture from flue gas and the atmosphere: a perspective.Front. Energy Res. 2020; 8https://doi.org/10.3389/fenrg.2020.560849Crossref PubMed Scopus (90) Google Scholar,40IEADirect Air Capture.2022Google Scholar While considered key in abating the emissions of hard-to-abate industries, CCS routes rely on the continued use of fossil fuels and on the availability of large CO2 storage capacity, which result in social acceptability challenges for CCS deployment.41Paltsev S. Morris J. Kheshgi H. Herzog H. Hard-to-Abate Sectors: the role of industrial carbon capture and storage (CCS) in emission mitigation.Appl. Energy. 2021; 300117322https://doi.org/10.1016/j.apenergy.2021.117322Crossref Scopus (52) Google Scholar In the carbon capture and utilization (CCU) route, the chemical industry achieves net-zero carbon emissions by substituting the provenience of carbon for C-based chemicals: from the high-energy reduced fossil carbon to the oxidized low-energy carbon in the CO2, which has been previously captured fro