key: cord-0976511-1wtwlul3 authors: Kaiser, Simon; Bringezu, Stefan title: Use of Carbon Dioxide as Raw Material to close the Carbon Cycle for the German Chemical and Polymer Industries date: 2020-06-29 journal: J Clean Prod DOI: 10.1016/j.jclepro.2020.122775 sha: 2d72bf014e937a1689da288e9c92879a115b80c1 doc_id: 976511 cord_uid: 1wtwlul3 This article explores how far the use of CO(2) as raw material could enable the German chemical and polymer industries to contribute to a circular economy. Material Flow Analysis was conducted for all carbon flows for material use in Germany, comprising chemical production, polymer production, domestic use and waste management. For scenario modelling, Carbon Capture and Utilization technologies were included, and key parameters determining carbon flows were altered to show potential corridors for the future development. The results show that current carbon flows are dominated by fossil sources and are highly linear, with a secondary input rate of only 6 %. Additionally, 11 % (2 Mt/a) of the primary carbon input is lost due to dissipation. Currently available Carbon Capture and Utilization technologies would allow reaching a secondary input rate of 65 % for the chemical industry. However, to achieve this rate between 80 % (processes of direct synthesis) and 103 % (methanol-based processes) of the total net supply for renewable electricity in Germany would be required in 2030 and between 41 % and 50 % in 2050. In contrast, the unavoidable substance related CO(2)-point sources in Germany could probably fulfill the carbon requirement for material use of the chemical industry in 2050. The authors conclude that the utilization of CO(2) as a carbon source is necessary to close the carbon cycle where material or chemical recycling is technically not feasible or reasonable. The very high demand for renewable electricity indicates that the required production facilities for CO(2)-based chemicals will probably not be completely based in Germany. The reduction of greenhouse gas (GHG) emissions and a more efficient usage of natural 28 resources are two important goals to reduce environmental pressures of production and 29 consumption. Both goals in combination with concrete regulations are part of national 30 (Federal Government of Germany, 2018) and international political strategies (European 31 Commission, 2015) and legislation (German Federal Parliament, 2019 Parliament, , 2017b . To reduce 32 GHG emissions it is necessary to substitute fossil resources in production and consumption. 33 To raise the resource efficiency, natural resources should be used in a circular and not linear 34 way within an economy. 35 Carbon plays a key role for today's chemical and polymer industries for energy as well as 36 material purposes. Carbon carriers like coal or hydrocarbons are burnt to generate heat, 37 electricity or both. Furthermore, carbon is the basic material in organic chemistry. It is 38 necessary to produce products like polymers, solvents or hygienic products. In Germany, 39 15 % of the consumed petroleum is used as material input to produce organic chemical 40 products (VCI, 2019). In both cases, the carbon emitted into the atmosphere as CO 2 at the 41 end of its life cycle. Since around 90 % of the used resources are fossil based (VCI, 2019), 42 the use of carbon as material leads to net emissions of CO 2 (>20 Mt /a in Germany) (UBA, 43 2018) . 44 While options exist to substitute carbon for energy related purposes, the material use of 45 carbon is more challenging. Combustion processes to generate electricity and heat can be 46 substituted with renewable power sources like wind and solar together with the electrification 47 of heat production (Bazzanella and Ausfelder, 2017) . In contrast, alternatives for the 48 substitution of fossil carbon used as material are lacking. 49 Biogenic resources could be an alternative, but the expansion of the currently used amount 50 is critical. An increased use of biogenic carbon sources to produce chemicals would lead to 51 similar problems caused by the production of 1 st generation biofuels, like an increase in 52 eutrophication (Weiss et al., 2012) . Since the amount of global cropland is limited, an 53 increased use of cropland for material use would raise the competition with food crops 54 (UNEP, 2014) and counteract the necessary development towards sustainable land use 55 rates . Additionally, recent publications show that the risk of 56 biodiversity losses would increase globally (Di Fulvio et al., 2019; IRP, 2017) . Hence, the 57 expansion of the use of biogenic sources for material use is not regarded as option in this 58 article. 59 The utilization of CO 2 as a source for carbon used as material seems like a more promising 60 option. First, the feasibility is well described in theory and shown in practice. There are 61 multiple technological options to use CO 2 in combination with additionally produced H 2 as a 62 carbon source to produce a variety of organic chemicals (Mikkelsen et al., 2010; Styring et 63 al., 2015) . Moreover, Bringezu (2014) qualitatively showed pathways for a circular use of 64 carbon within an economy using CO 2 as the carbon source. Von der Assen and colleagues 65 (2016) analyzed the availability of CO 2 -sources in Europe. They concluded that there are 66 enough CO 2 sources to satisfy a demand of 500 Mt CO 2 /a in Europe. Recent To calculate the carbon input of the system, two sets of parameters are necessary. The first 120 set contains the amount of non-energetically used energy carriers, i.e. energy carriers used 121 as raw material for the production of chemicals or polymers instead of the use as fuel 122 (Destatis, 2019a) . The second set contains the stoichiometric carbon content of the 123 respective energy carriers. Finally, the carbon input flows for material use are quantified by 124 multiplying the amount of the non-energetically used energy carriers with the specific carbon 125 content. This calculation procedure was done likewise for all following product and waste 126 flows, within and out of the system. 127 In case of complex and highly variant material compositions or a lack of flow data, the carbon The High Circularity (HC) scenario represents an ambitious development where a completely 171 regenerative (secondary input + biogenic input) carbon supply for the system is reached by 172 2050. Therefore, the annual growth rates for material recycling are twice as high (+1 % per 173 year) compared to the LC scenario and the application of CCU technologies is accelerated. Therefore, it was assumed that this technology or a different technology with a similar 213 sequestration rate can be applied for all cases presented in Table 1 . However, the availability 214 of a specific point source for CCU technologies was determined by certain criteria to ensure 215 that emissions avoidance has a higher priority than emission utilization. CO 2 point sources 216 whose only function is the burning or processing of fossil energy carriers, like coal, lignite 217 and natural gas fired power plants or refineries are not considered. Their future substitution 218 in Germany is probable and necessary to reach the GHG reduction goals. In 2017, these 219 sources accounted for a total emission volume of 478 Mt CO 2 /a (DEHSt, 2018) or 60 % of 220 the total CO 2 -emissions in Germany (UBA, 2019b). Furthermore, CO 2 -emissions from the 221 remaining point sources are distinguished into energy and substance related emissions 222 according to UBA (2019b). Energy related emissions usually result from the incineration of 223 fossil fuels, and thus are neither regarded as sustainable sources of CO 2 . Substance related 224 emissions have their origin in the processing of materials and the related stoichiometry 225 ( Currently, substance related emissions usually come along with energy related emissions 228 (except for Biogas Production) because of the energy requirement of the respective process. 229 The energy related emissions can be avoided by substitution of the energy supply (or higher 230 energy efficiency). In contrast, substance related emissions can only be avoided if the basic 231 technology for the provision of materials such as cement and biogas is substituted as well. In 232 2017 the substance related emissions in Germany accounted for 85 Mt of CO 2 /a (Table 10 in 233 SI-5) or 11 % of the total CO 2 -emissions in Germany (UBA, 2019b). 234 Three of the possible substance related point sources are also considered as avoidable in 235 the longer term (Table 1) . The respective emissions are considered as an available 236 CO 2 -source in 2030 but not in 2050. First, the substance related emissions of ammonia (NH 3 ) 237 production can be avoided by using electrolysis instead of methane to produce the required 238 H 2 . Therefore, the substance related emissions of the ammonia production are considered 239 avoidable. Second, the non-energy related emissions of petrochemical processes will be 240 avoided if CO 2 is used as a carbon source instead of fossil energy carriers. Third, substance 241 related emissions of iron and non-iron metal production with coke as a reduction medium can 242 be avoided using direct reduction technologies via H 2 (Arcelor Mittal, 2019). In total 19 Mt of carbon (including recycled carbon) were converted and used as material in 296 the system. Fossil resources accounted for 89 % (crude oil derivates: 81 %; natural gas: 297 8 %) and biogenic sources for 11 % of the carbon input. Two thirds of the carbon are used to 298 produce polymers and polymer products while one third is used in form of non-polymer 299 products such as paints, coatings, carbon black, cosmetic products or washing powder. The 300 net-addition to the anthropogenic stock of 7 Mt shows that a high share of the carbon input is 301 additionally accumulated in the economy. The highest losses (5 Mt) occur in waste 302 management due to waste incineration. The dissipation into the environment also accounts 303 for significant losses (2 Mt). It occurs using chemical products, for example, when the solvent 304 component of a coating evaporates after its application. Even though there is recycling of 305 industrial and pc-waste, the amount of carbon recycled is rather low compared to the primary 306 input. 307 Table 2 shows the results for the circularity indicators of the CPUW-System. They express 308 the strong linearity of the system as well as differences between the industries. All values for 309 the SI-Rate are below 10 % or even 1 %. Comparison of the SI-Rates shows that the share 310 of used secondary material is significantly higher in the polymer industry than in the chemical 311 industry. The R-Rates for industrial recycling are higher with a factor 3.5 to 4 than for pc-312 recycling. This is a result of purer waste streams within the industry. However, the high 313 recycling rates within the industry do not have a significant influence on the overall R-Rate 314 (18 %) because of their comparably low magnitude. Especially for the chemical industry, the 315 existing recycling flows hardly have a relevance. Additionally, more than half of the carbon 316 input is lost in the form of emissions caused by waste incineration, dissipation and foreign 317 trade. The latter accounts for only 28 % of the losses. The scenario analysis outlines a broadening corridor of potential future development (Table 330 3). In the LC scenario only a moderate circularity for carbon used as material can be 331 achieved. Although the circularity indicators are much higher in 2050 than in the status quo, 332 about two thirds of the carbon input of the overall system would still be primary and fossil. 333 Additionally, in none of the industries a SI-Rate greater than 50 % is achieved. In the HC 334 scenario a completely regenerative carbon input is achieved for the whole system. This 335 means, that no fossil carbon input is necessary anymore. This is caused by the utilization of 336 CO 2 as carbon source as well as the increased rates for recycling in combination with the 337 absence of a net addition to the anthropogenic stock. With the currently known CCU-Technologies to produce base chemicals a maximum SI-Rate 381 of 65 % can be achieved. The production of high-volume base chemicals like buta-1,3-dien 382 and butylene or other chemical products like carbon black cannot be substituted with 383 CO 2 -based processes, yet. Thus, it was analyzed how high the SI-Rate could be using the 384 available REE to produce the H 2 -demand for the described CCU process routes. The main data sources are federal statistics for Germany and Europe, recent scientific 407 publications or life cycle databases. Therefore, data reliability as well as temporal and 408 geographical correlation can be regarded as very good. Nevertheless, due to the 409 combination of databases with different system boundaries and data gaps several 410 uncertainties had to be considered. They are described in detail in the SI-6. However, these 411 uncertainties do not affect the order of magnitude and main ratios of the shown material 412 flows in the system but should be addressed in further research. for CCU may not provide the highest environmental benefit. For example, the direct 444 utilization of REE for battery electric vehicles or heat pumps would have a higher GHG 445 mitigation potential (Sternberg and Bardow, 2015) . Another constraint for the planning of 446 CCU installations is that in the current models for the future German energy system, the 447 chemical industry is hardly seen as a consumer of REE to produce non-energetically used 448 hydrocarbons. If CCU productions plants are built in Germany, there will be a competition for 449 REE between the chemical industry and other sectors like transport or heating. This needs to 450 be considered in future scenarios for sustainable energy and material supply. Furthermore, 451 the limited availability of REE will also have a limiting impact on the CO 2 -requirement. 452 Therefore, it seems probable that the existing non-avoidable substance related point sources 453 will fulfill the future CO 2 -requirement for CCU processes based in Germany. In contrast, the 454 application of DAC as a CO 2 -source in Germany seems rather unlikely. 455 In general, the chemical and polymer industries will have to consider the possible future role 456 of CO 2 -utilization and the options for a more circular use of carbon. On the one hand, the 457 analysis clearly showed that due to non-avoidable dissipative losses in the use phase and a 458 net export, recycling of waste flows is by no means sufficient to secure a regenerative supply 459 of carbon. The use of CO 2 as a carbon source is necessary to compensate these carbon 460 losses. Furthermore, the expansion of material recycling processes is already critical and 461 uncertain due to technical constraints (Rudolph et al., 2017) . On the other hand, there are 462 barriers for the application of CCU processes. First, they require high amounts of the scarce 463 resource REE, since the energy hitherto bound in fossil energy carriers must be provided in a 464 renewable way. Second, actual estimations of production costs for CO 2 -based base 465 chemicals are much higher than for fossil-based alternatives (Hoppe et al., 2018b) . This is 466 mainly caused by high energy costs and the still small scales. Third, chemical recycling 467 processes such as pyrolysis or gasification also offer the potential to recycle carbon in waste 468 flows which cannot be materially recycled (Stapf et al., 2019) . However, this technology is 469 limited to waste flows and cannot compensate dissipative losses. Therefore, ecological and 470 economical aspects of CCU as well as material and chemical recycling technologies need to 471 be compared systematically to identify favorable application fields. Additionally, there are 472 regions with higher availability and lower costs for REE than in Germany, for example the 473 Maghreb region (Agora, 2018) . Here, the production of CO 2 -based chemicals is likely to be 474 more competitive than in Germany. Hence, it is unlikely that the German chemical industry 475 will produce all required CO 2 -based chemicals on itself but import relevant shares. However, 476 the targeted transition of the current energy system towards mostly renewable energy 477 sources requires concepts for efficient and large-scale energy storages. Synthetic gases like 478 H 2 or CH 4 as well as synthetic Hydrocarbons like Methanol are discussed as options to store 479 volatile electricity production from renewable energy sources (Specht et al., 2009) . Hence, 480 the CO 2 -based production of chemicals could be used to produce sustainable raw material 481 for the chemical industry while delivering storage services to the energy system at the same instance metal production, the circularity for carbon used as material is significantly lower. 499 Most of the carbon losses occur as emissions after waste incineration. Additionally, 500 dissipative use of carbon containing products cause relevant losses. This shows the 501 requirement as well as the potential for enhanced and additional recycling of carbon used as 502 material in order to develop towards a circular economy. CCU technologies can enhance the 503 circularity of carbon used as material by creating additional recycling cycles and also 504 compensate dissipative losses. However, the high REE-requirement of CCU processes 505 implies that CO 2 should only be used if material recycling, in particular of polymers, can 506 hardly be applied. 507 With respect to the necessary resources in Germany, the situation is different for CO 2 and 508 REE now and in the future. Even if only non-avoidable substance related CO 2 point sources 509 are regarded, the CO 2 -requirement is mostly fulfilled while DAC technology or imports could 510 fill the remaining gap. In contrast, REE-availability is limited and REE will remain a scarce 511 resource in the future. A competition between chemical and polymer industries with other 512 production sectors and with transport for REE can be expected. Probably, the application of 513 CCU technologies to produce base chemicals for the German market will mostly take place 514 at international locations with better conditions for REE production. 515 Further research is advisable to enhance the results of the MFA, and to shed light on 516 dissipative losses of carbon used as material and about carbon stocks within the society. 517 Furthermore, the environmental and economic performance of CCU processes should be 518 compared to material as well as chemical recycling to identify the most efficient way to 519 recycle carbon used as material. At the macro level, the production of base chemicals should 520 be included in future energy models for Germany, which need to be developed towards 521 integrated energy and material supply models, considering REE-availability and 522 requirements of all economic sectors. Finally, possible international production locations 523 should be identified and compared with locations in Germany with respect to environmental 524 and economic conditions. 525 The Future Costs of Electricity based Fuels. (Original German title: Die 530 zukünftigen Kosten strombasierter synthetischer Brennstoffe) World first for steel: ArcelorMittal investigates the industrial use of pure 533 hydrogen Selecting CO2 536 Sources for CO2 Utilization by Environmental-Merit-Order Curves. Environmental science 537 & technology Low carbon energy and feedstock for the European 539 chemical industry. DECHEMA, Society for Chemical Engineering and Biotechnology, 540 Frankfurt am Main Status Report of the German Circular Economy -Insights and Perspectives Federation of the German Waste, Water and Raw Materials Management 544 Industry Non-fossil CO2 recycling-The technical potential for the present and future 547 utilization for fuels in Germany Growth, Structural Transformation and Employment Comission -Final Report The Federal Ministry for Economic Affairs and Energy Carbon Recycling for Renewable Materials and Energy Supply Beyond biofuels: Assessing global land use for 555 domestic consumption of biomass Guidelines 558 for Biogas Processing and Feed-in. (Original German Title: Leitfaden Biogasaufbereitung 559 und -einspeisung) Handbook of material flow analysis: For environmental, 561 resource, and waste engineers Carbon capture and storage (CCS): the way forward The Next Generation of Carbon for the Process Industry: Deliverable 2.1 569 -Report on fully integrated and intensified value chain concepts for process selection Greenhouse Gas Emissions Housing stock shrinkage: vacancy and 576 demolition trends in Germany List of Goods for Production Statistics. (Original German Title: 579 Güterverzeichnis für Produktionsstatistiken (GP 2019)). Federal Statistics Office Definition of "Non-energetical Usage Index of production in manufacturing Spatially explicit 589 LCA analysis of biodiversity losses due to different bioenergy policies in the European 590 Union Closing the loop -An EU action plan for the circular economy Identification and analysis of promising carbon capture and 595 utilisation technologies, including their regulatory aspects Techno-economic assessment of CO2 direct air 597 capture plants Update. The Federal Government of Germany Coalition Agreement between CDU, CSU and SPD -602 19th Legislative Period Roadmap 605 Chemistry 2050 -On the Way torwards a GHG neutral Chemical Industry in Germany Law on further Development of the Seperate 609 Registration of Domestic Wastes containing Valuable Material. (Original German Title: 610 Gesetz zur Fortentwicklung der haushaltsnahen Getrennterfassung von wertstoffhaltigen 611 Abfällen Law on the Support of the Circular Economy and the 613 Securing of an Environmentally Compatible Managment of Waste. (Original German Title: 614 Gesetz zur Förderung der Kreislaufwirtschaft und Sicherung der umweltverträglichen 615 Bewirtschaftung von Abfällen National Climate Protection Law resolved by the German 617 Federal Parliament (Original German Title: Klimaschutzgesetz im Bundestag 618 beschlossen). German Federal Parliament Effects of Demographic Change on the Material Stock and 621 Flows of the exisiting Building Stock -Germany 2050. (Original German Title: 622 Auswirkungen des demografischen Wandels auf das Stofflager und die Stoffflüsse des 623 Wohngebäudebestandes -Deutschland 2050) How to monitor environmental 625 pressures of a circular economy: An assessment of indicators System Analysis Comparison of Raw Material Usage Options for CO2 628 using Renewable Energy with a special consideration of the Ressource Efficiency and the 629 GHG Balance Nutzungsoptionen von CO2 bei Verwendung regenerativer Energien unter besonderer Berücksichtigung der Ressourceneffizienz und Treibhausgasbilanz) Economic assessment of CO 2 -based 634 methane, methanol and polyoxymethylene production Life Cycle Assessment of Carbon Dioxide-637 Based Production of Methane and Methanol and Derived Polymers Global Energy and CO2 Status Report Monthly Oil Prices Statistics Assessing Global Resource Use: A systems approach to resource efficiency and 644 pollution reduction. United Nationes Environment Program Climate change mitigation 646 potential of carbon capture and utilization in the chemical industry The teraton challenge. A review of fixation 650 and transformation of carbon dioxide The socio-economic implications of the coronavirus pandemic (COVID-19): A 654 review Long-660 term Scenarios for the Transformation of the German Energy System. Modul 3: 661 Reference Scenario and Basis Scenario Fraunhofer Institut für System-und Innovationsforschung Understanding plastics recycling: Economic, 665 ecological, and technical aspects of plastic waste handling Storage of Bioenergy and Renewable Electricity in the Natural Gas 669 Original German Title: Speicherung von Bioenergie und erneuerbarem Strom im 670 Erdgasnetz) Thermal Methods for the Feedstock Recycling of 674 Polymer containing Waste. (Original German Title: Thermische Verfahren zur 675 rohstofflichen Verwertung kunststoffhaltiger Abfälle) Power-to-What?: -Environmental assessment of energy 677 storage systems Life cycle assessment of CO2-based C1-680 chemicals Carbon dioxide utilisation: Closing the carbon 682 cycle Energy Generation from Waste -Status and Potentials in Germany until 2030. 684 (German Original Title: Energieerzeugung aus Abfällen -Stand und Potenziale in 685 Deutschland bis 2030) A resource efficient pathway towards a greenhouse gas neutral Germany Submission under the United Nations Framework Convention on Climate 689 Change and the Kyoto Protocol Greenhouse Gas Inventory Grid Development Plan Electricity 2030 -Second Draft of the Transmission Grid 692 German Original Title: Netzentwicklungsplan Strom 2030 -Zweiter Entwurf 693 der Übertragungsnetzbetreiber). 50Hertz Transmission GmbH; Amprion GmbH Assessing global land use: Balancing consumption with sustainable supply: A 696 Report of the Working Group on Land and Soils of the International Resource Panel. 697 United Nationes Environment Program Chemical Industry in Numbers 2012. (German Original Title: Chemiewirtschaft in 699 Zahlen Association of the German Chemical Industries Association of the German Chemical Industries Association of the German Chemical Industries Association of the German Chemical Industries Verband der Chemischen Industrie e Association of the German Chemical Industries Raw Material Basis of the Chemical Industry 716 A Review of the Environmental Impacts of Biobased Materials Substance Related Emissions -Higher Limit Substance Related Emissions -Lower Limit Substance Related Emissions -Lower Limit (large sources) CCU-processes (Methanol-based) The authors thank the German Federal Ministry of Education and Research (BMBF) for their 527 support within the framework of CO 2 Plus (Funding Number: 033RC001C). 528