The technological and economic prospects for CO2 utilization and removal

Previous reviews have shown that non-conventional utilization pathways offer substantial CO2 removal potential.

“Previous reviews 18,28,[52][53][54] have shown that these pathways offer substantial CO 2 removal potential:”

• cites [18] Smith, P. et al. Biophysical and economic limits to negative CO2 emissions. Nat. Clim. Change 6, 42–50 (2016). This paper quantifies potential global impacts of various negative emissions technologies in the context of biophysical resource constraints. sourcePartly supported

  The Global resource implications of NETs deployment section estimates gigatonne-scale CO₂ removal for technologies including BECCS, supporting substantial removal potential. But the review assesses negative-emissions technologies, not the cited sentence’s specific category of “non-conventional utilization pathways”; our copy does not establish that those pathways have the stated potential. (LLM, conf=0.82)

  Experimental — accuracy not yet measured
• cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. sourceDisputed

  Section 3.8 (page not provided) discusses CO₂ utilization pathways but raises doubts that they can contribute much to large-scale negative emissions. It also reports a concern that chemical conversion is highly unlikely to provide more than 1% of the mitigation needed for the Paris temperature goal, contrary to the claim of substantial removal potential. (LLM, conf=0.87)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured
• cites [52][53][54]Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

In the short term, the creation of products from concentrated CO2 could leverage the industrial capture of flue gases following the extraction and combustion of fossil fuels.

“In the short term, the creation of products from concentrated CO 2 , as in step L (albeit, CO 2 conversion is not a necessary requirement for utilization), could leverage the industrial capture of flue gases following the extraction and combustion of fossil fuels (KC) 27 .”

• cites [27] Naims, H. Economics of carbon dioxide capture and utilization—a supply and demand perspective. Environ. Sci. Pollut. Res. 23, 22226–22241 (2016). This paper analyses CO 2 supply and demand scenarios to conclude that the business case for CO 2 utilization is technology-specific. sourcePartly supported

  The Short-term scenarios section says near-term CO2 product demand could be met by capturing high-purity emissions, including those from natural gas production. The Conclusions and perspectives section also describes recovered industrial CO2 as a feedstock for consumer goods. But the paper associates capture from coal-fired power plants with longer-term, larger-scale scenarios, rather than the short-term pathway the claim suggests. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

Perverse indirect effects such as land-use change resulting from BECCS could increase net atmospheric CO2 concentrations.

“For instance, perverse indirect effects-such as land-use change resulting from BECCS 14 -could increase net atmospheric CO 2 concentrations.”

• cites [14] Harper, A. B. et al. Land-use emissions play a critical role in land-based mitigation for Paris climate targets. Nat. Commun. 9, 2938 (2018). sourceSupported

Some CO2 chemical technologies are commercialized, such as the production of urea and polycarbonate polyols.

“Some are commercialized 29 , such as the production of urea 30 and polycarbonate polyols 31 .”

• cites [29] Otto, A., Grube, T., Schiebahn, S. & Stolten, D. Closing the loop: captured CO2 as a feedstock in the chemical industry. Energy Environ. Sci. 8, 3283–3297 (2015). sourceSupported
• cites [30] Pérez-Fortes, M., Bocin-Dumitriu, A. & Tzimas, E. CO2 utilization pathways: Techno-economic assessment and market opportunities. Energy Procedia 63, 7968–7975 (2014). sourceSupported
• cites [31] Langanke, J. et al. Carbon dioxide (CO2) as sustainable feedstock for polyurethane production. Green Chem. 16, 1865–1870 (2014). sourceNot checked — no full text of the source

Such plastic products have lifespans of decades or even centuries.

“Such products have lifespans of decades or even centuries 36 .”

• cites [36] Geyer, R., Jambeck, J. R. & Law, K. L. Production, use, and fate of all plastics ever made. Sci. Adv. 3, e1700782 (2017). sourcePartly supported

  The Results and Discussion section (page unavailable) models product lifetimes ranging from less than a year for packaging to decades for building and construction plastics. It does not establish that products remain in use for centuries; the paper’s discussion of plastics persisting after disposal is distinct from product lifespan. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

The production of more complex hydrocarbons is energetically and therefore economically expensive.

“Although the production of more complex hydrocarbons is energetically and therefore economically expensive 11”

• cites [11] Bushuyev, O. S. et al. What should we make with CO2 and how can we make it? Joule 2, 825–832 (2018). sourceSupported

Increasing urea production may therefore have a negative impact on climate.

“Increasing urea production may therefore have a negative impact on climate 35 .”

• cites [35] Luo, J., Ledgard, S. & Lindsey, S. Nitrous oxide emissions from application of urea on New Zealand pasture. N. Z. J. Agric. Res. 50, 1–11 (2007). sourcePartly supported

  The Introduction links nitrous oxide emissions to global warming, and the Abstract reports that applying urea to New Zealand pasture generally increased those emissions. This supports a potential climate impact from increased urea use, but the paper does not assess the impact of increasing urea production itself. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

Some CO2 chemical technologies are technically possible but not widely adopted, such as the production of CO2-derived methanol in the absence of carbon monoxide.

“Some are technically possible but are not widely adopted, such as the production of CO 2 -derived methanol in the absence of carbon monoxide 32”

• cites [32] Shih, C. F., Zhang, T., Li, J. & Bai, C. Powering the future with liquid sunshine. Joule, 2, 1925–1949 (2018). sourcePartly supported

  The “Roadmap from Fossilized Sunshine to Liquid Sunshine” section describes methanol production from captured CO₂ and says the first commercial deployment of this green-methanol technology could be expected in 2040, supporting that it was not widely deployed. The “5G Liquid Sunshine: Green Alcohol Production” section describes CO₂ hydrogenation approaches, but neither passage establishes production in the absence of carbon monoxide. (LLM, conf=0.83)

  Experimental — accuracy not yet measured

In recent years, several wind and solar power auctions around the world have been won with prices below $0.03 kWh-1.

“In recent years, several wind and solar power auctions around the world have been won with prices below 41 $0.03 kWh -1 .”

• cites [41] De Luna, P. et al. What would it take for renewably powered electrosynthesis to displace petrochemical processes? Science 364, eaav3506 (2019). This paper reviews the potential for and costs of using renewable energy for electrochemical conversion of concentrated CO 2 into formic acid, carbon monoxide, ethylene and ethanol, and compares biocatalytic and Fischer–Tropsch routes to long-chain chemical production. sourcePartly supported

  In “Pathways toward industrial implementation” (page not supplied), the paper reports recent onshore wind auctions in several countries with costs as low as $0.03/kWh. It does not report solar auctions at that price, and “as low as” $0.03/kWh does not establish prices below it. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

The flux of carbon from fossil fuels and industry to the atmosphere (34 Gt CO2 yr-1) is dwarfed by the gross flux to land via photosynthesis in plants (440 Gt CO2 yr-1).

“The flux of carbon from fossil fuels and industry to the atmosphere (34 Gt CO 2 yr -1 ) 15 is dwarfed by the gross flux to land via photosynthesis in plants (440 Gt CO 2 yr -1 ) 16 .”

• cites [15] Le Quéré, C. et al. Global carbon budget 2018. Earth Syst. Sci. Data 10, 2141–2194 (2018). sourceCould not verify

  The citation is attached to the 440 Gt CO2 yr−1 gross photosynthetic flux. The Figure 2 caption (section 2.8.3, p. 19) says that natural-cycle fluxes appear in the figure, but our copy contains only an image placeholder, not its values. Searches for photosynthesis, gross primary production, 120 GtC yr−1, and 440 Gt CO2 yr−1 found no passage stating the claimed flux. (LLM, conf=0.72)

  Experimental — accuracy not yet measured
• cites [16] IPCC Climate Change 2014: Mitigation of Climate Change (eds. Edenhofer, O. et al.) (Cambridge Univ. Press, 2014).Not checked yet

  Not checked in the free run.

In the current market structure, around 60% of plastics have applications in sectors other than packaging, including as durable materials for construction, household goods, electronics, and in vehicles.

“In the current market structure, around 60% of plastics have applications in sectors other than packaging-including as durable materials for construction, household goods, electronics, and in vehicles.”

• cites [36] Geyer, R., Jambeck, J. R. & Law, K. L. Production, use, and fate of all plastics ever made. Sci. Adv. 3, e1700782 (2017). sourcePartly supported

  The Results and Discussion report that 42% of primary nonfiber plastics produced in 2015 entered use as packaging, implying about 58% entered other sectors; they also identify construction as a major use. The figure is for primary nonfiber plastics, not all plastics, and the passages do not identify household goods, electronics, or vehicles as examples. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

CO2-derived fuels could find a role in sectors that are harder to decarbonize, such as aviation, since hydrocarbons have energy densities orders of magnitude above those of present-day batteries.

“Such fuels could also find a role in sectors that are harder to decarbonize, such as aviation 39 , since hydrocarbons have energy densities that are orders of magnitude above those of present-day batteries 32 .”

• cites [39] National Academies of Sciences, Engineering, and Medicine. Commercial Aircraft Propulsion and Energy Systems Research: Reducing Global Carbon Emissions (National Academies Press, 2016).Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites [32] Shih, C. F., Zhang, T., Li, J. & Bai, C. Powering the future with liquid sunshine. Joule, 2, 1925–1949 (2018). sourcePartly supported

  The “Supply Chain: Short-and Long-Term Storage” section says liquid energy carriers have energy densities typically 10–50 times those of batteries, supporting the comparison but not the claim of multiple orders of magnitude. The “Roadmap from Fossilized Sunshine to Liquid Sunshine” section discusses CO2-derived alcohol fuels; the passages found do not address their use in aviation. Page numbers were not available in our copy. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

For pathways that have high capital costs, the benefits of economies of scale and learning could be considerable.

“For pathways that have high capital costs, the benefits of economies of scale and learning could be considerable 42 .”

• cites [42] Dimitriou, I. et al. Carbon dioxide utilisation for production of transport fuels: process and economic analysis. Energy Environ. Sci. 8, 1775–1789 (2015). sourcePartly supported

  Section 5.5 links sensitivity to capital costs with the importance of economies of scale, and the Conclusions report substantially lower production costs for a larger CCU fuel plant. The paper does not establish benefits from learning, and its analysis concerns the evaluated CCU pathways rather than high-capital-cost pathways generally. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

A recent scoping review gives afforestation/reforestation removal potential of 0.5 to 3.6 Gt CO2 yr-1.

“a recent substantive scoping review 28 gives values of 0.5 to 3.6 Gt CO 2 yr -1 for afforestation/ reforestation,”

• cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. sourceSupported

Life-cycle analyses on some industrial CO2 utilization pathways suggest that the potential for net emission reductions is much larger than for net removals, which appears very modest.

“Life-cycle analyses on some industrial CO 2 utilization pathways suggest that the potential for net emission reductions is much larger than for net removals, which appears very modest 94 .”

• cites [94] Cuéllar-Franca, R. M. & Azapagic, A. Carbon capture, storage and utilisation technologies: a critical analysis and comparison of their life cycle environmental impacts. J. CO 2 Utilization 9, 82–102 (2015). This paper compares the environmental impacts of CO 2 utilization and CCS technologies by reviewing the literature of life cycle assessment studies. sourcePartly supported

  The Conclusions report life-cycle emissions reductions for several CO₂-utilisation pathways, while the Introduction says chemical demand has little capacity to sequester CO₂ and that fuel production delays emissions rather than removing them. The paper does not directly compare the overall potential for net emissions reductions with the potential for net removals, so the claimed relative magnitude is an inference. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

A recent scoping review gives BECCS removal potential of 0.5 to 5 Gt CO2 yr-1.

“and 0.5 to 5 Gt CO 2 yr -1 for BECCS.”

• cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. sourceSupported

Literature cost estimates for BECCS typically assign all costs to the CO2 removal service and implicitly assume that no revenue is received for the bioenergy services generated.

“Although several cost estimates exist in the literature-for example, around $200 per tonne of CO 2 28 -these typically assign all costs to the CO 2 removal service, and thus implicitly assume that no revenue is received for the bioenergy services that are generated.”

• cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. sourcePartly supported

  The BECCS costs discussion reports estimates reaching about US$200 per tonne of CO₂, supporting the cited cost example. It does not say that estimates typically assign all costs to CO₂ removal or assume no revenue from bioenergy services; those accounting claims are unsupported by our copy. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

The use of terrestrial enhanced weathering on croplands could increase crop yields.

“The use of terrestrial enhanced weathering on croplands could increase crop yields 28 .”

• cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. sourceSupported

Yield enhancement from enhanced weathering is unlikely to originate directly from increases in soil carbon, but from nutrient uptake facilitated by pH effects.

“This yield enhancement is unlikely to originate directly from increases in soil carbon, but from nutrient uptake that is facilitated by pH effects 57 .”

• cites [57] Beerling, D. J. et al. Farming with crops and rocks to address global climate, food and soil security. Nat. Plants 4, 138–147 (2018). sourcePartly supported

  In “Crop production and protection” (page unavailable), the paper says that reversing soil acidification improves nutrient uptake and crop yields, supporting the pH-related mechanism. But “Rocks for food and soil security” says increased soil organic carbon benefits yields and that the long-term carbon effects of applying silicate rocks remain unknown. It does not establish that soil-carbon increases are unlikely to contribute directly to the yield enhancement. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

A recent scoping review gives land management removal potential of 2.3 to 5.3 Gt CO2 yr-1.

“2.3 to 5.3 Gt CO 2 yr -1 for land management,”

• cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. sourcePartly supported

  The authors’ assessment in the soil carbon sequestration section gives a realistic technical potential of 3.8 (2.3–5.3) Gt CO₂ yr⁻¹ for 2050. The number matches, but it is an estimate for soil carbon sequestration specifically, not for land management as a whole. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

A recent scoping review gives biochar removal potential of 0.3 to 2 Gt CO2 yr-1.

“0.3 to 2 Gt CO 2 yr -1 for biochar,”

• cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. sourceSupported

In an economy with high supply-chain emissions, the climate benefit from BECCS is low.

“Conversely, in an economy with high supply-chain emissions, the climate benefit from BECCS is low 72 .”

• cites [72] Fajardy, M. & Mac Dowell, N. Can BECCS deliver sustainable and resource efficient negative emissions? Energy Environ. Sci. 10, 1389–1426 (2017). sourcePartly supported

  Section 3.5 says biomass supply-chain emissions can offset a BECCS plant’s carbon negativity, supporting the claim that such emissions reduce its climate benefit. But the paper assesses BECCS supply chains, not economies with high supply-chain emissions generally, and its Conclusion says BECCS can still deliver net CO₂ removal under suitable conditions. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

Wood products have potential as long-term stores of carbon, particularly when used in long-lived buildings, the lifespans of which can be conservatively estimated at 80-100 years.

“Wood products have potential as long-term stores of carbonparticularly when used in long-lived buildings, the lifespans of which can be conservatively estimated at 80-100 years 59 .”

• cites [59] Lippke, B. et al. Life cycle impacts of forest management and wood utilization on carbon mitigation: knowns and unknowns. Carbon Manage. 2, 303–333 (2011). sourcePartly supported

  The ‘Life cycle forest, product & integrated processing energy carbon pools’ section describes wood in housing and similar buildings as long-lived carbon storage and estimates a useful life of 80 years for US housing. It also says newer housing may last more than 80 years, but it does not give a 100-year upper estimate or call the 80–100-year range conservative. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Impacts on yield are likely to be highly variable, for example according to climatic zone.

“Impacts on yield are likely to be highly variable-for example, according to climatic zone 64 .”

• cites [64] Jeffery, S. et al. Biochar boosts tropical but not temperate crop yields. Environ. Res. Lett. 12, (2017). sourceSupported

The net climate impact of the CO2 utilization pathways will, in many cases, depend upon the emissions intensity from the prevailing processes.

“The net climate impact of the CO 2 utilization pathways will, in many cases, depend upon the emissions intensity from the prevailing processes 73 .”

• cites [73] Kätelhön, A., Meys, R., Deutz, S., Suh, S. & Bardow, A. Climate change mitigation potential of carbon capture and utilization in the chemical industry. Proc. Natl Acad. Sci. USA 116, 11187–11194 (2019). sourceSupported

In terms of the climate impact per kWh of electricity use, available renewable electricity is more efficiently directed towards e-mobility and heat pumps rather than towards hydrogen-based CCU technologies in the chemical industry.

“In terms of the climate impact per kWh of electricity use, available renewable electricity is more efficiently directed towards e-mobility and heat pumps rather than towards hydrogen-based CCU technologies in the chemical industry 73 .”

• cites [73] Kätelhön, A., Meys, R., Deutz, S., Suh, S. & Bardow, A. Climate change mitigation potential of carbon capture and utilization in the chemical industry. Proc. Natl Acad. Sci. USA 116, 11187–11194 (2019). sourceSupported

BECCS has a range of well-articulated risks, including considerable increases in emissions as a result of land-use change.

“BECCS has a range of well-articulated risks, including considerable increases in emissions as a result of land-use change 72 .”

• cites [72] Fajardy, M. & Mac Dowell, N. Can BECCS deliver sustainable and resource efficient negative emissions? Energy Environ. Sci. 10, 1389–1426 (2017). sourceSupported

The estimates are based on currently reported yield increases of 0.9% to 2% associated with soil carbon sequestration techniques and 10% associated with biochar, from sparse literature, using crop production as a proxy for net primary productivity.

“These estimates are based on currently reported yield increases (of 0.9% to 2% associated with soil carbon sequestration techniques 61,62 and 10% associated with biochar 63 ) from sparse literature, using crop production as a proxy for net primary productivity.”

• cites [61] Lal, R. Enhancing crop yields in the developing countries through restoration of the soil organic carbon pool in agricultural lands. Land Degrad. Dev. 17, 197–209 (2006). sourceNot checked — no full text of the source
• cites [62] Soussana, J.-F. et al. Matching policy and science: Rationale for the ‘4 per 1000-soils for food security and climate’ initiative. Soil Tillage Res. 188, 3–15 (2019). sourcePartly supported

  Section 3.3 reports that, across 32 studies in developing countries, a 1.3% annual increase in grain yield was associated with a 0.4% annual increase in soil organic carbon. This supports an association between soil-carbon gains and higher yields, but the paper does not report the cited 0.9%–2% range. Section 3.4 does not support a 10% yield increase from biochar; it notes that yield reductions have sometimes occurred. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [63] Jeffery, S., Verheijen, F. G., Van Der Velde, M. & Bastos, A. C. A quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis. Agric. Ecosyst. Environ. 144, 175–187 (2011). sourceNot checked — no full text of the source

Variations in yield effects are likely to hinder the economic decision made by farmers to apply biochar.

“A major challenge is to improve variations in yield effects, which are likely to hinder the economic decision made by farmers to apply biochar 86 ,”

• cites [86] Dickinson, D. et al. Cost-benefit analysis of using biochar to improve cereals agriculture. Glob. Change Biol. Bioenergy 7, 850–864 (2015). sourceSupported

Between 0.2 and 3.2 Gt CO2 yr-1 could be removed and stored in the lithosphere or in the biosphere for centuries or more.

“We also estimate that between 0.2 and 3.2 Gt CO 2 yr -1 could be removed and stored in the lithosphere or in the biosphere for centuries or more.”

Each of the conventional pathways-chemicals, fuels, microalgae, building materials and CO2-EOR-might utilize around 0.5 Gt CO2 yr-1 or more in 2050.

“Dependent on a multitude of technological, policy and economic factors that remain unresolved, each of the conventional pathways-chemicals, fuels, microalgae, building materials and CO 2 -EOR-might utilize around 0.5 Gt CO 2 yr -1 or more in 2050.”

The permanence of CO2 storage varies greatly from one utilization pathway to another, with storage timeframes ranging from days to millennia.

“however, the permanence of CO 2 storage varies greatly from one utilization pathway to another, with storage timeframes ranging from days to millennia.”

Breakeven costs per tonne of CO2 for urea (around -$100) and for polyols (around -$2,600) reflect that these markets are currently profitable.

“Breakeven costs per tonne of CO 2 , calculated from the scoping review, for urea (around -$100) and for polyols (around -$2,600) reflect that these markets are currently profitable.”

The estimated potential for the scale of CO2 utilization in fuels varies widely, from 1 to 4.2 Gt CO2 yr-1, reflecting uncertainties in potential market penetration.

“The estimated potential for the scale of CO 2 utilization in fuels varies widely, from 1 to 4.2 Gt CO 2 yr -1 , reflecting uncertainties in potential market penetration.”

The interquartile range for breakeven costs for CO2 fuels from the scoping review was $0 to $670 per tonne of CO2.

“The interquartile range for breakeven costs for CO 2 fuels from our scoping review was $0 to $670 per tonne of CO 2 .”

Each of the ten CO2 utilization pathways could scale to over 0.5 gigatonnes of CO2 utilization annually.

“Our assessment suggests that each pathway could scale to over 0.5 gigatonnes of carbon dioxide utilization annually.”

Of the ten pathways discussed, five leverage the ability to perturb land-based fluxes.

“Of the ten pathways we discuss, five leverage our ability to perturb these land-based fluxes.”

For the production of polymers, the utilization potential of CO2 is estimated to be 10 to 50 Mt yr-1 in 2050.

“For the production of polymers, the utilization potential of CO 2 is estimated to be 10 to 50 Mt yr -1 in 2050.”

The estimated breakeven costs for BECCS are between $60 and $160 per tonne of CO2 utilized.

“we estimate breakeven costs of between $60 and $160 per tonne of CO 2 utilized.”

The breakeven cost for concrete building materials is -$30 to $70 per tonne of CO2 utilized.

“breakeven costs of -$30 to $70 per tonne of CO 2.”

Negative breakeven costs for CO2 fuels appear in studies that model particularly beneficial scenarios, such as low discount rates, free feedstocks, or free or low-cost renewable electricity.

“Negative breakeven costs appear in studies that model particularly beneficial scenarios, such as low discount rates, free feedstocks, or free or low-cost renewable electricity.”

Of the volumes of CO2 sequestered via afforestation/reforestation in 2050, between 0.07 and 0.5 Gt of CO2 utilized per year may flow into industrial roundwood products.

“We estimate that, of the volumes of CO 2 sequestered via afforestation/reforestation in 2050, between 0.07 and 0.5 Gt of the CO 2 utilized per year may flow into industrial roundwood products,”

In CO2-EOR, the CO2 utilized can remain in the oil formation rather than being re-emitted into the atmosphere.

“For instance, obtaining a barrel of oil via CO 2 -EOR utilizes CO 2 , which can remain in the oil formation rather than being re-emitted into the atmosphere.”

The estimated 2050 CO2-EOR utilization rate is around 0.1 to 1.8 Gt CO2 yr-1.

“We estimate a 2050 utilization rate of around 0.1 to 1.8 Gt CO 2 yr -1 .”

Some CO2 utilization pathways involve chemical transformations that require the input of substantial amounts of energy.

“Some CO 2 utilization pathways involve chemical transformations that require the input of substantial amounts of energy (Supplementary Fig. 2).”

The remainder of the carbon in the wood-product pool will return to the atmosphere as a fraction (about 0.5 Gt CO2 yr-1) of the 5 Gt CO2 yr-1 land-use change flux depicted in Fig. 1.

“The remainder of the carbon in the wood-product pool will return to the atmosphere as a fraction (about 0.5 Gt CO 2 yr -1 ) of the 5 Gt CO 2 yr -1 land-use change flux that is depicted in Fig. 1.”

Approximate breakeven costs for biochar are between -$70 and -$60 per tonne of CO2 utilized.

“at approximate breakeven costs of between -$70 and -$60 per tonne of CO 2 utilized.”

The approximate breakeven costs for industrial roundwood products from afforestation/reforestation are between -$40 and $10 per tonne of CO2 utilized.

“at approximate breakeven costs of between -$40 and $10 per tonne of CO 2 utilized.”

Of the yearly inflows of carbon used as wood products, 0.6 Gt CO2 may arise from industrial roundwood products sustainably harvested for use in the construction industry.

“Of these, 0.6 Gt CO 2 may arise from the portion of those flows that are industrial roundwood products sustainably harvested for use in the construction industry (Supplementary Materials);”

The specific assumptions of the low scenario, which do not account for potential overlaps in utilization volumes between pathways, imply an upper bound of over 1.5 Gt CO2 yr-1 at well under $100 per tonne of CO2 utilized.

“The specific assumptions of the low scenario, which do not account for potential overlaps in utilization volumes between pathways, imply an upper bound of over 1.5 Gt CO 2 yr -1 at well under $100 per tonne of CO 2 utilized.”

• AssumptionThe authors state this as an assumption: The low scenario does not account for potential overlaps in utilization volumes between pathways.

The top-end estimate is 1.1 Gt CO2 utilized per year from afforestation/reforestation and sustainable forestry techniques.

“this leads to a top-end estimate of 1.1 Gt CO 2 utilized per year from afforestation/reforestation and sustainable forestry techniques.”

Prices for a fuel product made using CO2 currently exceed market prices considerably.

“Prices for a fuel product made using CO 2 currently exceed market prices considerably (Table 3).”

Around 0.9 to 1.9 Gt CO2 yr-1 may be used by soil carbon sequestration techniques on croplands and grazing lands by 2050.

“We estimate that around 0.9 to 1.9 Gt CO 2 yr -1 may be used by soil carbon sequestration techniques on croplands and grazing lands by 2050;”

Approximately 0.2 to 1 Gt CO2 yr-1 may be utilized via yield increases after the application of biochar on managed lands.

“We tentatively estimate that approximately 0.2 to 1 Gt CO 2 yr -1 may be utilized via yield increases after the application of biochar on managed lands,”

The four closed pathways, except for CO2-EOR, are mainly at low technology readiness levels (TRLs).

“The four closed pathways, except for CO 2 -EOR, are mainly at low technology readiness levels (TRLs).”

Yearly inflows of carbon used as wood products are estimated to be around 1.8 Gt CO2 in 2050.

“Yearly inflows of carbon used as wood products are estimated to be around 1.8 Gt CO 2 in 2050.”

Around half of the carbon in the wood-product pool might continue to be stored beyond the usable life of the products.

“We estimate that around half of the carbon in the wood-product pool might continue to be stored beyond the usable life of the products”

Approximate breakeven costs for soil carbon sequestration are between -$90 and -$20 per tonne of CO2 utilized, owing to yield increases associated with increases in soil organic carbon stock.

“approximate breakeven costs are estimated at between -$90 and -$20 per tonne of CO 2 utilized, owing to yield increases that are associated with increases in soil organic carbon stock.”

For methanol, the cost of product made with CO2 utilization is 30% higher than the selling price of the product.

“| Methanol | 510 | 400 | +30% | Insufficient consensus | Downward |”

For dimethyl ether, the anticipated cost relative to the incumbent in 2050 has insufficient consensus.

“| Dimethyl ether | 2,740 | 660 | +320% | Insufficient consensus | Downward |”

For aggregates, the cost of product made with CO2 utilization is 20% higher than the selling price of the product.

“| Aggregates | 21 | 18 | +20% | Insufficient consensus | Downward |”

For methanol, the anticipated cost relative to the incumbent in 2050 has insufficient consensus.

“| Methanol | 510 | 400 | +30% | Insufficient consensus | Downward |”

For methane, the cost of product made with CO2 utilization is 380% higher than the selling price of the product.

“| Methane | 1,740 | 360 | +380% | Likely to be more expensive | Downward |”

For aggregates, the anticipated direction of cost relative to the incumbent in 2050 is downward.

“| Aggregates | 21 | 18 | +20% | Insufficient consensus | Downward |”

For microalgae, the cost of product made with CO2 utilization is 170% higher than the selling price of the product.

“| Microalgae | 2,680 | 1,000 | +170% | Likely to be more expensive | Insufficient consensus |”

For methane, the anticipated cost relative to the incumbent in 2050 is likely to be more expensive.

“| Methane | 1,740 | 360 | +380% | Likely to be more expensive | Downward |”

For Fischer-Tropsch fuels, the anticipated direction of cost relative to the incumbent in 2050 is downward.

“| Fischer-Tropsch | 4,160 | 1,200 | +250% | Likely to be more expensive | Downward |”

For polymers, the anticipated direction of cost relative to the incumbent in 2050 is downward.

“| Polymers | 1,440 | 2,040 | -30% | Likely to be cheaper | Downward |”

For methanol, the anticipated direction of cost relative to the incumbent in 2050 is downward.

“| Methanol | 510 | 400 | +30% | Insufficient consensus | Downward |”

For cement curing, the anticipated cost relative to the incumbent in 2050 is likely to be cheaper.

“| Cement curing | 56 | 71 | -20% | Likely to be cheaper | Downward |”

For polymers, the anticipated cost relative to the incumbent in 2050 is likely to be cheaper.

“| Polymers | 1,440 | 2,040 | -30% | Likely to be cheaper | Downward |”

For microalgae, the anticipated cost relative to the incumbent in 2050 is likely to be more expensive.

“| Microalgae | 2,680 | 1,000 | +170% | Likely to be more expensive | Insufficient consensus |”

For CO2-EOR, the anticipated direction of cost relative to the incumbent in 2050 is upward.

“| CO 2 -EOR | n.a. | n.a. | n.a. | Likely to be more expensive | Upward |”

For methane, the anticipated direction of cost relative to the incumbent in 2050 is downward.

“| Methane | 1,740 | 360 | +380% | Likely to be more expensive | Downward |”

For CO2-EOR, the anticipated cost relative to the incumbent in 2050 is likely to be more expensive.

“| CO 2 -EOR | n.a. | n.a. | n.a. | Likely to be more expensive | Upward |”

For aggregates, the anticipated cost relative to the incumbent in 2050 has insufficient consensus.

“| Aggregates | 21 | 18 | +20% | Insufficient consensus | Downward |”

For Fischer-Tropsch fuels, the anticipated cost relative to the incumbent in 2050 is likely to be more expensive.

“| Fischer-Tropsch | 4,160 | 1,200 | +250% | Likely to be more expensive | Downward |”

Closed pathways with scalability, such as BECCS and building materials, would be sensitive to a subsidy for CO2 removals.

“For instance, our analysis suggests that closed pathways with scalability-such as BECCS and building materials-would be sensitive to a subsidy for CO 2 removals.”

• AssumptionRests on an assumption: BECCS and building materials are scalable closed pathways.

For cement curing, the cost of product made with CO2 utilization is 20% lower than the selling price of the product.

“| Cement curing | 56 | 71 | -20% | Likely to be cheaper | Downward |”

For cement curing, the anticipated direction of cost relative to the incumbent in 2050 is downward.

“| Cement curing | 56 | 71 | -20% | Likely to be cheaper | Downward |”

For dimethyl ether, the anticipated direction of cost relative to the incumbent in 2050 is downward.

“| Dimethyl ether | 2,740 | 660 | +320% | Insufficient consensus | Downward |”

For Fischer-Tropsch fuels, the cost of product made with CO2 utilization is 250% higher than the selling price of the product.

“| Fischer-Tropsch | 4,160 | 1,200 | +250% | Likely to be more expensive | Downward |”

For dimethyl ether, the cost of product made with CO2 utilization is 320% higher than the selling price of the product.

“| Dimethyl ether | 2,740 | 660 | +320% | Insufficient consensus | Downward |”

For polymers, the cost of product made with CO2 utilization is 30% lower than the selling price of the product.

“| Polymers | 1,440 | 2,040 | -30% | Likely to be cheaper | Downward |”

Resource constraints prevent the simultaneous deployment of all ten CO2 utilization pathways.

“and resource constraints prevent the simultaneous deployment of all pathways.”

Net zero CO2-based fuels must shift the current flows of carbon from a lithosphere-to-atmosphere to an atmosphere-to-atmosphere cycle.

“For instance, net zero CO 2 -based fuels must shift the current flows of carbon, from a lithosphere-to-atmosphere (KCLG) to an atmosphere-to-atmosphere cycle (ALG) (Fig. 2).”

CCS and CDR can fail to deliver a climate benefit.

“Furthermore, CCS and CDR can fail to deliver a climate benefit.”

Barriers to implementation of CO2 utilization pathways remain substantial.

“However, barriers to implementation remain substantial”

For CO2 utilization to contribute usefully to reducing atmospheric CO2 concentrations, the scale of the pathways must be meaningful in comparison with the net flows of CO2.

“For CO 2 utilization to contribute usefully to the reduction of atmospheric CO 2 concentrations, the scale of the pathways must be meaningful in comparison with the net flows of CO 2 shown in Fig. 1.”

These plants represent special cases that may be difficult to replicate because they are exploiting geographic advantages, such as the availability of cheap geothermal energy.

“However, these plants represent special cases that may be difficult to replicate because they are exploiting geographic advantages, such as the availability of cheap geothermal energy.”

Other life-cycle analyses have found neutral or negative impacts of CO2 utilization on reducing emissions.

“Other life-cycle analyses have found neutral or negative impacts of CO 2 utilization on reducing emissions 74,[96][97][98] .”

• cites [74] Jaramillo, P., Griffin, W. M. & McCoy, S. T. Life cycle inventory of CO2 in an enhanced oil recovery system. Environ. Sci. Technol. 43, 8027–8032 (2009). sourceNot checked — no full text of the source
• cites [96][97][98]Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Under conventional CO2-EOR operation, between 1.1 and 3.3 barrels of oil can be produced per tonne of CO2 injected.

“between 1.1 and 3.3 barrels (bbl) of oil can be produced per tonne of CO 2 injected under conventional operation and within the constraints of natural reservoir heterogeneity 49 .”

• cites [49] Heidug, W. et al. Storing CO 2 through enhanced oil recovery: combining EOR with CO 2 storage (EOR+) for profit. (International Energy Agency, 2015).Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

If CO2-EOR oil displaces the use of renewable electricity in an electric vehicle, CO2-EOR generates a net increase in emissions.

“If the CO 2 -EOR oil displaces the use of renewable electricity in an electric vehicle, CO 2 -EOR generates a net increase in emissions.”

If EOR is deployed to maximize CO2 storage rather than oil output, genuine CO2 emission reductions are possible, depending on the emissions intensity of the counterfactual and on relevant inefficiencies.

“If EOR was deployed to maximize CO 2 storage-rather than oil output-then genuine CO 2 emission reductions are possible, depending on the emissions intensity of the counterfactual and on the relevant inefficiencies (Box 1).”

CO2-EOR can be operated such that, on a life-cycle basis, more CO2 is injected than is produced upon consumption of the final oil product.

“However, in principle-and depending on operating conditions and project type-CO 2 -EOR can be operated such that, on a life-cycle basis, more CO 2 is injected than is produced upon consumption of the final oil product 50 .”

• cites [50] Stewart, R. J. & Haszeldine, R. S. Can producing oil store carbon? Greenhouse gas footprint of CO2EOR, offshore North Sea. Environ. Sci. Technol. 49, 5788–5795 (2015). sourceNot checked — no full text of the source

Nearly 4 tonnes of CO2 emissions may be avoided for each tonne of dry wood used that displaces concrete-based materials.

“Nearly 4 tonnes of CO 2 emissions may be avoided for each tonne of dry wood used that displaces concrete-based materials 95 .”

• cites [95] Sathre, R. & O’Connor, J. Meta-analysis of greenhouse gas displacement factors of wood product substitution. Environ. Sci. Policy 13, 104–114 (2010). sourceNot checked — no full text of the source

Various direct and indirect effects over the relevant life cycle must be considered and compared to a plausible baseline or counterfactual to determine whether CO2 utilization leads to a climate benefit.

“But various direct and indirect effects over the relevant life cycle must be considered and compared to a plausible baseline or 'counterfactual'-what would have happened without CO 2 utilization 83 .”

• cites [83] Zimmermann, A. et al. Techno-Economic Assessment & Life-Cycle Assessment Guidelines for CO 2 Utilization (Global CO2 Initiative, 2018).Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Assiduously calculating direct impacts in one place and at one time is of little use if there is a waterbed effect in which emissions occur somewhere else or later.

“Assiduously calculating direct impacts in one place, and at one time, is of little use if there is a 'waterbed effect' (also referred to as a 'rebound' or 'leakage') in which emissions occur somewhere else, or later.”

In reality, emissions from the baseline barrel of oil displaced by CO2-EOR oil might be higher or lower depending on its origin and production process.

“In reality, the emissions from the baseline barrel of oil that was displaced by the CO 2 -EOR oil might be higher or lower, depending on its origin and its production process.”

CO2 utilization pathways that involve the input of energy from nondecarbonized sources may result in net life-cycle increases in CO2.

“For instance, CO 2 utilization pathways that involve the input of energy from nondecarbonized sources may result in net life-cycle increases in CO 2 96-99 .”

• cites [96] van der Giesen, C., Kleijn, R. & Kramer, G. J. Energy and climate impacts of producing synthetic hydrocarbon fuels from CO2. Environ. Sci. Technol. 48, 7111–7121 (2014). sourceNot checked — no full text of the source
• cites [97] Sternberg, A., Jens, C. M. & Bardow, A. Life cycle assessment of CO2-based C1-chemicals. Green Chem. 19, 2244–2259 (2017). sourceNot checked — no full text of the source
• cites [98] Abanades, J. C., Rubin, E. S., Mazzotti, M. & Herzog, H. J. On the climate change mitigation potential of CO2 conversion to fuels. Energy Environ. Sci. 10, 2491–2499 (2017). sourceNot checked — no full text of the source
• cites [99] Sternberg, A. & Bardow, A. Life cycle assessment of power-to-gas: syngas vs methane. ACS Sustain. Chem. Eng. 4, 4156–4165 (2016). sourceNot checked — no full text of the source

More than 90% of the world's oil reservoirs are potentially suitable for CO2-EOR.

“More than 90% of the world's oil reservoirs are potentially suitable for CO 2 -EOR 51 ,”

• cites [51] Godec, M. L. Global Technology Roadmap for CCS in Industry: Sectoral Assessment CO 2 Enhanced Oil Recovery. (United Nations Industrial Development Organization, 2011).Not checked — no full text of the source

As much as 140 Gt CO2 could be used and stored via CO2-EOR.

“which implies that as much as 140 Gt CO 2 could be used and stored in this way 5 .”

• cites [5] Mac Dowell, N., Fennell, P. S., Shah, N. & Maitland, G. C. The role of CO2 capture and utilization in mitigating climate change. Nat. Clim. Change 7, 243–249 (2017). This paper assesses the potential for CO 2-derived fuels and chemicals to be a fraction of that possible via CO 2-EOR. sourceNot checked — no full text of the source

Unless calcination is paired with carbon capture and sequestration, it is difficult for building-related pathways to deliver reductions in CO2 emissions on a life-cycle basis.

“As such, unless calcination is paired with carbon capture and sequestration, it is difficult for building-related pathways to deliver reductions in CO 2 emissions on a life-cycle basis.”

• AssumptionRests on an assumption: Cement requires the use of lime (CaO), which is produced by the calcination of limestone in an emissions-intensive process.

New sorbents could reduce the cost of energy-intensive separation of CO2 from flue gases and industrial streams.

“New sorbents could reduce the cost of energy-intensive separation of CO 2 from flue gases and industrial streams 40,78 .”

• cites [40] Secretary of Energy Advisory Board. Letter Report: Task Force on RD&D Strategy for CO 2 Utilization and/or Negative Emissions at the Gigatonne Scale. (US Department of Energy, 2016).Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites [78] Senftle, T. P. & Carter, E. A. The holy grail: chemistry enabling an economically viable CO2 capture, utilization, and storage strategy. Acc. Chem. Res. 50, 472–475 (2017). sourceNot checked — no full text of the source

Life-cycle emissions and costs of CO2 utilization depend upon the source of the energy used.

“Life-cycle emissions and costs depend upon the source of the energy used.”

The cycling pathways other than the production of urea and polyols must compete with lower-cost incumbents.

“The cycling pathways (other than the production of urea and polyols) must compete with lower-cost incumbents.”

Some CO2 utilization pathways require energy to increase CO2 concentrations from 0.04% towards 100%.

“Some require energy to increase CO 2 concentrations from 0.04% towards 100% 66 .”

• cites [66] Darton, R. & Yang, A. Removing carbon dioxide from the atmosphere – assessing the technologies. Chem. Eng. Trans. 69, 91–96 (2018). sourceNot checked — no full text of the source

The emissions-reduction potentials of the three cycling pathways would be facilitated by declines in the costs of CO2 capture.

“The emissions-reduction potentials of the three cycling pathways would be facilitated by declines in the costs of CO 2 capture.”

CO2-EOR might currently contribute to an overall reduction in atmospheric CO2, compared to business-as-usual.

“For instance, CO 2 -EOR might currently contribute to an overall reduction in atmospheric CO 2 , compared to business-as-usual 49 .”

• cites [49] Heidug, W. et al. Storing CO 2 through enhanced oil recovery: combining EOR with CO 2 storage (EOR+) for profit. (International Energy Agency, 2015).Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

In general, low TRLs will also challenge the ability of pathways to scale rapidly enough and within the desired timeframe for mitigation.

“In general, low TRLs will also challenge the ability of pathways to scale rapidly enough and within the desired timeframe for mitigation 5 .”

• cites [5] Mac Dowell, N., Fennell, P. S., Shah, N. & Maitland, G. C. The role of CO2 capture and utilization in mitigating climate change. Nat. Clim. Change 7, 243–249 (2017). This paper assesses the potential for CO 2-derived fuels and chemicals to be a fraction of that possible via CO 2-EOR. sourceNot checked — no full text of the source

Much of the potential CO2 utilization, notably in closed and open pathways, may be economically viable without substantial shifts in prices.

“Much of this potential CO 2 utilizationnotably in 'closed' and 'open' pathways-may be economically viable without substantial shifts in prices.”

Biological pathways are not necessarily more expensive than industrial pathways.

“biological pathways are not necessarily more expensive.”

Land availability means that choosing one land-based pathway (for example, BECCS) might preclude the application of another at scale (for example, biochar).

“Furthermore, land availability means that choosing one land-based pathway (for example, BECCS) might preclude the application of another at scale (for example, biochar).”

As decarbonization proceeds, the climate benefit of CO2-EOR is reduced.

“As decarbonization proceeds, however, the climate benefit of CO 2 -EOR is reduced.”

In the longer term, cheaper direct air capture based on clean energy would support the scale-up of these pathways.

“In the longer term, cheaper direct air capture (based on clean energy) would support the scale-up of these pathways 79 .”

• cites [79] Keith, D. W., Holmes, G., St., Angelo, D. & Heidel, K. A process for capturing CO2 from the atmosphere. Joule 2, 1573–1594 (2018). sourceNot checked — no full text of the source

The non-decomposed fraction of the portion of total wood products that are presently committed to landfill (around 60%) is approximately 77%.

“the non-decomposed fraction of the portion of total wood products that are presently committed to landfill (around 60%) is approximately 77% 60”

• cites [60] FAOSTAT (Food and Agricultural Organization of the United Nations, accessed 10 May 2018); http://fao.org/faostat/en/#dataNot checked yet

  Not checked in the free run.

The expert opinion survey, which included sources from both academia and industry, reflected great uncertainty about future costs.

“Our expert opinion survey, which included sources from both academia and industry, reflected great uncertainty about future costs.”

Each of the potentially large-scale, low-cost pathways also faces challenges as mitigation strategies.

“Each of the potentially large-scale, low-cost pathways also face challenges as mitigation strategies.”

Research into materials and catalysts for CO2 reduction could enable the efficient transformation of CO2 into a broader range of products at a lower cost.

“Research into materials and catalysts for CO 2 reduction could enable the efficient transformation of CO 2 into a broader range of products at a lower cost 78 .”

• cites [78] Senftle, T. P. & Carter, E. A. The holy grail: chemistry enabling an economically viable CO2 capture, utilization, and storage strategy. Acc. Chem. Res. 50, 472–475 (2017). sourceNot checked — no full text of the source

Individual CO2 utilization potentials cannot be arbitrarily summed because some access the same demand, for instance for transport, which may or may not be filled by a process that utilizes CO2.

“An important caveat is that individual potentials cannot be arbitrarily summed: some access the same demand, for instance for transport, which may or may not be filled by a process that utilizes CO 2 .”

The economics of many CO2 utilization pathways, in particular those involving products in construction and plastics, are driven not only by price but also by the performance characteristics of the end product.

“Many of the other pathways-in particular those involving products in construction and plastics-have economics that are driven not only by price but also by the performance characteristics of the end product.”

Notwithstanding the many caveats, the potential scale of CO2 utilization could be considerable.

“Notwithstanding the many caveats, the potential scale of utilization could be considerable.”

At some point before full decarbonization, EOR without direct air capture will result in a net increase in CO2 emissions.

“At some point before full decarbonization, EOR without direct air capture will result in a net increase in CO 2 emissions 74 .”

• cites [74] Jaramillo, P., Griffin, W. M. & McCoy, S. T. Life cycle inventory of CO2 in an enhanced oil recovery system. Environ. Sci. Technol. 43, 8027–8032 (2009). sourceNot checked — no full text of the source

New wood-based products such as cross-laminated timber and acetylated wood, which are aimed at new markets, also have potential.

“new wood-based products such as cross-laminated timber and acetylated wood 87 -which are aimed at new markets-also have potential.”

• cites [87] Song, J. et al. Processing bulk natural wood into a high-performance structural material. Nature 554, 224–228 (2018). sourceNot checked — no full text of the source