The consequences of inaction on carbon dioxide removal

TL;DR: In this article, the authors investigated the implications of delaying carbon dioxide removal (CDR) actions, focusing on integrating direct air capture and bioenergy with carbon capture and storage (DACCS and BECCS) into the European Union power mix.

Abstract: Carbon dioxide removal (CDR) will be essential to meet the climate targets, so enabling its deployment at the right time will be decisive. Here, we investigate the still poorly understood implications of delaying CDR actions, focusing on integrating direct air capture and bioenergy with carbon capture and storage (DACCS and BECCS) into the European Union power mix. Under an indicative target of − 50 Gt of net CO2 by 2100, delayed CDR would cost an extra of 0.12 − 0.19 trillion EUR per year of inaction. Moreover, postponing CDR beyond mid-century would substantially reduce the removal potential to almost half (− 35.60 Gt CO2) due to the underused biomass and land resources and the maximum technology diffusion speed. The effective design of BECCS and DACCS systems calls for long-term planning starting from now and aligned with the evolving power systems. Our quantitative analysis of the consequences of inaction on CDR —with climate targets at risk and fair CDR contributions at stake —should help to break the current impasse and incentivize early actions worldwide.

Summary

Introduction

• Due to the growing carbon emissions and rising global temperatures, carbon dioxide removal (CDR) will become essential to combat climate change1–4.
• Nature-based strategies sequester the CO2 in natural sinks (e.g., afforestation/reforestation, AR, and tailored agricultural practices), while engineered CDR stores the CO2 either in geological sites or minerals (e.g., enhanced weathering, Bio-Energy with Carbon Capture and Storage, BECCS, and Direct Air Carbon Capture and Storage, DACCS)8–10.
• The consequences of delaying mitigation actions have already been studied40–48, while the implications of postponing CDR remain unclear19,36,49,50.
• Here the authors fill this gap by exploring the economic, environmental, and technical implications of CDR inaction, focusing on BECCS and DACCS deployment in the European Union (EU) as key engineered CDR strategies intrinsically linked to the evolving energy sector51,52.
• Moreover, postponing CDR actions would drastically reduce their removal potential due to the underuse of resources and slow capacity expansions of the CDR technologies, putting the EU at risk of missing targets (e.g., from −73.73 to −35.60 Gt CO2 by delaying CDR action from 2020 to 2050, respectively).

Results and discussion

• Consequences of delayed CDR actions: extra-costs and under-exploitation of resources 5 (i.e., 𝜇 ± 2𝜎, Methods for details on the uncertainty analysis).
• DACCS would play a role complementing BECCS and ultimately helping to remove CO2 at the pace required, benefitting from the carbon-negative electricity delivered in the system, and exploiting its flexibility to be located closer to the geological sites in countries with scarce biomass resources51,64.
• Regarding electricity trade, countries such as France, Spain, and Sweden would emerge as pivotal in the power system, acting as net exporters of electricity to exploit their abundant low-carbon intensity resources (e.g., electricity trades from France to Germany, Italy, Netherlands, Belgium, and the United Kingdom, Fig. 4c).

Conclusions

• Here the authors studied the implications of delaying the roll-out of CDR to raise concerns on the need to set effective plans to promote its large-scale deployment at the right time to avoid extra costs and miss climate targets.
• To shed light on the economic, environmental, and technical implications of the prolonged delay of CDR actions, the authors focused on the deployment of BECCS and DACCS in the EU as prominent strategies intrinsically linked to the power system.
• Hence, postponing CDR deployment beyond mid-century might prevent the EU from delivering a CDR level aligned with its fair responsibility and its expected leading role37,55.
• Nevertheless, their findings demonstrate that failure to start CDR at the right time would increase the total costs and make climate targets slipping out of reach.

Figures

Fig. 1. Implications on costs and emissions of delayed-actions on CDR considering different starting points for BECCS and DACCS deployment until 2100 (x-axis). Subplot a shows the minimum costs of the EU power system associated with increasing CDR targets. Subplot b shows the maximum cumulative net CDR that could be attained considering the deployment of BECCS and DACCS from a particular point in time onwards (green profile only with BECCS, blue with DACCS, and yellow considering both BECCS and DACCS). Dots correspond to the optimal solutions for the 5-year time steps starting in 2020 and ending in 2100. The shaded area in subplot b indicates the uncertainty in the life cycle CO2 emissions

Fig. 3. Regional implications for the EU energy system starting the deployment of BECCS and DACCS in 2020 (“Now” scenario). Subplot a corresponds to the optimal electricity generation by 2100 in each European country. The pie charts show the share of generation per electricity technology depicted with different colors, while the size of the pie charts is proportional to the generation by 2100 (TWh). Each country is colored according to the CO2 stored in the geological sites; the darker the shade, the greater the CO2 stored. Subplot b shows the breakdown by country of the gross CO2 removed from the atmosphere considering the different biomass resources for BECCS and DACCS technologies. Countries in subplot b are labeled according to the ISO3 code abbreviation.

Fig. 2. CO2 emission pathways and breakdown in the EU energy sector considering the three illustrative scenarios with different starting points for the BECCS and DACCS deployment by 2100. Subplot a corresponds to the “Now” scenario starting CDR in 2020. Subplot b corresponds to the “Slow” scenario starting CDR in 2055. Subplot c corresponds to the “Late” scenario starting CDR in 2085. Stacked bars on the right show the breakdown by the source of the life cycle residual emissions, gross negative emissions, and stored emissions.

Frequently asked questions

Q1. What contributions have the authors mentioned in the paper "The consequences of inaction on carbon dioxide removal" ?

Here, the authors investigate the still poorly understood implications of delaying CDR actions, focusing on integrating direct air capture and bioenergy with carbon capture and storage ( DACCS and BECCS ) into the European Union power mix. Moreover, postponing CDR beyond midcentury would substantially reduce the removal potential to almost half ( −35. 60 Gt CO2 ) due to the underused biomass and land resources and the maximum technology diffusion speed. 

Q2. What are the future works in "The consequences of inaction on carbon dioxide removal" ?

Here the authors studied the implications of delaying the roll-out of CDR to raise concerns on the need to set effective plans to promote its large-scale deployment at the right time to avoid extra costs and miss climate targets. Moreover, delaying CDR actions would critically limit the removal potential ( e. g., −73. After 2050, the maximum CDR potential would be reduced to −56. Retrofitting the existing coal and gas-fired power plants with CCS to decarbonize the power sector would limit the storage capacity available, potentially raising competition issues with atmospheric CO2 sequestration. 

Q3. What would be the consequences of delaying the deployment of CDR?

delaying the CDR deployment would lead to the underuse of biomass and land resources, tighter bounds on the BECCS and DACCS facilities, and domestic storage sites depleted with fossil carbon, which altogether would reduce the future ability of individual countries on CDR. 

Q4. How much of the CO2 removed by BECCS would be from forestry?

Forestry residues would contribute the most to the CO2 removal (i.e., 45% of the total gross CO2 removed by 2100), while miscanthus production would occupy all the marginal land available due to its overall superior carbon sequestration potential, removing −15.87 Gt CO2 by 2100 (17% of the total gross removed) and becoming the main carbon sink in some countries (i.e., −6.16 Gt CO2 removed in Spain). 

Q5. What are the main barriers for CDR deployment?

The main barriers for CDR deployment include the lack of consensus on the need to start CDR today —as it is often perceived as “a problem for later” —, the absence of market incentives and strong political drivers, and governance challenges. 

Q6. What is the role of BECCS in the energy portfolio?

BECCS becomes relevant in the generation portfolio, providing firm capacity and ancillary services to support the high penetration of intermittent technologies with dispatchable carbon-negative electricity. 

Q7. What would be the main reason for the BECCS plants?

BECCS plants would13be mostly installed near the biomass sources, leading to decentralized supply chains spread across the EU territory. 

Q8. How much of the biomass resources available from 2055 to 2100 would be exploited?

86% of the residues and 90% of the marginal land available from 2055 to 2100 would be exploited, representing only 63% and 57% of their respective total potentials (if actions were started in 2020 and continued until 2100). 

Q9. How many t of CO2 has been removed from the atmosphere?

The CDR deployment to date has been minimal20,21 with only 1.5 million t CO2/yr removed via BECCS9,22 and around 0.01 million t CO2/yr18 with DAC technologies, often deployed without long term CO2 storage. 

Q10. How much CO2 would be removed from BECCS by 2050?

Gt of CO2 by 2100 (i.e., 42% of the total gross −72.94 Gt of CO2 removed), while the DACCS share starting after 2080 would become negligible (i.e., <2%). 

Q11. How many countries would be able to deliver the maximum net negative emissions by 2100?

Only four countries would deliver almost half of the gross removal by 2100, with France and Spain at the top deploying both BECCS and DACCS, followed by Germany and Sweden deploying only BECCS (i.e., 44.37 Gt out of 94.05 

Q12. What countries would be almost self-sufficient in terms of biomass resources?

Some countries would be almost self-sufficient in terms of biomass resources, like Portugal, which would transport CO2 to the Spanish geological sites due to its low geological capacity. 

Q13. What regions would be net exporters of biomass?

Some regions would be net exporters of biomass (e.g., France or Sweden) and some net importers (e.g., Netherland, Germany, or Denmark). 

Q14. How much of the carbon-negative electricity produced by BECCS would be removed by 2020?

The removal potential would be limited by the maximum diffusion rates of BECCS and DACCS, which8would even impede reaching CO2 neutrality in the EU power sector (+1.54 Gt of net CO2 emissions by 2100) and constrain the use of residues and land to 40% and 20% of their maximum availability from 2020 to 2100, respectively. 

Q15. Why does the behavior of BECCS vary linearly over time?

This behavior is due to the unused biomass and land resources, the main factors constraining BECCS, which accumulate almost linearly over time. 

Q16. How much extra cost could be avoided by postponing CDR?

The authors found that postponing CDR could substantially increase the total cost of the power system, with each year of inaction translating into 0.12–0.19 trillion EUR2015 of extra cost to meet the - 50 Gt of net CO2 target. 

Q17. How much CO2 would be removed from the atmosphere by 2020?

net negative CO2 emissions would not be achieved until 2070 due to the need to offset the residual emissions taking place until that year. 

Q18. How much CO2 would be removed from the biomass?

France, Germany, Sweden, and Poland would provide most of the biomass resources, i.e., 54% of the total gross CO2 removed via BECCS (−38.99 out of −72.59 Gt of CO2 removed with BECCS, Fig. 3b). 

Q19. How much CO2 would be removed with BECCS?

in the United Kingdom, which lacks enough biomass resources to exploit its storage capacity only with BECCS, −3.64 Gt CO2 would be removed with DACCS and stored in domestic geological sites. 

Q20. How much CO2 would be stored in the EU?

The overall storage efficiency —i.e., total net CO2 removed per kg of CO2 stored— would reach 81%, where most geological sites would store the biogenic CO2 captured via BECCS (71%), a smaller amount of atmospheric CO2 captured with DACCS (24%), and finally the captured emissions linked to the heating needs of DACCS (5%). 

Q21. How many Gt of CO2 removed by 2100?

In the “Now” scenario, DACCS would be established in eleven countries, with France, Spain, the United Kingdom, Italy, and Romania providing 97% of the gross removal from DACCS (i.e., −18,72 out of the −21.46 Gt CO2 by 2100), all of them with enough geological sites for storing the captured CO2 domestically (Fig. 3b). 

Q22. How many Gt of CO2 removed by BECCS?

In practice, this roadmap would require a substantial number of DACCS facilities across the EU, i.e., around 268, with a capacity of 1 Mt CO2/yr (i.e., the largest DAC plant under development today), out of which 83 would be installed in France, 61 in Spain and 46 in the United Kingdom. 

Q23. What countries would have the largest exchanges of biomass and CO2?

The largest exchanges of biomass and CO2 would occur between France-the Netherlands, and the Netherlandsthe United Kingdom, respectively (Fig. 4a, b). 

Q24. What are the main barriers to CDR deployment?

In practice, however, future technological, social, and environmental barriers remain largely unexplored29–31, which may hinder the implementation of CDR and the attainment of the longterm temperature targets26,32–35.