This week’s publication highlights include articles studying various issues such as the impact of CDR measures for the ‘cost and energy transformation of the electricity sector by 2050’, CDR in aqueous media, ‘fair carbon removal obligations’ as well as direct air capture-related matters.
Targeted Carbon Dioxide Removal Measures are Essential for the Cost and Energy Transformation of the Electricity Sector by 2050
Abstract
Carbon dioxide removal is crucial for moderating the rapid pace of power sector transformation, while electrification can reduce the emission intensity of the carbon removal process. Here, we use a multisector model to explore the impact of varying levels of CO2 removal (1 to 10 gigatonnes CO2 per year) on the electricity sector by 2050 under 1.5 °C and 2 °C future warming. Our results show that under high CO2 removal pathways, up to 5% of electricity consumption could be dedicated to removing CO2. Limited CO2 removal by 2050 could increase asset stranding costs by US$165-225 billion in fossil-intensive countries like China, the US, and India. Also, a 15% additional mitigation of committed emissions in the power sector would be needed under constrained CO2 removal pathways. While a high CO2 removal future is key to alleviating the burden of power sector transformation, it carries the risk of increased committed emissions. Careful planning is required to balance a less disruptive transformation without compromising climate targets.
Afrane, S. et al. (2025) Targeted Carbon Dioxide Removal Measures are Essential for the Cost and Energy Transformation of the Electricity Sector by 2050. 227 (6) Communications Earth & Environment.
Read the full paper here: Targeted Carbon Dioxide Removal Measures are Essential for the Cost and Energy Transformation of the Electricity Sector by 2050.
Bio-Inspired Catalyst-driven Efficient CO2 Capture and Subsequent Mineralization in Aqueous Media under Practical Conditions
Abstract
Efficient carbon management and the successful implementation of innovative technologies are a necessity for environmental mitigation and the realization of a sustainable circular economy. Current carbon dioxide removal (CDR) and CO2 capture and storage (CCS) technologies fail to meet the gigatonne-level CO2 removal targets, lack profitability, and thus are not widely adopted/retrofitted in the current industrial settings. To address these issues, unique alternative solutions are required that possess the versatility for application in various CO2-emitting industries, have economic viability, and do not cause secondary pollution effects. Our pursuit in this regard led to the development of a catalyst C1, inspired by the architectural design of the Carbonic anhydrase enzyme, where a Zn (II) ion is bound tetrahedrally at the N3-primary coordination site and a peripheral ethereal O3-site which functioned as the outer coordination sphere (OCS). This promoted the facile generation of the potent Zn-OH– motif in near-neutral media for rapid hydrolysis of CO2 in aqueous solution to carbonate and bicarbonate ions. Mineralization of this captured CO2 was performed with the appropriate addition of Ca(II) ions leading to the formation of pure CaCO3. Practical application and industrial relevance were established with CO2 capture and mineralization experiments performed in seawater, flue-gas mixture with 15% (v/v) CO2, and air containing only 0.04% (v/v) CO2 in a separate set of experiments. The kinetic parameters and biomimetic nature of the metal complex C1 were confirmed through detailed pNPA hydrolysis studies. Our results indicate that bio-inspired catalysts can be a cost-effective, viable solution for mass-scale carbon mitigation and management strategy using only environmentally benign resources.
Read the full paper here: Bio-Inspired Catalyst-driven Efficient CO2 Capture and Subsequent Mineralization in Aqueous Media under Practical Conditions.
Fair Carbon Removal Obligations under Climate Response Uncertainty
Abstract
Deploying carbon dioxide removal (CDR) is considered unavoidable to meet global climate goals. However, current assessments of the potential role of CDR tend to overlook uncertainty in the Earth System response to our emissions. Here, we assess the level of ‘preventive’ CDR needed to draw warming down to 1.5°C in case of a stronger-than-median Earth System response. Using the ‘1.5°C with no or limited overshoot’ ensemble of pathways assessed by the Intergovernmental Panel on Climate Change (IPCC), we estimate that around 323–787 Gt CO2 (interquartile range) of additional CDR (beyond the 418–763 Gt CO2 (interquartile range) already deployed in these pathways) may be required after net zero CO2 for a very likely (> = 90%) chance of reaching 1.5°C in 2100. We cannot know now whether a net zero society will need to utilize the preventive capacity, but the option must be available to them. Feasibility and sustainability concerns associated with large-scale CDR deployment raise fundamental questions over reducing potential future CDR reliance in light of Earth System uncertainty. Our analysis shows that reducing residual emissions from long-lived (e.g. CO2 and N2O) and short-lived climate forcers (e.g. CH4) can significantly reduce the scale of preventive CDR required. We also explore an illustrative approach to equitably allocate global preventive CDR needs. North America is allocated a per-capita removal responsibility of 13 t CO2/capita annually between 2020 and 2100 in a pathway with limited residual emission cuts, which is more than halved in another with deeper residual emission cuts. Our results underscore the importance of limiting so-called ‘hard-to-abate’ emissions in addition to rapid near-term cuts in emissions as preventive measures to avoid over-reliance on unsustainable levels of preventive CDR.
Ganti, G. et al. (2025) Fair Carbon Removal Obligations under Climate Response Uncertainty. Climate Policy.
Read the full paper here: Fair Carbon Removal Obligations under Climate Response Uncertainty I Climate Policy.
Integration of direct air capture with Allam cycle: Innovative pathway in negative emission technologies
Abstract
The advancement of negative emission technologies (NETs) is crucial for addressing climate change by reducing atmospheric carbon dioxide levels. This study presents a comprehensive evaluation of a High Temperature Direct Air Capture (HT-DAC) system integrated with a supercritical CO2 (S-CO2) cycle, representing a significant advancement in carbon capture, energy optimization, and NET systems. Given to significant energy demands of HT-DAC, the primary objective of this research is to address the process’s energy intensity by focusing on the development of a more efficient power island. Specifically, this study investigates the energy demands of the Air Separation Unit (ASU) to minimize energy consumption and improve the overall efficiency of the Allam cycle when coupled with the ASU. Additionally, the study examines the thermal integration of the system using pinch analysis to assess the impact of this innovative power island on energy efficiency. Key results indicate that the proposed system is capable of capturing 0.99 million tons of CO2 per year directly from the air, achieving a capture efficiency of 75 %. The specific energy requirement for the process is initially 3.19 kWh per kg of captured CO2, which is reduced to 2.21 kWh/kgCO2 following process optimization and heat integration. Through this optimization, hot and cold utility demands are reduced by 69.7 % and 36.9 %, respectively, while 110.1 MW of heat is recovered through the design of heat exchangers network, resulting in an 9.66 % reduction in overall energy demand compared to the base case. Furthermore, the integration of captured and regenerated CO2 (135.1 tons per hour with a purity of 98.1 mol%) offers substantial potential for synthetic fuel production and underground storage.
Ghorbani, A. et al. (2025) Integration of direct air capture with Allam cycle: Innovative pathway in negative emission technologies. 332 (119746) Energy Conversion and Management.
Read the full paper here: Integration of direct air capture with Allam cycle: Innovative pathway in negative emission technologies I Energy Conversion and Management.
—-----------------------------------------------------------------------------------------------------
Integrating Solid Direct Air Capture Systems with Green Hydrogen Production: Economic Benefits and Curtailment Reduction
Abstract
The transition to a low-carbon energy system has positioned green hydrogen as a key clean energy carrier. However, the intermittent nature of renewable energy sources introduces significant challenges, such as substantial electricity curtailment, which affects both the economic feasibility and grid stability. Solid sorbent-based direct air capture systems, known for their high operational flexibility, offer a promising complementary solution to effectively utilize curtailed renewable power from green hydrogen production. This study examines the economic viability of integrating green hydrogen systems with solid direct air capture technology. The findings indicate that the integration can reduce curtailed renewable energy by up to 40 %, subsequently decreasing total annualized costs by approximately 6 % compared to operating these systems independently. Further economic improvements could be realized by optimizing the CO2 capture-to-H2 production ratio, capitalizing on anticipated cost reductions in direct air capture technology, and enhancing heat pump flexibility. With these improvements—including a 50 % reduction in direct air capture costs, an optimized CO2-to-H2 ratio, and enhanced heat pump flexibility—the economic benefits could increase from 6 % to 12 %. These results underscore the transformative potential of sector coupling in addressing the scalability challenges of green hydrogen, reducing renewable energy curtailment, and accelerating progress towards achieving net-zero and net-negative emissions goals.
Kim, S. et al. (2025) Integrating Solid Direct Air Capture Systems with Green Hydrogen Production: Economic Benefits and Curtailment Reduction. 198 (109102) Computers & Chemical Engineering.
Read the full paper here: Integrating Solid Direct Air Capture Systems with Green Hydrogen Production: Economic Benefits and Curtailment Reduction I Computers & Chemical Engineering.