This week’s selected publications cover a wide range of issues related to Direct Air Capture, CO2 Mineralization, (CDR) potential in temperate macroalgal forests, global carbon flux estimation methodology and carbon capture by honeycombs.
Addressing Solar Power Curtailment by Integrating Flexible Direct Air Capture
Abstract
Direct air capture (DAC) is one of the principal negative emission technologies for addressing climate change, but its deployment is hindered by the high cost and substantial energy consumption. Only being powered by low-cost renewable energy, DAC can maximize its negative emission potential, in return, DAC can help the decarbonization of the power sector. Due to the intermittency of renewable energy, effectively integrating renewable energy with DAC currently remains a significant challenge. To address this research gap, this study focuses on exploring flexible operation strategies of the adsorbent based DAC system, coupling them with an actual photovoltaic (PV) power station, and making DAC systems participate in minute-level dispatch. The adsorbent based DAC system adopts a modular design, allowing each unit to operate as an independent load, not requiring continuous operation and enabling interruption between cycles or processes. Additionally, the adsorption process is curtailable and extendable to dynamically adjust the time of activating desorption. The flexible operational combination allows the DAC to better match the fluctuation of PV. Based on actual data and time-of-use pricing, this paper conducts a comparative techno-economic analysis of DAC and battery energy storage (BES) systems. The results indicate that deploying flexible DAC is the most cost-effective among different given scenarios. Deploying 46,800 DAC units primarily powered by solar curtailment can achieve the lowest cost of $30,000/MW-year for the selected 1000 MW PV power station, along with an 80 % curtailment consumption rate and annual 634,000 tons CO2 captured. Before 2030, coupling DAC with PV can effectively address the curtailment issues and assist with peak shaving. As carbon prices gradually rise and adsorbent costs decrease, by 2040, DAC will release its negative emission potential, playing a crucial role in achieving net zero or even negative carbon emissions.
Liu, Y, Miao, Y, Wang, L., Gu, X., Li, Z, Fujikawa, S., Yu, L. (2025) Addressing Solar Power Curtailment by Integrating Flexible Direct Air Capture. Carbon Capture Science & Technology 14 (100304)
Read the full paper here: Addressing Solar Power Curtailment by Integrating Flexible Direct Air Capture I Carbon Capture Science & Technology
Synergy of CO2 Mineralization in Produced Water with Enhanced Oil Recovery: An Experimental Study
Abstract
Addressing climate change necessitates innovative strategies to reduce atmospheric carbon dioxide (CO2) levels, significantly contributing to global warming. While traditional CO2 sequestration in geological formations is a viable mitigation method, it often presents high costs and logistical challenges. This study proposes a novel, cost-effective approach integrating CO2 mineralization with produced water treatment to enhance oil recovery (EOR). By mixing CO2 into produced water and subsequently adding sodium hydroxide (NaOH), we facilitate the precipitation of valuable minerals, specifically brucite (Mg(OH)2) as a surface process, which is then filtered out, improving water quality and making it efficient for EOR. Our findings demonstrate that the resulting treated water, referred to as “smart water,” increases oil recovery by 22.2% compared to conventional water flooding, highlighting the dual benefits of this mineralization process. Comprehensive analyses employing zeta potential measurements, X-ray Diffraction (XRD), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS), interfacial tension (IFT) measurements, and contact angle assessments elucidate significant alterations in wettability and interfacial properties due to brucite precipitation. This innovative method not only enhances oil recovery and produces valuable minerals but also plays a crucial role in reducing CO2 emissions by transforming produced water into a resource for carbon mineralization. By utilizing this approach, we mitigate the environmental impact of CO2 while demonstrating the potential to turn produced water into a sustainable solution for EOR. The novelty of our study lies in its integrated benefits, which combine mineralization, enhanced oil recovery, and CO2 emission reduction, offering a cost-effective and environmentally responsible strategy for the oil and gas industry.
Alyousef, M., Alshammari, S & Yaseri, A. (2025) Synergy of CO2 Mineralization in Produced Water with Enhanced Oil Recovery: An Experimental Study. Fuel 382 (133694)
Read the full paper here: Synergy of CO2 Mineralization in Produced Water with Enhanced Oil Recovery: An Experimental Study I Fuel
Carbon dioxide removal (CDR) potential in temperate macroalgal forests: A comparative study of chemical and biological net ecosystem production (NEP)
Abstract
The carbon dioxide removal (CDR) capacity of macroalgae, a crucial component in climate regulation, has gained increasing attention. However, accurately estimating the CDR potential of macroalgae in natural conditions remains challenging, necessitating the use of multiple independent methods to reduce the uncertainties in these estimates. In this study, we compared two methods for estimating net ecosystem production (NEP), a key parameter in determining CDR potential: 1) NEPChem., derived from seawater carbonate chemistry and 2) NEPBiol., based on photorespiratory measurements using benthic tent incubation. This study, conducted in a macroalgal forest dominated by Ecklonia cava, involved simultaneous measurements of NEPChem. and NEPBiol. over a course of one year. Our findings revealed that NEPBiol. was 1.23 times higher than NEPChem., with an annual rate of 3.69 tons CO2 ha−1 yr−1. These results suggest that both independent methods are reliable and can be used complementarily to improve the accuracy of NEP measurements, thereby enhancing estimates of the CDR potential of macroalgae.
Kim, J., Lee, H., Lee, J., Kim, M., Lee, K., Kim, C., Kang, E., Kim, Y, Yoon, Y., Lee, S., Kim, H., Choi, E., Yoon, H., Boseong, K., Kang, J., Oh, H., Kim, J., Choi, I. (2025) Carbon Dioxide Removal (CDR) Potential in Temperate Macroalgal Forests: A Comparative Study of Chemical and Biological Net Ecosystem Production (NEP) Marine Pollution Bulletin 210 (117327)
Read the full paper here: Carbon dioxide removal (CDR) potential in temperate macroalgal forests: A comparative study of chemical and biological net ecosystem production (NEP) I Marine Pollution Bulletin
A new global carbon flux estimation methodology by assimilation of both in situ and satellite CO2 observations
Abstract
Accurate estimation of carbon removal by terrestrial ecosystems and oceans is crucial to the success of global carbon mitigation initiatives. The emergence of multi-source CO2 observations offers prospects for an improved assessment of carbon fluxes. However, the utility of these diverse observations has been limited by their heterogeneity, leading to much variation in estimated carbon fluxes. To harvest the diverse data types, this paper develops a multi-observation carbon assimilation system (MCAS), which simultaneously integrates both satellite and ground-based observations. MCAS modifies the ensemble Kalman filter to apply different inflation factors to different types of observation errors, addressing the heterogeneity between satellite and in situ data. In commonly used independent validation datasets, the carbon flux derived from MCAS outperformed those obtained from a single source, demonstrating a 20% reduction in error compared to existing carbon flux products. We use MCAS to conduct ecosystem and ocean carbon flux inversion for the period of 2016–2020, which reveals that the 5-year average global net terrestrial and ocean sink was 1.84 ± 0.60 and 2.74 ± 0.49 petagrams, absorbing approximately 47% of human-caused CO2 emissions together, which were consistent with the global carbon project estimates of 1.82 and 2.66 petagrams. All these facts suggest MCAS is a better methodology than those for assimilating single-source observation only.
Su, W., Wang, B., Chen, H., Zhu, L., Zheng, X., Chen, S. (2024) A New Global Carbon Flux Estimation Methodology by Assimilation of Both in Situ and Satellite CO2 Observations. Climate and Atmospheric Science 287.
Read the full paper here: A New Global Carbon Flux Estimation Methodology by Assimilation of Both in Situ and Satellite CO2 Observation I Climate and Atmospheric Science
Aiming at the Valorization of CO2 through Its Capture by Simply Extruded High Cell-Density Honeycombs
Abstract
Integral coal honeycomb monoliths were easily prepared achieving the cell densities typical of commercial cordierites through extrusion plus physical activation. Different techniques such as volumetric adsorption, TGA, TPD and transient kinetic analysis were employed to study their interaction with CO2 at different temperatures (35–100 ◦C) and under both static and dynamic atmosphere. The CO2 capture capacity resulted to be 0.95 mmol/ g at 35 ◦C, much higher than that of previously studied clay honeycomb adsorbents. The CO2 uptake exhibited fast second order kinetics, and a wide operative window for a highly efficient CO2 removal was found. Moreover, due to a weak interaction, most CO2 absorbed could be released at 110 ◦C, what allows minimizing the costs related to controlled regeneration if ones wants to reuse the captured CO2 but at the same time prevents from desorption when this is undesirable. Treatment of the coal honeycomb monolith with a 1:1 CO2+CH4-containing stream revealed, through gas chromatography analysis, the conversion into syngas at relatively low temperatures (50% at 750 ◦C) in spite of the metal-free character of the monolith. Moreover, this activity reached 90% and remained quite stable for at least 12 h at 900 ◦C. These results demonstrate the potential of preparing honeycomb monoliths from coal as a strategy to diversify the uses of this abundant natural resource and as an alternative in the field of CO2 capture and valorization.
Yeste, M., Ahrouch, M., Goma, D, Garcia, R., Vidal, H. & Gatica, J. (2024) Aiming at the Valorization of CO2 through its Capture by Simply Extruded High Cell-Density Coal Honeycombs Journal of CO2 Utilization 102790.
Read the full paper here: Aiming at the Valorization of CO2 through its Capture by Simply Extruded High Cell-Density Coal Honeycombs I Journal of CO2 Utilization