CO₂-removal News

Shahbaz et al. (2024): Evaluating negative emission technologies in a circular carbon economy: A holistic evaluation of direct air capture, bioenergy carbon capture and storage and biochar

Muhammad Shahbaz, Mohammad Alherbawi, Eric C. Okonkwo, Tareq Al-Ansari IN: Journal of Cleaner Production, 466, https://doi.org/10.1016/j.jclepro.2024.142800

The current study aims to develop an intelligent system incorporating various mitigation technologies. In this investigation, three technologies; Direct Air Capture (DAC), Bioenergy with Carbon Capture and Storage (BECCS), and Biochar production from pyrolysis are evaluated for their capacity to mitigate one million tonnes of CO2. Process models are developed for each method,followed by techno-economic analyses and optimization to derive the most effective solution. The holistic approach considers objectives such as net energy gain, minimized water usage, and product sales.

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Gilmour et al. (2024): Microbially induced calcium carbonate precipitation through CO2 sequestration via an engineered Bacillus subtilis

Katie A. Gilmour, Prakriti Sharma Ghimire, Jennifer Wright, Jamie Haystead, Martyn Dade-Robertson, Meng Zhang, Paul James IN: Microbial Cell Factories, 23, https://doi.org/10.1186/s12934-024-02437-7

Bacteria play a crucial role in producing calcium carbonate minerals, via enzymes including carbonic anhydrase—an enzyme with the capability to hydrolyse CO2, commonly employed in carbon capture systems. This study describes previously uncharacterised carbonic anhydrase enzyme sequences capable of sequestering CO2 and subsequentially generating CaCO3 biominerals and suggests a route to produce carbon negative cementitious materials for the construction industry.

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Han et al. (2024): Quantifying the negative effects of dissolved organic carbon of maize straw-derived biochar on its carbon sequestration potential in a paddy soil

Lanfang Han, Beibei Liu, Yu Luo, Liying Chen, Chuanxin Ma, Chao Xu, Ke Sun, Baoshan Xing IN: Soil Biology and Biochemistry, 196, https://doi.org/10.1016/j.soilbio.2024.109500

This study conducted incubation experiments on maize straw-derived 300/450 °C biochar, Biochar dissolved organic carbon (BDOC) extracted biochar residues and BDOC, and applied δ13C analysis to quantify biochar’s mineralization and their priming effects on native soil organic carbon in a paddy soil. The findings proved that BDOC extraction appears a feasible strategy to enhance the short-period carbon sequestration potential of biochar.

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Nature – Xu et al. (2024): Dynamics of carbon sequestration in vegetation affected by large-scale surface coal mining and subsequent restoration

Yaling Xu, Jun Li, Chengye Zhang, Simit Raval, Li Guo, Fei Yang IN: Scientific Reports, 14, https://doi.org/10.1038/s41598-024-64381-1

Here, the authors provided a novel approach to assess the dynamics of carbon sequestration in vegetation (VCS) affected by large-scale surface coal mining and subsequent restoration. This approach effectively overcomes the limitations imposed by the lack of finer scale and long-time series data through scale transformation. The findings deepen insights into the intricate relationship between coal resource development and ecological environmental protection.

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Fernandes de Souza et al. (2024): The potential of microalgae for carbon capture and sequestration

Marcella Fernandes de Souza, Erik Meers, Silvio Mangini IN: EFB Bioeconomy Journal, 4, https://doi.org/10.1016/j.bioeco.2024.100067

Here, the authors calculated the potential of microalgae for the capture of CO2 by integrating it with a large emitter (gas-based energy plant) and a low emitter (dairy farms), and also discussed if such integrated systems can be considered as carbon sequesters given that the final use of the biomass often quickly releases the captured CO2. Moreover, the CO2 footprint of microalgal systems is highlighted as a critical point of attention for future developments. Such considerations are of utmost importance to avoid false promises that ultimately harm this sector, as large investments are made following untruthful claims that, when proven wrong, result in a loss of interest. Finally, key definitions are proposed to improve clarity and help in such discussions.

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Ferderer et al. (2024): Investigating the effect of silicate- and calcium-based ocean alkalinity enhancement on diatom silicification

Aaron Ferderer, Kai G. Schulz, Ulf Riebesell, Kirralee G. Baker, Zanna Chase, Lennart T. Bach IN: Biogeosciences, 21, https://doi.org/10.5194/bg-21-2777-2024

The authors conducted an experiment with 10 pelagic mesocosms in Raunefjorden, Bergen, Norway, to assess the implications of simulated silicate- and calcium-based mineral OAE on a coastal plankton community. The experiment explored many components of the plankton community, from microbes to fish larvae, and here the authors report on the influence of simulated mineral based OAE on diatom silicification. This research underscores the importance of understanding the full breadth of different OAE approaches, their risks, co-benefits, and potential for interactive effects.

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Fulham et al. (2024): Managing intermittency of renewable power in sustainable production of methanol, coupled with direct air capture

George J. Fulham, Paula V. Mendoza-Moreno, Ewa J. Marek IN: Energy and Environmental Science, DOI: 10.1039/D4EE00933A

Coupling direct air capture (DAC) with methanol production is a technically attainable opportunity for CO2 capture and utilisation (CCU). The process, known as power-to-methanol (PtM), consumes large amounts of renewable electricity for water electrolysis and DAC. However, the time-variability of renewable power remains a major challenge. Here, the authors consider erecting a wind farm as part of a PtM facility and propose using four parallel reactors to adjust the methanol production according to daily wind power generation, which we model for 90 onshore and offshore locations with real-world data. Batteries and reserve storage of compressed H2 and CO2 allow methanol production during near-zero availability of wind power. They investigate different operation strategies, aiming to either minimise the reserve storage or maximise production, ultimately finding minimised storage as more cost-effective.

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Gray et al. (2024): The role of direct air carbon capture in decarbonising aviation

Nathan Gray, Richard O’Shea, Beatrice Smyth, Piet N.L. Lens, Jerry D. Murphy IN: Renewable and Sustainable Energy Reviews, 199, 114552; https://doi.org/10.1016/j.rser.2024.114552

This study compares two use cases of direct air carbon capture to decarbonise aviation, from an economic and environmental perspective. The first is where continued use of fossil jet fuel is offset by capturing and sequestering CO2 from the atmosphere. The second is where CO2 captured from the atmosphere is used as a feedstock, in conjunction with hydrogen from electrolysis, to produce a synthetic jet fuel.

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Nature – Schmitz et al. (2024): Trophic rewilding can expand natural climate solutions

Oswald J. Schmitz, Magnus Sylvén, Trisha B. Atwood, Elisabeth S. Bakker, Fabio Berzaghi, Jedediah F. Brodie, Joris P. G. M. Cromsigt, Andrew B. Davies, Shawn J. Leroux, Frans J. Schepers, Felisa A. Smith, Sari Stark, Jens-Christian Svenning, Andrew Tilker, Henni Ylänne IN: Nature Climate Change, 13, https://doi.org/10.1038/s41558-023-01631-6

Natural climate solutions are being advanced to arrest climate warming by protecting and enhancing carbon capture and storage in plants, soils and sediments in ecosystems. These solutions are viewed as having the ancillary benefit of protecting habitats and landscapes to conserve animal species diversity. However, this reasoning undervalues the role animals play in controlling the carbon cycle. The authors present scientific evidence showing that protecting and restoring wild animals and their functional roles can enhance natural carbon capture and storage. They call for new thinking that includes the restoration and conservation of wild animals and their ecosystem roles as a key component of natural climate solutions that can enhance the ability to prevent climate warming beyond 1.5 °C.

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