CO₂-removal News

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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Niron et al. (2024): Exploring the Synergy of Enhanced Weathering and Rhizobacteria in Sustainable Agriculture

Harun Niron, Laura Steinwidder, Jet Rijnders, Lucilla Boito, Sara Vicca IN: EGU24-16303, https://doi.org/10.5194/egusphere-egu24-16303

In a maize mesocosm experiment combining B. subtilis, basalt, and water content as variables, we observed a significant impact of B. subtilis on plant biomass in treatments, while basalt showed no major effect. In treatments with reduced irrigation, plants that were amended with basalt and B. subtilis displayed elevated leaf chlorophyll levels and improved nitrogen balance compared to plants that were not amended with B. subtilis.

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Tang et al. (2024): Environmental and economic spatial analysis system for biochar production – Case studies in the East of England and the East Midlands

Yuzhou Tang, Yue Li, Tim T. Cockerill IN: Biomass and Bioenergy, 184, 107187, https://doi.org/10.1016/j.biombioe.2024.107187

The authors develop a space-based environmental economic model to quantify the impact of feedstock supply and plant strategies on costs and benefits. The results show that biochar production in the East of England and the East Midlands could achieve significant net GHG reduction and GGR benefits. Environmental benefits are not related to factory strategy but are positively correlated with feedstock supply strategy.

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Olsson et al. (2024): Expectations on biochar as a climate solution in Sweden: Carbon dioxide removal with environmental co-benefits

Alexander Olsson, Mathias Fridahl, Stefan Grönkvist IN: Renewable and Sustainable Energy Transition, 5, 100087, https://doi.org/10.1016/j.rset.2024.100087

This paper draws on the Swedish case to explore expectations put on biochar and the significance of public support for fulfilling these expectations. The analysis shows that biochar is expected to contribute to several environmental objectives. However, while biochar producers and users voice expectations on strengthening the multifunctionality of landscapes, e.g., improved ecosystem resilience and reduced nutrient run-off, the authorities rather narrowly direct attention to the stability of biochar as a carbon storage.

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Clarkson et al. (2024): A Review of Measurement for Quantification of Carbon Dioxide Removal by Enhanced Weathering in Soil

Matthew O. Clarkson, Christina Larkin, Philipp Swoboda, Tom Reershemius, Tim Jesper Suhrhoff, Cara N. Maesano, James Campbell IN: Frontiers in Climate, 6, doi: 10.3389/fclim.2024.1345224

Here, the authors provide a review of the current literature showing the state-of-play of different methods for monitoring EW. They focus on geochemical characterization of weathering processes at the weathering site itself, acknowledging that the final storage of carbon is largely in the oceans, with potential losses occurring during transfer. There are two main approaches for measuring EW, one focused on solid phase measurements, including exchangeable phases, and the other on the aqueous phase. Additionally, gas phase measurements have been employed to understand CO2 fluxes, but can be dominated by short-term organic carbon cycling

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Stuart et al. (2024): Non-mycorrhizal root-associated fungi increase soil C stocks and stability via diverse mechanisms

Emiko K. Stuart, Laura Castañeda-Gómez, Wolfram Buss, Jeff R. Powell, Yolima Carrillo IN: Biogeosciences, 21, https://doi.org/10.5194/bg-21-1037-2024

Here, with the aim of identifying novel organisms that could be introduced to crop plants to promote C sequestration, the authors assessed the soil C storage potential of 12 root-associated, non-mycorrhizal fungal isolates (spanning nine genera and selected from a wide pool based on traits potentially linked to soil C accrual) and investigated fungal, plant and microbial mediators. They grew wheat plants inoculated with individual isolates in chambers allowing continuous 13C labelling. After harvest, the authors quantified C storage potential by measuring pools of different origin (plant vs. soil) and different stability with long-term soil incubations and size/density fractionation. They assessed plant and microbial community responses as well as fungal physiological and morphological traits in a parallel in vitro study.

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The State of Carbon Dioxide Removal: A global independent scientific assessment of Carbon Dioxide Removal, 2nd edition

Stephen M. Smith, Oliver Geden, Matthew J. Gidden, William F. Lamb, Gregory F. Nemet, Jan C. Minx, Holly Buck, Josh Burkev, Emily Cox, Morgan R. Edwards, Sabine Fuss, Injy Johnstone, Finn Müller-Hansen, Julia Pongratz, Benedict S. Probst, Stephanie Roe, Felix Schenuit, Ingrid Schulte, Naomi E. Vaughan, University of Oxford’s Smith School of Enterprise, June 4, 2024

Although the Paris Agreement states that climate change mitigation must be done “in the context of sustainable development”, most scenarios do not explicitly consider social and environmental sustainability. The authors therefore identified a subset of scenarios that can be considered “more sustainable”. Across this group of scenarios, the central range of CDR deployment is 7 to 9 GtCO2 per year in 2050. The lowest scenarios reach 4 GtCO2 per year in 2050. While this range is similar in 2050 to that for all below 2°C scenarios, the more sustainable scenarios cumulatively remove 170 GtCO2 between 2020 and the time of net zero CO2, compared with 260 GtCO2 cumulatively in all below 2°C scenarios.

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Policy Brief: Eckpunktepapier für ein integriertes Carbon Management

Aysel Aliyeva, Lukas Daubner, Ralf Fücks und Julia Hönnecke, Zentrum Liberale Moderne, Mai 2024

Carbon Management ist eine notwendige Säule des Klimaschutzes. Ein integriertes Carbon Management muss dabei komplexe klima-, industrie- und umweltpolitische Fragen zusammendenken. Das Eckpunktepapier erklärt Methoden, diskutiert Lösungen, aber auch Herausforderungen und zeigt konkrete Handlungsempfehlungen auf, wie ein integriertes Carbon Management rasch etabliert werden kann.

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