Search

Although CO2 impacts the environment negatively, it can be a valuable resource due to its carbon content. The U.S. industry emits over 825 Mt of CO2 annually, with an expected increase in the future. This article analyzes 27 different technology combinations for capturing and using CO2 for industrial feedstocks, including the production of synthetic methane, methanol, and Fischer-Tropsch fuels. The study also estimates and compares the energy requirements for capturing and converting CO2 from 16 different industrial sources, as well as the energy requirements for hydrogen production through state-of-the-art and emerging electrolyzer technologies. Additionally, the study develops a combined scenario that outlines a design for applying an inclusive approach to achieve net-zero CO2 emissions in the industrial sector, incorporating multiple decarbonization measures. The results suggest that the use of CO2 for methane production has the potential to replace all natural gas demands considered in the base case and combined scenarios. However, using CO2 utilization-based Fischer-Tropsch products alone to replace naphtha feedstock and transportation fuels is not sufficient to achieve complete decarbonization in the studied end uses. CO2 utilization-based methanol could potentially substitute for several times the current U.S. methanol production and meet the current global demand for methanol. Moreover, the study conducts an economic analysis to estimate the costs of CO2 utilization, which vary for different industrial sectors and depend on the technologies employed. Overall, this study provides valuable information for policymakers and industry stakeholders who are striving to develop effective strategies to decarbonize the industrial sector.

Ruddlesden‐Popper (RP) oxides have emerged as a promising alternative to Ni cermet electrodes for high‐temperature steam electrolysis due to their superior oxide ion mobility and conductivity. Combining RP with perovskite (P) can provide superior electrocatalytic activity toward hydroxide oxidation and reduction reaction, driving higher efficiency in solid oxide cells (SOC). This work provides a novel approach to enhancing SOC performance by employing A‐site Ce‐substituted Sr0.6Pr0.4‐xCexMnO3 (x = 0.1‐0.3) electrodes, investigating their phase evolution, crystal properties, and cation oxidation states under oxidizing and reducing atmospheres. X‐ray diffraction analysis of heat‐treated powder in a reducing atmosphere revealed forming mixed P and RP structures at 600–800 °C for x = 0.1 and 0.2, which provides excellent conductivity and electrocatalytic activity. Consequently, outstanding cell performance is achieved, with low polarization resistances of 0.053 ± 0.004 Ω cm2 at 800 °C. The voltage response at different current densities in an electrolyte‐supported cell revealed a high power density of 1.084 W cm−2 in fuel cell operation and a current density of 1.00 A cm−2 at the thermoneutral voltage at 850 °C in steam electrolysis. Moreover, a low overpotential degradation rate of 45 mV kh−1 demonstrated the remarkable potential of the SPCM electrode as a promising Ni‐free candidate for SOC application. [ABSTRACT FROM AUTHOR]

Power‐to‐methane (PtM) offers an efficient opportunity for surplus renewable energy storage, but heat management is a major challenge for conducting the highly exothermic methanation reaction. To address this challenge, this study presents the first successful demonstration of core‐shell catalyst pellets in a pilot‐scale reactor for CO2 methanation. Experiments in a wall‐cooled fixed‐bed reactor are conducted with diluted and undiluted reactant feed under systematic variation of cooling temperature and inlet gas flow rate. The results show that core‐shell catalyst pellets significantly reduce the hot‐spot temperature while maintaining comparable reactant conversions to uncoated catalyst pellets at the same conditions. Additionally, core‐shell catalyst pellets allow for undiluted reactant feed at comparably low hot‐spot temperatures (approx. 600 °C). [ABSTRACT FROM AUTHOR]

The synergies from integrating direct air capture and CO2 methanation are assessed and quantified. Three direct air capture and methanation processes with different integration strategies are proposed: only heat integration, direct air capture sorbent regeneration with high‐pressure H2, and complete integration in a single unit. The heat integration study via pinch analysis evaluated the potential energy demand reduction. Overall autothermal operation is achievable, as the heat generated in methanation often exceeds that required for direct air capture sorbent regeneration. A novel process combining CO2 adsorption and methanation in one reactor provided the best productivity and energy demand results. However, this design requires complex cycles and strict demands on the sorbent and catalyst, requiring further development and experimental demonstration. [ABSTRACT FROM AUTHOR]

With the lowest power access rate in the world (51.4%), Sub-Saharan Africa is experiencing a severe energy crisis. Many of the region's countries report access rates of less than 20%. Even though Sub-Saharan Africa has the lowest global greenhouse gas emissions, the region still suffers from climate change, especially extreme droughts. Efforts to tackle these issues by implementing a macro-grid system that integrates natural gas and renewable energy resources have not been successful in reducing the adverse environmental effects and energy poverty. This study highlights research on the technological approaches used in hybrid hydrogen/natural gas in heavy-duty dual-fuel power plants, their benefits and drawbacks, and their economic viability. The goal of this is to suggest an improved and more reliable hub energy system for Sub-Saharan Africa. While all countries in Sub-Saharan Africa utilize natural gas plants, only 17% are involved in hydrogen production, and none have implemented hybrid methods for electrical energy generation. Studies using experimental and numerical analyses have shown that adding hydrogen to natural gas plants increases overall efficiency and lowers CO2 emissions. Furthermore, this research introduces an energy hub approach that incorporates carbon capture and power-to-X technologies, potentially improving efficiency by 42%. These strategies not only support environmental sustainability but also provide economic advantages by decreasing operational and financial losses in power plants. The results reveal a new pathway for the region's transition to sustainable energy: identifying key locations for the technological and economic viability of hybrid hydrogen/natural gas power plants in Sub-Saharan Africa. [ABSTRACT FROM AUTHOR]

Methanol is a versatile substance that can be used in combustion engines and fuel cells and as a feedstock for the production of various chemicals. However, the majority of methanol is currently produced from fossil fuels, which is not sustainable. The aim of this study was to analyze and evaluate the feasibility of methanol production from renewable sources as a bridge to a low-carbon economy and its potential as an alternative to fossil-derived chemicals. For this purpose, the process of methanol production from captured CO2 and water as an H2 source was simulated in Aspen Plus. For CO2 capture, the monoethanolamine (MEA) absorption process was assumed. The H2 required for methanol synthesis was obtained by alkaline water electrolysis using electricity from renewable sources. The captured CO2 and the produced H2 were then converted into methanol through the process of CO2 hydrogenation in two ways, direct and two-step synthesis. In the direct conversion, the hydrogenation of CO2 to methanol was carried out in a single step. In the two-step conversion, the CO2 was first partly converted to CO by the reverse water-gas shift (RWGS) reaction, and then the mixture of CO and CO2 was hydrogenated to methanol. The results show that direct synthesis has a higher methanol yield (0.331 kmol of methanol/kmol of H2) compared to two-step synthesis (0.326 kmol of methanol/kmol of H2). The direct synthesis produces 13.4 kmol of methanol/MW, while the two-step synthesis produces 11.2 kmol of methanol/MW. This difference amounts to 2.2 kmol of methanol/MW, which corresponds to a saving of 0.127 $/kmol of methanol. Besides the lesser energy requirements, the direct synthesis process also produces lower carbon emissions (22,728 kg/h) as compared to the two-step synthesis process (33,367 kg/h). [ABSTRACT FROM AUTHOR]

The research is devoted to the issues of determining the EU’s long-term strategic choice in the context of energy transformation and studying the key elements of the EU’s hydrogen diplomacy. The main idea of the paper is to assess the key elements of the EU’s hydrogen diplomacy at the moment in the context of the geopolitics of energy transformation. The potential key centres of hydrogen production in Europe has been identified in the paper. The study also highlights that the EU plans to become an importer of green hydrogen and Power-to-X products. Hydrogen is likely to have a significant impact on the geography of energy trade, further regionalising energy relations. It should also be borne in mind that pure hydrogen will not generate profits comparable to today’s oil and gas. Hydrogen is a transformation, not an extraction, and it has the potential to be produced competitively in many places. It is argued that there is an urgent need to transform the EU’s hydrogen diplomacy in the paper, aligning Europe’s interests in enhancing its competitiveness and energy security in times of crisis with global goals of decarbonisation and sustainable economic development. The implementation of effective hydrogen diplomacy and partnerships within the H2-diplo initiative will consolidate the geopolitical and security environment on the way to the EU’s strategic autonomy. At the same time, it is noted that the EU needs to think deeply about the potential contribution of the EU to territorial defence and deterrence in the paper and how its defence instruments can strengthen the Atlantic Alliance’s deterrence and territorial defence strategy. This refocusing on traditional defence will significantly increase the EU’s added value. The National Security Strategy, approved by the Biden administration on 12 October 2022, makes this clear, distinguishing between China as a ‘systemic’, ‘global’ challenge and russia as an ‘immediate’, albeit more local, threat. It has been explaind that as the United States increases its focus on China and Asia, Europe will have to assume more responsibility for the security and defence of the continent.

Abstract Nigeria currently relies on 80% thermal energy generation. However, studies have shown that less than 60% of the population have access to power. To address this issue, Nigeria has developed an energy transition plan to achieve net-zero emissions by utilizing eco-friendly and sustainable renewable energy sources. However, the effectiveness of renewable energy resources is often hampered by seasonal variations, which limit the amount of energy that can be produced to meet growing demand. One effective solution to this challenge is long-term energy storage, particularly during periods of low demand. Power-to-X (PtX) technology offers a promising approach by enabling long-term sustainable energy generation and storage for future use when renewable energy availability decreases during peak demands. This study critically reviews the latest advancements in renewable PtX technology and evaluates its potential application within Nigeria's energy sector. Furthermore, it explores the potential obstacles to the widespread adoption of PtX technology in Nigeria. Despite Nigeria’s significant potential for implementing PtX initiatives, the country currently falls behind in technology deployment and viable production pathways for sustainable PtX implementation. This shortfall is primarily due to lack of policies, frameworks, and financing schemes to support infrastructural development, especially for long-term energy storage. Given the intermittent nature of renewable energy, a transition strategy that includes adequate storage capacity is crucial. Although green hydrogen, a key component of PtX, has substantial potential as an energy carrier in Nigeria, its immediate use is limited by high production costs. Nonetheless, ongoing efforts to diversify Nigeria’s energy mix through infrastructure and policy developments could eventually establish a roadmap for PtX implementation, promoting long-term energy sustainability and distribution efficiency.

Recently, Power-to-X (PtX) has come to play a prominent role in the public discussion of a green energy future, with high hopes expressed by political and business players. In the Danish news media, PtX has experienced a steep rise in attention, which calls for studies of how PtX is made sense of as a societal, not only a technological, phenomenon. Informed by the notion of sociotechnical imaginaries, this article investigates the local introduction of PtX in Frederica, one of the forerunner towns for PtX in Denmark, as represented in the coverage of the daily newspaper Fredericia Dagblad. The study analyses how PtX is made sense of by being connected to local actors, circumstances, and imagined futures. Two diverging sociotechnical imaginaries are identified, centring on 1) local (business) cooperation for green energy solutions towards a PtX adventure, and 2) concerns for scarce nature in a densely industrialised area. The findings show both similarities with and differences to already known mediatised environmental conflicts and point to dynamics between media, market, politics, and civil society in future mediatised environmental conflicts.

For decades, fossil fuels have been the backbone of reliable energy systems, offering unmatched energy density and flexibility. However, as the world shifts toward renewable energy, overcoming the limitations of intermittent power sources requires a bold reimagining of energy storage and integration. Power-to-X (PtX) technologies, which convert excess renewable electricity into storable energy carriers, offer a promising solution for long-term energy storage and sector coupling. Recent advancements in machine learning (ML) have revolutionized PtX systems by enhancing efficiency, scalability, and sustainability. This review provides a detailed analysis of how ML techniques, such as deep reinforcement learning, data-driven optimization, and predictive diagnostics, are driving innovation in Power-to-Gas (PtG), Power-to-Liquid (PtL), and Power-to-Heat (PtH) systems. For example, deep reinforcement learning has improved real-time decision-making in PtG systems, reducing operational costs and improving grid stability. Additionally, predictive diagnostics powered by ML have increased system reliability by identifying early failures in critical components such as proton exchange membrane fuel cells (PEMFCs). Despite these advancements, challenges such as data quality, real-time processing, and scalability remain, presenting future research opportunities. These advancements are critical to decarbonizing hard-to-electrify sectors, such as heavy industry, transportation, and aviation, aligning with global sustainability goals. [ABSTRACT FROM AUTHOR]

This work examines the electrochemically enhanced production of succinic acid using the bacterium Actinobacillus succinogenes. The principal objective is to enhance the metabolic potential of glucose and CO2 utilization via the C4 pathway in order to synthesize succinic acid. We report on the development of an electro-bioreactor system to increase succinic acid production in a power-2-X approach. The use of activated carbon fibers as electrode surfaces and contact areas allows A. succinogenes to self-initiate biofilm formation. The integration of an electrical potential into the system shifts the redox balance from NAD+ to NADH, increasing the efficiency of metabolic processes. Mediators such as neutral red facilitate electron transfer within the system and optimize the redox reactions that are crucial for increased succinic acid production. Furthermore, the role of carbon nanotubes (CNTs) in electron transfer was investigated. The electro-bioreactor system developed here was operated in batch mode for 48 h and showed improvements in succinic acid yield and concentration. In particular, a run with 100 µM neutral red and a voltage of −600 mV achieved a yield of 0.7 gsuccinate·gglucose−1. In the absence of neutral red, a higher yield of 0.72 gsuccinate·gglucose−1 was achieved, which represents an increase of 14% compared to the control. When a potential of −600 mV was used in conjunction with 500 µg∙L−1 CNTs, a 21% increase in succinate concentration was observed after 48 h. An increase of 33% was achieved in the same batch by increasing the stirring speed. These results underscore the potential of the electro-bioreactor system to markedly enhance succinic acid production. [ABSTRACT FROM AUTHOR]

Nigeria currently relies on 80% thermal energy generation. However, studies have shown that less than 60% of the population have access to power. To address this issue, Nigeria has developed an energy transition plan to achieve net-zero emissions by utilizing eco-friendly and sustainable renewable energy sources. However, the effectiveness of renewable energy resources is often hampered by seasonal variations, which limit the amount of energy that can be produced to meet growing demand. One effective solution to this challenge is long-term energy storage, particularly during periods of low demand. Power-to-X (PtX) technology offers a promising approach by enabling long-term sustainable energy generation and storage for future use when renewable energy availability decreases during peak demands. This study critically reviews the latest advancements in renewable PtX technology and evaluates its potential application within Nigeria's energy sector. Furthermore, it explores the potential obstacles to the widespread adoption of PtX technology in Nigeria. Despite Nigeria's significant potential for implementing PtX initiatives, the country currently falls behind in technology deployment and viable production pathways for sustainable PtX implementation. This shortfall is primarily due to lack of policies, frameworks, and financing schemes to support infrastructural development, especially for long-term energy storage. Given the intermittent nature of renewable energy, a transition strategy that includes adequate storage capacity is crucial. Although green hydrogen, a key component of PtX, has substantial potential as an energy carrier in Nigeria, its immediate use is limited by high production costs. Nonetheless, ongoing efforts to diversify Nigeria's energy mix through infrastructure and policy developments could eventually establish a roadmap for PtX implementation, promoting long-term energy sustainability and distribution efficiency. [ABSTRACT FROM AUTHOR]

E-fuels represent a crucial technology for transitioning to fossil-free energy systems, driven by the need to eliminate dependence on fossil fuels, which are major environmental pollutants. This study investigates the production of carbon-neutral synthetic fuels, focusing on e-hydrogen (e-H2) generated from water electrolysis using renewable electricity and carbon dioxide (CO2) captured from industrial sites or the air (CCUS, DAC). E-H2 can be converted into various e-fuels (e-methane, e-methanol, e-DME/OME, e-diesel/kerosene/gasoline) or combined with nitrogen to produce e-ammonia. These e-fuels serve as efficient energy carriers that can be stored, transported, and utilized across different energy sectors, including transportation and industry. The first objective is to establish a clear framework encompassing the required feedstocks and production technologies, such as water electrolysis, carbon capture, and nitrogen production techniques, followed by an analysis of e-fuel synthesis technologies. The second objective is to evaluate these technologies' technological maturity and sustainability, comparing energy conversion efficiency and greenhouse gas emissions with their electric counterparts. The sustainability of e-fuels hinges on using renewable electricity. Challenges and future prospects of an energy system based on e-fuels are discussed, aiming to inform the debate on e-fuels' role in reducing fossil fuel dependency. [ABSTRACT FROM AUTHOR]

Addressing the environmental challenges posed by CO2 emissions is crucial for mitigating global warming and achieving net-zero emissions by 2050. This study compares CO2 storage (CCS) and utilization (CCU) technologies, highlighting the benefits of integrating captured CO2 into fuel production. This paper focuses on various carbon utilization routes such as Power-to-Gas via the Sabatier reaction, indirect production of DME, and Power-to-Fuel technologies. The maturity of these technologies is evaluated using the Technology Readiness Level (TRL) method, identifying the advancements needed for future implementation. Additionally, global regulations and policies surrounding carbon capture and storage are reviewed to provide context for their current status. The study emphasizes the potential of CCU technologies to reduce future CO2 emissions by converting captured CO2 into valuable fuels and chemicals, thus supporting the transition to a sustainable energy system. The findings indicate that while CCS technologies are more mature, promising CCU technologies can significantly contribute to reducing greenhouse gas emissions if green hydrogen becomes more affordable. This research underscores the importance of further technological development and economic evaluation to enhance the feasibility and adoption of CCU technologies in the pursuit of long-term environmental sustainability. [ABSTRACT FROM AUTHOR]

The escalating demand for renewable energy solutions and the imperative for efficient energy storage mechanisms have catalyzed the evolution of Power-to-X (PtX) technologies. Germany has the most PtX projects, accounting for 44% of all projects that have been reported. PtX encompasses a spectrum of processes engineered to convert surplus renewable energy into versatile energy carriers or chemical commodities, such as hydrogen, methane, or synthetic fuels. The Paramount to this domain is to synergistically harness renewable energy sources and hydrogen carriers to curtail waste and bolster sustainability. Central to achieving this synergy is the effective control of PtX processes, ensuring optimal performance, cost efficiency, and seamless integration within existing energy frameworks. This paper delves into the control processes and environmental prerequisites within the PtX landscape, elucidating key challenges, and strategies within this dynamic realm. While providing an initial overview of fundamental PtX process chains, this paper accentuates the critical role of geographical considerations. Subsequently, it conducts a thorough analysis of equipment modeling challenges, addressing performance metrics, operational requisites, and capital investments, particularly focusing on methanol and hydrogen production and storage. Through holistic examination, this paper endeavors to delineate the evolving landscape of PtX control processes and conditions, advancing our understanding of this expanding field. [Display omitted] • Comprehensive overview of PtX control process, challenges, strategies, and advancements. • Overview of PtX process chains and geographical conditions. • Analysis of equipment modeling challenges for methanol and hydrogen. • Addressing crucial storage challenges in PtX system. • Exploration of diverse influences on PtX control processes. [ABSTRACT FROM AUTHOR]

The sustainable synthesis of long carbon chain molecules from carbon dioxide, water and electricity relies on the development of waste‐free, highly selective C−C bond forming reactions. An example for such a power‐to‐chemicals process is the industrial‐scale fermentation for the production of hexanoic acid. Herein, we describe how this product is transformed into 6‐undecanone via decarboxylative ketonization using a heterogeneous manganese oxide/silica catalyst. The reaction reaches full conversion with near‐complete selectivity when carried out in a continuous flow reactor, requires no solvent or carrier gas, and releases carbon dioxide and water as the only by‐products. The reactor was operated for several weeks with no loss of reactivity, producing 7 kg of 6‐undecanone from 10 g of catalyst and achieving a productivity of 1.135 kg per litre of reactor volume per hour. 6‐Undecanone and other long‐chain ketones accessible this way can be hydrogenated to industrially meaningful alkanes, or converted into valuable fatty acids via a hydrogenation/elimination/isomerizing hydrocarboxylation sequence. [ABSTRACT FROM AUTHOR]

Given China's ambition to realize carbon peak by 2030 and carbon neutralization by 2060, hydrogen is gradually becoming the pivotal energy source for the needs of energy structure optimization and energy system transformation. Thus, hydrogen combined with renewable energy has received more and more attention. Nowadays, power-to-hydrogen, power-to-methanol, and power-to-ammonia are regarded as the most promising three hydrogen-driven power-to-X technologies due to the many commercial or demonstration projects in China. In this paper, these three hydrogen-driven power-to-X technologies and their application status in China are introduced and discussed. First, a general introduction of hydrogen energy policies in China is summarized, and then the basic principles, technical characteristics, trends, and challenges of the three hydrogen-driven power-to-X technologies are reviewed. Finally, several typical commercial or demonstration projects are selected and discussed in detail to illustrate the development of the power-to-X technologies in China. [ABSTRACT FROM AUTHOR]

The application of chemical looping for reverse water gas-shift provides an efficient way for the conversion of CO2 to CO, enabling the transformation of captured CO2 into value-added products. For example, by using the produced CO along with renewable H2 to synthesise liquid fuels. In this study, we applied the concept of a chemical ‘memory’ reactor, employing a perovskite-based oxygen carrier (La0.6Sr0.4FeO3-δ, LSF) in a counter-current packed-bed reactor for CO2 splitting. This approach overcomes the chemical equilibrium limitation and could produce high purity CO.Our work experimentally investigated the performance of LSF pellets as oxygen carriers in a large lab-scale packed-bed reactor with gas switching technology for chemical looping CO2 splitting. We evaluated the effects of changes in feed time, bed temperatures, and flow rates on CO2 to CO conversion. Optimal conditions gave over 90 % CO2 to CO conversion via counter-current flow, compared to 45 % for conventional co-current flow in the same reactor. Higher bed temperatures enhanced the CO2 to CO conversion.

Proton exchange membrane (PEM) electrolysis is widely considered an integral part of the energy transition. Thinner membranes can reduce Ohmic losses and increase efficiency. However, hydrogen crossover limits the use of thinner membranes. For the first time, this review provides a comprehensive overview of both model and experimental works on hydrogen crossover and crossover mitigation. By combining the experimental data and state-of-the-art models, we discuss the recent progress in understanding crossover mechanisms. The dominant mechanism for hydrogen crossover is the diffusion driven by both the high hydrogen partial pressures at the cathode and supersaturation in the catalyst layer due to transport limitations. The reviewed models successfully reproduce the experimental data obtained by different groups. A variety of strategies for including recombination catalysts in the cell are currently investigated in academic and corporate research. Some of these show promising results with potential for near-term industrial application. • H 2 crossover conventionally limits the use of thin membranes in PEM electrolysis. • Supersaturation and electroosmotic water drag can significantly affect gas crossover. • Mechanistic crossover models describe various experimental results accurately. • Recombination catalysts mitigate safety issues associated with H 2 crossover. • Multiple approaches for including recombination catalysts in MEAs are promising. [ABSTRACT FROM AUTHOR]

Copyright of Low-Carbon Chemistry & Chemical Engineering is the property of Low-Carbon Chemistry & Chemical Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)