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To explore the potential of oxy-fuel technology, this study performs a detailed thermodynamic analysis of four combustion cycles: SCOC-CC, Matiant, S-Graz, and Allam. Using Aspen Plus simulations with standardized boundary conditions, the Allam cycle demonstrated the highest net energy efficiency (56.04%) and exergy efficiency (52.87%), followed by the S-Graz cycle. The analysis revealed that the Allam cycle incurred the lowest Carbon Capture and Storage (CCS) efficiency penalty (0.42%) due to its optimized condenser pressure, whereas the S-Graz cycle faced a significantly higher penalty of 3.88%. While Air Separation Unit (ASU) penalties were consistent across all systems, exergy destruction was most pronounced in the combustor and turbine components. Overall, the findings identify the Allam cycle as the superior configuration for high thermal efficiency and reduced complexity in oxy-fuel applications.

Direct fired supercritical CO2 (sCO2) power cycles allow for the combustion of gaseous fuels under oxyfuel conditions with inherent carbon capture. As the CO2 is captured intrinsically, the efficiency penalty of capture on the overall plant is small, meaning that power plants achieve a similar efficiency to traditional fossil fuel power plants without carbon capture and storage. However, at high pressures and in large dilutions of CO2, combustion mechanisms are poorly understood. Therefore, in this paper sensitivity and quantitative analysis of four established chemical kinetic mechanisms have been employed to determine the most important reactions and the best performing mechanisms over a range of different conditions. CH3O2 chemistry was identified as a pivotal mechanism component for modelling methane combustion above 200 atm. The University of Sheffield (UoS) sCO2 mechanism created in the present work better models the ignition delay time (IDT) of high-pressure combustion in a large dilution of CO2. Quantitative analysis showed that the UoS sCO2 mechanism was the best fit to the greatest number of IDT datasets and had the lowest average absolute error value, thus indicating a superior performance compared to the four existing chemical kinetic mechanisms, well-validated for lower pressure conditions.

This study investigates potential solutions for low-carbon power generation with hydrogen firing and carbon capture. Multi-dimensional system modeling was used to assess the effects on plant performance, size, and cost. The examined cycles include advanced dry-, wet-, bottoming-, oxyfuel cycles with air-separation units, and post-combustion carbon capture with exhaust gas recirculation. The results identify three distinct low-carbon technology pathways. While conventional combined-cycle plants are suitable for hydrogen retrofits, hydrogen firing (both blue and green) results in levelized costs of electricity 50%–300% higher than carbon capture solutions, making carbon capture more attractive for long-term energy storage. When carbon capture is applied to conventional combined cycles, they become suboptimal compared to alternative solutions. The intercooled-recuperated (ICR) gas turbine cycle integrated with post-combustion carbon capture offers superior performance: over 3% higher efficiency, 12% lower capital costs, and 70% smaller physical footprint compared to conventional combined cycles with carbon capture. The Allam cycle represents a third pathway, achieving 100% capture with efficiency comparable to combined cycles at 90% capture. Gas separation units emerge as the dominant source of both capital costs and efficiency penalties across all carbon capture configurations, representing the key area for future optimization to reduce overall electricity costs.

As the transition to renewable energy accelerates, advanced energy storage systems (ESS) are essential to address intermittency and ensure grid stability. This review evaluates various ESS technologies—ranging from mechanical and electrochemical to superconducting magnetic systems—before focusing on supercritical carbon dioxide (sCO2) as a promising storage medium. The analysis highlights Underground Adiabatic Compressed Carbon Dioxide Energy Storage (UA-CCES) as a standout solution, demonstrating exceptional efficiency through effective heat recovery. The study concludes that while sCO2 technologies offer a viable pathway for high-density energy storage and emissions reduction, realizing their full potential requires continued technological innovation and robust policy support.

In recent years, the supercritical Carbon Dioxide (sCO2) cycle has been considered a future advanced technology for power conversion because of its distinctive characteristics, such as compactness, high efficiency and flexibility in handling different heat sources. So far, most studies on sCO2 cycles have focused on thermodynamics and dynamic modelling, with much less attention given to control systems. Effective control strategies are crucial for optimising performance and ensuring safety. This paper aims to address the gap in the existing literature through providing a detailed review of the control strategies for sCO2 power cycles, including basic control strategies for startup/shutdown and off-design performance, combined control strategies, and advanced control strategies. The review shows that the combined control strategies approach and control strategies with AI/data-driven techniques are promising approaches, but further research is needed to understand their long-term effectiveness and how well they adapt to different operating conditions. The sCO2 cycle could also work better if it used advanced control strategies currently proven in other systems, such as fuzzy PID, model predictive control, and fuzzy neural network adaptive controllers. These methods, proven effective in managing complex systems like micro gas turbines, may offer significant improvements for sCO2 cycle performance.

Supercritical carbon dioxide (sCO2) emerges as an effective working fluid in closed-loop energy conversion cycles, offering significant advantages over traditional steam-based Rankine cycles. This research focuses on optimizing combined cycle systems utilizing sCO2 to enhance energy efficiency, improve exergy performance, increase stability, reduce emissions, and lower costs. Various configurations of the sCO2 cycle are analyzed, with an emphasis on their impact on efficiency as dictated by the first and second laws of thermodynamics. Key parameters include a gas turbine outlet temperature of 489 °C, a smoke flow rate of 89 kg/s, and a maximum cycle pressure of 230 bar, alongside turbine pinch temperatures of 30 °C and condenser pinch temperatures of 20 °C. The study evaluates three configurations: simple cycle, recuperator cycle, and split cycle, achieving first law efficiencies of 17.73%, 19.26%, and 23.56%, respectively. By minimizing exergy losses, this research enhances environmental sustainability and system stability, leading to reduced pollutant emissions. Economic analyses further compare the electricity generation costs of sCO2 cycles to those of steam cycles, revealing cost ratios of 0.80, 0.92, and 0.98 for the simple, recuperator, and split cycles, respectively. Additionally, sustainability indices for the simple, recuperator, and split cycles are calculated at 1.92, 2.09, and 2.76, respectively. The findings underscore that advancements in sCO₂ cycles not only improve power output, energy efficiency, and environmental sustainability but also reduce cycle costs and environmental pollution.

E-fuels, or synthetic fuels produced from green hydrogen and captured CO2, are a promising solution for achieving climate neutrality by replacing fossil fuels in transportation and industry. They help reduce greenhouse gas emissions and efficiently utilize renewable energy surpluses. This study aims to assess the current state and future potential of e-fuel production technologies, focusing on their scalability and market integration. A comprehensive literature review and market trend analysis, including modeling based on historical data and growth forecasts, were used to estimate market penetration. Results indicate that e-fuels could reach a 10% market share within the next 5 years, potentially reaching 30% in 20 years, particularly in aviation, maritime transport, and the steel industry. Ongoing projects expected to be completed this decade may cover about 20% of the global liquid fuel demand for transportation. However, challenges such as high costs, scalability, and recent project terminations due to funding shortages highlight the need for substantial investment, regulatory support, and innovation. Global collaboration and policy alignment are essential for the successful development and integration of e-fuels as a critical pathway to decarbonization.

Sustainable fuels, including biofuels, biogases, and low-emissions hydrogen, are critical for decarbonizing "hard-to-abate" sectors such as aviation, shipping, and heavy industry where electrification faces limits. This report, prepared in support of Brazil’s COP30 Presidency, provides a sectoral analysis of global pathways to accelerate the deployment of these fuels through 2035. While current policies could see sustainable fuel use double by 2030, significant barriers remain in cost, infrastructure, and carbon accounting standards. The study synthesizes cumulative policy experience to identify key technology requirements and infrastructure needs for scaling production. It concludes with priority actions for governments to bridge the cost gap with conventional fuels, harmonize sustainability criteria, and unlock financing for emerging economies, thereby enhancing energy security and economic development while achieving deep emissions reductions.

The report is an output of the Clean Energy Ministerial Hydrogen Initiative and is intended to provide an update to energy sector stakeholders on the status and future prospects of hydrogen, and to inform discussions at the Hydrogen Energy Ministerial Meeting organised by Japan. The sector has progressed significantly since the first publication of the Global Hydrogen Review in 2021. Low-emissions hydrogen production projects have gone from just a handful of demonstrations to more than 200 committed investments for projects that are increasing in number and in scale, reflecting the importance of hydrogen for climate goals, energy security and industrial competitiveness. Nevertheless, growth has not met all of the expectations raised at the start of the decade and remains uneven. Uncertainties about costs, infrastructure readiness and evolving regulatory frameworks all present barriers to faster deployment. This fifth edition of the Global Hydrogen Review takes stock of the progress to date and explores the challenges ahead, in order to provide a thorough assessment of the level of hydrogen adoption that could be achieved by 2030. This report includes a special chapter on Southeast Asia, exploring the region’s potential for the production and use of low-emissions hydrogen and hydrogen-based fuels and products in the near term.

Supercritical combustion is a promising technique for improving the efficiency and reducing the emissions of next-generation gas turbines. However, accurately modeling combustion under these conditions remains a challenge, particularly due to the complexity of chemical kinetics. This study aims to evaluate the applicability of a reduced global reaction mechanism compared to the detailed Foundational Fuel Chemistry Model 1.0 (FFCM-1) when performing hydrogen combustion with supercritical carbon dioxide and argon as diluents. Computational fluid dynamics simulations were conducted in two geometries: a simplified tube for isolating chemical effects and a combustor with cooling channels for practical evaluation. The analysis focuses on the evaluation of velocity, temperature, and the water vapor mass fraction distributions inside the combustion chamber. The results indicate good agreement between the global and detailed mechanisms, with average relative errors below 2% for supercritical argon and 4% for supercritical carbon dioxide. Both models captured key combustion behaviors, including buoyancy-driven flame asymmetry caused by the high density of supercritical fluids. The findings suggest that global chemistry models can serve as efficient tools for simulating supercritical combustion processes, making them valuable for the design and optimization of future supercritical gas turbine systems.

This study investigates the combustion of hydrogen in supercritical gas turbines, emphasizing the optimization of combustor design through computational fluid dynamics (CFD) simulations. Key parameters analysed include the number of oxygen inlets, operating pressure, excess working fluid in oxygen inlets, power output, and the use of different working fluids: supercritical argon (sAr) and supercritical xenon (sXe). The results highlight how these parameters influence temperature distribution, flame stability, and overall combustion efficiency. Findings suggest that increasing the number of oxygen inlets can significantly affect temperature profiles, while higher operating pressures lead to shorter flames. The dilution of oxygen by argon reduces the peak temperatures, and the choice of working fluid impacts cooling efficiency and flame dynamics. This study provides valuable information on optimizing the design of supercritical combustion chambers for hydrogen combustion in novel supercritical gas turbine systems.

The Global Hydrogen Review is an annual publication by the International Energy Agency that tracks hydrogen production and demand worldwide, as well as progress in critical areas such as infrastructure development, trade, policy, regulation, investments and innovation.

IEA report that explores the feasibility and implications of setting up common criteria to enable fair comparisons of sustainable fuels. It maps commonalities and differences among the standards, regulations and certifications used for sustainable fuels across different regions and markets. It reviews typical carbon intensities and the improvement potential of various fuel production pathways and sets out policy considerations for governments that wish to work toward common criteria for sustainable fuels.

Review paper that aims to provide a broad overview of sCO2 power cycles, highlighting their main advantages and limitations and reflecting the challenges associated with the industrialization of that technology which actually requires disruptive and innovative designs.

CONCAWE has updated its reference work on techno-environmental (Part 1) and economic (Part 2) analysis of different e-fuels pathways produced in different regions of the world (North, Centre, and South of Europe, as well as Middle East and North Africa) in 2020, 2030 and 2050. The e-fuels pathways included in the scope of this study are: e-hydrogen (liquefied and compressed), e-methane (liquefied and compressed), e-methanol, e-polyoxymethylene dimethyl ethers (abbreviated as OME3-5), e-methanol to gasoline, e-methanol to kerosene, e-ammonia, and e-Fischer-Tropsch kerosene/diesel (low temperature reaction). The e-hydrogen is considered a final fuel but also as a feedstock for producing other e-fuels.

Publication by the European Commission that aims to investigate and analyze factors contributing to the development of advanced and sustainable biofuels production within the relevant European policy and regulatory framework. Its primary goal is to facilitate the timely market entry of advanced biofuels and endorse technological solutions through reliable findings to achieve the 2030 and 2050 targets. This study takes into account the evolving EU policy context for sustainable alternative fuels, which is undergoing significant revision and forms a core component of both the Fit for 55 package and the REPowerEU plan.