Search Results (4,322)

This article presents the design and evaluation of a hybrid groundwater pumping system with battery storage, implemented in the Puntahacienda community of Quingeo, Ecuador, as a sustainable alternative for energy supply in isolated rural areas. The system integrates solar photovoltaic, wind, and a backup diesel generator, whose operation was analyzed using HOMER Pro software. The simulation allowed for component sizing, technical performance evaluation, and operating costs estimation, prioritizing the use of renewable sources and reducing dependence on fossil fuels. The results show that solar and wind energy can cover a large portion of the demand, while the diesel generator ensures resilience during critical periods. The battery bank optimizes stability and continuous supply, ensuring the availability of water for human and agricultural consumption. Furthermore, a significant reduction in greenhouse gas emissions and an improvement in economic sustainability compared to the exclusive use of diesel were evident. The final results show that the levelized cost was $0.186/kWh, making it competitive for an isolated rural community. It was also determined that the renewable energy fraction (RES) was 83.70%, the unmet demand was 0.42%, and CO₂ emissions were 14,850 kg/year when including a diesel generator in the hybrid system. This study demonstrates the viability of hybrid renewable solutions as a tool to strengthen water and energy security in rural communities, constituting a replicable model in similar contexts in Latin America. Full article

The spread of alternative fuel vehicles (AFVs) poses new technological and legal challenges. While these vehicles contribute to sustainable transport, their specific operational characteristics require specific regulation and infrastructure. The study analyses the risks associated with AFVs, in particular with regard to occupational safety and operation, and the extent to which the current legal framework in Hungary is able to address these challenges. It also examines the integration of AFVs into the existing transport and service network and makes recommendations for improving regulation, training and infrastructure. The study aims to contribute to enhancing road safety and legal clarity by showing that the safe integration of AFVs requires the modernisation of regulation and the adaptation of technical protocols. Full article

In the aviation industry, momentum for reducing emissions has rapidly increased in recent years. From international systems like the EU ETS and CORSIA, to the introduction of new fuels such as electricity and SAF as alternatives to conventional fuels, various approaches are being considered. Within this context, there is a further movement to reduce aviation emissions through a modal shift from air to high-speed rail. In this research, a Systematic Literature Review is undertaken to detail the nature of the modal shift from air to rail, uncovering energy policy and economic considerations. While research targeting China has increased recently, prior studies focus on Europe, leaving some regions understudied. From an emissions reduction perspective, the power source supplying rail is a critical factor. Capacity constraints on rail are also a key challenge to be addressed. Future research should address the need for additional regional studies. In the age of modal shift movements, the aviation industry is attempting to reduce emissions through the introduction of alternative low-carbon fuels. Policies to reduce emissions must consider this. Discontinuing flights could lead to unintended emissions. A synergistic approach combining modal shift and internal decarbonization is likely to be the most economically feasible and sustainable approach. Full article

Energy shortage is a significant global concern due to the heavy reliance of industrial and residential sectors on energy. As fossil fuels diminish, there is a pressing shift towards alternative energy sources such as solar and wind. However, the intermittent nature of these renewable resources, such as the absence of solar energy at night, necessitates robust energy storage solutions. This study focuses on enhancing the performance of a thermal storage unit by employing multiple fin configuration with solar salt (NaNO₃-KNO₃) as a phase change material (PCM) and Duratherm 630 as a heat transfer fluid (HTF). Notably, W-shaped and trapezoidal fins achieved reductions in melting time from 162 min to 84 min and 97 min, respectively, while rectangular fins were the least effective, albeit still reducing melting time to 143 min. Reduction in thermal gradients due to well-developed thermal mixing significantly reduced phase transition duration. Impact of fins geometries on localized vortexes generation within the unit was identified. W-shaped and trapezoidal fins were notably efficacious because of greater heat transfer area and better heat distribution through conduction and convection. Full article

The present paper proposes a novel approach for the estimation of the in-cylinder pressure and heat release in diesel engines from basic testbed measurements (i.e., brake mean effective pressure (BMEP), gross indicated mean effective pressure (IMEP360), peak firing pressure (PFP), crank angle at which 50% of fuel mass has burnt (MFB50) and exhaust gas temperature (T_exh). The method exploits a previously developed low-throughput combustion model, based on the accumulated fuel mass approach, which has been tuned by a genetic algorithm (GA) optimizer. The latter adjusts the main combustion model parameters to minimize an objective function, which depends on the prediction errors of BMEP, IMEP360, PFP, MFB50 and T_exh. Several scenarios were evaluated in which different subsets of the four previous quantities were assumed to be known from experimental activities. The proposed method is particularly useful when in-cylinder pressure traces are unavailable and only basic testbed data exist. The results show that the in-cylinder pressure and heat release profiles are estimated with a high level of accuracy, since the root mean squared error is of the order of 1–2.5 bar and 2–2.7 × 10⁻² kJ, respectively, depending on the considered scenario, while requiring a modest computational effort which is of the order of 3–6 min per test. Moreover, the low-throughput nature of the method makes it straightforward for other researchers to implement and reproduce results on different engines. The approach is also fuel-independent and can be applied to engines running on alternative/zero-carbon fuels, which are currently being extensively studied as potential ways to reduce the environmental impact of internal combustion engines. Full article

The global demand for sustainable fuels has intensified interest in bioethanol production. Conventional distillation is limited by the ethanol–water azeotrope at ~95.8 wt.% ethanol, necessitating alternative separation methods. This study presents a technical and economic comparison of bioethanol dehydration via azeotropic distillation using cyclopentane as a novel entrainer and extractive distillation with ethylene glycol. Steady-state simulations were conducted in AVEVA PRO/II v.2024 under identical feed conditions, targeting a final ethanol purity of 99.94 wt.%. Cyclopentane proved effective, producing high-purity ethanol and water streams free of entrainer, while ethylene glycol also achieved comparable purity. Economically, the azeotropic process required ~36.5% higher capital investment due to taller columns, larger condensers, and the entrainer cost, resulting in a total annual cost (TAC) ~25.6% higher than the extractive process. Nevertheless, the azeotropic configuration offers lower operating costs, relying solely on low-pressure steam, and residual cyclopentane in ethanol does not compromise fuel quality, unlike ethylene glycol. The study demonstrates that cyclopentane-based azeotropic distillation is technically viable for fuel-grade ethanol production and provides a quantitative framework for evaluating entrainer selection and process economics, particularly in regions where cyclopentane is available or cost-effective. Full article

Hydrogen peroxide is a promising oxidizer and monopropellant for space propulsion, offering a green alternative to conventional propellants. In combination with microencapsulated hydrocarbon fuels, a new type of monopropellant can be formed that unites the high specific impulse of a bipropellant with the efficient hardware of a monopropellant. However, the stabilization of these microcapsule/hydrogen peroxide mixtures is problematic as they tend to separate after a short period of time. This work uses organic gelling agents to stabilize these mixtures by creating hydrogen peroxide gels. For this, the compatibility of hydrogen peroxide with several gelling agents was investigated and found to be suitable. Next, the dispersion stability of microcapsule/gel dispersions was examined and showed no sign of destabilization over four weeks or at high accelerations at 50× g in the centrifuge, even with gelling agent concentrations as low as 0.1%. A formulation with a polyacrylic acid-based gelling agent at a concentration of 0.3% showed favorable characteristics and good processability. Together with a subsequent rheological characterization of the gels, these results are critical for the further development of the fuel-filled microcapsule/hydrogen peroxide monopropellant. The hydrogen peroxide gel formulations developed in this study could also have potential applications beyond the scope of this work. Full article

Maintaining air quality is an important environmental challenge, affecting both urban and regional areas where industrial, agricultural, and energy activities intersect. The Upper Hunter Valley, NSW, experiences emissions from coal mining, power generation, agriculture, and wood fires, compounded by local meteorology, geology, and climate change. This study applies a political economy framework to examine historical governance structures including colonial legacies, institutional arrangements, and power relations and how they shape stakeholder roles and influence decision-making related to air quality. Technical applied research including improving dust monitoring, occupational health studies, and investigations into alternative fuels provided an empirical basis for identifying key stakeholders, including mining and energy companies, regulatory agencies, local councils, community groups, and environmental organisations. The analysis demonstrates how these actors influence governance processes, social licence to operate, and public perceptions of environmental risk. Findings indicate that effective air quality management requires multi-level, collaborative approaches that integrate technical expertise, regulatory oversight, and community engagement. The study highlights the importance of systemic strategies that align economic, environmental, and social objectives, providing insight into the governance of contested environmental resources in historically and politically complex regional contexts. This article is a rewritten and expanded version of the study “Analysis of air quality stakeholders in the Upper Hunter”, presented at the Clean Air conference, in Hobart, Australia, August 2024. Full article

The European industries are transitioning from natural gas usage to renewable gases to enhance climate neutrality and energy security—therefore, hydrogen and ammonia gases could be great alternatives to natural gas. Hydrogen can be produced via electrolysis powered by renewable energy or from natural gas with carbon capture. Moreover, ammonia, composed of hydrogen and nitrogen, could also act as an energy carrier and storage medium. This study investigates the combustion process and efficiency of the hydrogen-enriched NH₃ and CH₄ blends using nonthermal plasma assistance. The experiments were performed with a gas burner with a thermal power of 1.30 kW using fully premixed gas blends. The nonthermal plasma was created with a high-voltage and high-frequency generator at 120 kHz and 8.33 kV. Time-resolved chemiluminescence data for OH* and NH₂* were captured using an ICCD camera, an MIR emission spectrometer and a thermal irradiance flux meter. The results indicated that nonthermal plasma enhances the flame stability and increases the infrared radiation intensity. The MIR spectroscopy showed an intensity increase of 13% for ammonia-hydrogen blends under plasma assistance and heat flux measurements showed a 15% increase for the 70% ammonia and 20% hydrogen mixture. These results demonstrate that plasma-assisted combustion can enhance the efficiency and stability of low-carbon fuel blends, facilitating their integration into current infrastructure while reducing greenhouse gas emissions. Full article

In the context of the growing adoption of alternative gas separation processes, combined with the interest in hydrogen as a fuel and energy carrier, the use of membrane technology in H₂/CH₄ purification is analyzed in this work, focusing on the techno-economic aspects. In particular, the separation and economic performance of three Pd–Ag/Si-CHA membrane plants are simulated, aiming to achieve high degrees of purity and recovery paired with cost-effective configurations. A single Pd–Ag membrane stage operating at 20 atm and 350 °C can theoretically guarantee a CH₄ concentration of 95%, while a completely pure H₂ stream leaves the plant as a permeate product. The choice of a less selective Si-CHA membrane allows a temperature reduction but implies the use of more stages to achieve the desired CH₄ target. In addition, H₂ purity does not exceed 98%. A two-stage hybrid process, in which the retentate gas leaving the Pd–Ag membrane is cooled and fed to the Si-CHA unit, is also a cost-effective solution, as feed pressure can be reduced to 10 atm with significant compression cost savings. All the configurations are able to provide positive values of economic potential (EP); however, the single Pd–Ag membrane plant is the best option since it guarantees the highest EP, net profit and net present value (NPV). Full article

Biomass has long been a major source of energy for residential heating and, in recent decades, has regained attention as a renewable alternative to fossil fuels. This review explores the current state and prospects of domestic biomass-based heating technologies, including biomass-fired boilers, local space heaters, and hybrid systems that integrate biomass with complementary renewable energy sources to deliver heat, electricity, and cooling. The review was conducted to identify key trends, performance data, and innovations in conversion technologies, fuel types, and efficiency enhancement strategies. The analysis highlights that biomass is increasingly recognized as a viable energy carrier for energy-efficient, passive, and nearly zero-energy buildings, particularly in cold climates where heating demand remains high. The analysis of the available studies shows that modern biomass-fired systems can achieve high energy performance while reducing environmental impact through advanced combustion control, optimized heat recovery, and integration with low-temperature heating networks. Overall, the findings demonstrate that biomass-based technologies, when designed and sourced efficiently and sustainably, can play a significant role in decarbonizing the residential heating sector and advancing nearly zero-energy building concepts. Full article

Amid growing concerns over fossil fuel depletion and environmental degradation, developing alternative energy sources is imperative. While MoS₂-based catalysts are known for their syngas conversion activity, their selectivity toward alcohols remains limited. This study addresses this gap by developing Cu-promoted MoS₂ catalysts to enhance alcohol synthesis. The results indicated that the introduction of copper significantly modulates the catalytic performance of MoS₂. We demonstrate that incorporating Cu significantly modulates the catalytic properties of MoS₂. The optimized catalyst with 9 wt% Cu loading exhibited a CO conversion of 17.9% and a markedly improved total alcohol selectivity of 46.4%, with a space-time yield of 67.6 mg·g⁻¹·h⁻¹. Although Cu addition slightly reduced CO conversion, it markedly improved alcohol selectivity by facilitating active site dispersion, suppressing Fischer-Tropsch side reactions, and stabilizing heteroatomic active phases. Finally, a catalytic mechanism for the synthesis of low-carbon alcohols from syngas on MoS₂-based catalysts was proposed based on the catalyst analysis and reaction results. Full article

Global shipping is an essential, energy-efficient enabler of trade, yet it remains a hard-to-abate sector. With shipping demand projected to continue to rise in the coming decades, identifying scalable and sustainable fuel alternatives is critical. Biofuels, and particularly biomethanol, offer a promising option due to their compatibility with existing infrastructure. However, their sustainability critically hinges on land use impacts. From this Perspective, we argue that biomethanol derived from a dedicated crop could contribute to maritime decarbonisation, with ~71–77% well-to-wake greenhouse gases (GHG) reductions under cropland-only constraints. We further point to the fact that a wider adoption faces challenges such as higher costs, limited availability, and lower energy density relative to fossil fuels. Continued research and monitoring are essential to ensure that biofuel production does not inadvertently contribute to deforestation or biodiversity loss. We underscore the need for spatially sensitive biofuel deployment strategies that align maritime decarbonisation with land-system sustainability and climate objectives. Full article

Hydrogen is widely regarded as a promising carbon-free alternative fuel. However, the development of low-emission marine gas turbine combustion systems has been hindered by the associated risks of combustion instability, also termed as thermoacoustic oscillations. Although there is sufficient literature on hydrogen fuel and combustion instability, systematic reviews addressing the manifestations and mechanisms of these instabilities remain limited. The present study aims to provide a comprehensive review of combustion instabilities in hydrogen-enriched marine gas turbines, with a particular focus on elucidating the characteristics and underlying mechanisms. The review begins with a concise overview of recent progress in understanding the fundamental combustion properties of hydrogen, and then details various instability phenomena in hydrogen-enriched methane flames. The mechanisms by which hydrogen enrichment affects combustion instabilities are extensively discussed, particularly in relation to the feedback loop in thermoacoustic combustion systems. The paper concludes with a summary of the key combustion instability challenges associated with hydrogen addition to methane flames and offers prospects for future research. In summary, the review highlights the interaction between hydrogen-enriched methane flames and thermoacoustic phenomena, providing a foundation for the development of stable, low-emission combustion systems in industrial marine applications incorporating hydrogen enrichment. Full article

The growing global demand for clean energy and sustainability has increased interest in lignocellulosic biomass as a viable alternative to conventional fossil fuels. Among the various biomass resources, sugarcane bagasse, an abundant agro-industrial by-product, has emerged as a promising feedstock to produce renewable fuels and value-added chemicals. Its high carbohydrate content offers significant potential for bioconversion. However, its complex and recalcitrant lignocellulosic matrix presents significant challenges that necessitate advanced pretreatment techniques to improve enzymatic digestibility and fermentation efficiency. This review consolidates recent developments in the valorization of sugarcane bagasse focusing on innovative pretreatment and fermentation strategies for sustainable bioethanol production. It emphasizes the synergistic benefits of integrating various pretreatment and fermentation methods to improve bioethanol yields, reduce processing costs and enhance overall process sustainability. This review further explores recent technological advancements, the impact of fermentation inhibitor, and emerging strategies to overcome these challenges through microbial strains and innovative fermentation methods. Additionally, it highlights the multi-faceted advantages of bagasse valorization, including waste minimization, renewable energy production and the promotion of sustainable agricultural practices. By evaluating the current state of research and outlining future perspectives, this paper serves as a comprehensive guide to advancing the valorization of sugarcane bagasse in the transition towards a low-carbon economy. The novelty of this review lies in its holistic integration of technological, economic, and policy perspectives, uniquely addressing the scalability of integrated pretreatment and fermentation processes for sugarcane bagasse, and outlining practical pathways for their translation from laboratory to sustainable industrial biorefineries within the circular bioeconomy framework. Full article