Replace Fossil Fuels Research Articles

Biohydrogen production by a novel strain Petroclostridium sp. X23 isolated from the production water of oil reservoirs

Biohydrogen production from H2-producing has been considered a promising alternative for the replacement of fossil fuels. However, the mechanisms that affect the H2-producing capacities of wild-type strains remain largely elusive. To explore the capabilities of biohydrogen production from microorganisms in the deep subsurface oil-reservoir environment, we isolated an H2-producing bacteria identified as the genus Petroclostridium from a long-term methanogenic crude oil-degrading enrichment culture of the production water from oil reservoir. The impact of various temperature, pH, and glucose concentrations on hydrogen production by Petroclostridium sp. X23 was investigated. Under the conditions of 37 °C, initial pH 8.0, and glucose concentration of 4 g/L, the strain X23 achieved its maximum hydrogen yield at 1.82 ± 0.12 mol H2/mol glucose. When compared to the previously reported strain SK-Y3, X23 exhibited enhanced H2-producing ability, with lesser energy biomass production. Comparative genomic analysis revealed that the genome of X23 contains more genes associated with hydrogen generation than SK-Y3. These findings proposed Petroclostridium sp. X23 is a potential candidate for dark fermentative hydrogen production under alkaline and mesophilic conditions. It also increased our knowledge of genotypes related to high H2-producing capability, which may provide instructions for future selection of high-yielding strains and reasonable metabolic engineering of wild-type H2-producing strains.

Green hydrogen as a source of renewable energy: a step towards sustainability, an overview

AbstractHydrogen has emerged as a promising energy source for a cleaner and more sustainable future due to its clean-burning nature, versatility, and high energy content. Moreover, hydrogen is an energy carrier with the potential to replace fossil fuels as the primary source of energy in various industries. In this review article, we explore the potential of hydrogen as a part of the global energy mix and the current state of its development. The majority of hydrogen production currently occurs through steam methane reforming, which produces significant greenhouse gas emissions and limits the potential of hydrogen as a clean energy source. Significant investment and advancements in renewable hydrogen production through electrolysis are necessary to overcome this limitation. There is also a growing demand for hydrogen infrastructure, including hydrogen refueling stations and storage and transportation systems, which are crucial for the growth and success of the hydrogen industry. The future of hydrogen as a part of the global energy mix will depend on continued investment and commitment to develop and commercialize this promising energy source. Our review also explores the relationship between eco-industrial parks and hydrogen production, including the benefits and challenges of hydrogen production in EIPs and the various technologies being developed to facilitate this process.

Nanotechnology-based biodiesel: A comprehensive review on production, and utilization in diesel engine as a substitute of diesel fuel

As a sustainable replacement for fossil fuels, biodiesel is a game-changer in the energy sector. There is no strategy to minimize biodiesel's significance as a sustainable, clean fuel source in light of the increasing climate change and environmental sustainability concerns. Nevertheless, conventional biodiesel production methods often run into problems like inadequate conversion efficiency and inappropriate fuel properties, which impede their broad adoption. The revolutionary potential of nanotechnology to circumvent these limitations and revolutionize biodiesel consumption and production is explored in this review paper. There are new possibilities for improving biodiesel output and engine efficiency, thanks to nanotechnology, which can alter matter at the atomic and molecular levels. Using nano-catalysts, nano-emulsification processes, and nano-encapsulation procedures, researchers have made significant advances in improving biodiesel qualities such as stability, combustion efficiency, and viscosity. Through a comprehensive analysis of current literature and research data, this article elucidates the crucial role of nanotechnology in advancing biodiesel technology. By shedding light on the most current advancements, challenges, and potential future outcomes in nano-based biodiesel manufacturing and consumption, this review hopes to add to the growing corpus of knowledge in the field and inspire additional innovation. In conclusion, there is great hope for a sustainable energy future, increased economic growth, and reduced environmental impacts through the application of nanotechnology.

Review—Self-Supporting Electrocatalysts for HER in Alkaline Water Electrolysis

Hydrogen is a prime candidate for replacing fossil fuels. Electrolyzing water to produce hydrogen stands out as a particularly clean method, garnering significant attention from researchers in recent years. Among the various techniques for electrolyzing water to produce hydrogen, alkaline electrolysis holds the most promise for large-scale industrialization. The key to advancing this technology lies in the development of durable and cost-effective electrocatalysts for the hydrogen evolution reaction (HER). Self-supporting electrode is an electrode structure in which a catalyst layer is formed directly on a substrate (such as carbon cloth, nickel foam, stainless steel, etc) without using a binder and with good structural stability. In contrast to traditional nanocatalysts, self-supporting electrocatalysts offer significant advantages, including reduced resistance, enhanced stability, and prolonged usability under high currents. This paper reviews recent advancements in HER electrochemical catalysts for alkaline water electrolysis, focusing on the utilization of hydrogen-evolving catalysts such as metal sulfides, phosphides, selenides, oxides, and hydroxides. With self-supported electrocatalysts as the focal point, the paper delves into progress made in their preparation techniques, structural design, understanding of reaction mechanisms, and strategies for performance enhancement. Ultimately, the future development direction of promoting hydrogen evolution by self-supported electrocatalysts in alkaline water electrolysis is summarized.

Evaluation of the CH4/CO2 separation by adsorption on coconut shell activated carbon: Impact of the gas moisture on equilibrium selectivity and adsorption capacity

Upgrading biogas to biomethane is of great interest to change the energy matrix by feeding the renewable fuel produced from biomass waste into natural gas grids or directly using it to replace fossil fuels. The study aimed to assess the adsorption equilibrium of CH4, CO2, and H2O on a coconut-shell activated carbon (CAC 8X30) to provide data for further studies on its efficiency in upgrading biogas by Pressure Swing Adsorption (PSA). The adsorbent was characterized, and equilibrium parameters were estimated from monocomponent CH4, CO2, and H2O equilibrium isotherms. Binary and ternary equilibrium isotherms were simulated, and the selectivity and adsorption capacity of the CAC 8X30 were calculated in dry and wet conditions and then compared with zeolite 13X as a reference material. Regarding characterization, Nitrogen and Hydrogen Physisorption results indicated that 94 % of the pore volume is concentrated in the region of micropores. The adsorption affinity with CAC 8X30 estimated from monocomponent isotherms was in the order KH20>KCO2>KCH4. IAST-Langmuir model simulations presented good agreement with experimental binary equilibrium data. Further simulations indicated equilibrium selectivity for CO2 over CH4 (e.g., 4.7 at 1 bar and 298 K for a mixture of CH4/CO2, 60/40 vol%), which increased in the presence of moisture, indicating its suitability for upgrading humid biogas. Simulations for zeolite 13X suggested that the material is unsuitable in the presence of water vapor but presents higher selectivity than the CAC 8X30 in dry conditions. Hence, the integration of both materials might be helpful for biogas upgrading.

Comparative Analysis of Solar Tower and Parabolic Trough Systems for Solar Heat in a Steel Industry

Concentrated Solar Thermal (CST) systems emerge as a promising alternative to replace fossil fuels used in industrial thermal processes due to their high energy density and dispatchability. In this study, a comparative analysis of two CST systems, Solar Tower (ST) and Parabolic Trough Collector (PTC), has been made to replace natural gas used in the steam generation process in Türkiye's largest steel production plant, located in the Mediterranean Region of Türkiye. Both the ST and PTC systems were placed in a field area of approximately 0.4 km2. The results have shown that, on a monthly basis, the PTC system could exceed the plant's thermal energy for two-thirds of the year, while the ST system could meet the plant's energy requirements for one-third of the year. This could reduce CO2 by about 12.7 and 19.1 kilo-tones for ST and PTC at LCOH of about 68.9 and 36.9 EUR/MWh, respectively.

Comparative Evaluation on Enhancing Fuel Properties of Biocoal from Bagasse Using Hydrothermal Carbonization and Torrefaction Processes

This research investigates the thermochemical conversion of sugarcane bagasse into biocoal using a subcritical aqueous medium (water, 200–250°C) and a limited oxygen atmosphere (nitrogen, 250–300°C). The aim is to discover alternative renewable energy sources to replace fossil fuels. The effects of those different methods on the physiochemical properties of the solid product were determined. The best results of fixed carbon (37.13%), carbon content (62.17%), fuel ratio (0.61), and higher heating value (HHV) (25.75 MJ/kg) were obtained under hydrothermal carbonization (HTC) at 250°C. Additionally, the HTC process effectively reduced the ash and sulphur content of the solid products. Moreover, HTC was found to be a promising method for depolymerizing hemicellulose. Hydrochar produced at 250°C is located within the range of lignite, which is typically obtained at lower reaction temperatures compared to biochar samples. Consequently, the conversion of sugarcane bagasse into solid biofuel through HTC shows great potential from a thermochemical perspective.

Application of Evolutionary Computation to the Optimization of Biodiesel Mixtures Using a Nature-Inspired Adaptive Genetic Algorithm

The present research work introduces a novel mixture optimization methodology for biodiesel fuels using an Evolutionary Computation method inspired by biological evolution. Specifically, the optimal biodiesel composition is deduced from the application of a nature-inspired adaptive genetic algorithm that first examines percentages of the ingredients in the optimal mixtures. The innovative approach’s effectiveness lies in problem simulation with improvements in the evaluation of the specific function and the way to define and tune the genetic algorithm. Environmental imperatives in the era of climate change currently impose the optimized production of alternative environmentally friendly biofuels to replace fossil fuels. Biodiesel in particular, appears to be more attractive in recent years, as it originates from renewable bio-derived resources. The main ingredients of the specific biofuel mixture investigated in this research are diesel and biodiesel (100% from bioresources). The assessment of the new biodiesel examined was performed using a fitness function that estimated both the density and cost of the fuel. Beyond the evaluation criterion of cost, density also influences the suitability of this biofuel for commercial use and market sale. The outcomes from the modeling process can be beneficial in saving cost and time for new biodiesel production by using this novel decision-making tool in comparison with randomized laboratory experimentations.

Unveiling the pros and cons: Consequences of biodiesel in shaping the future of engine fuels

The worldwide search for eco-friendly energy sources has raised interest in biodiesel as a possible replacement for traditional fossil fuels. The goal of this study is to thoroughly examine the benefits and drawbacks of biodiesel while considering possible future developments for engine fuels. Researchers have focused a lot of interest on biodiesel since its introduction as a renewable alternative fuel. The fundamental components of biodiesel are created through the transesterification of plant, animal, or even waste cooking oil. Biodiesel is used to fully use natural resources and lessen the severity of oil shortages and environmental harm. Without requiring any modifications, biodiesel can be used straight to car engines to enhance engine combustion and lower negative emissions. This study's main goal is to give a general overview of how biodiesel applications affect diesel engines, considering how they affect emissions, vibration, noise levels, compatibility, engine performance and combustion characteristics. This study covers unregulated emissions, concentrating on two topics that have not been thoroughly studied: Polycyclic Aromatic Hydrocarbons (PAHs) and Volatile Organic Compounds (VOCs). This will be crucial that regulators, researchers and industry stakeholders understand the full spectrum of consequences associated with biodiesel as they collaborate to develop engine fuels in a sustainable and ethical manner.

CO2 Photoreduction over Semiconducting 2D Materials with Supported Single Atoms: Recent Progress and Challenges.

In the face of the growing energy crisis and environmental challenges, substantial efforts are now directed toward sustainable clean energy as a replacement for traditional fossil fuels. CO2 photoreduction into value-added chemicals and fuels is widely recognized as a promising approach to mitigate current energy and environmental concerns. Photocatalysts comprising single atoms (SAs) supported on two-dimensional (2D) semiconducting materials (SAs-2DSemi) have emerged as a novel frontier due to the combined merits of SA catalysts and 2D materials. In this study, we review advancements in metal SAs confined on 2DSemi substrates, categorized into four groups: (1) metal oxide-based, (2) g-C3N4-based, (3) emerging, and (4) hybridized 2DSemi, for photocatalytic CO2 conversion over the past few years. With a particular focus on highlighting the distinct advantages of SAs-2DSemi, we delve into the synthesis of state-of-the-art catalysts, their catalytic performances, and mechanistic elucidation facilitated by experimental characterizations and theoretical calculations. Following this, we outline the challenges in this field and offer perspectives on harnessing the potential of SAs-2DSemi as promising photocatalysts. This comprehensive review aims to provide valuable insights for the future development of 2D photocatalytic materials involving SAs for CO2 reduction.

Physicochemical Study of Ethanol Ratio in the Transesterification Process for Biodiesel Synthesis from Kesambi (Schleichera Oleosa) Seed Oil

The demand for energy, particularly for fossil fuels, has been increasing in line with the growing number of transportation units. However, natural resource conditions such as fossil fuels are not always fulfilled. This is because fossil fuels are categorized as non-renewable resources. Moreover, all countries in the world are required to reduce the use of fossil resources and increase the use of green energy. Therefore, alternative green energy sources are needed to replace fossil fuels. Biodiesel is a green energy source that could be produced from renewable resources. Biodiesel could be obtained from non-food sources such as kesambi oil. In this research, the biodiesel production process was carried out by esterification and transesterification methods. The transesterification process was performed by varying the molar ratio between ethanol and kesambi oil. The molar ratio used in the transesterification process were 4:1, 6:1, 8:1, 10:1, and 12:1. The results showed that the molar ratio of 12:1 produced the lowest values of density, viscosity, and flash point, which were 0.839 g/ml, 3.98 CST, and 109.4°C, respectively, but the highest values of calorific value and yield, which were 9,040 cal/g and 91.30%, respectively.

Energy recovery from sewage sludge waste blends: Detailed characteristics of pyrolytic oil and gas

Using waste as an alternative energy source may partially replace fossil fuels. In this paper, energy recovery from waste blends (sewage sludge (SS), polyethylene (LDPE) and polypropylene (PP), paper rejects (PR), and waste tyres) was tested through laboratory-scale co-pyrolysis. For each co-pyrolysis test, 7 l of waste blend in different ratios were used. The results of pyrolytic oil and gas analyses show valuable compounds and chemical materials recovered. The detailed analyses show the effects of co-pyrolysis parameters, especially the ratios of waste blends with respect to the process temperature of 600°C, on the pyrolytic gas and oil. The highest volumes of gas (0.66 m3) and oil (699 ml) were obtained from sample 5_8 (PES:SS:PR). Waste blend 15_1 (LDPE:SS) had the highest gross calorific value (GCV) of 43.82 MJ/m3 in gas, and had the highest proportion of flammable components (46.31% of methane). Sample 5_8 had the highest calorific value in pyrolytic oil (45 MJ/kg) and sample 5_3 had the lowest (28.113 MJ/kg), which is comparable to coal. High-quality pyrolytic gas and oil were obtained with average GCV of 44 MJ/m3 and 40 MJ/kg respectively, where the average GCV of the most calorific fossil fuels is 43.6 MJ/kg in crude oil and 34 MJ/m3 in natural gas. We conclude that co-pyrolysis of sewage sludge and waste is a convenient and simple method of waste disposal under a synergetic effect of efficient waste management, energy production, and reduction of dependence on fossil fuels.

Biproduct to product: Lignin derived from wood and plants could replace fossil fuels in various applications

Lignin provides structure to plant cell walls and is often removed from wood pulp to make paper, but its wide-ranging potential applications make lignin a desired material.

Analysing the Techno-Economic Viability of Different Solar Heating Systems in South African Beverage Plants

With ongoing real-term reductions in the cost of renewable energy technologies, opportunities to reduce carbon emissions within industry have improved. While the South African industrial sector has been investing in photovoltaics to meet electricity requirements, little has been done to replace fossil fuels used for the generation of process heat, representing two-thirds of the energy consumed. While previous studies have demonstrated the benefits and limitations of solar thermal (ST) energy solutions for industrial applications, recent developments in high-temperature heat pumps (HTHP) offer opportunities for novel configurations, including the use of renewable energy like photovoltaics (PV). This study compares the techno-economic benefits of solar thermal energy systems with PV-supported HTHP systems within the South African beverage sector. After a general consideration, simulation calculations are presented for selected applications. The cost of heat is determined for PV-heat pump systems operating on a stand-alone basis and with heat storage. The study finds that the levelised cost of heat of US$0.050-0.073/kWhth is at least twice that of coal-fired steam boilers. The study, therefore, calls for further work on optimising systems minimising steam requirements, and thereby improving the economics of heat pumps and for a coordinated effort to support the development and financing of high-temperature heat pumps for industrial applications.

Investigating the potential of geothermal energy as a sustainable replacement for fossil fuels in commercial buildings

Commercial Buildings release large volumes of greenhouse gases, expediting global warming. The commercial building industry accounts for 37% of global CO2 emissions. Geothermal energy technologies are an intriguing solution that provides a low-impact, emission-free, and cost-effective thermal fuel source for baseload energy production. Geothermal energy systems offer a potential solution to dramatically halt global warming and facilitate the transition to a carbon-neutral civilization. This study develops a framework for assessing the geothermal power capabilities of innovative house and district heating systems. The energy requirements are first assessed, and then the spatial evaluation of district heating infrastructure is carried out using a Python-based program. Economic comparisons between geothermal energy and fossil fuels are made using LCC analysis. Environmental impacts are measured by Life Cycle Analysis (LCA). This study compares geothermal energy to fossil fuels, and the LCA results show that geothermal energy has a low environmental impact. With a Net Present Value (NPV) of 34.81 USD, it displays economic viability as well as a satisfactory financial return. The study's findings show that geothermal energy has the ability to compete with fossil fuels in commercial heating applications while still being environmentally beneficial.

Tailored Two‐Dimensional Transition Metal Dichalcogenides for Water Electrolysis: Doping, Defect, Phase, and Heterostructure

AbstractThe demand for hydrogen production technology to replace fossil fuels and address the global climate crisis has become one of the most urgent tasks in the modern era. Among the promising breakthroughs, electrochemical water splitting using renewable energy sources offers a path to green hydrogen production that is both feasible and economically viable. However, the current state‐of‐the‐art catalysts for the water‐splitting reaction predominantly rely on scarce and costly noble metals, posing a significant challenge to the mass production of green hydrogen. In this context, two‐dimensional transition metal dichalcogenides (2D TMDs) have emerged as compelling candidates to replace noble metals, owing to their impressive reactivity and cost‐effectiveness. These TMD‐based electrocatalysts demonstrate exceptional reactivity at their active edge sites, while the basal planes remain catalytically inert. Several tailored strategies can activate these basal planes by modifying the chemical bonding nature and electronic band structure of the constituent atoms, thus enhancing the overall reactivity of TMDs. This review summarizes recent advancements in the modulation methodologies of 2D TMDs to enhance their water‐splitting reactivity. We highlight various chemical modification strategies, including heteroatom doping, defect‐engineering, and heterostructure formation, and provide insights into future research directions for the development of advanced 2D TMD‐based water‐splitting catalysts.

Solid biofuel preparation from eucalyptus bark by hydrothermal treatment and pelletization: Fuel properties, combustion behavior and ash slagging tendency

Eucalyptus bark (EB) is a promising biomass to replace fossil fuels, but its ash content is high and the energy density is particularly low. In this paper, it was proposed to upgrade EB to prepare solid biofuel by mild hydrothermal treatment (HTT) and pelletization. It was found that HTT could effectively remove troubling elements like Na, K, Zn, Mn, S, Cl, and P in EB. The remaining ashes tend to form higher melting point compounds, whose softening temperature (ST) and flow temperature (FT) increased from 1326 °C to 1399 °C and from 1348 °C to 1425 °C, respectively. The higher heating value of EB increased from 16.32 to 17.68 MJ/kg after HTT. The density, volume expansion, compressive strength, and durability of the bio-pellet fuel after HTT were all superior to raw EB. HTT and pelletization is a promising method to prepare solid biofuel from EB.

Comparative analysis of Benchmark and Aeon Blue Technologies for sustainable eFuel production: Integrating Direct Air Capture and Green Hydrogen approaches

Renewable Fuels of Non-Biological Origin (RFNBOs, a.ka. “eFuels”) are drop-in replacements for fossil fuels in the “hard-to-abate” sectors, and utilise existing distribution and storage infrastructure, but suffer from low synthetic efficiency. In particular, the low efficiency and high energy consumption of hydrogen synthesis by freshwater electrolysis remains a problem to be addressed. In the current study, we explore the potential of saltwater electrolysis (chloralkali) for the synthesis of eFuels generally, and specifically eMethanol. The study explores the use of chlorinated water in carbonate-loop pH-swing “cold capture” of carbon dioxide, and the resulting synergetic integration of the chloralkali process in eFuel syntheses. Doing so eliminates the high energy consumption of the calciner and the slaker of the benchmarked carbonate-loop thermal-swing method. It is replaced with a spontaneous chemical process in which chlorine is neutralized in the presence of carbonates. This allows the simultaneous solution of “The Chlorine Problem” of saltwater electrolysis, and a lower overall energy consumption of direct air capture when combined with green hydrogen synthesis. The only limitation on the comparison is that a large amount of carbon dioxide is over-captured when using chloralkali. That is, the ratio of hydrogen generated to carbon dioxide captured is fixed by the stoichiometry of chloralkali and not that of the eFuel. This results in an excess of carbon captured and thus a carbon-negative eFuel. We examine one configuration of secondary revenue and use it to inform the marginal cost of CO2 capture. In the system proposed by Aeon Blue Technologies (ABT), carbon dioxide is absorbed into caustic according to the standard method. Hydrogen gas is produced in a standard chloralkali electrolyzer, along with caustic for the contactor, and chlorine. Water oxidation by chlorine gives the strong acid, hydrochloric acid, and the weak acid, hypochlorous acid, which react directly with wet carbonate to release CO2. H2 and CO2 react in a methanol reactor to produce eFuel. H2 is the limiting reagent for eFuel synthesis, giving an excess of cold captured CO2. Thus, the current study underscores significant advancements in renewable fuel synthesis, particularly eMethanol, and evaluates the carbon capture and energy efficiency of a novel method. The simulation indicates that the marginal energy cost for a tonne of CO2 is ∼ 184kWh. This gives ∼ 76 % theoretical carbon capture efficiency and an overall process efficiency of 79.5 % (approximately a threefold improvement over the benchmark). The authors are unaware of a comparable method. The overall system yields a tonne of carbon-neutral e-methanol (eMeOH) while capturing an additional 3 tonnes of carbon dioxide, which means the modelled process captures over 300 % more carbon dioxide than is released upon combustion of the eFuel. In summary, this research contributes valuable insights into carbon-negative eFuel production, representing a significant scientific step in sustainable fuel production.

Techno-Economic Assessment of Electromicrobial Production of n-Butanol from Air-Captured CO2.

Electromicrobial production (EMP), where electrochemically generated substrates (e.g., H2) are used as energy sources for microbial processes, has garnered significant interest as a method of producing fuels and other value-added chemicals from CO2. Combining these processes with direct air capture (DAC) has the potential to enable a truly circular carbon economy. Here, we analyze the economics of a hypothetical system that combines adsorbent-based DAC with EMP to produce n-butanol, a potential replacement for fossil fuels. First-principles-based modeling is used to predict the performance of the DAC and bioprocess components. A process model is then developed to map material and energy flows, and a techno-economic assessment is performed to determine the minimum fuel selling price. Beyond assessing a specific set of conditions, this analytical framework provides a tool to reveal potential pathways toward the economic viability of this process. We show that an EMP system utilizing an engineered knallgas bacterium can achieve butanol production costs of <$6/gal ($1.58/L) if a set of optimistic assumptions can be realized.

Potential Applications of Metal‐Doped Nanomaterials for Enhancing Solid‐State Hydrogen Storage

AbstractHydrogen energy is the primary replacement for fossil fuels in the future because of its advantages in terms of efficiency, cost‐effectiveness, and environmental friendliness. The fundamental issue with hydrogen, however, arises from its exceedingly low volumetric density; thus, developing efficient storage methods is critical to achieving a sustainable hydrogen economy. Hydrogen storage has demonstrated tremendous potential as a possible alternative for effective large‐scale storage. Due to their low cost, and high volumetric and gravimetric capacities, metal hydride‐based storage is considered the most prospective solid‐state storage material. Their low storage capacity nevertheless restricts their application effectively. Hence, the need to enhance the storage capacity by doping active metals becomes an interesting study area. With considerable success, metals, particularly transition metals, have been used to modify hydrides to improve their storage capacities. Owing to their strong and superior performance, active metals have demonstrated tremendous potential in increasing the performance of storage materials. This review critically examined recent developments in enhancing hydrogen storage characteristics through the incorporation of active metals. The preparation techniques for metal infiltration through different techniques, such as impregnation, ball/mechanical milling, and reflux were reported. The review describes significant advances in hydrogen storage characteristics due to metal doping and offers perspective recommendations for future research.