Search Results (1,028)

This paper examines the relationship between macroeconomic scale, the structure of energy consumption, and carbon dioxide emissions in Poland over the period 2000–2023, against the background of the country’s energy transition under European Union (EU) climate policy. The study aims to identify the extent to which gross domestic product (GDP), hard coal consumption, natural gas consumption, and electricity generation from renewable energy sources (RES) explain the level of CO₂ emissions in a coal-dependent economy undergoing gradual structural change. The empirical analysis is based on annual data from Statistics Poland and applies two complementary econometric approaches: an Ordinary Least Squares (OLS) model to capture the baseline relationships and an Autoregressive Distributed Lag (ARDL) model to examine short-run dynamics and lagged effects. The OLS results show that the model explains a substantial share of emission variability and that coal consumption is the only statistically significant determinant of CO₂ emissions, with a strong positive coefficient. GDP, natural gas consumption, and RES production do not exhibit statistically significant effects in the baseline specification. The ARDL results indicate that coal has the strongest contemporaneous statistical association with emissions, while also suggesting weak autoregressive properties of the emission system and the absence of statistically significant short-run associations for GDP, gas, and renewables. Sensitivity analysis further shows that coal remains the variable most strongly associated with emission levels, whereas the estimated associations for GDP, gas, and RES are comparatively weak. The findings suggest that, in Poland, emission dynamics are more closely linked to the carbon intensity of the energy mix than to the scale of economic activity itself. The study suggests that effective decarbonization is likely to be associated with a structural reduction in coal dependence, while the emission-reduction potential of renewable energy expansion may become more visible over a longer time horizon. These results have important implications for the design of Poland’s energy and climate policy, suggesting that the success of the transition is closely linked to changes in the structure of energy carriers in a way consistent with economic and infrastructural constraints. Full article

Biogas produced from the anaerobic digestion of organic matter holds much promise as a renewable energy source for decentralized systems. However, raw biogas contains substantial volumes of carbon dioxide, hydrogen sulfide, water vapor, and other trace impurities. These impurities can reduce the calorific value of biogas and limit its direct use for household energy needs. Purifying biogas to high-grade biomethane (≥95%) is therefore important to improve methane (CH₄) content and combustion characteristics. This is a guarantee of its safe utilization in domestic appliances, including cooking, heating, lighting, and electricity generation. This article reviews and evaluates novel approaches for upgrading raw biogas into high-purity biomethane that can offset natural gas in domestic applications. It further examines recent developments in conventional and innovative upgrading technologies such as water scrubbing, chemical scrubbing, pressure swing adsorption, membrane separation, cryogenic separation, and biological upgrading. Particular emphasis is placed on low-cost and small-scale solutions suitable for off-grid or mini-grid rural energy systems. Moreover, the role of process optimization, intelligent monitoring, and data-driven control methods in increasing CH₄ recovery and process efficiency is discussed. Despite their relatively high capital costs and energy needs, conventional technologies such as water scrubbing, pressure swing adsorption, and membrane technology continue to dominate biogas purification systems. The findings show that coupling advanced separation technologies, including cryogenic separation, biological upgrading, and hybrid technologies, with optimized process control can significantly improve CH₄ purity, save energy use, and enhance the overall consistency of biogas purification systems. These innovative strategies have strong potential to promote the full-scale adoption of biomethane as a clean, sustainable, and affordable energy source for decentralized applications, particularly in the developing world. Full article

The steel sector is one of the main contributors to carbon dioxide emissions among the industrial activities. It is mostly the use of carbon-rich blast furnaces and natural gas direct reduction processes that cause this. Hydrogen-based direct iron reduction (H-DRI) is a demonstrated method of lowering steel production carbon emissions by using hydrogen rather than carbon monoxide as the reducing agent; therefore, water vapor is released instead of carbon dioxide. This work offers a detailed analysis of the trends, operating concepts, industrial-scale trials, difficulties, and advantages of H-DRI. It is well supported by both energetic and reaction rate considerations that hydrogen is an efficient agent for the reduction of iron oxides to iron metal, giving metallization rates up to those of the traditional processes and at the same time significantly reducing GHG emissions. Moreover, industrial trials confirm that the method is technically feasible on a large scale, which is not yet realized because green hydrogen is very expensive, infrastructure needs are high, and there are still hurdles to be overcome in process optimization, such as water vapor management, pellet quality, and reactor design. According to the studies of product life cycles, if the hydrogen is extracted from renewable sources of energy, then the reduction in CO can be as high as 90%. The article also discusses different aspects of the economy, environment, and law that are already there and the ones that need to be developed so that research, technological breakthroughs, and industrial harmonization can be directed to the right spots. Practical deployment requires control of hydrogen supply, optimizing reduction processes, integrating renewable energy, and regulatory support. The results offer operational insights to the steel industry, policymakers, and academia on the path to sustainable, energy-efficient, and carbon-neutral steel production while retaining the metallurgical quality and industrial scale of the steelmaking processes. Full article

Underground Gas Storage (UGS) is transitioning from traditional fossil fuel peak-shaving facilities into comprehensive hubs for Terawatt-hour-scale Terawatt-hour (TWh) scale renewable energy storage. The unique physicochemical properties of diverse fluids, such as the negative Joule–Thomson coefficient of hydrogen (−0.03 K/bar), present complex engineering adaptability challenges. Since existing studies primarily focus on single mechanisms or specific geological types, this review integrates a unified engineering framework to evaluate the repurposing potential and retrofitting requirements of existing oil and gas assets. By compiling a property benchmarking matrix for methane, carbon dioxide, and hydrogen, the storage adaptability of various geological formations is summarized. Salt caverns exhibit strong adaptability to highly diffusive and reactive fluids due to their high salinity (exceeding 150 g/L) and mechanical stability, whereas porous media offer massive capacity (more than 10 times) but require overcoming severe biogeochemical obstacles. Based on thermo–hydro–mechanical–chemical–biological (THMCB) coupling mechanisms, an integrity evaluation system for artificial wellbore and natural geological barriers is systematically reviewed. Critical risks, including fatigue failure under high-frequency cyclic loading, material degradation, gas leakage, and indirect Global Warming Potential (GWP), are elucidated. A future evolution route integrating physical, digital, and policy dimensions is outlined. This roadmap emphasizes Hydrogen-Enriched Compressed Natural Gas (HCNG)synergistic storage, dynamic risk control utilizing digital twins and Artificial Intelligence (AI), and standardized Life Cycle Assessment mechanisms (LCA), providing a scientific basis for the sustainable transition of UGS facilities. Full article

The cement industry is a major contributor to global energy consumption and greenhouse gas emissions, motivating the development of sustainable cementitious materials through partial cement substitution. This study investigates the combined mechanical, durability-related, and environmental performance of mortars incorporating a 20% replacement of Portland cement by volume with different natural and waste-derived mineral additions, including natural pozzolan, brick waste, glass powder, recycled concrete powder, and calcined clay as pozzolanic or potentially reactive supplementary materials, while silica sand was used as an inert mineral filler. Mechanical performance was evaluated through compressive strength, while durability-related behavior was assessed using water absorption by immersion at 28 days. In parallel, a Life Cycle Assessment (LCA) was conducted to quantify the environmental impacts associated with climate change, acidification, eutrophication, photochemical oxidant formation, material resource depletion, and non-renewable energy consumption. The results show that mortars incorporating natural pozzolan and brick waste achieved compressive strengths comparable to the reference mortar, while maintaining low water absorption values, indicating effective microstructural densification. Glass powder also provided acceptable mechanical and durability-related performances, whereas silica sand, recycled concrete powder, and calcined clay exhibited reduced strength and increased absorption due to dilution effects, inherited porosity, or delayed pozzolanic activity. From an environmental perspective, all cement-substituted mortars demonstrated significant reductions across all assessed LCA impact categories, with decreases typically ranging from 15% to 20% relative to the reference mix. The most pronounced environmental benefits were observed for mortars incorporating waste-derived materials, particularly brick waste. Overall, the combined mechanical and environmental assessment demonstrates that a 20% cement substitution using supplementary materials can substantially reduce the environmental footprint of mortars without compromising essential engineering properties. Full article

The decarbonization of existing buildings remains a major challenge, particularly in contexts characterized by high energy demand and heating systems based on fossil fuels. While electrification is widely recognized as a key pathway, its direct application is often limited by building and operating conditions. This study investigates the potential of hybrid heating systems as transitional solutions through a large-scale numerical parametric simulation analysis based on representative models of the Italian residential building stock. The analysis explores the interaction between climatic conditions, system operation, and energy performance under standardized assumptions. The results reveal that hybrid systems achieve significant reductions in non-renewable primary energy (up to 39–44%) and CO₂ emissions (approximately 50–58%), primarily through the substitution of natural gas with electricity. Conversely, total primary energy may increase (approximately 2–26%) due to the contribution of renewable energy associated with heat pump operation. Operating cost savings are observed in the 25–40% range, with slight variation depending on climatic conditions. The effectiveness is not uniform, with maximum benefits in intermediate climate zones and reduced performance under more severe conditions. Overall, hybrid systems show stable and reliable performance across heterogeneous building configurations, supporting their role as robust mid-term transition technologies toward building decarbonization. Full article

The increasing demand for energy, the finite nature of fossil fuel resources, and the necessity to reduce greenhouse gas emissions have intensified research on renewable energy sources of plant origin. Among potential energy feedstocks, herbaceous biomass has attracted growing interest due to its high productivity, rapid growth, and widespread occurrence. The aim of this study was to evaluate the energy potential of select sedge species (Carex spp.) commonly occurring in Poland as an alternative to fossil fuels. Aboveground biomass of eight sedge species was collected from natural habitats located in the Warta River valley. Cellulose, lignin, holocellulose, hemicellulose, and ash content in the biomass was determined. In addition, key energy parameters, namely net calorific value and gross calorific value, were analyzed. Differences among species were assessed using one-way analysis of variance, while similarities were explored using hierarchical clustering methods. The results revealed significant interspecific variation in both chemical composition and energy properties. Most analyzed sedge species had favorable lignocellulosic composition and energy parameters comparable to those of woody biomass, particularly willow and poplar. In contrast, Carex riparia was distinguished by a high ash content and lower calorific values, limiting its suitability for energy applications. Overall, the findings indicate that select Carex species may represent a valuable renewable feedstock for energy production, especially in the context of local and decentralized biomass-based energy systems. Full article

Biomethane is emerging as a key renewable gas in both mature and developing energy systems worldwide. Driven by climate-neutrality objectives, energy-security concerns, and rising waste-to-energy ambitions, global biomethane production is expected to expand rapidly in the coming decade. In Europe, this growth is accelerated by the REPowerEU target of 35 billion m³ by 2030. However, as biomethane production increases and natural gas demand declines over time, distribution networks face growing operational challenges, including pressure build-up and biomethane curtailment caused by supply and demand mismatches. This study evaluates whether surplus biomethane can be converted into electricity as a multi-commodity strategy to alleviate these constraints. Using hourly operational data from two Dutch Distribution System Operators (DSOs), a simulation model was developed to assess the impact of generator-based biomethane-to-power conversion on both gas and electricity distribution networks. The results show that, for RENDO, the approach increases effective biomethane injection by 49.0%, reduces natural gas deliveries from the transmission system by 20.0%, and lowers electricity imports by 9.2%. For Coteq, the corresponding impacts are 106.8%, 30.6%, and 16.2%, respectively. These findings indicate that multi-commodity coupling through biomethane-to-power conversion provides a promising strategy for increasing biomethane injection and renewable electricity generation. Full article

Hydrogen is a key energy carrier for the transition to renewable energy, but its storage remains a major challenge, mainly due to the energy requirements for its production and to its low volumetric energy density under ambient conditions. Clathrate hydrates have recently emerged as a promising medium for gas storage, yet their potential for hydrogen storage is still underexplored. This study presents a comprehensive bibliometric analysis of hydrogen storage research, focusing on clathrate hydrates. The analysis, based on publications indexed in Scopus over the past decades, reveals that research on gas hydrates is mature and interdisciplinary, encompassing hydrate formation, thermodynamics, and production from natural reservoirs. In contrast, hydrogen hydrates remain a marginal and emerging research area, characterized by limited scientific output and weak connections to dominant storage strategies such as metal hydrides, metal–organic frameworks, and adsorptive materials. The results highlight key research gaps, including a limited understanding of formation kinetics, thermodynamic stability under practical conditions, and challenges related to scalability and system integration. These findings suggest that targeted research efforts addressing these bottlenecks could support the development of hydrate-based systems as complementary solutions within the broader hydrogen storage landscape. Full article

Plastic manufacturing depends heavily on petroleum-derived monomers like terephthalic acid, the main component of polyethylene terephthalate (PET). However, the depletion of fossil resources and increasing environmental concerns have heightened the need for sustainable alternatives. Lignocellulosic biomass has emerged as a promising resource due to its renewable, abundant, and eco-friendly nature. Understanding its chemical composition enables conversion of this biomass into platform chemicals, such as 2,5-furandicarboxylic acid (FDCA) and lactic acid, derived from cellulose and hemicellulose. These can be polymerized into bio-based plastics such as polyethylene furanoate (PEF), polylactic acid (PLA), and polyhydroxyalkanoates (PHAs), offering greener alternatives to fossil-based plastics. PEF features rigid furan rings that enhance thermal stability, mechanical strength, and barrier properties, and reduce gas permeability compared to PET. PLA is a renewable, biodegradable plastic widely used in packaging and medical applications. This review covers the chemical composition of lignocellulosic biomass cellulose, hemicellulose, and lignin, and various pretreatment strategies, chemical, physicochemical, and physical, to overcome biomass recalcitrance and improve conversion efficiency. It also highlights recent catalytic advances in transforming cellulosic carbohydrates into bio-based plastic precursors such as FDCA and lactic acid. Lastly, this review discusses polymerization pathways for producing PEF and PLA, emphasizing their role in reducing the environmental impact of polymer manufacturing and promoting green chemistry principles. Full article

This study develops econometric models to examine greenhouse gas emissions associated with coal and natural gas consumption in Poland between 2015 and 2023. Poland has one of the most carbon-intensive energy systems in Europe. Three complementary log–log econometric models were estimated: a model explaining total CO₂ emissions, a model assessing emission intensity (CO₂ per unit of GDP), and a model capturing short-term variations in emission intensity. The results demonstrate that coal consumption remains the dominant determinant of absolute emissions, whereas the expansion of renewable energy significantly contributes to lowering the carbon intensity of economic growth. However, short-term fluctuations in emission intensity are still largely influenced by changes in fossil fuel consumption patterns. The findings highlight the gradual and sequential character of Poland’s energy transition, where gains in environmental efficiency precede a consistent reduction in total emissions. The proposed modeling framework offers an empirical basis for evaluating the effectiveness of climate and energy policies and can support the formulation of decarbonization strategies in economies heavily reliant on fossil fuels. Full article

The transition from non-renewable to renewable energy sources has emerged as a pressing global issue, driven by concerns over climate change, resource depletion, and the need for sustainable development. This study compares Canada, an energy-rich nation, and Bangladesh, an energy-scarce country, to understand the structural, institutional, and market factors driving their respective renewable energy transitions. Using univariate time-series models (ARIMA, ETS, and Prophet) for energy demand forecasting and extensive literature-based policy evaluation, the paper examines trends in energy production, consumption, and trade from 1990 to 2024. Our analysis indicates that Canada’s vast reserves of both renewable and non-renewable energy sources, its diversified energy portfolio, and carbon-pricing framework support a stable decarbonization pathway, with renewables projected to account for more than 20% of total supply by 2030. However, regional disparities and political resistance from the established energy sector continue to delay transition outcomes. On the other hand, Bangladesh has limited renewable and non-renewable energy sources, with its primary energy resource being natural gas reserves. Consequently, its heavy reliance on imports (over 75% of primary energy) and institutional bottlenecks expose its energy system to commodity-price volatility, undermining energy security and slowing renewable investment. Despite these challenges, targeted solar programs and concessional financing have modestly increased the penetration of renewable energy. The analysis highlights that commodity market fluctuations, technological innovations (such as smart grids and energy storage), and market-based policy instruments critically shape each country’s transition trajectory. A coordinated policy linking market stabilization, innovation investment, and social inclusion is essential for achieving a just and secure low-carbon transition in both countries. Full article

Alternative fuel and greenhouse emissions are always a keen focus for researchers aiming to cater to energy demands. There is an urgent need to find new clean and inexhaustible energy sources. In the past few years, hydrogen has gained attention from researchers as a green fuel. The scientific and policy maker circles have now widely recognized the practicality of hydrogen as an energy carrier through the due to its clean combustion, ease of transportation, distribution, and utilization. Different ways of its production and its use in different applications have also been widely studied. In this study, a review is carried out on how to produce hydrogen using the electrolysis process by renewable energy and its potential for application in different industries. Hydrogen gas can be used as a fuel to power catalytic boilers, gas-powered heat pumps, and direct-flame combustion boilers that are more or less the same as natural gas boilers. A large variety of district heating techniques can be repurposed to employ hydrogen cost-effectively. The use of hydrogen gas is not limited to combustion engines and industrial applications but is also applicable for house heating purposes. Finally, it is suggested that an alkaline electrolyzer could be energized with renewable sources to produce hydrogen which could be used as an alternative auxiliary fuel for the incineration system in managing municipal solid waste. This could be a step towards a green environment in terms of alternative clean fuel and municipal solid waste management. Full article

The injection of green hydrogen in the natural-gas infrastructure is an efficient option for the transport, consumption, and storage of large amounts of renewable energy, helping to overcome the balancing problems of the electricity network as well as to decarbonize the energy use in different sectors (e.g., civil, transport, industry). However, the injection of H₂ can determine relevant implications on the safety and integrity of pipelines and of the main components of the networks, as well as unwanted issues in the combustion process. In this paper, the effects of hydrogen injection in methane up to 35%vol on an industrial combustor under lean conditions have been evaluated from a theoretical and experimental point of view. In particular, the emissions of the combustion process have been investigated through experimental analysis and numerical simulation of key parameters (e.g., flame temperature, flame stability, flame speed, etc.) and the flue-gas analysis (e.g., flue-gas temperature, emissions of CO, NO_x, etc.). From the point of view of the combustion process, the obtained results show that no issues occur from the injection of hydrogen into methane up to 23%vol under lean conditions. Full article

Fuel cell technologies are increasingly investigated as alternatives to conventional auxiliary diesel generators in order to enhance shipboard energy efficiency and reduce greenhouse gas emissions. This study presents a unified and uncertainty-driven system-level assessment of solid oxide fuel cell (SOFC) and proton exchange membrane fuel cell (PEMFC) systems operating as auxiliary power sources on a 200 m bulk carrier. Both technologies are evaluated under identical vessel characteristics, operating profiles, auxiliary load levels (360–600 kW), and cost assumptions, and are benchmarked directly against a conventional three–diesel-generator configuration. A modular numerical framework is developed to model propulsion–auxiliary interactions for ship speeds between 10 and 14 knots. SOFC systems are assessed using grey, bio-derived, and green natural gas pathways, while PEMFC systems are examined under grey, blue, and green hydrogen supply routes. Performance indicators include annual fuel consumption, carbon dioxide (CO₂) emission reduction, net present value (NPV), internal rate of return (IRR), payback period (PBP), and marginal abatement cost (MAC). Economic uncertainty is explicitly embedded in the framework through Monte Carlo simulation, where fuel prices (±20%) and capital costs are sampled across defined ranges, generating probabilistic distributions rather than single deterministic estimates. This uncertainty-centred approach enables assessment of robustness, downside risk, and probability of profitability. Results show that replacing a single operating 600 kW diesel generator with fuel cell systems reduces auxiliary fuel energy demand by 25–35% for SOFC and approximately 15–25% for PEMFC relative to the diesel benchmark. Annual CO₂ reductions range from 1.1 to 1.3 kt for SOFC systems and 1.8–2.8 kt for PEMFC configurations. Under grey fuel pathways, median NPVs reach approximately 2–4.5 M$ for SOFC and 9–17 M$ for PEMFC as load increases, with IRRs exceeding 15% and 30%, respectively. Transitional pathways exhibit narrower margins, while renewable pathways remain more sensitive to fuel price variability. The findings demonstrate that fuel pathway cost dominates lifecycle outcomes under uncertainty and that hydrogen-based PEMFC systems exhibit the strongest economic resilience within the examined market ranges. The framework provides structured, uncertainty-aware decision support and establishes a foundation for integration into model-based systems engineering (MBSE) environments for early stage ship energy system design. Full article