Use Of Biofuels Research Articles

Optimizing Sorghum for California: A Multi-Location Evaluation of Biomass Yield, Feed Quality, and Biofuel Feedstock Potential

Sorghum cultivars, particularly those used for forage and biomass, present significant potential as drought-resistant crops suitable for animal feed and biofuel production. This study evaluated 59 sorghum hybrids over five years (2019–2023) across three University of California research farm locations in the Central Valley: Kearney REC (KARE), West Side REC (WSREC), and Davis. The primary aim was to identify genotypes that exhibit high yield and stability across diverse environments in California, which is crucial for meeting the state’s significant feed needs associated with dairy operations and animal production. The evaluation focused on biomass yields, forage quality traits such as Relative Feed Quality (RFQ) and milk yield per ton (milk/ton), and biofuel-relevant chemical compositions like Neutral Detergent Fiber (NDF) and starch. A multi-trait stability index was employed to pinpoint superior genotypes that combine high yield with desirable quality traits. Results indicated significant genotypic, environmental, and genotype-by-environment (GxE) interaction effects for all traits except fat and water-soluble sugars. Eight hybrids were notable for maintaining high and stable biomass yields across different locations. Additionally, high fat and starch content were found to correlate with improved milk/ton potential, while lower fiber content (ADF, NDF) was associated with enhanced RFQ. Specifically, nine hybrids were identified as optimal for dairy forage due to their combination of high yield, RFQ, and milk/ton. Furthermore, distinct hybrids were identified for first-generation (starch-based) and second-generation (NDF-based) biofuel strategies. Three hybrids stood out as having desirable traits for both feed and biofuel applications, underscoring their versatility. This study highlights the utility of a multi-trait stability index in selecting superior sorghum genotypes for specific trait combinations. The identified candidates for forage and biofuel use, especially the multipurpose varieties, offer valuable insights that can aid growers and industry stakeholders in developing more sustainable and versatile sorghum production systems in California. Findings from this study contribute significantly to the development of more resilient sorghum production systems. By identifying hybrids that excel in both yield and quality across various environments, this research supports future cropping decisions aimed at enhancing water use efficiency and drought resilience in sorghum cultivation. These advancements are crucial for maintaining competitive dairy operations and advancing biofuel production in the face of climate change-induced challenges.

Dynamics of Nanomotors Propelled by Enzyme Cascade Reactions

Enzyme-powered nanomotors have attracted significant attention in materials science and biomedicine for their biocompatibility, versatility, and the use of biofuels in biological environments. Here, we employ a hybrid mesoscale method combining molecular dynamics and multi-particle collision dynamics (MD–MPC) to study the dynamics of nanomotors powered by enzyme reactions. Two cascade enzymes are constructed to be layered on the same surface of a Janus colloid, providing a confined space that greatly enhances reaction efficiency. Simulations indicate that such a configuration significantly improves the utilization of intermediate products and, consequently, increases the self-propulsion of the Janus motor. By presenting the gradient fields of substrates and products, as well as the hydrodynamics surrounding the motor, we explore the underlying mechanism behind the enhanced autonomous velocity. Additionally, we discuss the improvements in environmental safety of the modified motor, which may shed light on the fabrication of biocatalytic nano-machines in experiments.

Effect of the Concentration of Bioethanol Mixed with Gasoline on the Energy and Environmental Performance of a Hybrid Vehicle in the Worldwide Harmonized Light Vehicles Test Cycle (WLTC)

Increasing the use of renewable biofuels in internal-combustion-engine (ICE) vehicles is a key strategy for reducing greenhouse gas emissions and conserving fossil fuels. Hybrid vehicles used in urban environments significantly reduce fuel consumption compared to conventional internal-combustion-engine cars. In hybrid vehicles integrating electric propulsion with biofuels offers even more significant potential to lower fuel consumption. One would like to think they should also be less polluted in all cases, but some results show that the opposite is true. This study’s aim was to evaluate a hybrid vehicle’s energy and environmental performance using different gasoline–bioethanol blends. A Worldwide Harmonized Light Vehicles Test Cycle (WLTC) study was conducted on a Toyota Prius II hybrid vehicle to assess changes in energy and environmental performance. During the WLTC test, data were collected from the chassis dynamometer, exhaust gas analyser, fuel consumption meter, and engine control unit (ECU). The collected data were synchronised, and calculations were performed to determine the ICE cycle work, brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), pollutant emissions (CO, HC, and NOx), CO2 mass emissions per cycle, and brake specific pollutant emissions per kilometre. The study shows that the performance of the hybrid vehicle’s ICE is strongly influenced by the utilisation of electrical energy stored in the battery, especially at low and medium speeds. As the bioethanol concentration increases, the engine’s ECU advances the ignition timing based on the knock sensor signal. A comprehensive evaluation using the WLTC indicates that increasing the bioethanol concentration up to 70% improves the energy efficiency of the hybrid vehicle’s internal combustion engine and reduces pollutant and CO2 emissions.

ASSESSING THE DEVELOPMENT OF THE BRAZILIAN ELECTRIC VEHICLES MARKET: A STUDY INTEGRATING A STRUCTURE-CONDUCT-PERFORMANCE (SCP) MODEL AND A PESTEL ANALYSIS

Climate change is one of the biggest political and economic challenges faced by global economy. To slow down climate change, mitigation actions and greenhouse gas (GHG) emission targets have been adopted, promoting electric vehicles (EVs) globally. In Brazil, however, emission reduction strategies for the transport sector are based on the broad use of biofuels. This paper studies the Brazilian light-duty vehicle EVs market investigating the reasons behind its current state. A Structure-Conduct-Performance Model with a PESTEL Analysis and the Herfindahl–Hirschman Index integrated to the structure analysis was used. The Brazilian EV market has grown in the period from 2019 to 2023, albeit timidly and restricted to a luxury market. The lack of actions promoting electric mobility, a less than promising economic scenario, the challenges in implementing a charging infrastructure and the conduct of the incumbent firm in the market – investing in high priced hybrid models – contribute to low penetration of EVs in the market and the dominance of hybrids amongst them. In the light of these findings, this study highlights that the Brazilian EVs market would benefit from public policies developed to promote electric mobility, and investment of private companies to develop EV models with more competitive prices.

Biomass minimum ignition temperature prediction through differential study of thermogravimetric analysis

With the global goal of minimising energy dependence on fossil fuels, biomass is taking on a crucial role, not only as an energy source, but also as a means of reducing greenhouse gas emissions and incorporating the use of new biofuels. However, the storage of processed biomass in dust form introduces several inherent hazards, e.g. the formation of fires due to self-ignition or the deposition of this powdery material on hot surfaces, thus reaching the minimum ignition temperature of dust layer. These hazards are not only observed in the industrial safety area but are also associated with the process of generating energy from biomass in controlled environments. In order to quantify these critical risks, this study focuses on correlating the devolatilization temperature ranges of the main polymers of biomass from the differential analysis of thermogravimetric curves (DTG) to obtain a prediction of the minimum ignition temperature of dust layer. This parameter has been experimentally determined according to UNE - EN ISO/IEC 80079-20-2:2016. Six samples of lignocellulosic biomass of different origin and composition were studied. The Fraser-Suzuki deconvolution method was used to determine the percentage of hemicellulose, cellulose, and lignin in order to establish a correlation between the composition and the flammability tendency of the samples. The results of the study underline the effectiveness of differential analysis of thermogravimetric curves as a fast and accurate tool for predicting the minimum ignition temperature of dust layer in lignocellulosic biomasses. This novel method, which requires only 60 mg and has an average error of 1.10% compared to experimental temperatures, improves the understanding of the combustibility of lignocellulosic biomasses by providing a more complete thermal record than that reported by international standard test methods. Therefore, its implementation would provide an improvement in terms of preventive and environmental risk management strategies related to combustible dust accumulation.

Evaluation of the Interest and Perception of Tourism Service Providers in Los Cabos, Baja California Sur, Mexico, Regarding the Alternative Use of Biofuels

This study addresses the need to implement sustainable alternatives in marine vessels, particularly in vulnerable environments, highlighting the potential of biofuels as a viable option for the transition towards renewable energy. The objective of the research was to evaluate the interest and perception of tourism service providers in Los Cabos, B.C.S., Mexico, regarding the alternative use of biofuels in their vessels. A total of 56 random surveys were applied and validated, and the results were as follows: 92% consider fuel to be their largest operational cost, 84.6% acknowledge that their activities impact the environment, and 80% are aware of biodiesel biofuel. Notably, more than 94% expressed interest in learning how to produce biodiesel and in using it as an alternative in their operations, while 95% believe that the use of biofuels could be a positive differentiating feature for their businesses, contributing to an eco-friendlier service. This introductory assessment is crucial as it highlights the importance of understanding the willingness of key stakeholders before adopting new technologies. It concludes that there is strong interest in exploring and adopting sustainable alternatives, reinforcing the need for further research to provide viable solutions, promoting a circular economy and fostering sustainable tourism in alignment with the Sustainable Development Goals.

Unlocking the potential: Key factors shaping the liquid biofuels market in Ukraine

This article examines the development of Ukraine's liquid biofuels market, driven by the need to diversify its fuel supply amidst complete reliance on imported fuels for road transport. The country also faces challenges exporting agricultural feedstock for first-generation biofuels due to geopolitical disruptions since early 2022. In response, the production and use of liquid biofuels represent a strategic move to reduce dependence on fossil fuels while fulfilling international obligations, including the ones within the Energy Community and the European Union (EU). Ukraine must align with the EU's renewable energy targets as a candidate for EU accession. Using the methods of fuel consumption quantification, blending mandate assessment, and excise tax rate calculation framework, the article finds that the potential market demand for bioethanol in Ukraine is projected to range from 125 to 278 thousand tonnes and for biodiesel from 196 to 431 thousand tonnes in 2025–2031. Ukraine's biofuel production potential could reach 2.54 million tonnes of oil equivalent by 2050, with advanced biofuels expected to dominate. Current excise tax rates for bioethanol are considered appropriate and supportive of market growth. To foster further development, legislative amendments are needed to mandate biodiesel blending, along with awareness campaigns highlighting the benefits of biofuels. Additionally, vehicles using high biofuel blends should receive incentives similar to those of electric vehicles, such as access to preferential parking.

MODERN TRENDS IN GLOBAL ENERGY IN THE CONTEXT OF SUSTAINABLE DEVELOPMENT AND DECARBONIZATION

The article presents data from authoritative international organizations on the noticeable change in the planet's climate compared to the pre-industrial period. It is emphasized that in recent years, climate change has become especially intense. One of the results of climate change is the increase in the frequency and destructive effects of hurricanes in various parts of the planet, droughts and crop losses in agriculture, floods, and rising sea levels, which leads to large economic losses. An important area of decarbonization of the global economy is the production of electricity using climate-neutral energy sources. The article provides a comprehensive comparative analysis of the efficiency of traditional large nuclear reactors and small modular reactors (SMRs). Significant technological, environmental and economic advantages of SMRs are noted. A comprehensive model for the development of global energy in the context of decarbonization is proposed, which includes innovative areas: SMRs, large nuclear power plants, wind, solar energy and the use of biofuels.

Effect of Biofuel Use on Ship Engine

This research examines the effect of biofuel use on ship engine performance, with a focus on performance, efficiency and environmental impact. Experimental studies were conducted using four-stroke marine diesel engines operated with various blends of biofuels and conventional fuels. The measured parameters include engine power, specific fuel consumption, thermal efficiency, and exhaust emissions. The results showed that the use of biofuels at certain concentrations can produce performance comparable to conventional fuels, with some significant differences. Engine power decreased slightly (2-5%) at high biofuel blends, but thermal efficiency increased up to 3% at optimal blends. Specific fuel consumption increased by about 5-8% compared to conventional fuel. Exhaust emissions analysis showed a significant reduction in carbon monoxide (CO) and particulate emissions, with up to 30% and 40% reductions respectively. However, there was a slight increase in oxides of nitrogen (NOx) emissions by 5-10%. The study also identified several technical challenges in the use of biofuels, including the potential degradation of certain engine components and the need for fuel system modifications.

Specific features of production and use of transportation biofuels in selected developing countries (part II)

Aim. To identify specific features of production and use of transportation biofuels in selected developing countries, as well as to assess the potential of bioethanol industry development in the Russian Federation (RF).Objectives. To assess the economic efficiency of bioethanol production in Russia; to reveal the potential of applying foreign experience in the development of bioethanol industry in our country.Methods. In the process of the research the methods of system analysis, comparative analysis, method of expert evaluations, mathematical, statistical methods were applied.Results. The actual estimation of economic efficiency of bioethanol production in Russia was obtained. The cost of a unit of bioethanol, which is equivalent to a liter of gasoline in terms of energy content, is 5-36% higher than the cost of a liter of gasoline (depending on the production technology). At the same time, state support for the production and use of bioethanol in our country is reasonable. This will allow to create additional demand for grain crops and reduce carbon dioxide emissions from motor transport. The production and use of bioethanol will form an additional supply in the gasoline market, will give an opportunity to support projects on deep processing of grain and wood chemistry.Conclusions. The experience of Brazil, China and Indonesia in the development of bioethanol industry is relevant for Russia. At the same time, in order to minimize possible risks in the field of food security at the initial stage of bioethanol industry development, low-quality grain stocks should be used as feedstock and the production of second-generation bioethanol should be stimulated.

Applications of Machine Learning Technologies for Feedstock Yield Estimation of Ethanol Production

Biofuel has received worldwide attention as one of the most promising renewable energy sources. Particularly, in many countries such as the U.S. and Brazil, first-generation ethanol from corn and sugar cane has been used as automobile fuel after blending with gasoline. Nevertheless, in order to continuously increase the use of biofuels, efforts are needed to reduce the cost of biofuel production and increase its profitability. This can be achieved by increasing the efficiency of a sequential biofuel production process consisting of multiple operations such as feedstock supply, pretreatment, fermentation, distillation, and biofuel transportation. This study aims at investigating methodologies for predicting feedstock yields, which is the earliest step for stable and sustainable biofuel production. Particularly, this study reviews feedstock yield estimation approaches using machine learning technologies that focus on gradually improving estimation accuracy by using big data and computer algorithms from traditional statistical approaches. Given that it is becoming increasingly difficult to stably produce biofuel feedstocks as climate change worsens, research on developing predictive modeling for raw material supply using the latest ML techniques is very important. As a result, this study will help researchers and engineers predict feedstock yields using various machine learning techniques, and contribute to efficient and stable biofuel production and supply chain design based on accurate predictions of feedstocks.

Fossil Diesel, Soybean Biodiesel and Hydrotreated Vegetable Oil: A Numerical Analysis of Emissions Using Detailed Chemical Kinetics at Diesel Engine Like Conditions

Nowadays, emissions from internal combustion engines are a relevant topic of investigation, taking into account the continuous reduction of emission limits imposed by environmental regulatory agencies around the world, obviously as the result of earnest studies that have pointed out the impact on the human health of high levels of contaminants released into the environment. Over recent years, the use of biofuels has contributed to attenuating this environmental issue; however, new problems have been raised, such as NOx emissions tend to increase as the biofuel percentage in the fuel used in engines increases. In this research, the emissions of a compression ignition internal combustion engine modeled as a variable volume reactor with homogeneous combustion were numerically investigated. To analyze the combustion process, a detailed kinetics model tailored specifically for this purpose was used. The kinetics model comprised 30,975 chemical reactions involving 691 chemical species. Mixtures of fuel surrogates were then created to represent the fuel used in the Brazilian fuel marketplace, involving (i) fossil diesel—“diesel A”, (ii) soybean diesel—“biodiesel”, and (iii) hydrotreated vegetable oil— “HVO”. Surrogate species were then selected for each of the aforementioned fuels, and blends of those surrogates were then proposed as mixture M1 (diesel A:biodiesel:HVO—90:10:0), mixture M2 (diesel A:biodiesel:HVO—85:15:0), and mixture M3 (diesel A:biodiesel:HVO—80:15:5). The species allowed in the kinetics model included all the fuel surrogates used in this research as well as the target emission species of this study: total hydrocarbons, non-methane hydrocarbons, carbon monoxide, methane, nitrogen oxides, carbon dioxide, soot, and soot precursors. When compared to experimental trends of emissions available in the literature, it was observed that, for all the proposed fuel surrogates blends, the numerical approach performed in this research was able to capture qualitative trends for engine power and the target emissions in the whole ranges of engine speeds and engine loads, despite the CO and NOx emissions at specific engine speeds and loads.

From biogas to biomethane: Comparison of sustainable scenarios for upgrading plant location based on greenhouse gas emissions and cost assessments

Addressing the global energy crisis and achieving sustainable development goals (SDGs) necessitates shifting towards renewable energy sources, with biomethane emerging as a viable alternative. This study evaluated three scenarios for biomethane production from biogas: localized upgrading for biofuel use, district upgrading for biofuel use, and district upgrading with grid injection. By utilizing economic assessments and spatial and network analysis, the optimal locations for upgrading plants were identified to minimize transportation costs and GHG emissions (CO2 equivalents). Results indicate that Scenario 1 achieves the lowest emissions and operating costs (41 MEUR), while Scenarios 2 and 3, despite higher initial investments (152–173 MEUR), offer significant economies of scale (1187–1321 MEUR) and substantial annual production capacities (8.8 × 106 Sm³ of biomethane). Comparative and sensitivity analyses show renewable energy sources reduce GHG emissions by up to 83.7% and significantly lower operating costs. This research underscores the critical role of strategic planning and renewable energy integration in optimizing the biomethane value chain for environmental sustainability and economic viability while also emphasizing the need for further research to refine these findings.

Respiratory Symptoms and Paper Dust Exposure among Workers in the Paper Industry in Ethiopia: A Comparative Cross-Sectional Study

Chronic respiratory symptoms are a health concern in the paper industry. This study evaluates the association between personal inhalable paper dust exposure and chronic respiratory symptoms among workers in this industry. In total, 270 workers from the paper industry and 267 from a water bottling factory participated. Chronic respiratory symptoms were assessed using a standardized questionnaire, modified from the American Thoracic Society. A job exposure matrix, based on cross-sectional personal measurements of inhalable paper dust, was used to estimate the exposure–response relationship between cumulative dust exposure and chronic respiratory symptoms. There was a higher prevalence of chronic coughs (27.4% vs. 7.5%), breathlessness (25.6% vs. 11%), coughs with sputum (21.1% vs. 1.1%), and wheezing (25.6% vs. 5%) among paper workers compared to those in the water bottling industry. A Poisson regression analysis revealed that the prevalence ratios for chronic coughs (APR = 3.3 and 95% CI: 2.0–5.4), breathlessness (APR = 2.2 and 95% CI: 1.4–3.4), and wheezing (APR = 4.3 and 95% CI: 2.3–7.7) were significantly higher in paper workers than in water bottling workers. Among paper workers, a significant exposure–response relationship was observed between cumulative dust exposure and chronic coughs after adjusting for age, sex, history of respiratory illnesses, work in other dusty industries, and use of biofuels. As there were only four ever-smokers, smoking was not included in the regression analysis. The results show a significant association between dust exposure and coughing, highlighting the need for control measures to prevent the development of respiratory symptoms among workers.

Carbon Footprint and GHG Reduction Potential of Bioethanol Production in the Philippines

Abstract As the Philippine bioethanol industry concluded its first decade, it is in due time to assess whether the objectives of the Biofuels Act of 2006 (Republic Act No. 9367) are being met. Specifically, the law aims to reduce the country’s dependence on oil importation, mitigate toxic and greenhouse gases (GHGs), and promote the use of biofuels from indigenous resources to boost the country’s rural economy, by mandating biofuels blending to fossil-based fuels for transport use. This study examined the contribution of seven bioethanol production systems to the country’s climate change mitigation efforts by assessing the environmental impacts, particularly the carbon footprint and GHG emission reduction potential of each bioethanol distillery through life cycle assessment (LCA). Results of the environmental impact assessment revealed that the weighted average carbon footprint of the seven bioethanol production systems is at 1,415.66 gCO2e L−1, which ranges from 287 to 1,726 gCO2e L−1, translating to an average GHG reduction potential of 47.54% or an average avoided GHG of 268,091.15 tons CO2e yr−1 for CY 2019-2020. With the environmental hotspots identified, recommendations were made to improve the distilleries’ carbon footprints, and a sensitivity analysis was conducted to quantify the benefits from the recommended strategies. By applying all strategies, the average GHG reduction potential of the seven bioethanol production systems can get as high as 85.63%, which can be translated to an average avoided GHG of 482,933.91 tons CO2e yr−1.

Методика оценки экологического эффекта от применения биотоплив

Purpose: the fight for ecology in the transport sector is ensured by improving the design of vehicles and engines, the working processes of internal combustion engines, as well as the use of alternative fuels. To determine the rational use of biofuels in vehicles, it is necessary to assess the environmental effect that will be achieved when using them. Methods: the existing methods of estimating exhaust gas emissions from motor vehicles are considered. Based on them, improvements have been made, which include the introduction of additional coefficients that take into account changes in the environmental load depending on the percentage of biofuels mixed with traditional hydrocarbon fuels. Results: the calculation of the environmental effect from the use of biofuels was carried out using the example of adding biodiesel to petroleum diesel fuel, for which, based on statistical data from the US Environmental Protection Agency and data, WE established dependences of changes in annual emissions of harmful substances and carbon dioxide for a heavy-duty cargo vehicle. In addition to the calculation, the article presents graphs of emissions of harmful substances, taking into account their relative aggressiveness and the amount of carbon dioxide released during the combustion of biodiesel mixtures. Practical significance: The proposed method for calculating the environmental effect makes it possible to estimate the volume of emissions of harmful substances and carbon dioxide depending on the concentration of biofuels mixed with traditional fuels. Such an approach can provide an overall picture of the effect of using biodiesel, and at the same time, the coefficients used need to be clarified.

Decarbonization in Shipping—The Hopes and Doubts on the Way to Hydrogen Use

This article presents the initial processes of changing ship fuels aimed at reducing emissions of carbon dioxide and other greenhouse gases. A significant reduction in GHG emissions is only possible by using carbon-free fuels. The process of reducing CO2 emissions was forced by legal regulations introduced in recent years by the International Maritime Organization and the Parliament of the European Union. The year 2050 was set as the target year for achieving the intended goals, but intermediate goals should be achieved already in 2030 and 2040. This article attempts to analyze the ongoing changes in the fuel market in maritime transport on the way to achieving the threshold of climate neutrality with this form of transport. A number of hopes related to this were indicated but also so were obstacles that may slow down this process. In 2023, there was an increased interest among shipowners in adapting ship engines to burn more ecological ship fuels. However, it is far from our expectations. Meeting the gradually increasing emission limits through imposed regulations was possible in the years 2020–2023 by using dual-fuel engines in which gaseous fuels, mainly LNG and LPG, were used for long periods of operation. The next step is the use of biofuels or synthetic fuels, which, however, will not meet the requirements after 2030. Interest is moving towards the use of ammonia and, ultimately, after 2040, hydrogen. The aim of this article is to analyze the ongoing processes and assess the directions of changes that justify the sense of the actions taken.

Sustainability and circularity assessment of the potential of a biofuel produced from black liquor as a substitute for conventional fuels

The European Bioeconomy Strategy aims to accelerate the deployment of a sustainable European bioeconomy to maximize its contribution to the 2030 Agenda and its Sustainable Development Goals (SDGs), as well as to the Paris Agreement on climate change. In this context, transport is considered as a key sector, with aviation and shipping playing an important role due to the need to meet its huge demand. In order to reduce potential emissions from the transport sector, the use of biofuels could be considered as a solution. However, with the aim of using biofuels to replace conventional fuels, it is important to assess their cost-effectiveness and feasibility, and in this aspect the valorization of waste streams for their production could help to meet this challenge. This is the framework of this research report, which is based on the use of black liquor (BL) from pulp and paper production to produce biofuel through a hydrothermal liquefaction (HTL) unit. Three technological designs and production capacities were considered: full extraction of the oil phase and its upgrading by catalytic hydrothermal deoxygenation (Scenario 1, S1), partial extraction of the oil phase (Scenario 2, S2) and full extraction but without upgrading (Scenario 3, S3). Low (100 t/d), medium (300 t/d) and high (600 t/d) production capacities were regarded.From the modelling data, a life cycle perspective was adopted, taking into account both the environmental analysis (LCA) and the life cycle costs (LCC), as well as the circular potential using different performance, resource-flow circularity and economic indicators. In addition, a composite indicator, CILCA-LCC-CA, has been proposed to obtain a single score taking into account the three assessments: environmental, cost and circularity. The results obtained show that S3, with a production of 300 t/d, has the lowest environmental impact and the highest profitability corresponds to a capacity of 600 t/d. In terms of circularity, S3 also shows the best performance, mainly due to its higher resource productivity and lower energy intensity. These results are in line with those obtained for the composite indicator, and also show that higher production capacities and a simple but efficient process technology, such as S3, is the alternative with the highest potential for both sustainability and circularity.

What are the costs of rigidity? A general equilibrium study of the fuel market in Argentina

The policy that is most widely applied to the biofuel market in the world is the mandatory blend. This policy aims to induce the use of biofuels by setting a minimum level of biofuel per unit of blended fuel. This paper studies the costs and benefits of such a policy. To do so, a Recursive Computable General Equilibrium model (CGE), calibrated with a new own-developed energy-oriented Social Accounting Matrix of Argentina for 2018, has been developed. Such a model is extended by explicitly embedding a constrained fuel blending model into the CGE setup. This research addresses the following questions: What are the costs and benefits of a mandatory blend compared to a full flexibility scenario? Is it better to induce the use of biofuels through a tax on fossil fuels or a blending constraint? What is the impact of international price shocks when considering different blending regimes? This paper finds that the mandatory policy has a negative impact on the economic activity, poverty, income distribution, and energy affordability, but a positive one on emissions. When analysing the convenience of a special tax on fossil fuels instead of a mandatory regime, this paper finds that the cost and benefits of each policy are distributed differently over time. The special tax on fossil fuels performs better in the short run while the mandatory blend does so in the long run. Finally, this paper finds that flexibility in the fuel market improves the country's performance when there are shocks on international prices.

Ensuring Operational Performance and Environmental Sustainability of Marine Diesel Engines through the Use of Biodiesel Fuel

This article considers the issues of ensuring operational performance and environmental sustainability of marine diesel engines by using biodiesel fuel. This research was conducted on 5S60ME-C8 MAN-B&W Diesel Group and 6DL-16 Daihatsu Diesel marine diesel engines, which are operated using RMG380 petroleum fuel and B10 and B30 biodiesel fuels. The efficiency of biofuel usage was assessed based on environmental (reduced nitrogen oxide concentration in exhaust gases) and economic (increased specific effective fuel consumption) criteria. It was found that the use of B10 and B30 biofuels provides a reduction in nitrogen oxide concentration in exhaust gases by 14.71–25.13% but at the same time increases specific effective fuel consumption by 1.55–6.01%. Optimum fuel injection advance angles were determined that ensure the best thermal energy, economic and environmental performance of diesel engines. The optimum angle of biofuel supply advance is determined experimentally and should correspond to the limits recommended by the diesel engine operating instructions. It has been proven experimentally that the use of biofuel increases the environmental sustainability of marine diesel engines by 13.75–29.42%. It increases the diesel engines environmental safety in case of emergency situations as well as accidental and short-term emissions of exhaust gases with an increased content of nitrogen oxides into the atmosphere phenomena that are possible in starting modes of diesel engine operation as well as in modes of sudden load changes. It is the increase in the environmental friendliness of marine diesel engines in the case of using biofuel that is the most positive criterion and contributes to the intensity of biofuel use in power plants of sea vessels.