Browse Topic: Climate change mitigation

Items (176)
With the United Kingdom’s goal to achieve a fully decarbonised energy sector by 2035 and achieve net zero greenhouse gas emissions by 2050, the transition of the UK’s passenger car fleet to battery electric vehicles (BEVs) plays a crucial role in reaching this goal. This study evaluates the environmental and energy impact of large-scale BEV adoption by modelling future uptake scenarios using historical fleet data combined with assumed impact of future policy such as the 2030 ban on the sale of new petrol and diesel vehicles. Three predictive models have been developed: fast uptake, in which approximately 100% of the passenger car fleet is replaced by BEVs; moderate uptake, where a large majority of passenger cars are BEVs; and slow uptake, in which BEV adoption does not reach a majority. The results have shown that, if a medium- or large-scale adoption is possible by 2040 predicting nearly 37 million BEVs on the road, the associated electricity demand is predicted to rise close to 110 TWh annually, signifying the need for rapid development in renewable energy generation. Although BEVs significantly reduce transport sector emissions, the overall climate impact is dependent on a continued effort of grid decarbonisation.
Burke, BradleyKateregga, SunnySodre, Jose Ricardo
Regulators and policymakers have introduced increasingly stringent limits on tailpipe CO₂ and pollutant emissions to accelerate the decarbonization of heavy-duty vehicle applications. The development of innovative propulsion technologies — such as advanced combustion systems, low-friction reciprocating components, and improved aftertreatment solutions — combined with hybridization and the adoption of alternative fuels (e.g., biogas, HVO, green hydrogen), is a key pathway for meeting future emission and GHG targets. In this study, advanced combustion systems were developed for a 13-liter diesel engine for heavy-duty truck applications, with the objective of meeting forthcoming Euro VII regulations while maximizing thermal efficiency. The combustion system architecture—including open-bowl geometry with high aspect ratio, injector nozzle with wider spray opening angle, and reduced swirl ratio—was optimized using a Machine Learning–algorithm trained on high-fidelity 3D CFD combustion data. The method enabled the identification of two optimized combustion-system “recipes”, one of which was evaluated through engine tests, which refined nozzle specifications and injection strategies, using a structured Design of Experiments (DoE) approach. Results were benchmarked against a MY24 baseline combustion system, assessing efficiency, NOx–soot trade-offs, and combustion behaviors. Based on 3D-CFD results, the advanced combustion concept achieved an improvement in Brake Thermal Efficiency (BTE) of up to +0.8% points and delivered substantial NOx reductions of up to 45%, while maintaining smoke emissions at or below baseline levels. The experimental results indicate that the advanced combustion system developments designed for next-generation heavy-duty engines can further increase BTE by up to ~1% relative to the baseline combustion system, without deteriorating the soot–NOx trade-off.
Belgiorno, GiacomoCentini, Maria PiaPezza, VincenzoCozza, Ivan F.Pesce, Francesco C.Vassallo, AlbertoColombo, GiovanniGallo, AlessandroMirzaeian, MohsenBorg, Jonathan
Vehicle fleet decarbonization is a key objective for the coming years, with electrification representing the primary pathway to achieving the targets set by the European Union. The share of battery electric trucks in new registrations has been gradually increasing especially in light and medium size trucks. The replacement rate of diesel long-haul trucks with zero emission trucks is still low due to challenges posed by added complexity and limitations of battery charging. Depot overnight charging is not sufficient to cover the energy needs of a truck covering large distances and careful planning of the route using public charging infrastructure is crucial for an optimized route minimizing extra costs and range anxiety. The current work aims to develop a methodology to propose the optimal charging locations for a given route of a battery electric truck based on nearby stations along the route. Our study uses an open-source optimization algorithm for the fixed route vehicle charging problem coupled with a powertrain simulation model that is used to calculate the energy consumption and the electric range of the vehicles. A variety of constraints, such as initial State of Charge, lowest allowed State of Charge threshold, maximum trip duration, distance deviation, have been implemented in different scenarios from real world locations with a goal to investigate the impact of planning constraints and charging infrastructure in the optimal planning of electric truck routing. The results of our analysis indicate that the integration of an accurate energy consumption calculation model to a route and charging optimisation algorithm can be proven beneficial for minimizing the time penalty due to charging.
Perdikopoulos, MichailDoulgeris, StylianosLivitsanos, GeorgiosKazakis, ThomasMellios, GiorgosNtziachristos, Leonidas
This study focuses on the engineering application and performance evaluation of shipboard carbon capture systems. A process combining amine absorption and membrane separation was constructed, and the combined process was applied to a typical 7000 TEU container ship. After sea trials, the average carbon dioxide capture efficiency achieved by the system exceeded 87%, and the power consumption was maintained within an acceptable range. The integrated system greatly improved the EEXI and CII index levels and verified its economic feasibility in the medium and high carbon price scenario. The payback period of the investment costs was reduced to five years. After port coordination tests, the operability of ship-shore carbon dioxide transfer was verified, which promoted future scalability. The engineering layout, energy recovery design, and operation data worked together to provide a practical solution for maritime decarbonization. This study provides a valuable technical reference for the implementation of the International Maritime Organization (IMO) carbon reduction strategy, and also lays a solid foundation for subsequent legislation and system standardization.
Yang, Yongjian
In the context of the global active response to climate change and the strong advocacy of green development, China’s energy industry is demonstrating a steadfast commitment to low-carbon transformation. In this process, green power trading has gained significant development by virtue of its unique advantages and potential. In this process, green power trading has gained significant development by virtue of its unique advantages and potential. The core objective of the Pinglu Canal Project, a pivotal initiative promoting green and low-carbon development in the region, is to establish a “net-zero carbon” initiative by facilitating the supply of green energy throughout its entire life cycle. This initiative is designed to promote a green and low-carbon transition. This paper conducts an in-depth study on the green power supply path during the construction period of the Pinglu Canal project, and proposes four practicable options. In order to scientifically and objectively determine the optimal path, this paper constructs a comprehensive evaluation index system and a TOPSIS evaluation method based on comprehensive weights. The system encompasses the four dimensions of feasibility, economy, technology, and demonstration, enabling a comprehensive and precise evaluation of the advantages and disadvantages of each path. The findings of the empirical analysis demonstrate that the combined scores of Path 1 (participation in green power trading), Path 2 (purchase of thermal power with green certificates), Path 3 (rooftop distributed photovoltaic system and purchase of new energy power), and Path 4 (rooftop distributed PV system and purchase of thermal power with green certificates) are 0.8166, 0.7486, 0.2197, and 0.2885, respectively. The comparative analysis reveals that participation in green power trading is the optimal strategy for the project’s construction period.
Huang, ZeyiWei, YuchenLi, XiayangWang, Cuixian
The decarbonization of heavy-duty trucks (HDTs) is a crucial path for China to achieve its “dual-carbon” goals and transition to decarbonized freight transport. Zero-carbon fuels are key alternatives to fossil fuels for these high-emission vehicles. This study develops an integrated scenario analysis framework to quantify the theoretical CO₂e emission trajectories of China’s long-haul HDT fleet from 2020 to 2060. Functioning as a macro-level stress test, the model derives theoretical equivalent stock from anticipated logistics turnover demand, integrating them with well-to-wheel (WTW) emission factors under six distinct policy stringencies (Projects 1 through 6), representing varying paces of fossil fuel vehicle phase-out. The results demonstrate that policy stringency primarily governs the timing and depth of emission reductions, while fuel technology defines the minimum achievable emission level. Three-dimensional visualization analysis reveals a nonlinear “emission cliff” under aggressive policies, marked by accelerated HDT fleet renewal and exponentially growing mitigation benefits. This cliff is more pronounced for the green hydrogen pathway and demonstrates its superior potential for deep decarbonization. In Project 1, CO₂e emissions reach a mid-term peak in 2035. Compared to the diesel baseline, the green hydrogen and green ammonia transition pathways reduce peak CO₂e emissions by 158 and 137 million tons, corresponding to reductions of 10.0% and 8.6%, respectively, under the modeled theoretical boundaries. In contrast, the aggressive Project 6 policy suppresses this peak, triggers the “cliff” effect much earlier, and achieves an extremely low stabilization level by 2040—15 years ahead of Project 1. This study provides a macro-theoretical quantitative decision-support tool for policymakers. It demonstrates that transparent and aggressive phase-out policies are essential to accelerate fleet turnover, trigger the “emission cliff,” and firmly cap total cumulative emissions.
Wu, YunmeiHuang, HuaLi, RuiHe, GuijiaLiu, BoLiu, RuoweiXie, Yongliang
To mitigate global warming, many countries are working toward carbon neutrality. Reducing CO₂ emissions from vehicles requires electrification technologies in hybrid and plug-in hybrid electric vehicles (HEVs, PHEVs) and improving thermal efficiency of internal combustion engines (ICEs). Lean-burn combustion is one approach to improving ICE thermal efficiency. Biofuels and synthetic fuels can also reduce CO₂ emissions in existing vehicles. Ethanol, a bio-derived fuel, is widely used in varying contents worldwide, and its further utilization is anticipated. This study examines the effects of ethanol blending on emissions, thermal efficiency, knocking, and combustion speed in a super-lean-burn engine. Gasoline surrogates with varying ethanol contents were tested at an excess air ratio (λ) of 2.5. Higher ethanol content reduced nitrogen oxides (NOx) emissions due to lower adiabatic flame temperature. Total hydrocarbon (THC) emissions measured by a Flame Ionization Detector (FID) showed a decreasing trend; however, after correction for low sensitivity to ethanol and aldehydes, no significant differences were observed. Thermal efficiency increased with ethanol content, due to reduced cooling losses. Knocking was mitigated by the higher Research Octane Number (RON) from ethanol blending; however, the extent was smaller than in the production engine operating at λ = 1. This mechanism was examined through ignition delay calculations. At λ = 2.5 and in-cylinder pressures above 9 MPa, the 50–90% combustion duration was prolonged, attributable to suppressed ethyl radical formation under lean conditions and a greater influence of the reaction in which methyl radicals consume hydrogen atoms to produce methane under high-pressure conditions.
Sugata, KenjiMatsubara, NaoyoshiYamada, RyotaKitano, Koji
As part of the decarbonisation process for passenger car fleet in Austria, battery electric cars in particular have been subsidised in recent years, as these vehicles are considered to be largely emission free during use and are expected to reduce emissions in future. However, in order to sustainably reduce the global greenhouse gas emissions of Austrian passenger car traffic, taking into account all types of fuel systems, it is necessary to apply a cradle-to-grave approach, as is commonly done in comparable analyses in the literature, which evaluates the emissions of the entire vehicle life cycle. The most important phase in the life cycle assessment remains the well-to-wheel phase, which includes emissions from energy supply and vehicle use. Due to the large number of influencing factors, highly simplified models are usually used for this phase in the literature. As part of this work, a methodology was developed that, allows an in-depth analysis of entire vehicle fleets by linking real vehicle movements with emissions data and energy consumption. By using real vehicle movements, environmental conditions (ambient temperature, etc.) and traffic situations (traffic jams, etc.) can be integrated into the emissions assessment. To capture the influencing factors more realistically, the assessment is performed at hourly rather than annual time intervals, unlike most previous studies. This new approach provides therefore a more detailed and realistic cradle-to-grave analysis of the Austrian passenger car fleet, making it possible to test individual measures in future scenarios and to define a coordinated strategy for minimizing the fleet’s future global greenhouse gas emissions.
Lischka, GregorTober, Werner
Electric vehicle (EV) battery life cycle assessment (LCA) is emerging as a strategic necessity amid booming demand and tightening environmental regulations. This report consolidates key findings and recommendations for EBRR (Electric Battery Reuse & Recycling) to implement a comprehensive LCA program covering EV lithium-ion batteries from cradle-to-grave and cradle-to-cradle perspectives. The study confirms that global Li-ion battery demand is skyrocketing – projected to increase 14-fold by 2030[1] – amplifying the urgency for sustainable battery management (see Figure 1). It outlines the full life cycle stages of EV batteries (raw material extraction, manufacturing, use, and end-of-life) and compares linear vs. circular approaches. Using the ISO 14040/44 framework[18, 19] and industry-standard LCA tools, the report evaluates environmental impacts and identifies hotspots. Key findings show that mining and manufacturing dominate the battery’s carbon footprint, but end-of-life strategies can reduce lifecycle emissions by 30–40% through hydrometallurgical recycling, renewable energy integration, and second-life battery reuse. The implementation plan details a phased approach: team setup and training, inventory data collection (3–6 months), impact assessment, interpretation, and integration into EBRR’s corporate strategy. Technical challenges – data uncertainty, regional energy variability, scaling new recycling tech, and regulatory compliance – are addressed with mitigation tactics like sensitivity analysis and scenario modeling. Finally, the roadmap recommends actionable steps: transitioning from pyrometallurgy to cleaner hydrometallurgy (cutting recycling greenhouse gas (GHG) emissions nearly in half [3]), powering battery manufacturing with renewables (potentially halving production emissions[4]), designing for disassembly and second-life reuse (extending battery life and reducing need for new materials[5, 6]), and proactive policy engagement. Implementing this LCA-driven strategy will position EBRR as a frontrunner in responsible battery stewardship, achieving verified reductions in environmental impact (~30–40% GHG reduction) while meeting or exceeding emerging global regulations such as the EU Battery Regulation 2023/1542[53]and various Extended Producer Responsibility laws. This not only mitigates environmental and social risks but also enhances long-term profitability and resilience for EBRR in the fast-evolving EV industry.
Asokan, GayathriRaju cEng, RajkumarDhananjaya, ChandanSattigeri cEng, Sudhir V
In a developing country like India, the growing energy demand across all sectors underscores the urgent need for clean, sustainable, and efficient energy alternatives. Hydrogen stands out as a promising fuel, offering virtually zero emissions and helping to reduce greenhouse gas (GHG) emissions, which directly contributes to mitigating global warming, ensuring a cleaner environment, and lowering dependency on fossil fuels. In line with Sustainable Development Goal 7 (SDG 7), which seeks to guarantee that everyone has access to modern, cheap, and sustainable energy, hydrogen is well-positioned to be a major player in India's energy transformation. However, hydrogen has unique properties such as its wide flammability range, high reactivity, and high energy content present significant challenges in terms of safety, particularly in its storage, transportation, and usage. Improper handling or inadequate safety measures can lead to hazardous incidents, making robust testing, certification, and infrastructure development is vital for its safe deployment. Technology for hydrogen detection is essential for maintaining safety and adhering to legal standards. However, detecting hydrogen leaks poses significant challenges due to its unique physical properties: colourless, odourless, and tasteless, no smoke or visible trail, low density and high buoyancy etc. This paper reviews the current literature on hydrogen safety, with a focus on detection technologies, leakage prevention, and key considerations essential for the safe application of hydrogen in accordance with regulatory requirements. The paper discusses various sensor technologies and their underlying detection principles, including Catalytic, Resistance, Thermal conduction, Electrochemical, Work Function, Mechanical, Optical, Acoustic etc. Each sensor type is assessed for sensitivity, response time, selectivity, detection range, and suitability for different applications. This review aims to support researchers, industry stakeholders, and policymakers in identifying effective detection solutions and enhancing hydrogen safety frameworks for widespread adoption.
Pawar, YuvrajDekate, Ajay DinkarThipse, SBelavadi Venkataramaiah, Shamsundara
The rising importance of sustainability in the automotive sector has led to increased interest in circular and environmentally responsible materials, particularly for plastic trims parts, both interior and exterior. This study focuses on developing textile solutions using recycled polyethylene terephthalate (r-PET) sourced from post-consumer plastic waste, along with bio-based fibres such as bamboo. These materials made into woven and knitted fabrics are studied to suit different vehicle interior applications. r-PET textiles show promising strength, aesthetic appeal, and durability performance. Bamboo fabrics are known for their natural antimicrobial properties and enhanced breathability. Extensive testing is performed to validate explored sustainable materials performance against key automotive requirements. With this study, we gain an understanding of the performance of variedly sourced sustainable raw materials for automotive specific textile applications by different manufacturing methods.
Deshpande, SanjanaBorgaonkar, Subodh
This paper compares carbon dioxide, carbon monoxide, methane, and oxides of nitrogen emissions from medium and heavy-duty buses using diesel, diesel-hybrid, and CNG powertrains. Comparisons are made using results from chassis dynamometer-based tests with driving cycles intended to simulate a wide range of operating conditions. Tail pipe emissions are measured by diluting the vehicle’s exhaust in a full-scale dilution tunnel by mixing with conditioned air. Samples are drawn through probes of raw exhaust, diluted exhaust and measured using laboratory grade emission analyzers. Fuel consumption of diesel is measured using a weighing scale, while a gas flow meter is used for measuring CNG consumption. Experimental data from 19 buses tested on a chassis dynamometer over the last 8 years has been analyzed and a comparison of results from similar buses with the differently fueled powertrains is presented. Based on these test results, it is shown that replacing diesel engines with CNG engines does not significantly reduce the emissions of carbon dioxide, while it increases carbon monoxide and methane emissions, reduces oxides of nitrogen emissions, and does not substantially help to reduce global warming.
Iyer, Suresh
The aviation sector currently accounts for 2-3% of global Greenhouse Gas (GHG) emissions, while the projected increased air travel demand (average 3.4% per year), might surge the aviation fuel use. This increase in jet fuel demand, associated with the current decarbonization pathway of other sectors might increase the aviation’s absolute emissions, as well as its relative global GHG share. This scenario has driven the aviation stakeholders into a decarbonization strategy, focused on an immediate and gradual GHG reduction effort associated with a net-zero commitment by 2050. Meanwhile, the aviation sector is known as one that set most difficulties to use alternative fuels and/or powertrains, such as battery electric or sustainable hydrogen fueled propulsion systems, already used on some road and rail applications, but still restricted to the aviation, due to the inherent weight and volume tight requirements. In this context, the sustainable aviation fuels (SAF) are set as the most promising short and medium term aviation decarbonization tool, due to their drop-in feature, which ultimately allows its use on the current aircraft fleet, as well as the fuel storage and distribution systems, provided the certified blends. The prominent SAF role brings increasing demand volumes in the foreseeable future. However, the SAF scaling process from the current 0.1% share of the global jet fuel market faces an array of challenges (technical, regulatory – including the sustainability associated with the feedstocks and the production pathways and economic), requiring collective efforts to boost the technology deployment, address demand reliability and set an efficient regulatory frameworks. Different regulatory approaches have been proposed, with the so called mandates, adopted, for instance, in the European Union and to be adopted in Brazil (from 2027), to encourage investments for SAF production, while the United States (U.S.), the larger jet fuel market in the world, has adopted the use of incentives, to foster the SAF production capacity. This work presents, in a review format, a chronological timeline of the challenges associated with the implementation and scale use of SAF. It highlights the technical, regulatory and economic topics associated with the aviation’s net zero commitment, as well as sets the required roles of the associated stakeholders to make SAF a feasible alternative.
Barbosa, Fábio Coelho
Lithium-ion batteries (LIBs) have consolidated their place in the technology market for the energetic transition, with global manufacturing capacity exceeding 1 TWh in recent years and costs falling in this competitive environment. At the same time, the number of end-of-life LIBs is increasing, stimulating the recycling industry to process battery streams, thus promoting the circular economy to meet the increased demand for strategic raw materials and decarbonization. Vehicle electrification is the main driver of battery production, but their end-of-life will take some time to be significant in volume in the next years. Consumer electronics such as smartphones, laptops and power tools are now available at an appropriate volume enabling the preparation of recycling industry for the moment. In this scenario, recyclers are looking for sustainable routes to absorb all these streams and the different LIBs chemistries (LFP, NCA, NMC, LCO, LMO) to recover the critical metals (Ni, Co, Cu, Mn and Li). Faced with these problems, Tupy in an Embrapii project with Tecnogreen LAREX at USP has developed a recycling route for EV batteries that extends its feed to electronic batteries in a flexible hydrometallurgical process. This work presents the results of this process, which includes the semi-pilot scale of 20kg LIBs obtained from electronics. Critical metals recovery efficiency was 71% of cell weight, leading for 83% of Co, 93% of Cu, 86% of Ni and 89% of Li. Such initial results exceed the Cu, Ni and Li efficiencies required by the European Union at the end of 2027.
Gobo, Luciana AssisFerrarese, AndreOliveira, Rafael Piumatti deMartins, Thamiris Auxiliadora GonçalvesGuillen, Daniela RomeroSilva Vasconcelos, David daTenório, Jorge Alberto Soares
The road transport mode is predominant in Brazil, representing more than 50% of greenhouse gas (GHG) emissions from energy sector [1]. Currently, trucks use internal compression combustion engine (ICCE) with fuel Diesel as propulsion, considering the reference for technical and economic studies for alternative propulsions such as: electrification or hydrogen (H2) as fuel. Both technologies are extremely important to achieve the goals defined by Brazilian nationally determined contribution (NDC) (commitment to Paris agreement target) to avoid climate changes catastrophic issues due climate temperature risk to exceed 2°C. In addition, several companies have announced sustainability compromises to contribute with reduction of GHG emissions in scopes 1,2 and 3, focusing on Environmental, Social and governance (ESG), where road transportation has a larger contribution to achieving the target. Contran Resolution (CR) n° 882/2021 defines the maximum weights and dimensions of vehicles to be authorized to circulate in Brazilian roads. A major challenge is the eligibility of the system to be installed, as well as the layout arrangement in the vehicle. In the context, during the concept phase, it is necessary to evaluate the load distribution on the axles, maximum weights and maximum dimensions of the vehicle complying with the legal requirements. Legal requirements modifying has been started in some countries, for example Chile where recently had public a resolution n° 181/2025 allowing to increase 350 kilograms (kg) in a single front axle, probably part of new policies to make feasible alternatives propulsions to reduce GHG emissions. The proposal of this work will evaluate the impact of load distribution through the assessment of possible layouts for purely electric propulsion or hydrogen fuel propulsion using software as tool, searching for greater agility in concept evaluation. The challenge is to create a model where it is possible to modify the gravity of center (CoG) along the vehicle considering curb weight, implementation, gross weight and payload, checking if it possible to follow the same premises of ICCE and current CR without miss customer by criteria. The results show the impact of reduced payload by 15-34% due to mass added in vehicle for zero emission vehicle (ZEV) using alternative propulsion (electric and hydrogen) in all scenarios simulated, considering the same dimensions of ICCE complying with CR. As conclusion, has been observe challenges for truck decarbonization due to payload reduction, generating direct impacts in customers due the possible total cost operation (TCO) increase. In additional this work can contribute to new decarbonization mobile polices discussion in the future (technical or compensation rules), where the tool used can contribute to build Fastly many different scenarios for decision. As recommendation, the CR updated n°1015/24 does not comply all decarbonization truck scenarios and will need be discussed how reduce the impact for ZEV concepts, resulting in CR updates to make the plan feasible for the truck decarbonization,
Ferreira, Bruno FranciscoOliveira Da Silva, Laura de
This study presents a comparative Life Cycle Assessment (LCA) of urban buses powered by Diesel S10 with three fuel blends: B7 (7% biodiesel), B15 (15% biodiesel), and B100 (100% biodiesel). Employing a well-to-wheel approach, the analysis covers the extraction, production, distribution, and use of the fuels, as well as vehicle manufacturing and maintenance. The environmental impacts were quantified using the CML-IA and ReCiPe 2016 (Midpoint and Endpoint) methods. Results indicate that B100 significantly reduces Global Warming Potential, yet exhibits higher impacts in eutrophication, abiotic depletion, and ecotoxicity. Sensitivity analysis regarding vehicle occupancy revealed greater variability for B100. In conclusion, the optimal fuel choice depends on the prioritization of specific impact categories, providing insights for sustainable transportation policies.
Cavaliero, Carla Kazue NakaoBarboza, Franciele AlvesSeabra, Joaquim Eugênio AbelFerreira, Marcela CravoCarpoviki, Renan SiqueiraCruz, Robson Ferreira
Whether it’s the meeting room of an office building, the exhibition room of a museum or the waiting area of a government office, many people gather in such places, and quickly the air becomes thick. This is partly due to the increased humidity. Ventilation systems are commonly used in office and administrative buildings to dehumidify rooms and ensure a comfortable atmosphere. Mechanical dehumidification works reliably, but it costs energy and — depending on the electricity used — has a negative climate impact.
The path toward carbon-neutral mobility represents one of the greatest cultural transformations in recent human history. Positioned between industrial heritage, emerging mobility technologies, and the energy supply sector are the users of 1.5 billion motor vehicles worldwide. Conflicting publications on raw material availability, energy efficiency, and the climate neutrality of propulsion systems have led to widespread uncertainty. This Illustrated Energy Primer provides a new foundation for orientation. It begins with a visual explanation of the basic concepts of energy and power, followed by illustrative comparisons of typical energy demands in vehicles and households. The focus then shifts to common types of energy generation systems. Using regional examples—from coal-fired power plants to wind farms, solar installations, and balcony solar panels—the guide provides clear and accessible performance benchmarks for energy production. Next, nine individual experience profiles highlight how people across different life stages manage their vehicles responsibly and resource-efficiently. These range from a 16-year-old driver of a light electric vehicle, to a 55-year-old electric sport utility vehicle (SUV) user, to a 91-year-old woman using an electric mobility aid limited to walking speed. A broad range of drive technologies is covered in the Energy Primer, including comparisons with alternatives such as electric microcars, pedal-assist electric bicycles (pedelecs), and walking. Each user narrative outlines annual personal financial savings as well as the potential reduction in CO₂ emissions. These individual results are also scaled up to reflect the commuter mobility patterns of the Federal Republic of Germany (BRD). In this way, the Energy Primer builds a bridge between technical experts and everyday users. It aims to strengthen awareness of the value of energy in mobility and to encourage deeper engagement with the sometimes complex calculations behind energy balances. This is the first time such a compact and illustrated educational resource on energy and mobility is made freely available.
Daberkow, Andreas
As global air traffic is expected to increase significantly in the coming decades, reducing the associated climate impact requires scalable solutions. While alternative propulsion technologies such as electric and hybrid-electric systems might offer long-term potential, their current applicability remains limited due to low energy density, limited range and scalability, and system complexity. Consequently, thermodynamic propulsion systems – such as gas turbines and piston engines – are expected to remain dominant in the medium term. In this context, sustainable hydrocarbon-based aviation fuels represent a practical and necessary solution. Certified sustainable aviation fuel (SAF) pathways are currently approved exclusively for use in gas turbines, with certification standards tailored to turbine-specific requirements. Consequently, fuel properties such as cetane number and evaporation behavior are not included in existing specifications. However, when SAF-kerosene blends are used in compression ignition engines, the impact of these properties on ignition quality, combustion behavior, and emissions must be specifically evaluated. For this purpose, a flight test campaign was conducted using a fully instrumented Diamond DA42 aircraft, configured as a flying laboratory and equipped with serial-production piston engines. Two synthetic fuel variants were evaluated: one certified according to ASTM D7566-23a Annex A2 (HEFA SPK) and a second, Tall Oil derived fuel with a distinctly different molecular composition – characterized by an increased content of cycloparaffins and low aromatics content. The aircraft as a flying air lab was equipped with special engine measurement technology including high-pressure in-cylinder indication to analyze the impact of these differing fuel compositions on engine efficiency and combustion characteristics, including ignition delay and peak pressure. Furthermore, a mobile emission and particle number measurement system enabled the assessment of environmental performance under real flight conditions. Both fuels demonstrated significant reductions in thermal NOx formation due to their low aromatics content. However, no clear benefit was observed in total particle number (PN), likely due to a shift in the particle size distribution towards the nanoparticle regime.
Kleissner, FlorianHofmann, PeterVogd, PhilippVauhkonen, VilleKäkölä, JaanaGreve, Alina
Letter from the Guest Editors
He, XinBelgiorno, GiacomoJoshi, Ameya
Amid escalating global warming challenges, the aviation industry must adopt low-carbon and green practices. China, aiming to meet its dual carbon goals, urgently requires enhanced research and development in sustainable aviation fuels (SAF), including their sustainability certification. However, China’s regulatory framework and limited research foundation in biofuels exacerbate this endeavor. This article summarizes the development status of SAF sustainability certification internationally and within China, encompassing the indicator framework, full life cycle greenhouse gas (GHG) calculation methodologies, and emission reduction thresholds. It also highlights issues encountered in the application of current international sustainability certification systems in China, such as high certification costs and inadequate data security. Advancement in domestic sustainability certification in China faces obstacles related to the incomplete foundational database, despite possessing life cycle assessment (LCA) calculation capabilities. To address these challenges, it is imperative to expedite the development of SAF certification systems, research in big data tracking systems, and establish targeted international mutual recognition data tracking platforms. Furthermore, enhancing GHG reduction thresholds in SAF sustainability certification is crucial. These steps will expedite SAF adoption in China, significantly contributing to global decarbonization efforts.
Zhang, ShupingHe, YinJia, QuanxingJia, QinTao, ZanMiao, JiaheShi, YaoZhang, XiangpingWang, Siyu
In the recent years, the urgency to decarbonize the mobility sector has highlighted the importance of the electrochemical hydrogen use in fuel cells to complement the battery-based electrification. Hydrogen is the greenest energy carrier, and low-temperature Polymer Electrolyte Membrane Fuel Cells (PEMFCs) are part of an ever-evolving scenario, with particularly promising use in high energy demand sectors. Hydrogen is the main player in decarbonisation scenarios, but there are many issues, including its production and storage. There are many categories of hydrogen; in these applications, the finest category of hydrogen, called green hydrogen, is required. To achieve completely green vehicle mobility, enormous technological advances are necessary. This paper presents a 3D-CFD study to analyse the behaviour of PEMFCs by examining the role of humidification, covering fully humidified (anode and cathode), anode-only, cathode-only, and fully dry operations. This is simulated for several membrane thicknesses, reproducing a wide matrix of operating conditions and separator choices, and examining their respective effect on the cell’s resistance. The obtained results confirm that the fully dry operation results in a significant increase in cell’s internal resistance, as well as the opposite is verified for fully humidified operation. However, maintaining an external anode-only humidification and relying on the internal self-humidification can be a highly effective strategy, allowing to reduce the complexity of the balance of plant by simplifying the humidifiers sub-system. This is analysed in conjunction with the effect of the electrolyte thickness, which opens to the possibility to enhance or even suppress self-humidification and water transport. Conclusions provide an overview of the design and operating choices to minimize the cell’s resistance at a minimum system complexity cost.
Scialpi, LeonardoD'Adamo, AlessandroMarra, Carmine
SAE TOMORROW TODAY - SAE J3341: Driving Sustainability Through Smarter Life Cycle Assessments1354010/24/2025
From pinpointing greenhouse gas (GHG) hot spots to modeling decarbonization scenarios, life cycle assessments (LCAs) can be a powerful tool for sustainability. However, a lack of standardized methodologies across the automotive industry makes progress difficult. That's where the SAE J3341 Task Force comes in. It's a cross-industry initiative uniting automakers, government, and academia to establish a more flexible yet transparent framework on carbon footprint reporting methodologies for passenger vehicles through smarter LCAs. To learn more, we sat down with Laurel Nelson, Chair of the SAE J3341 Task Force, and Staff Engineer of Sustainability Science at Rivian Automotive. She discusses how the task force is implementing a "disclosure addendum" approach that encourages OEMs to clearly communicate their assumptions and data for more accurate and meaningful carbon reporting. If you are interested in taking part in the SAE J3341 Task Force, please reach out to Laurel directly at laurelnelson@rivian.com or Dante Rahdar at dante.rahdar@sae.org. We'd love to hear from you. Share your comments, questions and ideas for future topics and guests to podcast@sae.org. Don't forget to take a moment to follow SAE Tomorrow Today--a podcast where we discuss emerging technology and trends in mobility with the leaders, innovators and strategists making it all happen--and give us a review on your preferred podcasting platform. Follow SAE on LinkedIn, Instagram, Facebook, Twitter, and YouTube.
Patterson, Lori
The nvPM Mission Emissions Estimation Methodology (MEEM) was previously developed to estimate nonvolatile particulate matter (nvPM) emissions from ground certification data using the publicly available data from the International Civil Aviation Organization (ICAO) Aircraft Engine Emissions Databank (EEDB). In order to potentially improve the accuracy of nvPM emissions estimation and to enhance its usefulness to modelers, the method was revised to make use of fuel flow correlations and similar altitude corrections as used in the Boeing Fuel Flow Method 2 (BFFM2). The new fuel flow approach allows for improved trade-off-type assessments between nvPM and gaseous emissions—i.e., less relative uncertainties when assessing results from the two methods. Like the former MEEM, the new method, MEEM2, can be used with just publicly available data such as nvPM emissions indices (EI) from the EEDB as well as predicted fuel flows from publicly available aircraft performance models. MEEM2 has been validated against proprietary original equipment manufacturer (OEM) data and methods, helping to understand prediction uncertainties of nvPM emissions, thus supporting environmental impact assessments, including those related to climate impacts from commercial aviation’s non-CO2 components as well as the use of sustainable aviation fuels (SAF).
Ahrens, DeniseKim, BrianMéry, YoannZelina, JosephDudebout, RudolphMiake-Lye, Richard C.
Faced with one of the greatest challenges of humanity – climate change – the European Union has set out a strategy to achieve climate neutrality by 2050 as part of the European Green Deal. Life Cycle Assessment (LCA), which among other aspects identifies climate change effects, is an important tool to assess the environmental characteristic of sustainable technologies or products to fulfill this ambitious target. In this context, research is presented that examines the ecological sustainability impacts of a metallic vs a composite bipolar plate made of innovative graphite-compound based foils for fuel cell applications. A bipolar plate is a central component of the fuel cell stack to ensure efficiency and durability. For this purpose, a LCA is performed for both bipolar plate materials. This assessment follows the methodology of DIN EN ISO 14040/44 and the EU Product Environmental Footprint framework. Focusing on cradle-to-gate system boundary conditions, the research emphasizes the manufacturing processes with the relevant material and energy flows. Dealing with uncertainties in the energy supply chain, a comprehensive sensitivity analysis is conducted defining current and future energy scenarios with various shares of renewable and fossil energy carriers. Furthermore, the impact of different material production locations on the outcome of the LCA is investigated, considering changing geopolitical conditions. To assess also the effect on a fuel cell stack, the study continues with a cradle-to-gate evaluation of the fuel cell system. Afterwards, to also consider the complete lifetime of a fuel cell vehicle, the study is extended to cradle-to-grave system boundary conditions for a C-segment SUV. Besides the evaluation of the global warming reduction potential, the study deals with the impact of the production processes of both bipolar plates on other impact categories like freshwater eutrophication or acidification. The investigations have shown that the use of foil-based graphite-compound bipolar plates can reduce the global warming potential by up to 75% compared to conventional steel bipolar plates.
van Sloun, AndreasSchroeder, BenediktKexel, JannikSchmitz, MaximilianBalazs, AndreasWalters, MariusKoßler, SilasPischinger, StefanJoemann, Michael
Replacing fossil fuels with renewable ammonia could provide a crucial step towards the decarbonisation of transport sectors. However, many challenges remain in utilising ammonia within combustion systems: the volumetric energy density of ammonia is significantly lower than that of gasoline, exposure to ammonia (including ammonia slip) can be detrimental to human health, and the production of emissions, including unregulated emissions (such as N2O), from ammonia combustion can be catastrophic for the environment if not treated appropriately. Therefore, there is a need to determine the efficacy of ammonia as a fuel for internal combustion engines and the impact on the efficiency of energy release and the resulting exhaust emissions. A modern spark ignition engine was modified such that ammonia was aspirated through the engine intake air to incrementally displace engine gasoline and maintain a constant work output. It was found that displacing the fuel energy supplied by direct injected gasoline with premixed ammonia by 10% to 40% on an engine work performed basis decreased the peak HRR (heat release rate) and delayed combustion. Spark timing was also advanced to up to 20 CAD BTDC (crank angle degrees before top dead centre) for fuel blends incorporating up to 40% ammonia to allow for optimal conversion of chemical energy to useful work. The corresponding exhaust emissions analysis showed a linear decrease in CO2, however, an exponential decrease in CO as the proportion of ammonia increased. Additionally observed was an initial increase in unburnt hydrocarbons followed by a decrease as peak HRR decreased. However, a clear effect of ammonia level on NOx emissions was not apparent.
Sivaranjitham, Annaniya MitchellHellier, PaulLadommatos, NicosMillington, PaulAlcove Clave, Silvia
Ammonia is a potential vector of renewably produced hydrogen for combustion systems and decarbonisation of transport. However, anhydrous ammonia has health risks and difficult to handle due to its volatility and toxicity. Therefore, a water-based solution of ammonium hydroxide (NH4OH) was proposed to investigate the potential use as a fuel in a compression-ignition engine. Ammonium hydroxide, also referred to as aqueous ammonia, is liquid phase under atmospheric conditions and, therefore, the storage of such a fuel does not require high pressure. Previous work has established that ammonium hydroxide solution could contribute to energy release during co-combustion with fossil diesel. However, the presence of water reduced combustion stability and limited the extent to which aqueous ammonia could displace diesel. In addition, the characteristics of co-combustion and pollutant emissions of burning such a fuel remain less understood. This study therefore explores the potential of using ignition improving additives for ammonium hydroxide and diesel dual-fuel co-combustion in a diesel engine. Two chemical additives, hydrogen peroxide and ammonium nitrate, were selected to blend with ammonium hydroxide at varied concentrations. The solution was aspirated into the engine via port injection into the preheated air intake, while diesel was supplied via direct injection at 500 bar. Tests were undertaken at constant engine indicated mean effective pressure (IMEP) but with varying levels of displacement of diesel fuel by aspirated aqueous ammonia. Measurements were made of combustion characteristics and both particulate and gaseous emissions in the exhaust. The addition of hydrogen peroxide reduced the duration of ignition delay relative to aqueous ammonia and diesel only co-combustion, especially at higher additive concentrations of 1% and greater. Furthermore, the presence of both ignition improvers saw an equivalent energy release from aqueous ammonia achieved with reduced injection duration and a higher proportional contribution to overall engine load. The aqueous ammonia and diesel dual-fuel co-combustion resulted in a general increase in both particulate mass and number. This trend was especially noticeable with 0.5% ammonium nitrate added to the fuel, where the number of particles was 122% greater than diesel only combustion and particle diameter mainly ranged between 10-50 nm. Meanwhile, despite an increase in fuel-bound nitrogen with the use of ammonia, exhaust emissions of nitrogen oxides did not linearly increase, and both ignition improvers reduced nitrogen oxides relative to ammonia and diesel co-combustion without additives.
Han, YanlinHellier, PaulSchonborn, AlessandroLadommatos, Nicos
Lin, RuiAdas, Camilo Abduch
Muelaner, Jody EmlynMoran, MatthewPhillips, Paul
To achieve carbon neutrality, manufacturers need to estimate Greenhouse Gas (GHG) emissions generated throughout the life cycle of motorcycles, namely the Carbon Footprint of Product (CFP). We developed a method that allows calculation of the per-unit CFP and the total CFP of sales volume of motorcycles with a common formula, and also enables the estimation of their future values. First, we made it possible to calculate the per-unit CFP of each individual model by setting factors that we quantified the characteristics of motorcycles such as material composition and replacement parts and incorporating them into the calculation formula. Next, we enabled the calculation of the total CFP of sales volume from the present to the future by standardizing the specs of individual models and calculating the CFP by product category and multiplying the sales volume. Furthermore, we made it possible to simulate future CFP according to scenarios of expansion of environmental protection actions such as the decarbonization of electricity by designating the factors that can change annually and entering any values. Using our method, we simulated the CFP under multiple scenarios. The results of the total CFP of sales volume showed the annual transition of the CFP and the impacts of each environmental protection actions. The results of the per-unit CFP showed that its volume and composition ratio of life cycle stages differ depending on the product, region, and powertrain. With this method established, it is expected that product and technology strategies for more effective CFP reduction can be developed more efficiently.
Mori, YuichiKawatsu, HirotakaYamaguchi, TakumiTanaka, KazuhikoAoki, ToshikiNiimura, Ryuta
The challenges with electrification in the automotive industry have led to rethinking the decisions to ban internal combustion engines. Nonetheless, decarbonization of transportation remains a regulatory priority in many countries, irrespective of the energy source for automotive powertrains. Renewable oxygenated fuel components can help with the rapid decarbonization of gasoline fuels in the current fleet. Ethanol is one of the primary renewable components typically used for blending in gasoline primarily at 10% v/v but up to 20% v/v substitution which corresponds to 3.7 to 8.0% oxygen by mass. However, a range of oxygenates could be used instead of ethanol. This study aimed to determine if the engine could discriminate between different oxygenates in gasoline fuels blended at the same octane (RON) and oxygen levels. Oxygenates such as methyl-tert-butyl-ether (MTBE) and ethyl-tert-butyl-ether (ETBE) were considered in this study. Blends were made using a combination of n-heptane, iso-octane, toluene, and oxygenated components. Seven blends with a nominal RON of 98 +/-2 were evaluated in a single-cylinder engine. Four E10 equivalent and three E20 equivalent fuel blends were studied. The engine was operated at a range of test conditions from throttled, low-load points to boosted, high-load points that required knock retard. The results indicated that all blends had minimal differences in engine performance in terms of knocking behavior, spark timing, burn duration, fuel flow, and injection duration which could all be compensated by the engine control unit (ECU). Particulate matter emissions (AVL micro soot sensor, PN10, PN23) were also evaluated at the test conditions. While the fuels had lower PM-generating components compared to commercial fuels, we could demonstrate that the PM emissions largely correlated with the particulate matter index (PMI) (or the toluene content) of the fuels.
Kalaskar, VickeyMitchell, RobertPourreau, Daniel
In the United States (US), the off-road sector (i.e., agriculture, construction, etc.) contributes to approximately 10% of the country’s transportation greenhouse gas (GHG) emissions, similar to the aviation sector. The off-road sector is extremely diverse; as the EPA MOVES model classifies it into 11 sub-sectors, which include 85 different types of equipment. These equipment types have horsepower ranging from 1 to greater than 3000 and have very different utilization, which makes decarbonization a complex endeavor. To address this, Argonne’s on-road vehicle fleet model, VISION, has been expanded to the off-road sector. The GHG emission factors for several energy carriers (biofuels, electricity, and hydrogen) have been incorporated from Argonne’s GREET model for a sector-wide well-to-wheel (WTW) GHG emissions analysis of the present and future fleet. Several technology adoption and energy decarbonization scenarios were modeled to better understand the appropriate actions required to drive towards net-zero emissions of the off-road sector. Results show that WTW decarbonization up to 67% can be achieved from 2023 to 2050 in a business-as-usual scenario. But with aggressive sales increases of electric and hydrogen powertrains, WTW decarbonization up to 77% can be achieved, which can further increase to 85% if electricity production is aggressively decarbonized by 2035.
Tripathi, ShashwatKolodziej, ChristopherGohlke, DavidBurnham, AndrewZhou, YanLongman, Douglas
Considered as one of the most promising technology pathways for the transport sector to realize the target of “carbon neutral,” fuel cell vehicles have been seriously discussed in terms of its potential for alleviating environmental burden. Focused on cradle-to-gate (CtG) stage, this article evaluates the environmental impacts of fuel cell heavy-duty vehicles of three size classes and three driving ranges to find the critical components and manufacturing processes in the energy context of China. The findings show that the greenhouse gas (GHG) emissions of the investigated fuel cell heavy-duty vehicle range from 47 ton CO2-eq to 162 ton CO2-eq, with the fuel cell system and hydrogen storage system collectively contributing to 37%–56% of the total. Notably, as the driving range increases, the proportion of GHG emissions stemming from fuel cell-related components also rises. Within the fuel cell system, the catalyst layer and bipolar plate are identified as the components with the most significant impacts, accounting for 62.9% and 32.7%, respectively, of the total GHG emissions from a fuel cell stack. The fundamental materials constituting these components namely, platinum, titanium, and carbon black are thus of considerable significance in the emission profile of the fuel cell stack. For the hydrogen storage system, carbon fiber-reinforced polymer (CFRP) layer stands out as the most important component, constituting 98% of the total GHG emissions. It is suggested that GHG emissions from fuel cell systems and hydrogen storage systems can be effectively curtailed by implementing strategies such as grid decarbonization, reducing Pt loading in catalysts, and enhancing fuel cell power density. Additionally, the potential for GHG emissions reduction in fuel cell heavy-duty vehicles can be reinforced through the adoption of lightweight materials and the integration of low-carbon alternatives into the glider components.
Mu, ZhexuanDeng, YunFengBai, FanlongZhao, FuquanLiu, ZongweiHao, HanLiu, Ming
As part of the Nano4 EARTH initiative, a national challenge launched by the White House and the National Nanotechnology Initiative, researchers are exploring how innovations at the nanoscale can lead to groundbreaking solutions for a more sustainable future.
The development of hydrogen economy is an effective way to achieve peak carbon emission and carbon neutralization. Therein, the green production of hydrogen is a prerequisite to reach the goal of decarbonization. As an ideal route, water electrolysis has triggered intense responses under the strong support from policies, which further presenting a phenomenon of water electrolysis equipment manufactures competing to enter the market. However, the extensive growth mode is not conducive to a long term healthy development of the water electrolysis hydrogen production market where products can be sold without requiring compulsory inspection or quality inspection process due to the absence of laws and test & evaluation standards. Considering the market status and technology maturity, the main working principles and characteristics of alkaline water electrolysis (AWE) and proton exchange membrane (PEM) hydrogen production systems are summarized, and the test frameworks of the AWE and PEM hydrogen production systems are mainly introduced. Combining the current technology and market status of water electrolysis system, and referring to the progress of its test & evaluation methods, this study analyzed the test & evaluation methods of the whole product chains from material, single cell, stack, balance of plant (BOP) to the system levels. At the same time, referring to the progresses in the test & evaluation methods, relevant suggestions are given for the establishment of test specifications and standards of water electrolysis hydrogen production system in emerging technology countries. The present study is significant to the improvement of water electrolysis technology and the standardized development.
Jiao, DaokuanWang, XiaobingHao, Dong
With the extensive production and widespread use of plastics, the issue of environmental pollution caused by plastic waste has become increasingly prominent. Consequently, researchers have been focusing on developing efficient methodologies for upcycling waste plastics and converting them into value-added materials. This hybrid review–conceptual article first provides an overview of strategies for upcycling waste plastic into carbon-capturing materials. It presents carbonization and activation as key steps in converting plastic waste into adsorbent materials and explores strategies for converting common waste plastics. Building upon this foundation, the article introduces and conceptualizes a novel upcycling approach with two manufacturing routes to convert plastic waste into carbon-capturing materials using supercritical fluid (ScF)-assisted injection molding process. It continues by investigating the potential of developing lightweight components made of such carbon-capturing materials for transportation and construction applications. Through a combination of review and conceptual exploration, this research demonstrates that the ScF-assisted foaming process can effectively convert plastic waste into materials with enhanced mechanical properties and effective carbon dioxide (CO2) absorption capacity. Successful realization of this concept will be a promising advancement in developing sustainable materials and technologies that can contribute to mitigating the negative effects of both plastic waste and CO2 emission, hence supporting the shift toward sustainable, environment-friendly transportation.
Pirani, MahdiMeiabadi, Mohammad SalehMoradi, MahmoudEnriquez, Lissette GarciaSreenivasan, Sreeprasad T.Farahani, Saeed
A Dartmouth-led research team set out to determine if managing green roof soil microbes could boost healthy urban soil development, a methodology that could be applied to support climate resilience in cities.
In the global scenario marked by the increasing environmental awareness and the necessity on reducing pollutant emission to achieve the decarbonization goals, action plans are being proposed by policy makers to reduce the impact of the climate change, mainly affecting the sectors that most contribute to CO2 emissions such as transportation and power generation. In this sense, by virtue of the National Energy Plan 2050, the Brazilian market will undergo the decommissioning of thermal power plants fueled by diesel and heavy fuel oil (HFO) by 2030, compromising about 6.7 GW of power capacity according to the Brazilian Electricity Regulatory Agency (ANEEL) database. An alternative to the scrapping of these engine power plants is their conversion to operate with fuels with a lower carbon footprint, such as the natural gas. This work, therefore, aims to numerically assess the conversion feasibility of a HFO large bore four-stroke turbocharged engine to operate with natural gas by means of a one-dimensional engine modeling. First, the 1D non-converted engine model operating with HFO is validated with experimental data. Then, the conversion of the HFO engine to natural gas is carried out by adding a wastegate for the air-fuel ratio control, changing the compression ratio and the fuel injection, and introducing the pre-chamber ignition system. At this stage, the performance of the engine operating with most of its stock components is evaluated, including the presence of knock, fuel slip, and components that may not be suitable for NG operation and must be adapted, redesigned, or replaced. After that, modifications on the valve timings are proposed to reduce the methane slip and allows a proper scavenging. In conclusion, this study numerically assessed converting an HFO engine to natural gas, identifying new component specifications and presenting alternatives to maintain engine performance post-conversion.
Gonçalves, Vinícius FernandezZabeu, Clayton BarcelosAntolini, JácsonSalvador, RobertoAlmeida, RogérioValiati, Allan SoaresFilho, Guenther Carlos Krieger
The (commercial) aviation sector (passenger and freight), which is strongly engaged with the world efforts to mitigate the carbon emissions and their inherent climate change effects, has accounted in 2018 for 2.4 % of global carbon dioxide (CO2) emissions (pre-pandemic levels). Despite the reductions in air travel demand during the 2020 pandemic, with a reduction of up to 80% in passenger travel during the peak pandemic period, the air travel demand has already recovered to around 80% of the pre-pandemic level, with aviation emissions in 2022 reaching around 800 Mt CO2, accounting for 2% of the global energy related CO2 emissions. Moreover, the demand for air travel is expected to double by 2040, growing at an annual average rate of 3.4%, which means that. despite the efficiency improvement trend (average 2%/year), will almost double the aviation’s greenhouse (GHG) emissions, with a significant increase in its relative GHG share, compared to the other transport modes. Meanwhile the aviation sector is one of the hardest to decarbonize, with few and costly pathways available. Zero emissions technologies, such hydrogen fuel and electric batteries are currently far from commercially ready for aviation use in the short to medium term, due to the technical challenges, such as aircraft onboard liquid hydrogen storage difficulties, as well as battery weight and volume, and are unlikely ever to be able to power large or long-haul flights. In this scenario, the so called sustainable aviation fuel (SAF), a drop-in fuel concept, already available in modest amounts on a commercial scale, are seen as a promising short to medium term alternative to tackle aviation emissions, by using existing aircraft designs and infrastructure. As a drop-in fuel, the SAF enables the replacement for the fossil jet fuel by using the existing fuel delivery and storage infrastructure and existing aircraft engines, with lifespan that still ranges from 20 to 30 years. From a chemical perspective, the SAF is the liquid aviation fuel derived from non fossil carbon resources, such as biomass or organic derived waste feedstocks, as well as synthetic fuels produced from carbon capture and renewable energy sources. They might be currently used in blends with fossil jet fuel, with current blending limits ranging from 5% to 50%, depending on the feedstock and production pathway. It is estimated from the International Air Transport Association (IATA) that to reach the net zero emission commitment, by 2050, around 65% of emission reductions should be reached by replacing conventional jet fuel with SAF. Despite its important role in the aviation decarbonization, the SAF share currently makes up only 0.1% of aviation fuel demand, which requires a huge increase in the production capacity, which might face challenges, such as feedstock availability, fuel sustainability and cost competitiveness. This work presents a review of the SAF technology, with a focus on the production pathways and their environmental footprint, their use on current aircraft engines and the associated required blends, as well as the challenges associated with SAF production increase and cost reductions, still required to make it a realistic aviation decarbonization tool.
Barbosa, Fábio Coelho
Mobility in Brazil, dominated by road transportation, is responsible for consuming around a third of the energy matrix and for emitting approximately half of the energy-related emissions in the country. Among the alternatives to reduce its greenhouse gas emissions, the use of low-carbon hydrogen has a strong potential for decarbonization and improvement of engine efficiency. Thus, this study experimentally investigated the partial replacement of commercial diesel (with 12% of fatty acids methyl esters (FAME) biodiesel) by hydrogen in a commercial vehicle equipped with a compression-ignition internal combustion engine. To investigate the effects of this substitution on performance and emission profile, the vehicles was adapted for dual-fuel operation and hydrogen was injected together with air into the MB OM 924 LA engine of a Mercedes-Benz Accelo 1016 vehicle. Tests were carried out on a chassis dynamometer with 0%, 2% and 4% slope and at speeds equal to 50, 60 and 70 km/h to simulate various loads. For each of these combinations, commercial diesel was replaced by hydrogen with hydrogen energy share of 0%, 2%, 4%, 6%, 8% and 10%, respectively. The results showed that replacing commercial diesel with hydrogen resulted in a relative reduction of up to 17.6% in CO2 emissions, 13.7% in CO and 25.5% in THC. However, the results of the performance parameters showed no improvement in efficiency under the tested conditions, with a reduction of up to 20.8% in thermal efficiency and an increase of up to 26.3% in specific fuel consumption. In conclusion, with minimal alterations, the results obtained with a commercial vehicle demonstrated the feasibility of hydrogen as a promising alternative fuel for use in compression ignition engines in the current fleet to reduce emissions.
Assis, GuilhermeSánchez, Fernando ZegarraBraga, Sergio LealPradelle, Renata Nohra ChaarSouza Junior, JorgePradelle, FlorianTicona, Epifanio Mamani
The world’s commitment towards the mitigation of climate changes has driven many sectors into an effort to reduce their carbon footprint. The transit bus sector, which currently strongly relies on diesel fueled buses, is challenged to reduce its carbon footprint, as well as to reduce the emission of criteria pollutant and noise, which negatively affect the world cities’ population, especially those living nearby the large transit bus corridors. In this context, the Battery Electric Buses (BEB), has been set as the transit sector’s workhorse for reaching the global, regional and local environmental targets. However, despite the relative maturity level of both the electric powertrain and the energy storage devices (ESD) technologies, the bus electrification transition is a disruptive process, from both a technological, operational and managerial standpoint, which might take into account both the (electrical) infrastructure, as well as the operational customization requirements. Moreover, it requires a strong coordination among the involved stakeholders and their different roles, such as the transit bus and charging equipment manufacturers, transit operators, transit authorities, as well as the electricity providers. This work presents a review of the challenges associated with the electrification of bus transit fleets. It sets the baselines of the electrification transition planning process, as well as the technological and infrastructure requirements and the inherent coordination roles between the stakeholders involved, based on the recent ongoing world’s bus electrification initiatives.
Barbosa, Fábio Coelho
This research paper explores India’s energy landscape, critically analyzing the challenges and potential solutions for sustainable development. With aspirations to become the third largest economy in the world, India faces heightened energy demands fueled by economic growth, population expansion, and urbanisation. The country grapples with a heavy reliance on imported crude oil and a substantial carbon footprint from existing primary energy sources, emphasizing the need for strategic interventions. The research paper advocates a multi-fuel strategy, particularly emphasising the promising role of bioethanol. Key stakeholders in India’s bioethanol ecosystem include farmers, Sugar mills/Grain-based distilleries, Oil Marketing Companies (OMCs), Original Equipment Manufacturers (OEMs) of vehicles, consumers, and the government. The National Policy on Biofuels (NPB) aims to boost bioethanol usage, aligning with national energy security, climate change mitigation, and employment generation objectives. The research underscores the positive energy value of bioethanol produced from sugarcane in India, proposing improvements in farming practices and its solarification. A core team of six Ministries/Departments of the government of India has been implementing the Roadmap for Ethanol Blending in India 2020-25. This paper analyses the progress and success of this roadmap in terms of the sustainability of the domestic supply chain, augmentation of bioethanol production capacity, contribution to achieving Nationally Determined Contributions (NDCs), advancements in vehicle technology to boost bioethanol consumption, and fostering rural economic growth and employment generation. Acknowledging the political sensitivity surrounding sugarcane crops, the report calls for initiatives to diversify feedstocks and enhance the competitiveness of domestically produced ethanol. Bioethanol’s alignment with Sustainable Development Goals, notably SDG-7, underscores its potential to contribute to social, economic, and environmental sustainability in India’s road transport sector.
Singh, Rajnesh
Backed by a consortium of companies, Southwest Research Institute's demonstrator vehicle aims to prove the commercial viability of hydrogen engines for on-road trucks. For decades, the running joke around hydrogen being a viable fuel for commercial trucks has been that it's “ten years away from being ten years away.” Though hydrogen-fueled rigs operating at scale has long seemed like a pipe dream, shifting winds around the globe blowing towards decarbonization have finally pushed this technology to be ready for the road. With the demand for the development of new propulsion technologies rising, organizations such as the Southwest Research Institute (SwRI) have ramped up R&D efforts to make this tech commercially viable. SwRI is an independent provider of research services and can rapidly assemble teams to tackle problems. SwRI's main mission is to push the boundaries of science and technology to develop innovative solutions.
Wolfe, Matt
There is great recognition regarding the importance of hydrogen as an energy route for the decarbonization of road vehicles. Several countries are making large investments to create products, services, and infrastructures that allow hydrogen to be used as a clean source for propulsion, but there are still many open questions. This complete hydrogen chain involves production, transformation, transport, storage, and use. Although many initiatives are seeking global production, the use of low-carbon hydrogen is not yet economically competitive. Therefore, for this industry to establish itself, and acknowledging the characteristics of each region, there needs to be more intense coordination of efforts between the different industrial and political segments. Low-carbon Hydrogen Use Across Economic Sectors and Global Regions establishes premises for the hydrogen economy and its main environmental aspects. It also includes proposals and scenarios to establish a strategy that relates to production, transport, and application with a focus on global integration. Click here to access the full SAE EDGETM Research Report portfolio.
Adas, Camilo Abduch
Sustainable Aviation Fuels (SAFs) offer great promises towards decarbonizing the aviation sector. Due to the high safety standards and global scale of the aviation industry, SAFs pose challenges to aircraft engines and combustion processes, which must be thoroughly understood. Soot emissions from aircrafts play a crucial role, acting as ice nuclei and contributing to the formation of contrail cirrus clouds, which, in turn, may account for a substantial portion of the net radiative climate forcing. This study focuses on utilizing detailed kinetic simulations and soot modeling to investigate soot particle generation in aero-engines operating on SAFs. Differences in soot yield were investigated for different fuel components, including n-alkanes, iso-alkanes, cycloalkanes, and aromatics. A 0-D simulation framework was developed and utilized in conjunction with advanced soot models to predict and assess soot processes under conditions relevant to aero-engine combustion. The simulations, conducted under combustion and inert conditions, revealed that aromatic fuels significantly enhance soot yield, exhibiting accelerated growth toward larger aromatics under both combustion and pyrolysis conditions. The results also highlight the necessity for higher gas temperatures for PAHs to grow, in agreement with pyrolysis experiments indicating soot onset temperatures between 1400 and 1500K. Furthermore, the study assessed the influence of precursors on soot formation, challenging the appropriateness of using C2H2 or mono-aromatics as precursors with the tested soot models. The simulation results indicate that such precursors lead to large errors, advocating for the use of larger PAHs as precursor in these soot models, as suggested by the models’ validation space. Finally, this work also explores the impact of fuel structure on soot formation, contributing to ongoing efforts to replace aromatics with cycloalkanes in jet fuels through examining reference fuel blends representative of petroleum-based jet fuel and cycloalkane-based SAFs. The “SAF” blends result in a reduced soot yield compared to the jet fuel surrogate, underscoring SAFs’ capability to diminish emissions in the aviation industry.
Yi, JunghwaManin, JulienWan, KevinLopez Pintor, DarioNguyen, TuanDempsey, Adam
Critical Mass: The One Thing You Need to Know About Green CarsR-57510/23/2024
In an era where climate change dominates global discourse, Felix Leach and Nick Molden dive deep into the complexity of vehicle emissions in their groundbreaking new book. Building on the insights from Felix's previous work, Racing Toward Zero, this new release confronts the bewildering landscape of automotive pollution with a clear, rigorous approach: what one piece of information can best describe the environmental impact of cars? Our digital age bombards us with information, yet meaningful understanding often eludes us, particularly when it comes to climate issues like road vehicle emissions. As simple solutions to such a complex problem remain elusive, Leach and Molden advocate for a sophisticated, yet accessible perspective. They propose a radical simplification of how we consider the environmental impact of cars and explore the multifaceted impacts of various vehicle powertrains, pushing beyond CO2 emissions to address broader environmental and societal concerns. The authors introduce the Molden-Leach Conjecture, a bold, universal solution that evaluates vehicles through a holistic lens. This conjecture offers a comprehensive framework to assess and regulate environmental impact, aiming to simplify complex choices for consumers and policymakers alike. They propose a new paradigm for taxing vehicles as we move away from fossil gasoline and diesel, enabling policymakers to address pollution and underpin tax revenues simultaneously. In a world where climate action is critical yet convoluted, Leach and Molden's book promises clarity and actionable insight. It's not just about finding answers-it's about finding the right ones. Join the journey to demystify automotive emissions and drive meaningful change. "As a former Secretary of State for the Environment and, later, Industry I welcome this contribution to the most important challenge of our time." Michael Heseltine, former Deputy Prime Minister of the United Kingdom
Leach, FelixMolden, Nick
Since signing the legally binding Paris agreement, fighting climate change has been an increasingly important task worldwide. One of the key energy sectors to emit greenhouse gases is transportation. Therefore, long term strategies all over the world have been set up to reduce on-road combustion emissions. One of the emerging alternative technologies to decarbonize the transportation sector is Mobile Carbon Capture (MCC). MCC refers to the on-board separation of CO2 from vehicle exhaust. To accurately assess this technology, a techno-economic analysis is essential to compare MCC abatement cost to alternative decarbonization technologies such as electric trucks. Adding to the system capital and operational costs, our study includes mass penalty costs, CO2 offloading and transport costs for different transport scenarios. To better relate to a single consumer (driver), the cost can be converted from euro per-tCO2 to euro per-trip or euro per-mile. A sensitivity analysis is then conducted to quantify the impacts of the most sensitive parameters on the overall abatement costs. This study shows that MCC should be explored as a viable climate mitigation option. The novelty of this work comes from the detailed cost categories taken into consideration in the analysis, for a better MCC technology feasibility and impact analysis study. The results show that MCC represents an economically promising solution to decarbonize the heavy-duty sector, through its decreased TCO and MAC values compared to BEVs and FCEVs.
SAAFI, Mohamed AliHamad, Esam
Decarbonization and a continuous reduction in exhaust emissions from combustion engines are key objectives in the further development of modern powertrains. In order to address both aspects, the DE4LoRa research project is developing an innovative hybrid powertrain that is characterized by the highly flexible combination of two electric motors with a monovalent compressed natural gas (CNG) engine. This approach enables highly efficient driving in purely electric, parallel and serial operating modes. The use of synthetic CNG alone leads to a significant reduction in CO2 emissions and thus in the climate impact of the drivetrain. With CNG-powered engines in particular, however, methane and other tailpipe emissions of climate gases and pollutants must also be minimized. This is possible in particular through efficient exhaust gas aftertreatment and an effective operating strategy of the powertrain. This publication presents measurement results that examine the critical aspect of cold starts. The engine is operated with a three-way catalyst with a coating specially tailored to CNG as well as an electrically heated disk and secondary air injection. The powertrain operating strategy makes it possible to preheat the catalyst when the engine is not running, which enables the catalyst to reach higher temperatures prior to the engine start, thus effectively reducing methane slip and other emissions during cold start. The combination of electrical heating power, secondary air mass flow and pre-heating duration are three of the factors in the optimization carried out here. Added to this is an analysis of the most efficient and low-emission engine start using a serial operating mode.
Noone, PatrickHerold, TimBeidl, Christian
With the COP28 decisions the world is thriving for a future net-zero-CO2 society and the and current regulation acts, the energy infrastructure is changing in direction of renewables in energy production. All industry sectors will extend their share of direct or indirect electrification. The question might arise if the build-up of the renewables in energy production is fast enough. Demand and supply might not match in the short- and mid-term. The paper will discuss the roadmaps, directions and legislative boundary parameter in the regenerative energy landscape and their regional differences. National funding on renewables will gain an increasing importance to accelerate the energy transformation. The are often competing in attracting the same know-how on a global scale. In addition the paper includes details about energy conversion, efficiency as well as potential transport scenarios from production to the end consumer. Technologies are compared in respect of their TLR level and maturity for the market application. Furthermore the need for energy buffering on molecule or electron basis, availability and technical options will be evaluated. Finally the paper concludes with scenario calculations considering technology readiness and TCO for production, transport and infrastructure. Comparing all electricity based scenarios including molecules – respectively hydrogen and e-fuel are part of the evaluation.
Rothbart, Martin
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