Transportation in Sustainable Energy Systems

Mitigating CO₂ emissions from long-haul commercial trucking is a major challenge that must be addressed to achieve substantial reductions in greenhouse gas (GHG) emissions from the transportation sector. Extensive recent research and development programs have shown how significant near-term reductions in GHGs from commercial vehicles can be achieved by combining technological advances. This paper reviews progress in technology for engine efficiency improvements, vehicle resistance and drag reductions, and the introduction of hybrid electric powertrains in long-haul trucks. The results of vehicle demonstration projects by major vehicle manufacturers have shown peak brake thermal efficiency of 55% in heavy-duty diesel engines and have demonstrated freight efficiency improvements of 150% relative to a 2009 baseline in North America. These improvements have been achieved by combining multiple incremental improvements in both engine and vehicle technologies. Powertrain electrification through hybridization has been shown to offer some potential reductions in fuel consumption. These potential benefits depend on the vehicle use, the details of the powertrain design, and the duty cycle. To date, most papers have focused on standard drive cycles, leaving a research gap in how hybrid electric powertrains would be designed to minimize fuel consumption over real-world drive cycles, which are essential for a reliable powertrain design. The results of this paper suggest that there is no “one-size-fits-all” solution to reduce the GHGs in long-haul trucking, and a combination of technologies is required to provide an optimum solution for each application. Full article

With the development of the economy, urban road transportation has been continuously improved, and the number of motor vehicles has also increased significantly, leading to serious energy consumption issues. As critical nodes in the urban road transportation network, intersections have become a focal point of research on vehicle energy consumption. To investigate whether traffic signal lights affect fuel consumption and emissions, this study analyzed the operating characteristics, fuel consumption, and emissions of intersections with and without traffic signal lights using real-world vehicle data. The data from the INTERACTION dataset for both signalized intersection VA and unsignalized intersection MA are used in the study, with a time duration of 3200 s. The VT-micro energy consumption and emissions model was applied to calculate and comprehensively analyze the vehicle flow, fuel consumption, and emissions. Additionally, the study compared the fuel consumption and emissions for different driving scenarios, including straight through, left turn, right turn, and U-turn, within a single traffic signal cycle. The results revealed that at signalized intersections, the average fuel consumption per vehicle was 26.54 L/100 km, NO_x emissions were 68.76 g/100 km, and CO₂ emissions were 61.07 g/100 km. In contrast, at unsignalized intersections, the average fuel consumption per vehicle was 46.88 L/100 km, NO_x emissions were 149.26 g/100 km, and CO₂ emissions were 107.16 g/100 km. The study indicated that for traffic volumes between 50 and 103 vehicles per 100 s, signalized intersections demonstrated better fuel consumption and emission performance than unsignalized intersections. Signalized intersections could accommodate larger traffic volumes and provide enhanced traffic safety. In conclusion, the findings of this study are important for urban traffic planning and environmental policies. They provide a scientific basis for reducing fuel consumption and emissions and improving road traffic efficiency. Due to the advantages of signalized intersections in terms of energy consumption and emissions, future urban traffic planning should consider more signal light controls to achieve energy savings, emission reduction, and improved traffic operation efficiency. Full article

With the aim of promoting energy conservation and emission reduction, electric vehicles (EVs) have gained significant attention as a strategic industry in many countries. However, the insufficiency of accessible charging infrastructure remains a challenge, hindering the widespread adoption of EVs. To address this issue, we propose a novel approach to optimize the placement of charging stations within a road network, known as the charging station location problem (CSLP). Our method considers multiple factors, including fairness in charging station distribution, benefits associated with their placement, and drivers’ discomfort. Fairness is quantified by the balance in charging station coverage across the network, while driver comfort is measured by the total time spent during the charging process. Then, the CSLP is formulated as a reinforcement learning problem, and we introduce a novel model called PPO-Attention. This model incorporates an attention layer into the Proximal Policy Optimization (PPO) algorithm, enhancing the algorithm’s capacity to identify and understand the intricate interdependencies between different nodes in the network. We have conducted extensive tests on urban road networks in Europe, North America, and Asia. The results demonstrate the superior performance of our approach compared to existing baseline algorithms. On average, our method achieves a profit increase of 258.04% and reduces waiting time by 73.40%, travel time by 18.46%, and charging time by 40.10%. Full article

Conventional transportation systems are facing many challenges related to reducing fuel consumption, noise, and pollutants to satisfy rising environmental and economic criteria. These requirements have prompted many researchers and manufacturers in the transportation sector to look for cleaner, more efficient, and more sustainable alternatives. Powertrains based on fuel cell systems could partially or completely replace their conventional counterparts used in all modes of transport, starting from small ones, such as scooters, to large mechanisms such as commercial airplanes. Since hydrogen fuel cells (HFCs) emit only water and heat as byproducts and have higher energy conversion efficiency in comparison with other conventional systems, it has become tempting for many scholars to explore their potential for resolving the environmental and economic concerns associated with the transportation sector. This paper thoroughly reviews the principles and applications of fuel cell systems for the main transportation schemes, including scooters, bicycles, motorcycles, cars, buses, trains, and aerial vehicles. The review showed that fuel cells would soon become the powertrain of choice for most modes of transportation. For commercial long-rage airplanes, however, employing fuel cells will be limited due to the replacement of the axillary power unit (APU) in the foreseeable future. Using fuel cells to propel such large airplanes would necessitate redesigning the airplane structure to accommodate the required hydrogen tanks, which could take a bit more time. Full article

Recently, many activities have been undertaken to reduce the negative impact of transport on the environment, e.g., using propulsion sources and consumed energy. Electric and hybrid vehicles are becoming more and more popular. Methods of measuring the emissivity of the means of transport as well as devices for determining measurements are being developed. This work presents an indicator method (IM) for determining the emissivity of road transport, while omitting the use of quite complicated and expensive research equipment. For typical road vehicles, it is possible to determine the emissivity means of transport, taking into account statistical data. The values of the indicators selected, based on statistical data analysis, were verified by comparing their values with the results of the actual emissivity of air pollutants. As part of the research work, the emissivity values of selected means of transport in a distribution company were determined using the IM method. The results were compared with the actual emissivity measurements. The method of indicative determination of emissivity makes it possible to estimate the initial emissivity level, knowing the type of vehicle and the distance performed as part of the transport work. Thanks to a simple and uncomplicated method, delivery planning can become more sustainable, and the selection of less emissive means of transport can contribute to reducing the negative impact of transportation on the environment. Full article

Seaports are at the forefront of global trade networks, serving as hubs for maritime logistics and the transportation of goods and people. To meet the requirements of such networks, seaport authorities are investing in advanced technologies to enhance the efficiency and reliability of port infrastructures. This can be achieved through the digitalization and automation of core systems, aimed at optimizing the management and handling of both goods and people. Furthermore, a significant effort is being made towards a green energy transition at seaports, which can be supported through marine renewable sources. This promotes energy-mix diversification and autonomy, whilst reducing the noteworthy environmental footprint of seaport activities. By analyzing these pertinent topics under the scope of a review of container-terminal case studies, and these ports’ respective contexts, this paper seeks to identify pioneering smart seaports in the fields of automation, real-time management, connectivity and accessibility control. To foster the sustainable development of seaports, from an energy perspective, the potential integration with marine renewable-energy systems is considered, as well as their capabilities for meeting, even if only partially, the energy demands of seaports. By combining these fields, we attempt to construct a holistic proposal for a “model port” representing the expected evolution towards the seaports of the future. Full article

With the continuous development of intelligent transportation technologies, new ways of energy usage in transportation continue to emerge, which puts forward new requirements for the planning and design of energy systems. However, comprehensive analyses on the characteristics of transportation energy systems and the development trend of energy usage patterns brought by intelligent technologies have rarely been carried out so far. This paper explores this subject by reviewing the recent development and utilization of intelligent technologies in the transportation system and its impacts on energy usage. This review is carried out from three aspects, covering the representative intelligent transportation and energy technologies on vehicles, infrastructures and systems. The scope is limited within road, railway and water transport domains, with a focus on the recent developments in China as a representative. In terms of vehicles, the development trend of the power systems for new energy vehicles, the characteristics of energy usages in electric vehicles and the effects on energy saving and emission reduction are summarized. In terms of infrastructures, new technologies on smart road, smart port, intelligent railway energy system and the usage of clear energy on electric grid for transportation are reviewed, with the consideration of their potential influences on energy usages and the energy consumption characteristics of typical facilities also being analyzed. As for the transportation system, this review has focused on intelligent and connected transportation systems, train control and autonomous systems, and intelligent shipping system, with the emphasis on the energy saving and emission reduction effects of applying these intelligent technologies. The overall development trend of the transportation energy system is then analyzed based on the above materials, in particular, the future energy usage patterns in transportation system are given and the major challenges and obstacles approaching the future scenarios are also identified. Full article

Trams are a meaningful means of public transport in urban traffic. However, trams have some well-known disadvantages. These include, for example, possibly long distances to the stop, long waiting times, and lack of privacy, among others. The innovative mobility concept “FLAIT-Train” offers solutions to the problems mentioned. The FLAIT-train operates on ordinary roads and is intended to offer DOOR-2-DOOR transport. In the first application phase, the FLAIT-train runs on exclusive lanes but in the future can mix with other traffic. They are designed as vehicles with 2 seats and 1 m width. The vehicle technology of FLAIT-trains is similar/identical to battery-electric autonomous vehicles. This paper uses traffic simulations to investigate whether FLAIT trains are a suitable alternative to conventional trams, taking simulated/theoretical transport capacities in passenger-kilometers per day into account. Using the software SUMO (“Simulation of Urban Mobility”), a realistic traffic scenario is generated. In this scenario, the operation of the FLAIT-Trains and the trams are simulated under the same conditions and based on statistical data. Based on the simulation results, the performances of the FLAIT-Trains and the trams are compared. Full article

A lack of data collection on conscious mobility behaviors has been identified in current sustainable and smart mobility planning, development and implementation strategies. This leads to technocentric solutions that do not place people and their behavior at the center of new mobility solutions in urban centers around the globe. This paper introduces the concept of conscious mobility to link techno-economic analyses with user awareness on the impact of their travel decisions on other people, local urban infrastructure and the environment through systematic big data collection. A preliminary conscious mobility indicator framework is presented to leverage behavioral considerations to enhance urban-community mobility systems. Key factors for conscious mobility analysis have been derived from five case studies. The sample offers regional diversity (i.e., local, regional and the global urban contexts), as well as different goals in the transformation of conventional urban transport systems, from improving public transport efficiency and equipment electrification to mitigate pollution and climate risks, to focusing on equity, access and people safety. The case studies selected provide useful metrics on the adoption of cleaner, smarter, safer and more autonomous mobility technologies, along with novel people-centric program designs to build an initial set of conscious mobility indicators frameworks. The parameters were applied to the city of Monterrey, Nuevo Leon in Mexico focusing on the needs of the communities that work, study and live around the local urban campus of the Tecnologico de Monterrey’s Distrito Tec. This case study, served as an example of how conscious mobility indicators could be applied and customized to a community and region of interest. This paper introduces the first application of the conscious mobility framework for urban communities’ mobility system analysis. This more holistic assessment approach includes dimensions such as society and culture, infrastructure and urban spaces, technology, government, normativity, economy and politics, and the environment. The expectation is that the conscious mobility framework of analysis will become a useful tool for smarter and sustainable urban and mobility problem solving and decision making to enhance the quality of life all living in urban communities. Full article

A rising number of aerospace manufacturers are working on the development of new solutions in the field of Urban Air Mobility with increasing attention addressing electric and hybrid electric propulsive systems. Hybrid electric propulsive systems potentially offer performance improvements during transient maneuvers, as well as sustaining the engine during flight phases characterized by high power demands. Among the challenges of hybridization in rotorcraft, there is the necessity to predict the dynamic behavior and its effect on the control of rotor shaft speed. In the present study, the dynamic behavior of a parallel hybrid electric propulsive system for a coaxial-rotor air taxi is analyzed in response to a typical sequence of pilot commands that encompasses the range of operations from hover to forward flight. The system is modeled with a dynamic approach and includes sub-models for the coaxial rotors, the turboshaft engine, the electric machine, and the battery. The results of the investigation show a better performance during transients of the hybrid system than a conventional turboshaft configuration, especially if the electric contribution to the power request is coordinated to account for the lag due to slower engine dynamic response. Full article

The use an inverter is one of the representative ways to utilize regenerative braking energy in railway systems. Due to the nature of urban railways that generate a large amount of regenerative energy, the economic advantages are clear. However, in the case of the existing inverter operation method, a method of operating the inverter using the threshold voltage is used, which has a disadvantage in that power cannot be utilized between the no-load voltage and the threshold voltage. Therefore, in this paper, we propose an optimal location selection method and capacity calculation method for installing a regenerative inverter in an urban rail system, and a control method according to the train brake position to increase the regenerative energy utilization rate. First, the inverter capacity and location were selected by selecting the maximum regenerative energy generation for each substation section through the train performance simulation (TPS) based DC power simulation (DCPS). An inverter control method based on train brake position (BP method) is introduced. Finally, PSCAD/EMTDC, a power analysis program, was used to verify the proposed method. As a result, the use of regenerative energy by an inverter increased by about 62.6%, and more energy was saved at nearby substations through the BP method. Full article

Electric vehicles, particularly those in mass transit systems, make use of accurate power estimations for different routes to calculate powertrain and battery requirements and plan the location and times of charging stations. Hence, chassis dynamometers are a common tool for vehicle designers as they allow for the emulation of vehicle performance and energy consumption by simulating realistic road conditions. In this paper, a method is presented where inertia events and negative slopes can be represented in the dynamometer through a single motor; allowing researchers to perform fast and cheap tests, while also considering the effect of these variables. A dynamic simulation is used to distribute the energy used in three ways: first, accelerating the vehicle by overcoming the forces opposing motion; second, emulating the kinetic energy delivered by the vehicle mass when decelerating; and third, emulating the energy delivered to the vehicle by negative slopes. Tests were carried out on a dynamometer validating the method through an example route, estimating energy consumption and regeneration; this method reduces the error in energy consumption by inertial effects and negative slopes, otherwise not considered in one motor dynamometers, showing a 9.11% difference between total test energy and real bus energy for this route. Full article

This paper proposes a design for a one-coil long-stroke permanent magnet actuator (PMA) applied to a load breaker switch with a novel mechanism applicable to railways. As a new load breaker switch applicable to railway overhead lines has a double-insulation structure of the vacuum interrupter (VI) and a disconnect switch (DS) for higher insulation, the actuator to control the switch requires a very long stroke. While the traditional mechanism of the PMA implements a stroke of 10 to 30 mm, the load breaker switch with a double-insulation structure requires a stroke of 120 mm. To do so, we used the finite element method (FEM) and designed a novel one-coil long-stroke PMA. Then, values from FEM analysis were compared with measured holding force data, and a simplified prototype test-jig was used to confirm the actuator’s operating characteristics. In addition, the electromagnetic force, plunger rotation, and part weight ratio, which affect operating performance, were adapted in its design. By doing so, we confirmed the operating performance required for the one-coil long-stroke PMA for a new load breaker switch with a double-insulation structure with a VI average opening speed of 1.4 m/s and an average closing speed of 0.9 m/s at 1/2 of full stroke. Full article

Airport gate assignment is a critical issue in airport operations management. However, limited airport parking spaces and rising fuel costs have caused serious issues with gate assignment. In this paper, an effective multiobjective optimisation model for gate assignment is proposed, with the optimisation objectives of minimising real-time flight conflicts, maximising the boarding bridge rate, and minimising aircraft taxiing fuel consumption. An improved tunicate swarm algorithm based on cosine mutation and adaptive grouping (CG-TSA) is proposed to solve the airport gate assignment problem. First, the Halton sequence is used to initialise the agent positions to improve the initial traversal and allocation efficiency of the algorithm. Second, the population as a whole is adaptively divided into dominant and inferior groups based on fitness values. To improve the searchability of the TSA for the dominant group, an arithmetic optimisation strategy based on ideas related to the arithmetic optimisation algorithm (AOA) is proposed. For the inferior group, the global optimal solution is used to guide the update to improve the convergence speed of the algorithm. Finally, the cosine mutation strategy is introduced to perturb the optimal solution and prevent the target from falling into the local extrema as a way to efficiently and reasonably allocate airport gates. The CG-TSA is validated using benchmark test functions, Wilcoxon rank-sum detection, and CEC2017 complex test functions and the results show that the improved algorithm has good optimality-seeking ability and shows high robustness in the multiobjective optimisation problem of airport gate assignment. Full article

To achieve sustainable development in the road sector, the use of Electric Vehicles (EVs) appears as a positive response to transport emissions. Among the available technologies, dynamic charging seems to overcome the main weakness points of EVs, even if it requires that traditional roads (t-roads) be equipped with a system providing electricity for EVs. Thus, so-called electrified roads (e-roads) must be implemented into the urban road networks. Since it is not possible to electrify all roads simultaneously, and also to consider the demand needs of citizens, a selection criterion is essential. This research describes and develops a simple, self-explanatory, repeatable, and adaptable selection criterion aimed at helping city managers in prioritizing the roads of an urban network to be upgraded from t-road to e-road status. This method belongs to the so-called Multicriteria Spatial Decision Support Systems (MC-SDSS)—processes useful for solving spatial problems through the integration of multicriteria analysis (Fuzzy Analytic Hierarchy Process, F-AHP) with a geo-referenced data management and analysis tool (GIS). The developed algorithm is based on several criteria related to the infrastructure/transport, social and environmental areas. The result of the implemented method is a Feasibility Index (FI), able to prioritize the roads most eligible to be upgraded as e-roads, as also verified by its application on the urban area of Milan (Italy). Full article

The management of the global energy resources has stimulated the emergence of various agreements in favor of the environment. Among the most famous are the Conference of Parties (COP) and Route 2030, which aim to limit global warming to 1.5 °C by reducing the energy consumption and global emission levels. In order to comply with the international standards for energy consumption and pollutant emissions, the Brazilian government has been promoting the expansion of biofuels in the national energy matrix. Considering this scenario, the development of a novel internal combustion engine for the exclusive use of ethanol as a fuel, equipped with state-of-the-art technologies and employing modern design concepts, consists of an innovative and promising pathway for future Brazilian mobility, from both environmental and technological outlooks. In this sense, this work presents a method to determine the main engine dimensions as part of the initial process for a new ethanol prototype engine development. The Brazilian biofuel was selected due to its physicochemical properties, which allow the engine to achieve higher loads, and also due to its large availability as a renewable energy source in the country. Furthermore, a port water injection system was fitted to the engine in order to assist the combustion process by mitigating the knock tendency. The predicted overall engine performance was obtained by carrying out a GT-Power^TM 1D-CFD simulation, whose results pointed to a maximum torque of 279 Nm from 2000 to 4000 rpm and an indicated peak power of 135 kW at 5500 rpm. With a maximum water-to-fuel ratio of 19.2%, the engine was able to perform its entire full load curve at the MBT condition, a fact that makes the WI approach along with the ethanol fuel a very attractive solution. As a result of the specific design and optimization of each geometric parameter for this unique ethanol engine, a maximum indicated fuel conversion efficiency of 45.3% was achieved. Moreover, the engine was capable of achieving over 40% of the indicated fuel conversion efficiency in almost its entire full load curve. Full article