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Several challenges have emerged due to the increasing deterioration of urban mobility and its severe impacts on the environment and human health. Primary dependence on internal combustion engines that use petrol or diesel has led to poor air quality time losses noise traffic jams and further environmental pollution. Hence the transitions to using rail and or seaway-based public transportation cleaner fuels and electric vehicles are some of the ultimate goals of urban and national decision-makers. However battery natural gas hybrid and fuel cell vehicles require charging stations to be readily available with a sustainable energy supply within urban regions in different residential and business neighborhoods. This study aims to provide an updated and critical review of the concept and recent examples of urban mobility and transportation modes. It also highlights the adverse impacts of several air pollutants emitted from internal combustion engine vehicles. It also aims to shed light on several possible systems that integrate the electric vehicle stations with renewable energy sources. It was found that using certain components within the integrated system and connecting the charging stations with a grid can possibly provide an uninterrupted power supply to electric vehicles leading to less pollution which would encourage users to use more clean vehicles. In addition the environmental impact assessments as well as several implementation challenges are discussed. To this end the main implementation issues related to consumer incentives infrastructure and recommendations are also reported.

As a result of particular locations of large-scale energy producers and increases in energy demand transporting energy has become one of the key challenges of energy supply. For a long-distance ocean transportation transfer of energy carriers via ocean tankers is considered as a decent solution compared to pipelines. Due to cryogenic temperatures of energy carriers heat leaks into storage tanks of these carriers causes a problem called boil-off gas (BOG). BOG losses reduce the quantity of energy carriers which affects their economic value. Therefore this study proposes to examine the effects of BOG economically in production and transportation phases of potential energy carriers produced from natural gas namely; liquefied natural gas (LNG) dimethyl-ether (DME) methanol liquid ammonia (NH3) and liquid hydrogen (H2). Mathematical approach is used to calculate production and transportation costs of these energy carriers and to account for BOG as a unit cost within the total cost. The results of this study show that transportation costs of LNG liquid ammonia methanol DME and liquid hydrogen from natural gas accounting for BOG are 0.74 $/GJ 1.09 $/GJ 0.68 $/GJ 0.53 $/GJ and 3.24 $/GJ respectively. DME and methanol can be more economic compared to LNG to transport the energy of natural gas for the same ship capacity. Including social cost of carbon (SCC) within the total cost of transporting the energy of natural gas the transportation cost of liquid ammonia is 1.11 $/GJ whereas LNG transportation cost rises significantly to 1.68 $/GJ at SCC of 137 $/t CO2 eq. Consequently liquid ammonia becomes economically favored compared to LNG. Transportation cost of methanol (0.70 $/GJ) and DME (0.55 $/GJ) are also lower than LNG however liquid hydrogen transportation cost (3.24 $/GJ) is still the highest even though the increment of the cost is about 0.1% as SCC included within the transportation cost.

Co-optimizing energy and water resources in a microgrid can increase efficiency and improve economic performance. Energy-water storage (EWS) devices are crucial components of a high-efficient energy-water microgrid (EWMG). The state of charge (SoC) at the end of the first day of operation is one of the most significant variables in EWS devices since it is used as a parameter to indicate the starting SoC for the second day which influences the operating cost for the second day. Hence this paper examines the benefits and applicability of a lookahead optimization strategy for an EWMG integrated with multi-type energy conversion technologies and multienergy demand response to supply various energy-water demands related to electric/hydrogen vehicles and commercial/residential buildings with the lowest cost for two consecutive days. In addition a hybrid info-gap/robust optimization technique is applied to cover uncertainties in photovoltaic power and electricity prices as a tri-level optimization framework without generating scenarios and using the probability distribution functions. Duality theory is also used to convert the problem into a single-level MILP so that it can be solved by CPLEX. According to the findings the implemented energy-water storage systems and look-ahead strategy accounted for respectively 4.03% and 0.43% reduction in the total cost.

This work presents a feasibility study on the provision of electricity and hydrogen with renewable grid connected and off-the-grid systems for Bandar Abbas City in the south of Iran. The software HOMER Pro® has been used to perform the analysis. A techno-enviro-economic study comparing a hybrid system consisting of the grid/wind turbine and solar cell is done. The wind turbine is analyzed using four types of commercially available vertical axis wind turbines (VAWTs). According to the literature review no similar study has been performed so far on the feasibility of using VAWTs and also no work exists on the use of a hybrid system in the studied area. The results indicated that the lowest price of providing the required hydrogen was $0.496 which was achieved using the main grid. Also the lowest price of the electricity generated was $1.55 which was obtained through using EOLO VAWT in the main grid/wind turbine/solar cell scenario. Also the results suggested that the highest rate of preventing CO2 emission which was also the lowest rate of using the national grid with 3484 kg/year was associated with EOLO wind turbines where only 4% of the required electricity was generated by the national grid.

Hydrogen has attracted growing research interest due to its exceptionally high energy per mass content and being a clean energy carrier unlike the widely used hydrocarbon fuels. With the possibility of long-term energy storage and re-electrification hydrogen promises to promote the effective utilization of renewable and sustainable energy resources. Clean hydrogen can be produced through a renewable-powered water electrolysis process. Although alkaline water electrolysis is currently the mature and commercially available electrolysis technology for hydrogen production it has several shortcomings that hinder its integration with intermittent and fluctuating renewable energy sources. The proton exchange membrane water electrolysis (PEMWE) technology has been developed to offer high voltage efficiencies at high current densities. Besides PEMWE cells are characterized by a fast system response to fluctuating renewable power enabling operations at broader partial power load ranges while consistently delivering high-purity hydrogen with low ohmic losses. Recently much effort has been devoted to improving the efficiency performance durability and economy of PEMWE cells. The research activities in this context include investigations of different cell component materials protective coatings and material characterizations as well as the synthesis and analysis of new electrocatalysts for enhanced electrochemical activity and stability with minimized use of noble metals. Further many modeling studies have been reported to analyze cell performance considering cell electrochemistry overvoltage and thermodynamics. Thus it is imperative to review and compile recent research studies covering multiple aspects of PEMWE cells in one literature to present advancements and limitations of this field. This article offers a comprehensive review of the state-of-the-art of PEMWE cells. It compiles recent research on each PEMWE cell component and discusses how the characteristics of these components affect the overall cell performance. In addition the electrochemical activity and stability of various catalyst materials are reviewed. Further the thermodynamics and electrochemistry of electrolytic water splitting are described and inherent cell overvoltage are elucidated. The available literature on PEMWE cell modeling aimed at analyzing the performance of PEMWE cells is compiled. Overall this article provides the advancements in cell components materials electrocatalysts and modeling research for PEMWE to promote the effective utilization of renewable but intermittent and fluctuating energy in the pursuit of a seamless transition to clean energy.

Logistics is becoming more cost competitive while customers and regulatory bodies pressure businesses to disclose their carbon footprints creating interest in alternative fuels as a decarbonization strategy. This paper provides a thematic review of the role of alternative fuels in sustainable air land and sea logistics their challenges and potential mitigations. Through an extensive literature survey we determined that biofuels synthetic kerosene natural gas ammonia alcohols hydrogen and electricity are the primary alternative fuels of interest in terms of environmental sustainability and techno-economic feasibility. In air logistics synthetic kerosene from hydrogenated esters and fatty acids is the most promising route due to its high technical maturity although it is limited by biomass sourcing. Electrical vehicles are favorable in road logistics due to cheaper green power and efficient vehicle designs although they are constrained by recharging infrastructure deployment. In sea logistics liquified natural gas is advantageous owing to its supply chain maturity but it is limited by methane slip control and storage requirements. Overall our examination indicates that alternative fuels will play a pivotal role in the logistics networks of the future.

During the last two decades Gulf Cooperation Council (GCC) countries have seen their population economies and energy production growing steeply with a substantial increase in Gross Domestic Product. As a result of this growth GCC consumption-based carbon dioxide (CO2) emissions increased from 540.79 Metric tons of CO2 equivalent (MtCO2) in 2003 to 1090.93 MtCO2 in 2020. The assumptions and strategies that have driven energy production in the past are now being recast to achieve a more sustainable economic development. The aim of this study is to review and analyze ongoing energy transition strategies that characterize this change to identify challenges and opportunities for bolstering the effectiveness of current strategic orientations. The ensuing analysis shows that since COP26 GCC countries have been pursuing a transition away from carbon-based energy policies largely characterized by the adoption of solar PV with other emerging technologies including energy storage carbon capture and hydrogen generation and storage. While as of 2022 renewable energy adoption in the GCC only represented 0.15 % of global installed capacity GCC countries are making strong efforts to achieve their declared 2030 energy targets that average about 26 % with peaks of 50 % in Saudi Arabia and 30 % in the UAE and Oman. With reference to solar energy plans are afoot to add 42.1 GW of solar photovoltaics and concentrated solar power which will increase 8-fold the current installed renewable capacity (5.1 GW). At the same time oil and gas production rates remain stable and fossil fuel subsidies have grown in the last few years. Also there is a marked preference for the deployment of CCUS and utility-scale solar energy technology vs. distributed solar energy energy efficiency and nature-based solutions. The pursuit of energy transition in the GCC will require increased efforts in the latter and other overlooked strategic endeavors to achieve a more balanced portfolio of sustainable energy solutions with stronger emphasis on energy efficiency (as long as rebound effects are mitigated) and nature-based solutions. Increased efforts are also needed in promoting governance practices aimed to institutionalize regulatory frameworks incentives and cooperation activities that promote the reduction of fossil fuel subsidies and the transition away from fossil fuels.