Urban activities, including urban mobility, play a crucial role in climate change mitigation. Urban mobility is currently at a crossroads. In a business as usual scenario, CO2 emissions from urban transportation will grow by one fourth by 2050. Nevertheless, during this period, it may drop by about one third. To make the drop happen, we need to introduce comprehensive policies and measures. Electrifying urban transit is one feasible solution. This study investigates whether and how urban water transit systems have been electrified—a means of transport which has not been well researched in this respect. A multilevel perspective and the comparative case study method were employed to answer the research questions. The comprehensive study focussed on 24 cities representing the current experience in planning and operating water transport, based mainly on secondary, primarily qualitative, data, such as industry reports, feasibility studies, urban policies, and scientific papers. The primary... [more]

Heat flow patterns variability related to the age of the consolidated, and differences in, sedimentary thickness of the sedimentary succession are important constraints upon the thermal state of the sedimentary fill and its geothermal energy potential. Heat flow in the Permian basin of central Europe varies from a low of 40 mWm−2 in the Precambrian Platform to 80 mWm−2 in the Paleozoic basement platform influencing temperature for geothermal potential drilling depth. Continuity of thermal patterns and compatibility of heat flow Q across the Permian basin across the Polish−German basin was known from heat flow data ever since the first heat flow map of Europe in 1979. Both Polish and German heat flow determinations used lab-measured thermal conductivity on cores. This is not the case for the recent heat flow map of Poland published in 2009 widely referenced in Polish geological literature. Significant differences in heat flow magnitude exist between many historical heat flow maps of Pol... [more]

Uncertainty quantification in LIB manufacturing has received interest in order to improve the reliability of LIB. The uncertainty generated during the manufacturing causes variations in the performance of LIBs, thereby increasing capacity degradation and leading to failure. In this study, a reliability-based design optimization (RBDO) of LIBs is conducted to reduce performance failure while maximizing the specific energy. The design variables with uncertainty are the thickness, porosity, and particle size of the anode and cathode. The specific energy is defined as the objective function in the optimization design problem. To maintain the specific power in the initial design of the LIB, it is defined as the constraint function. Reliability is evaluated as the probability that the battery satisfies the performance of the required design. The results indicate that the design optimized through RBDO increases the specific energy by 42.4% in comparison with that of the initial design while r... [more]

Community microgrids are set to change the landscape of future energy markets. The technology is being deployed in many cities around the globe. However, a wide-scale deployment faces three major issues: initial synchronization of microgrids with the utility grids, slip management during its operation, and mitigation of distortions produced by the inverter. This paper proposes a Phasor Measurement Unit (PMU) Assisted Inverter (PAI) that addresses these three issues in a single solution. The proposed PAI continually receives real-time data from a Phasor Measurement Unit installed in the distribution system of a utility company and keeps constructing a real-time reference signal for the inverter. To validate the concept, a unique intelligent DC microgrid architecture that employs the proposed Phasor Measurement Unit (PMU) Assisted Inverter (PAI) is also presented, alongside the cloud-based Artificial Intelligence (AI), which harnesses energy from community shared resources, such as batte... [more]

The campus of the Karlsruhe Institute of Technology (KIT) contains several waste heat streams. In an effort to reduce greenhouse gas emissions by optimizing thermal power consumption on the campus, researchers at the KIT are proposing a ‘DeepStor’ project, which will sequester waste heat from these streams in an underground reservoir during the summer months, when the heat is not required. The stored heat will then be reproduced in the winter, when the campus’s thermal power demand is much higher. This paper contains a preliminary geochemical risk assessment for the operation of this subsurface, seasonal geothermal energy storage system. We used equilibrium thermodynamics to determine the potential phases and extent of mineral scale formation in the plant’s surface infrastructure, and to identify possible precipitation, dissolution, and ion exchange reactions that may lead to formation damage in the reservoir. The reservoir in question is the Meletta Beds of the Upper Rhein Graben’s Fr... [more]

The utilization of geothermal energy is favorable for the improvement of energy efficiency. A hybrid system consisting of a seasonal heating and cooling cycle, an absorption refrigeration cycle and a liquid dehumidification cycle is proposed to meet dehumidification, space cooling and space heating demands. Geothermal energy is utilized effectively in a cascade approach. Six performance indicators, including humidity efficiency, enthalpy efficiency, moisture removal rate, coefficient of performance, cooling capacity, and heating capacity, are developed to analyze the proposed system. The effect of key design parameters in terms of desiccant concentration, air humidity, air temperature, refrigeration temperature and segment temperature on the performance indicators are investigated. The simulation results indicated that the increase of the desiccant concentration makes the enthalpy efficiency, the coefficient of performance, the moisture removal rate and the cooling capacity increase an... [more]

Recently, several countries have made commitments to move to a net-zero emission by the year 2050 in a response to climate change. Among various renewable energy systems to realize the target, wind energy system has been gaining much attention as a favorable alternative source to fossil fuel energy. In particular, many floating offshore wind turbines (FOWT) are expected to be installed because of vast installation resources without water depth limit conditions, stable and strong wind resources, relatively low constraints on noise emission, and space restriction compared to onshore wind turbines. In this study, a 10 MW superconducting floating offshore wind turbine was modeled with a 1/90 scale ratio and was experimentally tested at the Ocean Engineering Widetank of the University of Ulsan. The model calibration of the scaled model was performed with free decay test and showed a good correlation with simulation results calculated from FAST V8 of NREL. The motion characteristics of the 1... [more]

Energy consumption is on the rise due to rapid technological progress and a higher standard of living. The use of alternative energy resources is essential to meet the rising energy demand and mitigate the carbon emissions caused due to use of fossil-based fuels. Biodiesel produced from non-edible oils such as castor seed oil (CO) can be used in diesel engines to replace fossil diesel. However, the quality and yields for CO biodiesel is low due to the presence of ricinolic acid C18:1OH (79%). In this study, two-stage conversion techniques were used to improve the yields and properties of CO biodiesel. The catalyst CaCu(OCH3)2 was prepared from waste eggshell and synthesized with copper oxide in the presence of methanol. The castor oil was subjected to pyrolysis at 450−500 °C and then transesterified in the presence of modified catalyst. The reaction parameters such as methanol-to-oil ratio and catalyst and reaction time were investigated, and the optimum combination was used to produce... [more]

For improving the hydrolytic stability of sulfonated polyimides consisting of five membered anhydrides, novel sulfonated polyimides (NSPIs) were prepared via polymerization of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), with a novel diamine monomer with a pendant sulfonic acid group and 4,4-oxydianiline. Water uptake of this NSPI with an excellent film-forming ability was almost equal to that of Nafion® 117, while their ion exchange capacity (IEC) was 22% higher than Nafion® 117. The loss in weight decreased by 53% and loss in IEC decreased by 66% compared to that of Nafion® 117; both were used to quantitatively measure hydrolytic stability, and radical oxidative stability also increased by 75% when compared with Nafion® 117. Mechanically, this NSPI was superior, and its proton conductivity was higher than Nafion® 117 at elevated temperatures. All these improvements were due to the introduction of this pendant group. Taken together, we herein report a promising renewable... [more]

Environmental problems are frequently related to energy use, estimated to grow at 1.6% per year until 2035. The transport sector accounts for 30% of energy demand and aviation is growing around 2.6% per year. Thus, low-emissions policies promote the use of sustainable aviation fuels. This work simulates a gasification and Fischer-Tropsch process to obtain biojet fuel from biomass and plastic waste. Syngas obtained through cogasification is purified by amine scrubbing and subjected to a Fischer-Tropsch process to produce hydrocarbons, which are upgraded for optimal fuel properties. Pinch analysis is applied to minimize energy usage, while Rankine cycles and a cooling tower are designed to cover the demand of electricity and cooling water. Results show that mass yields of the process towards biofuels are 13.06%, with an output of 1697.45 kg/h of biojet fuel. Density, kinematic viscosity, pour and flammability points and the lower calorific value of the biojet fuel comply with the ASTM D7... [more]

Hydrogen is an environmentally friendly biofuel which, if widely used, could reduce atmospheric carbon dioxide emissions. The main barrier to the widespread use of hydrogen for power generation is the lack of technologically feasible and—more importantly—cost-effective methods of production and storage. So far, hydrogen has been produced using thermochemical methods (such as gasification, pyrolysis or water electrolysis) and biological methods (most of which involve anaerobic digestion and photofermentation), with conventional fuels, waste or dedicated crop biomass used as a feedstock. Microalgae possess very high photosynthetic efficiency, can rapidly build biomass, and possess other beneficial properties, which is why they are considered to be one of the strongest contenders among biohydrogen production technologies. This review gives an account of present knowledge on microalgal hydrogen production and compares it with the other available biofuel production technologies.

This paper presents a literature review of the dynamics of offshore floating wind turbine platforms. When moving further offshore, there is an increase in the capacity of wind power. Generating power from renewable resources is enhanced through the extraction of wind energy from an offshore deep-water wind resource. Mounting the turbine on a platform that is not stable brings another difficulty to wind turbine modeling. There is a need to introduce platforms that are more effective to capture this energy, because of the complex dynamics and control of these platforms. This paper highlights the historical developments and progresses in the design of different types of offshore floating wind turbine platforms needed for harvesting the energy from offshore winds. The relative advantages and disadvantages of the platform types with the design challenges are discussed. The major types of floating platforms included in this study are tension leg platform (TLP) type, spar type, and semisubmer... [more]

Research on forecasting the seasonality and growth trend of natural gas (NG) production and consumption will help organize an analysis base for NG inspection and development, social issues, and allow industrials elements to operate effectively and reduce economic issues. In this situation, we handle a comparison structure on the application of different models in monthly NG production and consumption forecasting using the cross-correlation function and then analyze the association between exogenous variables. Moreover, the SARIMA-X model is tested for US monthly NG production and consumption prediction via the proposed method for the first time in the literature review in this study. The performance of that model has been compared with SARIMA (p, d, q) * (P, D, Q)s. The results from RMSE and MAPE indicate that the superiority of the best model. By applying this method, the US monthly NG production and consumption is forecast until 2025. The success of the proposed method allows the use... [more]

A Flying Ad-hoc network constitutes many sensor nodes with limited processing speed and storage capacity as they institute a minor battery-driven device with a limited quantity of energy. One of the primary roles of the sensor node is to store and transmit the collected information to the base station (BS). Thus, the life span of the network is the main criterion for the efficient design of the FANETS Network, as sensor nodes always have limited resources. In this paper, we present a methodology of an energy-efficient clustering algorithm for collecting and transmitting data based on the Optimized Low-Energy Adaptive Clustering Hierarchy (LEACH) protocol. The selection of CH is grounded on the new optimized threshold function. In contrast, LEACH is a hierarchical routing protocol that randomly selects cluster head nodes in a loop and results in an increased cluster headcount, but also causes more rapid power consumption. Thus, we have to circumvent these limitations by improving the LE... [more]

This study reports an integrated device of a lithium-ion battery (LIB) connected with Si solar cells. A Li(Ni0.65Co0.15Mn0.20)O2 (NCM) cathode and a graphite (G) anode were used to fabricate the lithium-ion battery (LIB). The surface and shape morphologies of NCM and graphite powder were characterized by field emission scanning electron microscopy (FE-SEM). The structural properties of NCM and graphite powder were determined by X-ray diffraction (XRD) analysis. XRD patterns of powders were well matched with those of JCPDS data. To investigate the electrochemical characteristics of NCM and graphite, cycling tests were performed after assembling the NCM-Li, the G-Li half-cell, and the NCM-G full-cell. The discharge capacity of the NCM cathode at 0.1C was 189.82 mAh/g−1. The NCM-graphite full-cell showed 98.25% cycle retention at 1C after 50 cycles. To obtain enough charging voltage for the LIB connected with solar cells in an integrated device, eight single Si solar cells were connected... [more]

The development of commercial aviation is being driven by the need to improve efficiency and thereby lower emissions. All-electric aircraft present a route to eliminating direct fuel burning emissions, but their development is stifled by the limitations of current battery energy and power densities. Multifunctional structural power composites, which combine load-bearing and energy-storing functions, offer an alternative to higher-energy-density batteries and will potentially enable lighter and safer electric aircraft. This study investigated the feasibility of integrating structural power composites into future electric aircraft and assessed the impact on emissions. Using the Airbus A320 as a platform, three different electric aircraft configurations were designed conceptually, incorporating structural power composites, slender wings and distributed propulsion. The specific energy and power required for the structural power composites were estimated by determining the aircraft mission... [more]

Corrosion in the oil and gas industry is very common due to the simultaneous action of a chemically active environment, temperature, and other non-chemical factors, for example, mechanical erosion by friction, and for these reasons corrosion is a very complex process. Corrosion at higher temperatures is an important aspect when extracting natural gas from a field with high temperatures (120 °C in the Lubiatow deposit and 180 °C in the gas well in Kutno). Water in the reservoir is often in the form of steam, with a pressure of about 25 MPa; as a result of its extraction, it cools down, which causes condensation. Condensed water in contact with the acid components of the gas causes corrosion, especially in the presence of aggressive gases, such as CO2 and H2S. Therefore, the aim of the work was to conduct research on the influence of water condensation, as a result of temperature changes in gasses containing CO2 and H2S on the corrosion of L80-1 steel at the junction of extraction pipes... [more]

The cryogenic industry has been experiencing continuous progress in recent years, primarily due to the global development of oil and gas activities. Natural gas liquefaction is a cryogenic process, with the refrigeration system being crucial to the overall process. The objective of the study presented herein is to carry out an exergoeconomic assessment for a dual nitrogen expander process used to liquefy natural gas, employing the SPecific Exergy COsting (SPECO) methodology. The air coolers and throttling valve are dissipative components, which present fictitious unit cost rates that are reallocated to the final product (Liquefied Natural Gas). The liquefaction process has an exergy efficiency of 41.89%, and the specific cost of liquefied natural gas is 292.30 US$/GJ. It was verified that this cost increased along with electricity. The highest exergy destruction rates were obtained for Expander 1 and Air cooler 2. The highest average cost per exergy unit of fuel was obtained for the ve... [more]

The effect of clay minerals on the methane adsorption capacity of shales is a basic issue that needs to be clarified and is of great significance for understanding the adsorption characteristics and mechanisms of shale gas. In this study, a variety of experimental methods, including XRD, LTNA, HPMA experiments, were conducted on 82 marine shale samples from the Wufeng−Longmaxi Formation of 10 evaluation wells in the southern Sichuan Basin of China. The controlling factors of adsorption capacities were determined through a correlation analysis with pore characteristics and mineral composition. In terms of mineral composition, organic matter (OM) is the most key methane adsorbent in marine shale, and clay minerals have little effect on methane adsorption. The ultra-low adsorption capacity of illite and chlorite and the hydrophilicity and water absorption ability of clay minerals are the main reasons for their limited effect on gas adsorption in marine shales. From the perspective of the... [more]

Integrated photovoltaic-fuel cell (IPVFC) systems, amongst other integrated energy generation methodologies are renewable and clean energy technologies that have received diverse research and development attentions over the last few decades due to their potential applications in a hydrogen economy. This article systematically updates the state-of-the-art of IPVFC systems and provides critical insights into the research and development gaps needed to be filled/addressed to advance these systems towards full commercialization. Design methodologies, renewable energy-based microgrid and off-grid applications, energy management strategies, optimizations and the prospects as self-sustaining power sources were covered. IPVFC systems could play an important role in the upcoming hydrogen economy since they depend on solar hydrogen which has almost zero emissions during operation. Highlighted herein are the advances as well as the technical challenges to be surmounted to realize numerous potenti... [more]

The article presents the results of work on an effective numerical study of selected transient states of a low-power electrical machine. The object of detailed research was a synchronized squirrel-cage induction motor. Its ability to work at a synchronous speed was enabled by obtaining reluctance torque, caused by an imposed asymmetry between the direct and quadrature reluctances of the rotor. The difference between the reluctances was achieved by changing the rotor geometry by milling additional deep grooves. The modifications of the rotor did not damage the continuity of the rotor cage. Imposed lots were arranged symmetrically around the rotor circumference. In order to study the performance of the modified motor, a parameterized, numerical model of the machine was developed to evaluate the impact of the geometry of the slots. The developed three dimensional (3D) model of the electromagnetic phenomena in the studied magnetic circuit employs the finite element method (FEM). The model... [more]

An inventive method was applied to determine the minimum major radius, R0, and the optimum build of a tokamak fusion reactor that simultaneously meets all physics, engineering, and neutronics constraints. With a simple cost model, tokamak systems analyses were carried out over ranges of system parameters to find an optimum build of a tokamak fusion reactor at minimum cost. The impact of a wide range of physics parameters and advanced engineering elements on costs were also addressed. When a central solenoid was used to ramp up a plasma current, design solutions with a cost of electricity (COE) between 109 and 140 mills/kWh, direct capital cost between 5000 and 6000 M/USD, and net electric power, Pe between 1000 and 1600 MW could be found with a minimum R0 between 6.0 and 7.0 m, and fusion power, Pfusion between 2000 and 2800 MW. When the plasma current was driven by a non-inductive external system, the system size and costs could be reduced further; a COE between 98 and 130 mills/kWh,... [more]

The risk of oscillation of grid-connected wind turbine generators (WTGs) is well known, making it all the more important to understand the characteristics of different WTGs and analyze their performance so that the problems’ causes are identified and resolved. While many studies have evaluated the performance of grid-connected WTGs, most lack clarity and precision in the modeling and simulation techniques used. Moreover, most of the literature focuses on a single mode of operation of WTGs to analyze their performances. Therefore, this paper updates the literature by considering the different operating conditions for WTGs. Using MATLAB/SIMULINK it expands the evaluation to the full range of vulnerabilities of WTGs: from the wind turbine to grid connection. A network representing grid-connected squirrel-cage induction generator (SCIG) and doubly-fed induction generator (DFIG) wind turbines are selected for simulation. The performances of SCIG and DFIG wind turbines are evaluated in terms... [more]

Natural gas hydrates are widely considered one of the most promising green resources with large reserves. Most natural gas hydrates exist in deep-sea porous sediments. In order to achieve highly efficient exploration of natural gas hydrates, a fundamental understanding of hydrate growth becomes highly significant. Most hydrate film growth studies have been carried out on the surface of fluid droplets in in an open space, but some experimental visual works have been performed in a confined porous space. In this work, the growth behavior of methane hydrate film on pore interior surfaces was directly visualized and studied by using a transparent high-pressure glass microfluidic chip with a porous structure. The lateral growth kinetics of methane hydrate film was directly measured on the glass pore interior surface. The dimensionless parameter (−∆G/(RT)) presented by the Gibbs free energy change was used for the expression of driving force to explain the dependence of methane hydrate film... [more]

Crude glycerol is a major byproduct in the production of biodiesel and contains a large number of impurities. The transformation of crude glycerol into valuable compounds such as 1,3-propanediol (1,3-PDO) using clean and renewable processes, like bioconversion, is an important task for the future of the chemical industry. In this study, 1,3-PDO bioproductions from crude and pure glycerol were estimated as 15.4 ± 0.8 and 11.4 ± 0.1 mmol/L, respectively. Because 1,3-PDO is a reductive metabolite that requires additional reducing energy, external supplements of electron for further improvement of 1,3-PDO biosynthesis were attempted using a bioelectrochemical system (BES) or zero-valent iron (ZVI). The conversions of crude and pure glycerol under electrode and iron-based cultivation were investigated for 1,3-PDO production accompanied by metabolic shift and cell growth. The BES-based conversion produced 32.6 ± 0.6 mmol/L of 1,3-PDO with ZVI implementation.