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Electrical energy becomes necessary for human being. Generation of electrical energy mostly depends on fossils fuel, they are limited in nature and also responsible for environmental pollution. Renewable energy resources provides a better alternative for future,In comparison to conventional energy resources economical aspect is a major issue of renewable energy sources with the feasibility and efficiency. These limitations are tried to overcome by deployment hybrid renewable energy resources. There are certain criteria to analyze and implement the sized, optimized and cost efficient system. This paper focus on hybrid energy systems based on solar photovoltaic (PV) and wind resources. This paper shed lights on various parameters of economic feasibility, sizing strategies with logical advancements to enhance their utilization, future prospects, and their arrangement. Strategies to develop an effective storage system is also presented here.A brief review on developments in optimization techniques, reliability index and cost analyzing techniques for hybrid renewable energy systems are also presented. [ABSTRACT FROM AUTHOR]

Faults in any components (modules, connection lines, converters, inverters, etc.) of photovoltaic (PV) systems (stand-alone, grid-connected or hybrid PV systems) can seriously affect the efficiency, energy yield as well as the security and reliability of the entire PV plant, if not detected and corrected quickly. In addition, if some faults persist (e.g. arc fault, ground fault and line-to-line fault) they can lead to risk of fire. Fault detection and diagnosis (FDD) methods are indispensable for the system reliability, operation at high efficiency, and safety of the PV plant. In this paper, the types and causes of PV systems (PVS) failures are presented, then different methods proposed in literature for FDD of PVS are reviewed and discussed; particularly faults occurring in PV arrays (PVA). Special attention is paid to methods that can accurately detect, localise and classify possible faults occurring in a PVA. The advantages and limits of FDD methods in terms of feasibility, complexity, cost-effectiveness and generalisation capability for large-scale integration are highlighted. Based on the reviewed papers, challenges and recommendations for future research direction are also provided. [ABSTRACT FROM AUTHOR]

Oxygenated fuels such as alcohols and ethers have the potential to provide reliable sources, and environmentally friendly fuel to world's increasing future energy demands. Oxygenated fuels have a promised future since are renewable and produced from several sources, also can be produced locally. The first objective of this paper is to systematically review of oxygenated fuels including alcohol and ether regarding the production, environmental impacts and potential using as octane booster of gasoline that used in spark ignition SI) engine. Another objective of this paper is to review the effects of oxygenated fuels on performances and emissions characteristics of spark ignition engine. Alcohol and ether burn very cleanly than regular gasoline and produce lesser carbon monoxide (CO) and nitrogen oxides (NO x ). Mainly the ether fuels (methyl tertiary butyl ether MTBE and Dimethyl Ether DME) are used as additives at low blending ratio to enhance the octane number and oxygen content of gasoline. Furthermore, alcohols and ethers have significant impacts on the environment, greenhouse gas and human health. In addition to this, application of oxygenated fuel on SI engines can decrease environmental pollution, strengthen agricultural economy and decrease gasoline fuel requirements. The increase in engine performance could be attained with an increased compression ratio along with the use of alcohol fuels which have a higher-octane value. Overall, oxygenated fuels have been found to be a very promising alternative fuel for SI engines, capable of providing high thermal efficiency, and lower NO x levels. [ABSTRACT FROM AUTHOR]

With the exponential growth in global photovoltaic (PV) power capacity, protection of PV systems has gained prodigious importance in last few decades. Even with the use of standard protection devices in a PV system, faults occurring in a PV array may remain undetected. Inspired by the ever increasing demand for a reliable fault detection technique, several advanced techniques have been proposed in literature; especially in the last few years. Hence, this paper carries out an in depth analysis of various fault occurrences, protection challenges and ramifications due to undetected faults in PV systems. Furthermore, with a widespread literature, the paper critically reviews numerous fault detection algorithms/techniques available for PV systems which are proven to be effective and feasible to implement. The proposed study is not only limited to surveying the existing techniques but also analyzes the performance of each technique with an emphasis on its: 1) Approach, 2) Sensor requirements, 3) Ability to diagnose and localize faults, 4) Integration complexity, 5) Accuracy, 6) Applicability and 7) Implementation cost. Overall, this paper is envisioned to avail the researchers working in the field of PV systems with a valuable resource, which will assist them to enrich their research works. [ABSTRACT FROM AUTHOR]

By year 2030, the world's energy demand is expected to increase by over 60% of current demand. Thus, the potential of renewable energy should be investigated. Renewable energy is the energy from natural and unnatural available forms including wind, biomass, solar, and waste heat energy generated through various human activities. Solar energy is an available and clean form of renewable energy used as an alternative to fossil fuel in generating energy. However, the maximum extraction of thermal energy from the sun is most challenging. This study focuses on energy generation using the parabolic trough collector (PTC). This review contains geometrical analysis including the thermal approach of the PTC model, heat transfer, and method of enhancing thermal efficiency on the PTC receiver. This paper also includes performance analysis, thermal efficiency, and applications of the solar-powered PTC and the history of PTC evolution. The PTC applications include desalination process, air heating system, power plants, refrigeration, and industrial heating purposes. This paper benefits researcher that focus on the solar-powered PTC. [ABSTRACT FROM AUTHOR]

Understanding the barriers that inhibit the deployment of renewable energy technologies to achieve long-term reductions in carbon emissions from the use of fossil fuels is paramount to Barbados. Although there are targets towards renewable energy (solar, wind, biomass, geothermal) uptake, the share of these technologies in the energy mix does not exist in Barbados due to the total dependence on fossil fuels. In this paper, a review of potential challenges and the main problems for deployment of alternative energy sources is presented. Through interviews, questionnaires with a focus group of key personnel's, the paper documents the lack of renewable energy sources (with emphasis on solar energy) as one of the main alternatives to meet the carbon emission targets set by the country. The barriers and challenges facing the implementation of solar energy deployment have been clarified. From the results, it is evident that significant policy barriers still exist at the country level, which has reduced the effectiveness of a concerted national effort to deploy renewables. The current policy landscape which benefits from fossil fuel imports, the lack of technical know-how and the lack of research and development in the renewable energy space are amongst the key barriers identified. The paper also outlines the key policy's frameworks, regulatory environment and the lack of incentives, which encompasses the renewable energy sector, and presents a critical analysis of the barriers faced by the industry. A mitigation framework is proposed to bridge the gap of solar energy (renewable energy) deployment. [ABSTRACT FROM AUTHOR]

This paper presents the technical, economic and environmental benefit of meeting the water requirements of some selected communities in 3 regions of Oyo state, using off-grid wind energy conversion system. The study is conducted using 16 years (2000–2015) daily average wind speed data obtained from Nigeria Meteorological Agency (NIMET), Oshodi, Lagos. The data are observed at anemometer height of 10 m and extrapolated to turbine hub height. The water requirements of the locations are estimated using water consumption data obtained from Nigeria Population Commission (NPC). The wind power analysis of the sites are conducted using 2-parameter Weibull probability distribution to ascertain the wind power potential for water pumping application. The complete system is designed in such a way that the energy requirement of the pumps matches the wind power of the sites. The annualized life cycle cost of the system over 20 years lifetime and the cost per cubic meter of pumped water are evaluated. The results show that the wind power densities of the 3 divisional areas range from 165.75to207.2 W/m 2 and it is sufficient to provide for the water requirements between 1987 m 3 /day to 2333 m 3 /day) for the areas. It is also revealed that Polaris P50 with rated power of 50 kW, cut-in, rated and cut-out wind speed of 2.7 m/s, 9 m/s and 25 m/s, respectively is the most suitable wind turbine. The water pumps that match the requirement of the sites are identified to be 320 L series Goulds model submersible pumps in the range of 30–50 hp. The annualized life cycle cost of the system ranges from $7,985-$11,594 and the unit cubic cost of pumped water ranges from $0.014–0.025 m 3 /day. This paper provides first-hand scientific information to the investors, government officials and policy makers at alleviating the water poverty in Nigerian communities. This would impact positively on the well-being of the local residence. [ABSTRACT FROM AUTHOR]

Biomass gasification receives attention as a promising method to utilize biomass, a fuel which is carbon neutral. The producer gas/syngas which is an energy carrier obtained through this method finds use in engines, fuel cells, Fischer-Tropsch reactors, methanol synthesis and as an input for chemical industries, after the required quality levels for the above applications are achieved. To use the producer gas/syngas for power generation on a commercial scale, the required gas quality has to be established. Producer gas obtained from biomass gasification has several contaminants like particulate matter, tar and gaseous species like H 2 S, NH 3 . The contaminants present in the producer gas, depending upon their nature and the amount, pose issues to power generation systems. Tar, which is a mixture of varying molecular weight hydrocarbon molecules, generated from the thermo-chemical conversion processes of organic materials, could condense at low temperatures, and lead to clogging or blockage in end-use application devices, filters, and fuel lines. So, it is essential to reduce or transform the tar present in the producer gas to utilize the biomass gasification systems for power generation. This paper attempts to provide a critical assessment of tar generated during biomass gasification, covering the sundry aspects of formation, evaluation, issues and mitigation strategies. The paper gives an introduction to biomass gasification systems, followed by a detailed description of tar, including the definition and the chemistry of formation and destruction. An explanation of the various aspects of tar sampling, characterization and analysis, is presented next. The suitability of different tar analysis approaches is compared from an end-use device perspective. Then the multifarious issues posed by the presence of tar in the syngas on the end-use devices is discussed. The last part of the paper describes several tar mitigation strategies used by researchers. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive review on solar tracking systems and their potentials in solar energy applications. The paper overviews the design parameters, construction, types and drive system techniques covering different usage application. There are two main solar tracking systems types that depending on their movement degrees of freedoms are single axis solar tracking system and dual axis solar tracking system, which are addressed in the recent studies. The solar tracker drive systems encompassed five categories based on the tracking technologies, namely, active tracking, passive tracking, semi-passive tracking, manual tracking, and chronological tracking. The paper described the various designs and components of the tracking systems. There are 42.57% of the studies discussed and presented single axis tracking systems while 41.58% of these studies to the dual axes tracking systems. In the recent research studies, the most common solar tracker drive type was active tracker by 76.42% usage in applications while in the second most impact type is the chronological solar tracker by 7.55%. Furthermore, in the solar tracking techniques, Azimuth and altitude tracking achieved 16.67% in usage, Horizontal tracking by 16.67%, Azimuth tracking by 10%, and polar tracking by 4.44%. [ABSTRACT FROM AUTHOR]

Solar thermal technology to supply process heat in different industrial sectors has become very promising in recent years. Industries can reduce their consumption of fossil fuels by replacing them with solar process heat with non-conventional system integration and using clean energy. In this paper, a systematic review of 10 countries is presented which demonstrated extensive use of solar industrial process heating systems in their manufacturing sectors. This country-wise analysis is then used to compare with current Australian scenario and identify future prospects of integrating solar process heating in Australian industrial sectors. The choice of countries is based on a database where promising industrial sectors and solar process heating applications are currently using incident solar energy. These are analyzed for their potential of integration to developing solar heat in industrial processes (SHIP) and a number of potential industrial sectors that have the highest potential like Motor vehicles, Textiles, Printing, Wood, Paper, Fabricated metal, Rubber and plastics, chemicals, Food, beverages, electrical equipment, machinery, and equipment are being identified. An overview of available studies is discussed in this paper focused on specific countries and the industrial heat demand of existing operational plants. Future trends due to solar energy potential are also outlined. [ABSTRACT FROM AUTHOR]

This paper is the first to provide an empirical analysis of the short run and long run effects of carbon dioxide (CO 2 ) emissions on health care spending across U.S. states. Accounting for the possibility of non-linearity in the data and the relationship among the variables, the analysis estimated various statistical models to demonstrate that CO 2 emissions led to increases in health care expenditures across U.S states between 1966 and 2009. Using quantile regressions, the analysis displayed that the effect of CO 2 emissions was stronger at the upper-end of the conditional distribution of health care expenditures. Results indicate the effect of CO 2 emissions on health care was relatively stronger for states that spend higher amounts in health care expenditures. The primary policy message of the paper is that there can be tangible health related benefits associated with policies that aim to reduce carbon emissions across U.S. states. [ABSTRACT FROM AUTHOR]

To meet the demands for screening out the optimal utilization channel for biomass from wheat straw, a number of researches have been reported in the comprehensive utilization about wheat straw including cellulose, hemicellulose and lignin. By reviewing the research status, processing method and comprehensive application of wheat straw, this paper summarizes the application fields, main pretreatment processing methods and bio-products of wheat straw. The paper also detailed novel pretreatment methods and bio-products during the comprehensive utilization of wheat straw. The assessment of more effective pretreatment methods has enabled the examination of wheat straw materials’ potential in the field of lignocellulose that, today, is little exploited. Bioconversion of lignocellulose to bioproducts e.g. bioethanol, biohydrogen and bio-composites has made achievements, however, several limitations such as pretreatment methods remain to be solved. [ABSTRACT FROM AUTHOR]

Carbon capture, utilization, and storage (CCUS) is a crucial strategy for achieving CO 2 emission reduction targets and mitigating the impacts of global warming and climate change. Among various CCUS technologies, chemical absorption of CO 2 has proven to be a mature and widely-used technique in various industrial sectors. However, the current CO 2 chemical absorption process involves large-scale equipment with low efficiencies, making it difficult to control. To address these issues, microfluidic devices have emerged as a promising technology to intensify the CO 2 absorption process by providing a smaller required volume, enhanced mass transfer, cleaner and safer operations, higher productivity, and more efficient energy use. This paper aims at presenting a comprehensive literature review on research advances of the microfluidic technology for CO 2 chemical absorption. The review covers various aspects, including microchannel geometries, two-phase flow patterns, mass transfer models, effects of operating factors, and measures to intensify the CO 2 absorption process. In addition, the paper discusses the measurement of interfacial and local parameters, such as liquid film thickness, velocity field, and local CO 2 concentration, which are primordial for understanding the transport phenomena and for optimizing the CO 2 absorbers. This paper may serve as an essential reference that contributes to the development and exploitation of highly-efficient microfluidic-based CO 2 chemical absorption technology for future large-scale industrial applications. [Display omitted] • Recent researches on microfluidic-based CO 2 chemical absorption are reviewed. • Absorption performance is determined by the mass transfer between CO 2 and absorbent. • Effects of influencing operational factors are discussed. • Optical techniques are frequently used to measure local & interfacial parameters. • Different techniques used to intensify the CO 2 absorption process are surveyed. [ABSTRACT FROM AUTHOR]

Existing pieces of literature on previous studies advocate the research focus by various researchers to reach the benchmark of energy efficiency of Wastewater Treatment Plants (WWTPs). The driving factors to improve the energy efficiency and mitigate the energy self-sufficiency of WWTP have been identified as the increase in population growth, rising energy costs, and tightening effluent discharge requirements. WWTP economy is directly related to energy consumption and thus affects smart grid economy. There has been limited research on energy self-sufficiency and optimizing the energy demand and cost of WWTP, where the significant contributing factors are in development an optimal pumping system and advanced motor technologies. Moreover, high quality WWTP's effluent depends on the concentration level of biochemical oxygen demand (BOD) and total kjedhal nitrogen (TKN). Even so, WWTPs are always subject to evident nonlinearities and uncertainties, making it difficult to define proper optimization objectives. Besides, controllers and control systems have a strong influence on the performance of the plants. Therefore, existing research gaps to achieve optimal efficiency with minimized energy consumption and costs are the design of the WWTP plant, pumping system, motors, selection of suitable controllers and control systems, and their parameter optimizations to get the optimal output from the plant, switching techniques, challenges and uncertainties associated with plant are highlighted in this paper. Thus, as a novel contribution to the literature, this study aims to review and analyze the history, current issues, and future directions of WWTP control technologies in the context of sustainable development. The rigorous study by the authors in this paper will definitely lead the academic researchers and industry partners toward the development of optimal WWTP technologies with improved efficiency and minimized energy consumption and costs. • Effective control techniques and monitoring of the wastewater treatment plant. • Optimal energy-efficient WWTPs with renewable sources and the utility grid. • Uncertainties of WWTP can be considered for improved operation. • Effective policies should be imposed by combining academics and industry. • Reduced energy consumption and cost can be achieved. [ABSTRACT FROM AUTHOR]

The so-called energy transition has been associated with decreasing dependence on fossil fuel energy and low environmental impacts. Additionally, several communities worldwide still face energy poverty, with no or limited access to energy services. This paper evaluates the environmental and economic aspects related to replacing diesel-based power systems with photovoltaic and battery storage systems in a small indigenous community in northern Brazil. Nine environmental categories were analyzed for the life cycle perspective, from which it was established that the benefits of the photovoltaic system outperformed the diesel-based system in seven of the nine categories i.e., climate change (by a difference of 189.8 t CO 2 -eq over the system's lifetime, i.e., 300 MWh generated over 25 years), fossil depletion (by 66.7 t oil-eq), environmental toxicity (by 1.4 t 1,4-DCB-eq), particulate matter formation (by 1.5 t PM10-eq), photochemical oxidant formation (by 4.8 t NMVOC), terrestrial acidification (by 2.5 t SO 2 -eq), and eutrophication (by 1.7 t nutrients-eq). On the other hand, metal depletion showed similar values for both cases, while the diesel-based system was associated with lower human toxicity (by 14.8 t 1,4-DCB-eq) given the high usage of toxic metals when manufacturing the battery systems. Regarding the economic aspects, from stochastic analysis, the results for replacing diesel-based systems result in average savings of around 9 thousand USD over 25 years. Hopefully, these positive results might stimulate policy efforts that lead to mitigating energy poverty in Brazilian indigenous communities. • LCA and economic analysis of a PV and battery system compared to a diesel-based one. • The PV and battery system is superior in seven out of nine environmental categories. • The PV and battery system leads to savings of around 9 thousand USD over 25 years. • Social benefits are highlighted with a loss of power supply probability of only 0.2%. • The results of the paper might stimulate policy efforts to mitigate energy poverty. [ABSTRACT FROM AUTHOR]

The emergence of peer-to-peer, collective or community self-consumption, and transactive energy concepts gives rise to new configurations of business models for local energy trading among a variety of actors. Much attention has been paid in the academic literature to the transition of the underlying energy system with its macroeconomic market framework. However, fewer contributions focus on the microeconomic aspects of the broad set of involved actors. Even though specific case studies highlight single business models, a comprehensive analysis of emerging business models for the entire set of actors is missing. Following this research gap, this paper conducts a systematic literature review of 135 peer-reviewed journal articles to examine business models of actors operating in local energy markets. From 221 businesses in the reviewed literature, nine macro-actor categories are identified. For each type of market actor, a business model archetype is determined and characterised using the business model canvas. The key elements of each business model archetype are discussed, and areas are highlighted where further research is needed. Finally, this paper outlines the differences of business models for their presence in the three local energy market models. Focusing on the identified customers and partner relationships, this study highlights the key actors per market model and the character of the interactions between market participants. [Display omitted] • Systematic literature review of 135 peer-reviewed journal articles. • Structured analysis with the business model canvas framework from Osterwalder. • Shedding light on emerging business models in markets for local energy trading. • Macro actor categories in P2P, CSC, and TE models are identified and characterised. • Value propositions, key partner and customers and financial structures are discussed. [ABSTRACT FROM AUTHOR]

A fiber-reinforced composite wind turbine blade (WTB) is exposed to numerous impact threats during its service life causing damages that can be detrimental to its structural integrity. Currently, impact loads are not considered during blade design, so high safety factors are introduced, which result in a conservative design. However, as wind turbine blades become stiffer and lighter and health monitoring systems become more sophisticated, the design process is shifting toward damage-tolerant approaches. The design philosophy accepts damages to the structure, but it also requires that the damaged blade still meet structural and functional requirements. This design procedure requires a comprehensive understanding of different impact threats and their characteristics, which is currently unavailable in the public domain. This paper is a first attempt to review the impact loads on composite wind turbine blades. The aim of the current paper is to (a) identify different sources of impact threats on wind turbine blades during different stages of their service life, (b) describe their qualitative (causes and vulnerable regions) as well as quantitative characteristics (size, mass, and velocity of impactor), and to (c) provide modeling guidelines by comparing these impact threats using five different criteria - (i) relative deformability of projectile and wind turbine blade, (ii) impact velocity, (iii) kinetic energy of impact, (iv) repeatability of impacts and (v) nature of the impact. The review paper will be of special interest to researchers working on wind turbine blades and will serve as a baseline report for designing damage-tolerant blades. Recommendations are also provided for future research. • Different sources of impact threats are identified on wind turbine blades during different stages of their service life. • Qualitative and quantitative characteristics of impact Loads are comprehensively described. • Modeling guidelines are provided by comparing the impact threats using five different criteria. [ABSTRACT FROM AUTHOR]

Over the past decade, energy storage in renewable energy-dominated systems has received increasing interest. Effective energy storage has the potential to enhance the global hosting capacity of renewable energy in power systems, accelerate the global energy transition, and reduce our reliance on fossil fuel-based generation. Pumped hydro storage (PHS) is the most common storage technology due to its high maturity, reliability, and effective contribution to the integration of renewables into power systems. Accordingly, it is essential to achieve the optimal operation of energy systems combined with PHS. Therefore, this paper comprehensively reviews recent efforts toward the optimal operation of PHS-based energy systems (PHS-BES), considering the diversified energy sources, configurations, grid connectivity, and research directions. The evaluation criteria for the optimal operation of these systems are mathematically addressed and discussed. Moreover, methods of solving the studied problem are categorized and several improvements are suggested. It is observed that more flexible energy policies are urgently needed to encourage new investments in PHS, and the existing environmental and social criteria require further research. Moreover, the hybridization of PHS with other storage devices should be further investigated, and the development of robust hybrid methods for solving the optimal operation of PHS-BES, especially for real-time applications, is highly promising. Based on an in-depth analysis, this paper provides a compendium of real-world research and industry-oriented challenges, and presents future research and industry trends for the optimal operation of PHS-BES. • The latest studies on the optimal operation of PHS-BES are reviewed. • PHS-BES are categorized based on the number and type of integrated energy sources. • The evaluation criteria and solving methods for the optimal operation of PHS-BES are discussed. • A compendium of real-world research and challenges is presented. • Future research on PHS-BES is concluded. [ABSTRACT FROM AUTHOR]

Much uncertainty surrounds the cost-effective deployment of green hydrogen technologies. Policy must navigate this uncertainty when deciding on policies of support. However, evidence to guide this process is scattered across multiple disciplines. This paper collates findings from fields of economics, engineering, political economy and behavioural science. We propose a method of progressive elimination to navigate the disparate strands of literature and associated uncertainties. We demonstrate a method to identify likely timescales of cost-effective deployment and associated policy interventions, for electricity, space heat, transport and industrial applications, conditional on assumed cost trajectories. The procedure proposed in this paper may be applied to many contexts and will be of increasing importance as decarbonisation constraints continue to bind. • Multidisciplinary literature review (economics, engineering, political economy and behavioural science) to inform hydrogen deployment and policy decisions. • Framework to navigate disparate literatures for policy decision-making proposed. • Public support for hydrogen-based heating systems is a high-risk strategy. • Many applications are market-driven and policy intervention should focus on facilitating timely adoption of those technologies. • Access to credit and behavioural interventions of particular importance for household-level interventions. [ABSTRACT FROM AUTHOR]

This paper presents a systematic literature review of solar energy studies conducted in Nordic built environments to provide an overview of the current status of the research, identify the most common metrics and parameters at high latitudes, and identify research gaps. 55 publications are included in the review and categorized according to three main urban spatial domains: (i) outdoor, (ii) envelope, and (iii) indoor. In addition, a category for publications investigating more than one spatial domain (multi-domain) is included. The first part of the paper presents a publication analysis of keywords, history and methods, channels, citations, geographical distribution, and spatial domain coverage. In the second part, the main findings for each urban spatial domain are presented and discussed. The results show that the majority of the studies applied numerical methods in their workflow and the envelope is the most researched spatial domain, with studies focusing either on the potential exploitation of solar energy through active solar systems, or the prediction of indoor daylight conditions by using the façade as a proxy for the indoor domain. Among the main findings, urban density, building morphology, and orientation are the most utilized parameters, while solar irradiation and direct sunlight are the most common metrics. This review paper reveals significant research gaps in the field of solar accessibility in high-latitude Nordic built environments: (i) numerical studies that simultaneously address and interlink all three urban spatial domains are missing; (ii) deeper investigation of the outdoor domain is needed. • Growing interest in the field of solar accessibility in high-latitude urban areas. • Urban density, building morphology and orientation identified as common parameters. • Solar irradiation and direct sunlight identified as the most utilized metrics. • Most researched urban spatial domain is the envelope while outdoor is the least. • Significant gap in the research of numerical studies overarching multiple domains. [ABSTRACT FROM AUTHOR]

Many studies have been conducted on the distribution network expansion planning (DNEP) problem in recent years. The primary goal of this issue is to satisfy electric load demand, taking into account economic and technical considerations. In the past, this planning was done in a centralized manner with all the information available. The restructuring of power networks and the emergence of renewable energy sources (RESs), energy storage systems (ESSs), and new market players with different interests have led to extensive changes in the DNEP issue. Subsequently, the solving methods of the DNEP problem will be important because many new goals, constraints, and other factors have caused the problem to become non-linear and non-convex. This paper prepares a comprehensive study on the DNEP problem from different aspects such as objective functions and constraints, design variables, planning horizon and phases, planning and system types, uncertainty, distributed generations (DGs) and storage units, planning level, solving methods, load models, and environmental issues. Finally, future research trends such as handling the conflicts, solving approaches, and other points facing the DNEP problem are suggested. • A comprehensive survey of studies that address the distribution network planning. • Proposing posterior approaches for the solving the DNEP problem. • Proposing bi-level model to consider medium and low voltage networks, simultaneously. • Providing suggestions for further research works. • A discussion about future work/research/challenge trends for the DNEP models. [ABSTRACT FROM AUTHOR]

Over the years, numerous studies have explored the green synthesis of ethylene. Within this context, the focus of this perspective shifts toward plasma technology, which has demonstrated the capability to convert methane into ethylene. Plasma catalysis creates distinctive physical and chemical environments, particularly at normal temperature and pressure, distinguishing it from alternative methods. Nevertheless, the utilization of atmospheric pressure plasma is intricate, posing scientific challenges in the realms of physics and chemistry. In this viewpoint, various key performance aspects are evaluated, encompassing methane conversion efficiency, ethylene selectivity, and specific energy input. These scientific pros and cons are then assessed for their readiness for industrial-scale implementation. Initially, the potential for small-scale ethylene production is examined, leveraging existing robust process technologies to unlock fresh market and supply chain opportunities. Subsequently, the sustainability of plasma technology for green ethylene production is compared to conventional ethylene production and alternative green ethylene production methods, including biomass-based approaches. Contrary to perhaps optimistic expectations, current literature evidence does not uniformly favor the latter, indicating the potential for plasma-based green ethylene processes. Additionally, this paper underscores the importance of considering Environmental, Social, and Governance factors that influence business decisions. Finally, this review underscores plasma technology as a potentially promising approach for green ethylene synthesis from methane, offering unique advantages under normal conditions while simultaneously presenting scientific challenges. It assesses its viability for small-scale production and benchmarks its sustainability against conventional and alternative methods, emphasizing the importance of a sustainable future for the green petrochemical industry. • Potentials of plasma catalytic methane conversion are compared with other green methods. • Conversion efficiency, selectivity, and sustainability are reviewed in terms of specific energy input. • Small-scale plasma technology enables robust ethylene production and opens new market opportunities for green synthesis. • Green ethylene is analyzed in relation to green hydrogen and ammonia from different aspects. • Plasma-based green ethylene processes are more sustainable than conventional and biomass-based methods. [ABSTRACT FROM AUTHOR]

Rapidly evolving renewable energy generation technologies and the ever-increasing scale of renewable energy installations are driving the need for more accurate, faster, and smarter health monitoring methods. Machine learning (ML) has been widely used for defect identification and fault diagnosis (DIFD) in renewable energy systems (RES) due to its excellent data analysis and pattern recognition capabilities. However, there is still a lack of comprehensive and in-depth research to summarize the progress of ML in RES DIFD. Considering their diversity and evolution, this research systematically reviews the application of ML to DIFD in photovoltaic and wind power systems, providing a detailed analysis of key points, including defects and faults in RESs, available data for DIFD, and ML-based solutions. For each ML application, the model and structure, input and output settings, sample size, equipment technology and scale, target defects/faults, performance, and limitations are discussed. In addition, based on the statistics, analysis, and summary of representative works on RES DIFD, several commonly used ML algorithms are compared. The main trends, challenges, and prospects of applying ML to RES DIFD are extracted and presented. This research is of great significance in guiding further improvements of ML techniques to address the problems of RES DIFD. [Display omitted] • Review of papers applying ML techniques to RES DIFD. • Common defects, faults, and their severity in RESs are discussed. • Available data when applying ML to RES DIFD are summarized. • Performance and limitations of various ML applications are investigated. • Challenges and prospects for RES DIFD using ML techniques are presented. [ABSTRACT FROM AUTHOR]

This paper presents a systematic review to align current and future research in smart grids (SG) and smart urban energy systems (SUES) and unify the diverse but fragmented research in urban energy management. First, the common research themes repeatedly appearing in the SG and SUES literature are categorized into logical physical, cyber, and social energy processes. Critical findings are summarized for each part, i.e., the advances and trends in physical energy generation, transmission, consumption, and storage processes of cities for energy interventions, the cyber process chain of energy sensing, modeling, forecasting, scheduling, coordinating, and adapting for enhancing the "smartness" of power and urban energy systems, and the social energy processes of understanding, protecting, engaging, and governing human to be a new smartness dimension. Second, the process-based framework provides insights on the design and implementation of SG and SUES for engineers, planners, and policymakers, such as optimizing the system performance by upgrading individual processes and exploring new links among identified physical, cyber, and social energy processes. The upscaling barriers and strategies of sustainable energy technologies in the development and deployment stages are also summarized to scale up sustainable energy processes to a higher level. Finally, future research directions are envisioned, including developing data markets, privacy-preserving data sharing and analytics for urban-scale energy modeling, refining policy and standards for safety, privacy, cybersecurity, and interoperability issues, assessing technology maturity and energy system success factors, and removing regulatory and structural barriers. [Display omitted] • A systematic review intersecting smart grid and smart urban energy systems is done. • A holistic multi-scale multi-process cyber-physical-social framework is developed. • Advances and trends in physical/cyber/social energy processes are reviewed. • Sustainable upgradation, integration, and scale-up of energy processes are suggested. • Guidelines and future directions are given for smart grid and urban energy systems. [ABSTRACT FROM AUTHOR]

This paper develops quantitative predictions for residential electricity demand and the potential for load shifting for Europe at a fine spatial scale for years 2022–2050. To date only theoretical and spatially coarse measurements of this potential exist for a subset of technologies used in the residential sector. As the EU moves towards an 'Energy Union', it will be increasingly necessary to consider the whole integrated energy system across the EU and thereby databases with large spatial coverage are needed. To fill this need, we generate hourly load profiles for the residential sector for key electricity consuming devices that take into account the most recent empirical studies of usage patterns, and of the cost and willingness of households to participate in load shifting programs. Additionally, we extend the list of investigated technologies by the important classes of electric mobility and heat pumps for electric space heating. Predictions and insights provided in our article serve multiple use cases, i. they can be used in energy system models to assess the value of load shifting for the future energy system including system costs, ii. they enable infrastructure planners and grid operators to calibrate their expectations of the future role of load shifting in the electricity systems and iii. enable policy makers and to include load shifting in their considerations of future market designs. • Quantitative predictions for residential electricity demand and the potential for load shifting for Europe at a fine spatial scale for years 2022–2050. • Residential coverage of electric vehicles, heat pumps, storage heaters, water heaters, air conditioners, refrigeration, and washing equipment. • Substantial potentials are identified for electric vehicles and heat pumps. [ABSTRACT FROM AUTHOR]

Solar energy offers over 2,945,926 TWh/year of global Concentrating Solar Power (CSP) potential, that can be used to substitute fossil fuels in power generation and mitigate 2.1 GtCO 2 of greenhouse gas (GHG) emission to support Sustainable Development Goals (SDGs) set by the United Nations (UN). Thermal energy storage (TES) is required in CSP plants to improve dispatchability, reliability, efficiency, and economy. Of all TES options, the latent heat thermal energy storage (LHTES) together with phase change materials (PCMs) exhibit the highest potential in terms of efficiency and economy. PCM properties thus become the ultimate decider of CSP performance. This paper reviews over 200 of published articles and websites to describe the history, identify the technologies, economics, and current trends of PCM as LHTES material for CSP plants. A list of 163 PCM candidates suitable for LHTES systems in low-temperature (T < 220 °C), medium-temperature (220 °C < T < 420 °C), and high-temperature (T > 420 °C) applications is presented for the first time. Research gaps are identified to determine the future directions. • CSP shows remarkable potential in global electricity generation. • Intermittency of solar has made the requirement of a TES for CSP system. • We evaluate the advantages of LHTES for storing thermal energy. • LHTES shows 5–14 times the energy density of SHTES allowing for more compact storage and lower inventory requirements. • Selection of a compatible PCM is crucial for operating the LHTES at desired performance level. [ABSTRACT FROM AUTHOR]

To meet environmental goals while maintaining economic competitiveness, worldwide ports have increased the amount of renewable energy production and have focused in optimizing performances and energy efficiency. However, carbon-neutral operation of industrial port areas (IPA) is challenging and requires the decarbonization of industrial processes and heavy transport systems. This study proposes a comprehensive review of decarbonization strategies for IPA, with a particular focus on the role that green hydrogen could play when used as renewable energy carrier. Much information on existing and future technologies was also derived from the analysis of 74 projects (existing and planned) in 36 IPAs, 80 % of which are in Europe, concerning hydrogen-based decarbonization strategies. The overall review shows that engine operation of ships at berth are responsible of more than 70 % of emissions in ports. Therefore, onshore power supply (OPS) seems to be one of the main strategies to reduce port pollution. Nevertheless, OPS powered by hydrogen is not today easily achievable. By overcoming the current cost-related and regulation barriers, hydrogen can also be used for the import/export of green energy and the decarbonization of hard-to-abate sectors. The technical and economic data regarding hydrogen-based technologies and strategies highlighted in this paper are useful for further research in the field of definition and development of decarbonization strategies in the IPA. • Comprehensive review of decarbonization strategies for industrial port areas. • Hydrogen-powered cold ironing can have a great impact in reducing emissions. • Hydrogen FC is an emission-free option for port heavy-duty vehicles/equipment. • Hydrogen hubs in ports can help decarbonize heavy industry and shipping sectors. • 74 projects considering hydrogen production/use to decarbonize IPA are analysed. [ABSTRACT FROM AUTHOR]

Energy justice is often approached through the four tenets of procedural, distributive, restorative and recognition justice. Though these tenets are important placeholders for addressing what type of justice issues are involved, they require further normative substantiations. These are achieved by using principles of justice to specify why – normatively speaking – something is just or unjust within each category or tenet of justice. In addressing the principles of justice, it is important to acknowledge normative uncertainties, or the fact that different (incompatible) conceptions of justice might be morally defensible, leading to different normative conclusions or policy recommendations. This paper reviews the definitions of tenets in energy justice scholarship, the occurrence of normative claims, and how these claims are justified. The review shows that the scholarship ignores to a large extent normative uncertainties. In response, we propose a revisited energy justice framework, focusing on four aspects that help us to articulate the normative uncertainties in both the principles and the tenets of energy justice. These aspects are (i) the scale of justice (i.e. whether justice is considered at a local, national, regional, multinational or global scale), (ii) the subject of justice, (iii) the body of knowledge that is assumed and (iv) the time frame in which justice issues are being considered. We hope to provide a conceptual framework that make explicit the different types of normative assumptions underlying claims of justice, which will ultimately improve the quality and legitimacy of normative conclusions such as policy recommendations that follow. • Tenets of justice are in need of further normative substantiations. • Most articles that apply the tenets do not explicitly justify normative claims. • Justifications that were provided considered one interpretation of justice. • The energy justice scholarship ignores to a large extent normative uncertainties. • Normative uncertainty pertains to principles, scale, subject, knowledge, and time. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) are widely used in electronic devices and electric vehicles. With the increasing demand for lithium-ion batteries, it is necessary to develop safe LIBs with high energy density. Nanofibers prepared by electrospinning have many advantages, including small diameters, large specific surface area, small pore sizes, high porosity, and good pore connectivity. Therefore, electrospun nanofibers are extensively used in energy-related applications, while electrospun films exhibit excellent ductility and can be potentially utilized in flexible batteries. This paper focuses on the recent advances in electrospinning nanomaterials for the anodes and separators of LIBs. In addition, electrospinning can be performed to produce materials for sodium/potassium-ion batteries and solid-state batteries. Finally, the commercialization of electrospinning technology and prospects of battery industrialization as well as the future development of LIBs and other alternative materials are discussed. • Recent progress on separators and anodes of LIBs fabricated by electrospun and industrialization prospects are reviewed. • Methods for enhancing electrospinning materials for LIBs are summarized. • Challenges for the development of electrospinning materials as anode and separator are outlooked. [ABSTRACT FROM AUTHOR]

To achieve the goal of carbon neutrality, society must undertake a comprehensive green transformation and build a decarbonization roadmap. Model simulation is a primary method for designing and analyzing long-term low-carbon roadmaps. This paper aims to examine the various capabilities of Energy-Economy-Environment (3E) models to gain an intuitive understanding of the current status, as well as future development directions and potential, from a low-carbon analysis perspective. By reviewing various existing 3E models considering their modeling approach, theoretical framework and spatiotemporal resolution, the 10 most representative models are selected for an in-depth analysis. According to the evaluation results of the selected models while considering five challenges for future model development, most models perform well in terms of techno-economic resolution and transparency. However, there is still potential for improvement regarding spatiotemporal resolution and the consideration of social factors. Moreover, to bridge the gap between top-down models and the real-world context, it is recommended to combine them with bottom-up models to form hybrid models. Generally, the PRIMES model demonstrates the best overall performance, although it cannot be regarded as perfect. The review and assessment results can provide references for modelers to improve 3E models and serve as a basis for users to choose the most suitable model. • Ten typical 3E models with the highest use frequency are summarized and classified. • Challenges of 3E models for long-term low-carbon roadmaps research are discussed. • An evaluation framework is established for 3E models considering five abilities. • The prospects for future development of 3E models are proposed. [ABSTRACT FROM AUTHOR]

Storing CO 2 and H 2 in underground reservoirs represents an effective approach to sequester increasing amounts of captured CO 2 for carbon neutrality and to store H 2 to promote clean energy revolutions. However, commercial/pilot-scale CO 2 /H 2 storage sites are mainly restricted to conventional oil reservoirs or salt caverns – both capacity and geographic-location limited. This paper presents a systematic review of the feasibility and prospects of CO 2 and H 2 storage in fractured shale reservoirs as secure repositories. Both field pilot and laboratory studies of CO 2 injection in shales are cross-analyzed across various spatial and time scales, to provide a reliable and substantial basis to support new findings. The presence of suitable injectivity and adequate sealing capacity in shale are demonstrated. The fracture networks are shown to provide major storage space in shales, contrasting with the pore system in conventional reservoirs. This difference in storage mechanisms results in an overestimation in the storage capacity of shales when applying porous-medium-based methods. An underestimation in the mass of injection, however, is apparent from a single well for the reported cases due to unknown characteristics of underground fracture networks. The symbiotic storage of CO 2 and H 2 in shale is discussed in its feasibility and ability to improve both CO 2 storage but principally H 2 recovery – due to the presence of a gas cushion. A new equivalent-fracturing method is proposed as a supplement to recalibrate the over- and under-estimated prospects of CO 2 /H 2 storage in shales – a necessary component in reducing carbon emissions and accelerating the energy transition. [Display omitted] • Field pilots and laboratory studies are cross-analyzed and validated. • Fracture networks in shale reservoirs dominate CO 2 and H 2 storage. • Over- (in shales) and under- (in wells) estimations of CO 2 storage are revealed. • New estimation method is proposed for the technically achievable storage capacity. • Symbiotic storage of CO 2 and H 2 in shales is feasible and promising. [ABSTRACT FROM AUTHOR]

Wood chips are the primary sources of raw materials for numerous industries, including pelleting mills, biorefineries, pulp-and-paper industries, and biomass-based power generation facilities. Unfortunately, when wood chips are utilized as a renewable and environmentally friendly resource, industries are constantly challenged by the consistency of the wood chip qualities (e.g., moisture/ash contents, size distributions) - a historically recognized problem on a global scale. Among other wood chip quality attributes, the moisture content is considered the most pressing one as it directly impacts the energy content, storage stability, and handling properties of the raw and finished products. Therefore, accurate wood chip moisture content prediction can help optimize the drying process and reduce energy consumption. In this review, a survey was conducted on various techniques and models employed for predicting wood chip moisture content. The advantages and limitations of these approaches, as well as their potential applications and future directions were also discussed. This review aims to provide a comprehensive overview of the current state-of-the-art in wood chip moisture content prediction and to highlight the challenges and opportunities for further research and development in this field. • Oven drying is the most used method despite being slow and prone to sampling errors. • Indirect methods are fast but have individual shortcomings based on applications. • Due to reliance on direct method for data labeling, wood chip datasets are small. • Box-based data collection methods and regression-based models are prevalent. [ABSTRACT FROM AUTHOR]

Coal-fired power plants still dominate the electricity market in Southeast Asia, supplying around 30 % of the total demand, and the demand trend for this sector will continue to be high for decades to come. As a result, coal fly ash (CFA) production has also increased rapidly. However, most countries in this region consider them hazardous waste due to the immense potential for destroying living things and the environment. An increase in the utilization rate of CFA will undoubtedly result in numerous economic and environmental benefits. This article provides an intensive update regarding the current development of CFA utilization research and its realization. This article also provides a specific summary of its use as a medium for valuable materials. Recent studies have proven that CFAs have significant potential due to their physical and chemical characteristics. CFA can be further utilized as an adsorbent, catalyst, mesoporous, and synthesis material for high-efficiency zeolite. By working out the strategies proposed in this paper and the latest research results, the possibility of their utilization can be increased. Thus, the potential of CFA can be utilized to its fullest extent as one of the instruments for Southeast Asia to become a better and more sustainable region. [Display omitted] • Intensive updates regarding the current research developments on using coal fly ash and its realization in Southeast Asia. • Provide information on the potential utilization of coal fly ash due to its physical and chemical properties. • Coal fly ash can be further utilized as adsorbents, catalysts, and in the synthesis of high-efficiency zeolites. • The potential for optimal utilization of coal fly ash can make Southeast Asia a better and more sustainable region. [ABSTRACT FROM AUTHOR]

The global demand for raw materials in technology, combined with environmental regulations and growing social awareness about the negative impacts of traditional metal extraction processes, has led to a shift towards green technology. Green technology has been defined as the use of science and technology to create less harmful products that protect the environment. Since biogenic cyanide (bio-CN) is naturally produced by microorganisms and is biodegradable, its use in precious metals (PMs) recovery from metal-bearing resources can be considered a viable and green alternative to chemical cyanidation. Several microorganisms are known to produce bio-CN, however, only a few such as Chromobacterium violaceum (C. violaceum), Pseudomonas fluorescence (P. fluorescence), Bacillus megaterium (B. megaterium), Pseudomonas aeruginosa (P. aeruginosa), Pseudomonas chlororaphis (P. chlororaphis) have been quantified. The present review summarizes research on cyanogenic microorganisms known to produce bio-CN, the mechanism and metabolic pathways involved in bio-CN production, and the genetics of cyanide production. This paper also discusses the factors influencing bio-CN production and the methods used for its quantification. The application of bio-CN in leaching PMs i.e., gold (Au), palladium (Pd), platinum (Pt), and rhodium (Rh) from primary and secondary resources, pre-treatment approaches used, and the mechanism of residual bio-CN detoxification are systematically and comprehensively reviewed and provided. Further, the review provides essential insights into challenges faced during bio-CN production and its application in PMs leaching and offers insight into new ways of thinking to move the process towards commercialization. [Display omitted] • Bio-CN is a natural, eco-friendly, and green alternative to chemical cyanide for a sustainable future. • A comprehensive review of the microbiology and chemistry of bio-CN production. • Discussion on the feasibility of bio-cyanidation in precious metal extraction from metal-bearing resources. • Review of the bio-CN analytical methods and the mechanism of biological detoxification of cyanide. • Challenges in bio-CN production and its application, and suggestions on the way forward to mitigate them. [ABSTRACT FROM AUTHOR]

Through the use of effectively unlimited energy from the environment, contemporary heat pump installations have proven to be a highly efficient means for satisfying both heating and cooling needs. As such, they are often regarded as a key driver in the electrification process of the thermal domain. Keeping in mind the significant share of the thermal demand in building energy requirements, this aspect in particular is projected to have a great impact on the overall energy efficiency improvement of buildings and increase of demand-side flexibility. The latter point is considered crucial for improving the precarious balance against the contemporary intermittent power supply obtained from a variety of renewable sources. However, in the process of increasing their efficiency, heat pump systems are becoming significantly more complex with combinations of various different sources of energy from the ground, air and the Sun. By extension, the complexity of managing their operation has also increased and proves to be a challenge even for experienced plant operators. In order to aid in this regard, relevant literature suggests that optimization algorithms can be considered as a viable tool. This paper explores the limited extent of existing state-of-the-art approaches for hybrid heat pump control via metaheuristic optimization and broadens the subject matter with a comparative study that analyzes and benchmarks several metaheuristic approaches found in the literature on similar problems. A real-world multisource heat pump installation in Ferrara is utilized as the basis for the study. [Display omitted] • Novel systematization of optimization applications for heat pump operation and design. • Modeling approach suitable for novel optimization-assisted control algorithms. • Optimization as an enabler for increased operational efficiency of future HP systems. • Comparative analysis of optimization performances for a selection of metaheuristics. • Analysis of reference tracking and convergence results in GA being the best algorithm. [ABSTRACT FROM AUTHOR]

The increasing participation of intermittent renewable energy sources (RES) in modern power systems makes expansion and operational planning an even more complex task, especially in hydro-based systems. To properly assess the impact that intermittent generation may have on generation expansion planning (GEP) decisions, higher temporal resolution methodologies for GEP are required that take into consideration the system operation as well. This paper proposes a soft-linking methodology for the GEP problem of large hydrothermal power systems with increasing expansion of RES. The proposed methodology coordinates power system models ranging from expansion planning to hourly hydrothermal scheduling. It has been applied to a ten-year expansion planning of the Brazilian power system: the importance of considering the short-term wind generation intermittency is demonstrated by the necessity of changing the original expansion plan both in terms of installed generation and interconnection capacity. • Soft-linking of mature tools for expansion planning of hydrothermal systems with RES • Quantifies changes needed in expansion plan due to uncertainty and variability of RES • Results for large-scale actual hydro-thermal system of engineering practice interest [ABSTRACT FROM AUTHOR]

By exploiting the 3 K coldness of outer space as heat sink of terrestrial thermal radiation, passive daytime radiative cooling (PDRC) can achieve sub-ambient temperatures without any energy consumption, and thus exhibiting extraordinary application potentials. By pursuing the dual-band (solar and atmosphere window) optical properties to approach ideal 100 %, PDRC can maximize dissipating long wavelength infrared radiation to space and minimize absorbing sunlight simultaneously. PDRC technology can reach146 W/m2 theoretical cooling power and up to 120 W/m2 during application. This article focuses on the fundamental physics mechanism of radiative transfer and natural radiative cooling phenomena. Methodologies of infrared absorption functional group selection, optical band gap selection for solar reflection, photon and phonon enhanced resonance by micro-structure were discussed in detail to give a comprehensive instructing strategy of radiative cooling power improvement. Although PDRC technology can achieve sum-ambient temperature cooling without consuming any energy, its drawbacks such as single function of cooling and high whiteness requirement needed to hinder its large-scale application. This article also outlines the current primary applications of PDRC technology, along with summarizing the challenges and potential opportunities it encounters in practical implementation. This paper aims to provide a comprehensive overview on the fundamental physical mechanisms, methods for enhancing its power output, as well as the current state and future developments of PDRC applications, providing potential guidance for reducing greenhouse gas emissions and energy consumption. • Advancements of radiative cooling technology were reviewed comprehensively. • Fundamental physics of passive radiative cooling was reviewed comprehensively. • Material selection methodology and optical mechanism were discussed in detail. • The recent application of passive daytime radiative cooling was reviewed. • Some current challenges and potential applications were presented and discussed. [ABSTRACT FROM AUTHOR]

Patent bases are still underused in academic studies. On the other hand, the development and implementation of cleaner production requires innovative solutions. The present paper aims to analyze the state of the art that uses the information in patents for scientific production and technological monitoring in cleaner production. Its construction is based on applying bibliometric techniques using the Scopus database, considering 1993–2022, and analyzing the basic characteristics of fifty identified publications. This analysis shows that the relationship between scientific production and technological monitoring of cleaner production through patents is still incipient. In contrast, most studies identified used patent data for statistical, economic and production evaluations, but not exactly on clean technologies and their evolution and application concerning the state of the art contained and available in patents. Patent documents present detailed information regarding products and processes, becoming a valuable data and knowledge source for sustainability research, where, among several possibilities, it is possible to identify sustainable technologies, emerging trends, environmental impact assessments of various processes, technical and economic viability, research opportunities, among others. • Necessary to promote inclusive and sustainable industrialization, encouraging innovation based on the patents monitoring. • A reduced number of authors are part of the co-inventors network. • Patents should be used in academic and industrial studies to create research networks. • Patent monitoring is not yet being used to increase the quality of cleaner production studies. [ABSTRACT FROM AUTHOR]

Ammonia is a promising alternative for the storage and transport of renewable hydrogen over long distances. In this paper, a techno-economic assessment was conducted to evaluate the levelized cost of hydrogen (LCOH) produced from renewable ammonia feedstocks. Both thermal and electrochemical pathways were analyzed. For the thermal pathway we investigated the decomposition using fixed bed reactor and membrane technology, while alkaline electrolysis was studied for the electrochemical route. We evaluated different process scales corresponding to stationary reconversion in a hydrogen refueling station (1000 kgH 2 /day) or an ammonia import terminal (1500 tNH 3 /year) and mobile on-board reconversion for a heavy-duty truck (22 kgH 2 /day). The results show that currently the cheapest option to produce hydrogen from ammonia is the thermal decomposition with membrane technology for import terminal, fixed bed for the hydrogen refueling station, and electrolysis on-board a truck. The levelized cost of hydrogen for the thermal decomposition methods in an ammonia import terminal lie in the range of hydrogen prices produced from today's mix of renewable energy and water as feedstock in Europe. A sensitivity analysis shows that, regardless of the process scale, the parameters with the highest impact on the levelized cost of hydrogen are the reactor temperature for the membrane technology, and ammonia price for fixed bed and electrolysis technologies. The reconversion costs in the latter case are most sensitive to the cell voltage. A future scenario analysis indicates that ammonia electrolysis reconversion costs can be reduced between 14% and 44%, depending on the process scale. [Display omitted] • Currently, the lowest LCOH for NH 3 reconversion in to H 2 is achieved with a membrane reactor in large scale applications. • Electrolysis is the cheapest option to reconvert hydrogen on-board a truck. • In the future scenario ammonia electrolysis continues to be the cheapest option to reconvert hydrogen on-board a truck. • Long distance transportation of H 2 using NH 3 can be cost competitive when reconversion takes place in an import terminal. [ABSTRACT FROM AUTHOR]

Wind turbine nacelles are complex machines that are designed to operate under extreme loads and harsh environments. Extensive tests are performed throughout their development process to ensure that they can operate with high reliability. As both onshore and offshore wind turbine systems have rapidly evolved, so have the methods for testing the nacelle systems and subsystems. This paper presents the state of the art in wind turbine nacelle testing and the development trends in this field. It discusses the existing test requirements for certification and the different levels of testing that form part of a nacelle system's development. The latest changes to the nacelle certification requirements are highlighted, along with several important research activities related to drivetrain testing. Future challenges for nacelle testing are identified and their potential solutions are proposed. [Display omitted] • The state of the art of nacelle system and subsystem testing are described. • The current industrial approach on nacelle testing during the development process is discussed. • Advances made in nacelle system testing and certification relevant tests are described. • Major challenges in nacelle testing of modern wind turbines are highlighted. • Solutions to tackle some of the identified challenges in nacelle testing are suggested. [ABSTRACT FROM AUTHOR]

Air source heat pumps are an excellent electric alternative to fossil fuel based heating systems for reducing residential greenhouse gas emissions, but common mild climate systems suffer significant performance losses at the low outdoor air temperatures experienced in regions with cold climates. Improved heat pumps for cold climates are available on the market, but they are more expensive and their adoption to date has been relatively low, suggesting that there is work yet to be done in this field. This paper presents an analysis of market-available air source heat pumps identifying and discussing the cold climate technologies found in residential centrally-ducted cold climate systems. It shows that all of these heat pumps use rotary or scroll type variable-speed compressors, accumulators, and reverse cycle defrosting, and that a small number also include refrigerant injection and/or specialized refrigerant charge management devices. Available performance data for these heat pumps reveal that most of these systems still exhibit a significant loss of heating capacity at cold temperatures and are unlikely to meet the entire heating needs of a home in regions where temperatures drop below −15 °C, necessitating the use of auxiliary heating systems. A review of the literature on cold climate heat pumps is also included to highlight additional design concepts and innovations that have not yet been implemented by the industry, but might further improve the performance and uptake of heat pumps in cold climates. • The technical challenges facing air source heat pumps in cold climates are described. • Market-available cold climate air source heat pump technologies are analysed. • Most market-available systems operate on single-stage thermodynamic cycles. • New testing and rating methods are recommended to compare cold climate performance. • Cold climate innovations not yet implemented by the industry are highlighted. [ABSTRACT FROM AUTHOR]

Agricultural practices such as successive cropping and irrational fertilization have led to a steady decline in soil fertility in many regions. Humic acids (HAs) are a type of effective additives for enhancing soil fertility, but natural HAs reserves are limited. Artificial HAs can be produced from biomass by biotic composting and abiotic hydrothermal reaction (HTR). The principles, influencing factors, and product characteristics of these methods have been comprehensively summarized in previous reports, but less attention has been paid to issues linked to scaling up production, such as facilities, equipment, process control, and energy consumption. This paper presents a systematic review on the potential engineering issues involved in artificial HAs production to serve as a reference for actual project designs. Biotic method was summarized as mainly based on the type, scale, configuration and control of the reactor. The multifunctional compost reactor showed better HAs production performance, with yields ranging from 35 to 82 g kg−1 and 139–248 g kg−1 at lab- and pilot-scale, respectively. The abiotic method was categorized based on the HTR reaction steps. The two-step and hydrochar methods have high potential for HAs production from recalcitrant biomass, with maximum reported yields of 283 and 435 g kg−1, respectively. A method for evaluating the energy consumption of HTR is presented, estimating the energy input of HTR at 1825–31987 kJ kg−1 HAs, which is mainly influenced by the HAs yield and reaction duration. [Display omitted] • Three types of bioreactors for producing humic acids are summarized. • The structure and function of 16 compost facilities or equipment are analyzed. • Intelligent composting based on classical PID and machine learning is presented. • Hydrothermal reactions classified into three pathways. • Energy input analysis model developed for hydrothermal reactions. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSC) are known as a hot subject in the photovoltaic (PV) field. Several materials are used to fabricate a DSSC, including titanium dioxide/metal oxide-based photoanodes, counter electrodes (CEs), dyes, and electrolytes. An efficient CE should be able to dramatically improve the photovoltaic performance, i.e., power conversion efficiency (PCE) and longstanding stability, in addition to decreasing total DSSC fabrication cost. Platinum (Pt) is commonly applied as CE of DSSCs but Pt is expensive and hence numerous studies have developed cheaper CE alternatives. Herein, a comprehensive review is presented on application of perovskites oxides and spinels utilized as CEs in DSSC devices. Examples of perovskite oxide materials used as CEs of DSSCs are (La 0.8 Sr 0.2) 0.98 FeO 3−δ /MWCNTs, 4% graphene-La 2 CdSnTiO 4 –WSe 2 , SrCo 0.95 P 0.05 O 3-δ /MWCNTs, LaFeO 2.965−δ Cl 0.035 -2-BM, 15%graphene-La 2 CuNiO 6 –ZnSe, (La 0.8 Sr 0.2) 0.95 Ag 0.05 MnO 3−δ /MWCNTs, La 0.5 Sr 0.5 CoO 3 , La 0.67 Sr 0.33 MnO 3 , La 0.65 Sr 0.35 MnO 3 @8%reduced graphene oxide, La 0.5 Sr 0.5 CoO 2.91 @reduced graphene oxide, La 0.7 Sr 0.3 MnO 3 nanoparticles/nitrogen-doped graphene, La 0.7 Ca 0.3 MnO 3 , 2-La 0.9 Ce 0.1 NiO 3 @f-MWCNT-ZnSe-CoSe 2 @CAB, 1:1 La 2 MoO 6 @MWCNT, LaNiO 3 /MWCNTs, SrRuO 3 -graphene quantum dots, Bi 5 FeTi 3 O 15 /graphene-2, Bi 4 Ti 3 O 12 /graphene-3 so that the highest PCEs of 12.4, 12.23, 12.2, 11.4, and 11.00% are measured using the first five CEs. Examples of DSSC devices assembled with spinel cathode materials are FeNi 3 /NiFe 2 O 4 @mGr, FeNi 2 S 4 /rGO, MnCo 2 O 4 @NiCo 2 O 4 /carbon paper (CP), CoNi 2 S 4 /RGO, ZnFe 2 O 4 /CNFs-Ti, CoFe 2 O 4 /graphene, NiCo 2 S 4 /CNFs, NiCo 2 S 4 nanoflowers, NiCo 2 O 4 nanoflower/nanosphere, NiCo 2 O 4 /carbon black, RGO-NiCo 2 S 4 , CuCo 2 S 4 , NiCo 2 S 4 , NiIn 2 S 4 , FeIn 2 S 4 , CoIn 2 S 4 , NiIn 2 S 4 , Co 3 S 4 , CoCr 2 S 4 /CNTs, MoIn 2 S 4 @CNT, and MgAl 2 O 4 so that the highest PCEs of 12.14, 9.98, 9.58 ± 0.06, 9.22, 9.05 ± 0.05, 9.04, and 9 ± 0.06% are measured using the first seven CEs. These results verify that fabrication of CEs using priceless perovskite oxides and spinels affords higher efficiencies and device stability for DSSCs compared to Pt-based devices. [Display omitted] • Applications of AB 2 X 4 spinels were reviewed as cathodes of dye sensitized solar cells (DSSCs). • Applications of inorganic ABX 3 perovskite oxides were reviewed as cathodes of DSSCs. • Replacement and/or modification of the Pt counter electrodes in DSSCs were reviewed. • Improved power conversion efficiencies (PCEs) of DSSCs with Pt-free cathodes were reviewed. • Achievements on superior photovoltaic characteristics of modified DSSCs were reviewed. [ABSTRACT FROM AUTHOR]

Hybrid energy systems have proven their efficacy in improving energy sustainability. This paper focuses on the design and evaluation of various hybrid energy systems for hot water production in the experimental plant of the Laboratory for Quality Control in Buildings. The experimental facility was created to test and control various systems for energy supplies in buildings. In this work, three thermal installations were investigated: (1) a combined boiler cogeneration system, (2) a combined boiler solar collector system, and (3) a combined boiler heat pump system. After configuring each system in the laboratory, defining the control, and running the experimental essay, the corresponding data were obtained and treated. The exergy concept matches very well with the goal of promoting new systems that efficiently integrate renewable and nonrenewable energy resources. The exergy analysis and its extended assessments, the exergoeconomic and the exergoenvironmental, were applied to the designed systems. The results show that DHW production by the combined boiler solar thermal collector system is the most expensive in terms of the exergy cost index (about 33.29 kWh ex /kWh ex). DHW production by the combined boiler cogeneration system offers the lowest exergy unit cost (about 21.15 kWh ex /kWh ex). Based on economic and environmental indexes, DHW production by the combined boiler solar thermal collector system is the most suitable option. Its unit exergoeconomic cost is around 2.15 €/kWh ex , and its exergoenvironmental unit impact is equal to 9.35 kg CO 2 /kWh ex. [Display omitted] • Three hybrid thermal systems for DHW production are configured experimentally. • Exergy-based analyses are used as a tool for internal cost sharing. • The optimal exergy cost of DHW is 21.15 kWh ex /kWh ex by cogeneration boiler system. • The ideal exergoeconomic cost of DHW is 2.15 €/kWh ex by boiler solar collector system. • The best exergoenvironmental cost is 9.35 kgCO 2 /kWh ex by boiler solar collector system. [ABSTRACT FROM AUTHOR]

In recent decades, freshwater reserves have been under high threats, generated mainly by anthropogenic causes such as rapid population growth and climate change. Currently, one of the technologies that has been used to meet the freshwater global demand is seawater desalination. However, this solution has two major drawbacks. First, the discharge of reject brines with a high concentration of pollutants and nitrates, causing environmental problems such as eutrophication processes. Second, desalination systems, both membrane and thermal technologies, have a high energy consumption that is supplied with fossil fuels, contributing to the emission of greenhouse gas. Recently, to solve both problems, the zero —or minimal— liquid discharge strategy has emerged. This alternative for brine management is based on recovery of more than 90% of the freshwater fraction and salts, which can be revalued. Currently, there are some zero liquid discharge desalination plants that incorporate renewables to supply the necessary energy, making desalination a totally sustainable and environmentally-friendly process. Zero liquid discharge desalination plants powered by renewables already exist, although in an immature stage. This paper analyzes and discusses the potential of combining different renewables with the most developed and efficient desalination technologies. In addition, the most important plants and solutions currently installed on a real scale, mostly the result of different research projects, are described and compared. [Display omitted] • Water scarcity is a global problem that has promoted policies included in SDG 6. • Over 21,123 desalination plants produce 142 million m3/day of freshwater. • Reject brine and GHG emission reductions are crucial for sustainable desalination. • MLD and ZLD combined with RES are a strategy to solve desalination's negative impact. • The newest ZLD-desalination plants powered by RES are discussed. [ABSTRACT FROM AUTHOR]

Depletion of fossil fuel reservoirs, greenhouse gas emissions' impact on global warming, and rising energy costs are pushing the data center sector to reduce energy use. This paper reviews strategies for improving the energy performance of air-cooled systems in datacom facilities and enhancing temperature and flow distribution in white space by analyzing different airflow delivery architectures (hard floor and raised floor designs), eliminating cold and hot air mixing by incorporating cold/hot aisle containment or exhaust chimneys, and potential energy savings achievable by utilizing evaporative cooling systems. It was found that the optimal ventilation system is hard-floor architecture with locally-ducted supply and return air. Hard floor is less complicated than raised floor design, and overhead supply air can minimize hot spots at the top of racks. Airflow management strategies including cold and hot aisle formation, aisle containment, and exhaust chimneys can reduce annual cooling energy usage by 10–50% in conjunction with air-side and water-side economizers, minimize hot spots, and enhance thermal performance during cooling system failure. Hot-Aisle Containment or exhaust chimneys provide better thermal and energy performance than open and/or cold-aisle containment, but they require new ducting in traditional data centers. Depending on the climate and geographical location, evaporative cooling can reduce annual cooling energy usage by 20–70% and lead to Power Usage Effectiveness as low as 1.06. Evaporative coolers are more suitable for dry climates, but this limitation can be ameliorated by incorporating desiccant wheels and thermal energy storage. [Display omitted] • A hard-floor layout with locally ducted supply and return air is optimal. • Aisle containment can lower annual cooling load factor by 40–50% and PUE by 16%. • Evaporative cooling can lower cooling energy by 20–70% and PUE to as low as 1.06. • Hot-Water cooling and desiccant-assisted EC can reduce demand by 95%, cooling energy by 84%. [ABSTRACT FROM AUTHOR]

The current paper presents a numerical analysis of a multi-source renewable energy system for building air conditioning aiming at decarbonising the building envelope. The thermal management of the building is pursued through a radiant floor fed by a heat pump and integrated with phase change materials for thermal inertia enhancement. A fan coil is foreseen for humidity control. The heat pump can be fed through three parallel circuits involving different thermal sources: air with an ordinary air-to-water heat exchanger, sun through photovoltaic thermal solar collectors, and ground using shallow ground flat-panel heat exchangers. At need, the ground can be exploited for thermal energy storage when the heat pump is idle. A set of dedicated control rules chooses the optimal source or mix of sources to exploit at any time. Simulations of a reference building, namely a large single-room snack bar, are performed for various plant configurations, hypothesising the building as located in distinct climate zones and characterised by different thermal transmittance. The thermal performance of the building is given in terms of primary energy needs per year and compared to that of an analogous single-source plant. Results show that the proposed system can lead to primary energy savings of up to 16% compared to the corresponding state-of-the-art single-source plant, being more effective if the geothermal field is large enough and the building heating and cooling needs are comparable. The relevance of a proper control algorithm for plant performance optimisation is highlighted: a thermal power-based approach is proposed and successfully tested. • A multi-source renewable energy system for buildings thermal management is proposed. • Air, sun, and ground can be exploited as thermal sources by means of heat exchangers. • A phase change materials integrated radiant floor covers the building thermal needs. • A control algorithm selects the sources to be used for the optimal plant operation. • TRNSYS simulations foresee energy savings up to 16% in different operating conditions. [ABSTRACT FROM AUTHOR]

The current demand for wide temperature range promotes the development of mixed refrigerant throttling refrigeration technology. As a refrigeration technology using mixed refrigerants, auto-cascade refrigeration technology has a broad application prospect in the field of refrigeration and cryogenic because of its wide operating temperature range, simplicity and reliability. Although the cycle structure construction of the auto-cascade refrigeration cycle (ARC) and diversification of mixtures have received considerable progress, there are fewer reviews covering the influence factors that restrict the performance of ARC systems and providing guidelines for future development from the perspective of mixed refrigerant compositions. To bridge the gap, this paper comprehensively reviews and guidelines on the performance improvement methods of auto-cascade systems from perspective of mixed refrigerant compositions, including influence factors, research progress, research methods and technical challenges. The cycle structure construction and the factors that constrain performance improvement were summarized. It inferred that the improvement of composition separation and the modification of composition shift can improve the system performance. Then, the research on the composition separation was discussed in terms of the cycle structure modification, the separation performance of the gas-liquid separator and the separation mechanism of mixtures. The influence factors of composition shift, the composition shift characteristics and its theoretical prediction modeling are reviewed. Meanwhile, active regulation of composition concentration is a feasible measure to ensure operation safety and improve the performance of the ARC system. Finally, the technical challenges and prospects are proposed for outlining potential research directions in ARC technology. • A detailed review of performance improvement methods for ARC systems is presented. • Composition separation and shift are reviewed for ARC performance enhancement. • Regulation of composition concentration is a key measure to improve ARC performance. • Prospects and challenges of improving the ARC system are proposed. [ABSTRACT FROM AUTHOR]

Turkey has changed the essentials of its energy markets more than a decade ago. It was mainly a transition from a state-led model to a free-market one. Although some levels of progress is observable; security of supply, particularly in times of short term supply disruption had not been widely tested. Harsh winter conditions set a litmus test for Turkish energy markets. Basing on the this test, this paper provides an analysis of to what extent Turkey is open to the risks of energy supply security; and discusses possible measures to relieve future supply disruption risks. Energy policy-making should consider the fact that electricity and gas markets are highly intertwined in Turkey; and security of supply measures could have cross-market implications, paper concludes. [ABSTRACT FROM AUTHOR]

This paper presents an assessment of the obstacles to the development of non-conventional renewable energy sources in Colombia. In the study, eleven barriers were included in three clusters: technical, social and economic. These barriers obstruct renewable energy sources from contributing to the electricity market in Colombia, mainly in its non-interconnected areas. The energy sources analysed are solar photovoltaic power, wind power, biomass, geothermal and small hydroelectric power (less than 20 MW electricity). Obstacles and energy alternatives are included in an assessment model by means of Analytical Network Process. The method permits ranking the barriers and energy sources according to their influence in the network. That means, the more conflictive the obstacles and the more obstructed the energy sources, the higher their values. Four experts participated in the procedure representing different stakeholders in the electricity market of Colombia. The research showed the most important barriers are costs of investment and operating, lack of public and private coordination and lack of development planning for renewable energy sources. The most influenced (hindered by barriers) sources are wind power and geothermal power. However, the experts did not fully agree on those results and differences are discussed. The paper ends with some recommendations for overcoming the main obstacles against the participation of renewable energy sources in the Colombian electricity market. [ABSTRACT FROM AUTHOR]