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Plant operators and policy makers frequently use energy benchmarking to assess the potential for reducing energy consumption from industrial plants. As benchmarking studies require considerable resources and the cooperation of plant operators it is tempting to try to merge or compare data from different studies. This paper reviews published benchmarks and energy-saving estimates from the paper and pulp industries to explore how comparable data from independent studies are. A literature review was conducted which identified that benchmarks were either produced through a top-down process using annual production and fuel consumption data or through a bottom-up process from process-level data. It was concluded that top-down benchmarks are useful in measuring national trends but are of little value to individual plants. For common process such as Kraft pulp production it is possible to compare values from different studies but only if sufficient information is given in the original studies to confirm that their scope is identical. However, it is unlikely that improvement rates in energy use can be inferred from the difference between studies that use different sources, as the degree of disagreement between contemporary studies is of the same order as the identified potential energy savings. Benchmarking studies were found to provide good summaries of potential technological improvements although there is some inconsistency in estimations of potential impacts. [ABSTRACT FROM AUTHOR]

Every year the pulp and paper industry consumes billions of metres cubed of water and produces huge amounts of highly polluted wastewater that needs to be treated. Conventional techniques of wastewater treatment require a high energy input and their environmental impact is debatable. Thus, the need to find new sustainable, environmentally friendly and efficient treatment techniques is urgent. Microbial fuel cells (MFC) are the technology of the future since they simultaneously treat wastewater and produce clean energy. The historical development of this technology towards its application to wastewater treatment was described. The application of MFCs in pulp and paper wastewater treatment is a new and developing field of investigation that still needs to overcome many limitations before its use on an industrial scale. This article reviews the limits of conventional treatment methods and the current state of the art MFC systems for pulp and paper wastewater treatment. The paper provides an overview of the electrogenic microorganisms able to produce electricity from pulp and paper wastewater. The bacteria, isolated at different stages of pulp and papermaking, are best suited for electrogenic activity in harsh environments. It was shown that MFC technology fully meets the requirements of sustainable pulp and paper wastewater treatment and, in terms of the input-output energy balance, remains energetically and environmentally competitive when compared to conventional treatment methods. [ABSTRACT FROM AUTHOR]

Paper has shaped society for centuries and is considered one of humanity's most important inventions. However, pulp and paper products can be damaging to social and natural systems along their lifecycle of material extraction, processing, transportation, and waste handling. The pulp and paper industry is among the top five most energy-intensive industries globally and is the fourth largest industrial energy user. This industry accounts for approximately 6% of global industrial energy use and 2% of direct industrial CO 2 emissions. The pulp and paper industry is also the largest user of original or virgin wood, with deleterious impacts on both human health and local flora and fauna, including aquatic ecosystems. This critical and systematic review seeks to identify alternatives for mitigating the climate impacts of pulp and paper processes and products, thus making the pulp and paper industry more environmentally sustainable. This study reviews 466 studies to answer the following questions: what are the main determinants of energy and carbon emissions emerging from the pulp and paper industry? What are the benefits of this industry adopting low-carbon manufacturing processes, and what barriers will need to be tackled to enable such adoption? Using a sociotechnical lens, we answer these questions, identify barriers for the pulp and paper industry's decarbonization, and present promising avenues for future research. •This review identifies carbon-intensive processes in the pulp and paper industry. •Presents decarbonizing practices, potential transformations and innovations. •Presents promising avenues for future research. •No agreed consensus on the most promising technologies to achieve net-zero in the pulp and paper industry. •Pulp and paper products are associated with other sociotechnical systems that create compelling interdependencies among industries. [ABSTRACT FROM AUTHOR]

Abstract Although paper production demonstrates high energy and water sensitivity in their life cycles, only a few systematic analyses have focused on these issues. Therefore, an energy and carbon coupled water footprint analysis of five types of Kraft wood pulp-based paper (i.e., specialty-, art-, household-, light coated-, and tissue paper) is conducted in this study to help improve the environmental performance of the paper industry. All investigations are conducted with an impact-oriented approach based on ISO standards. Results show that elemental-chlorine-free bleaching is more environmentally friendly than chlorination-alkaline extraction-hypochlorite bleaching, specifically for global warming, aquatic eutrophication, and human health (i.e., carcinogens and non-carcinogens). Gray water footprint along whole life cycles of each product is approximately twice of blue water footprint. Direct processes contribute approximately 50% to water scarcity, while their impact on aquatic eutrophication ranges from 0.002% to 50.72%. For other midpoints, indirect processes dominate the influences. Meanwhile, COD, BOD 5 , CO 2 , TP, Cr (Ⅵ), Ti, Hg, and As are key contributors. Finally, reusing sludge by direct burning in the recovery furnace, reclaiming organic compounds in black liquor before alkali recycling, and integrating black liquor gasification technology are expected to provide substantial environmental benefits. Amelioration of wastewater treatment, optimization of the national energy structure, and improvement of the efficiency of chemicals and freshwater are recommended. Highlights • Energy and carbon coupled water footprint analysis of Kraft pulp paper is applied. • The environmental benefit of black liquor recovery is dominated by reused alkali. • Direct processes contribute a lot to water scarcity and aquatic eutrophication. • COD, BOD, TP, and heavy metals are key substances. • Optimizing waste reuse and availability efficiency of chemicals is recommended. [ABSTRACT FROM AUTHOR]

As an important recyclable and reusable resource, waste paper is traded in millions of dollars around the world every year. Global waste paper trade not only addresses resource scarcity issues, alleviates environmental pressures and brings substantial economic gains, but also contributes to the development of global circular economy. Using complex network methods, bilateral waste paper trade data, and temporal exponential random graph models (TERGM), we construct global waste paper trade networks (GWPTNs) during 2000–2018, and examine their structural evolution and determinants. We report that: (I) GWPTNs display obvious features of small-world network, low reciprocity, heterogeneity and disassortativity; (II) Asia is the leading recipient of global waste paper, while Europe and North America are the main exporters; (III) China and India dominate the waste paper import markets while the United States is the largest exporter, and Germany plays an essential role in both importing and exporting hubs of waste paper; (IV) The evolution of the GWPTNs is significantly influenced by endogenous reciprocity, transitivity and preferential attachment, and economies with more partners or within the same continents are more likely to trade waste paper. Economies with higher urbanization rates, more per capita income, stricter environmental regulation, or lower industrialization rates are more likely to export waste paper; conversely, they are more likely to be the importers. Economy-pairs sharing a language or religion, being a former colony of the same colonizer, historical colonial relationship or a border, or signing regional trade agreements are more likely to trade waste paper. • Global waste paper trade networks (GWPTNs) in 2000–2018 are established. • GWPTNs show the features of small-world network, low reciprocity, heterogeneity and disassortativity. • Asia is the leading recipient, while Europe and North America are the main exporters. • China and India dominate import markets, and the US is the largest exporter. • Key factors influencing waste paper trade are revealed using the TERGM. [ABSTRACT FROM AUTHOR]

The pulp and paper industry, which provides cellulose pulp and paper, bio-based energy and chemicals, is one of the largest energy consumers, greenhouse gases (GHG) and pollutant emitters among manufacturing industries. Although the environmental impact of the pulp and paper industry has been extensively studied, life cycle assessment (LCA) results have not yet reached a consensus. By means of a systematic review and meta-analysis, this article contributes to the quantification and harmonization of the life cycle environmental impacts of pulp making and paper making systems. Based on the screening of 45 cases of paper making and 18 cases of pulp making, we found that 1 t of paper results in about 950 kg carbon dioxide (CO 2 ) equivalent (CO 2 -eq) GHG emissions on average. However, there are distinct differences between countries and pulp and paper categories. The dominant factor influencing GHG emissions is energy use. In paper making, the pulp making process is responsible for 62% of energy use, 45% of GHG emissions, 48% of acidification potential, and 49% of eutrophication potential. The kg CO 2 -eq emissions of three different types of pulp were as follows: Kraft, 508 kg CO 2 -eq/t; chemi-mechanical, 513 kg CO 2 -eq/t; and recycled pulp, 408 kg CO 2 -eq/t. Excluding emissions from electricity and steam production, the convergence of carbon emissions is observed within the same categories of pulp. Straw-based pulp caused far more environmental impact than any other type because of the intensive inputs in agricultural activities as well as in the pulp making process. This research highlighted the inconsistencies in functional units, system boundaries, and methodologies and carbon neutrality assumptions in different LCA studies of pulp and paper making. Future studies should focus on the environmental impact of straw-based pulp making, system boundary unification, and calculation of biogenic carbon emissions. [ABSTRACT FROM AUTHOR]

The biorefinery design has attracted interest from the industry and scientific community due to its main role in a future transition to a sustainable bioeconomy. This paper provides a critical review of the integration of biorefinery concepts in the pulp and paper industry, focusing on gasification-based biorefineries, including technological and commercial drivers and barriers, and biorefinery general opportunities and challenges. The pulp and paper industry is commonly recognized as highly suitable to integrate biorefinery concepts. For this purpose, various integrable biorefinery designs composed of distinct conversion processes are proposed in the literature. However, key technologies and biorefinery concepts must firstly be improved and proven at a market level to increase stakeholders confidence. Gasification can be a driving force for this integration and efficient replacement of natural gas by producer gas in burners is the first and most immediate step. Nonetheless, drawbacks associated with the contaminants present in the producer gas (e.g., tars) must be addressed. Research rarely focus on this first step and is more centered on sophisticated gasification applications (e.g., methanol synthesis), without considering associated technological and commercial barriers. Furthermore, supporting policies are generally required to make the integration of biomass gasification technologies in the pulp and paper industry profitable and to avoid the interruption of operation of fully functioning large-scale gasification plants. • Integration of biorefinery concepts in the pulp and paper industry is reviewed. • Gasification-based biorefineries opportunities and drawbacks are discussed. • Producer gas has large potential by representing a middle platform compound. • Efficient replacement of natural gas by producer gas is a driving force. • Government policies and improvement of key technologies are main factors. [ABSTRACT FROM AUTHOR]

Pulp and paper industry is one of the eight critical industries for controlling carbon emissions in China. As the paper productions increase, the pulp and paper industry may fail in achieving the emission reduction target due to the rapid growth of greenhouse gas emissions. The study uses life cycle assessment to evaluate the greenhouse gas emissions of China's papermaking industry chain in order to propose emission reduction targets and find ways to achieve the emission reduction targets for China's papermaking industry. Considering the net carbon absorption of plant raw materials and the extensive paper industrial chain, this study obtained that the greenhouse gas emission of major paper types under corresponding pathways ranges from 1.96 t CO 2 eq/t paper to 6.55 t CO 2 eq/t paper. Plant carbon sink can reduce greenhouse gas emissions by 14.3%–42.9% under virgin fiber-based pathways. This study found that the greenhouse gas emissions caused by terminal products of 814 papermaking enterprises counted in China were 282.23 Mt CO 2 eq in 2015, accounting for 10.23% of the total greenhouse gas emissions of manufacturing industries and construction. To achieve the emission reduction target by 2050, emissions of the pulp and paper industry in China have been investigated from the perspective of three ideal energy structures. The research findings show that the emission reduction target of Intended Nationally Determined Contribution will be achieved in 30 years if the energy structure of the pulp and paper industry is adjusted only based on the optimal 450 scenario. In terms of other energy structures, the pulp and paper industry should assume afforestation areas ranged from 5900 km2 to 223,000 km2 at least to make up for the greenhouse gas emissions beyond allowance, which accounts for 0.85%–32.16% of the existing areas of plantation forestry in China. • Statistics in this work reveal the problem of excess capacity in China's pulp and paper industry. • GHG emission of paper products in different pathways range from 1.95 to 6.52 t CO 2 eq/t paper. • Energy supply mode transition is conductive to green development of pulp and paper industry. • Pulp and paper enterprises should assume afforestation areas to achieve emission reduction targets. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive review of significant studies that are relevant to thermal energy storage technologies using phase change materials (PCMs). The review focuses on the techniques applied to enhance the performance of thermal storage systems and the methods used to analyse the heat transfer problems in PCMs. In addition, this paper reviews the published results and discussions on the heat transfer intensification methods including application of fins, filling materials, nano-fluids, nano-particles, microencapsulation and the thermal conductivity enhancement method. Furthermore, the experimental and mathematical methods to enhance the thermal conductivity of PCMs are summarised, and the methods used to determine the nanofluid dynamic viscosity in recent investigations are also listed and discussed. The focus of this review is to provide a solid basis for the identification of the optimal design for the various heat transfer applications using PCM. [ABSTRACT FROM AUTHOR]

Paper-based analytical devices are lightweight, inexpensively produced, effective, and easily disposable; allowing for their suitable implementation in resource-limited areas. They allow effective handling of quantitative analysis in a diverse range of areas, from standard healthcare and environmental monitoring to water quality monitoring. Nonetheless, such devices often require an energy source for their complex assays or readings, preventing their effective use. Most commonly, conventional batteries are integrated into the device to serve as an energy source. However, considering its non-environmentally friendly approach to energy generation and its difficulty of being effectively disposed, a search for a new power source has begun. In light of the newly found potential of cellulose-based entities in the energy field, attention has been drawn towards a supposedly unlikely material: paper. Considering the potentials of such technology, this manuscript aims to describe the benefits of current and future technologies of paper-based devices in the energy sector. Here, we discuss the role of paper as a main platform or part of energy storage and conversion devices such as fuel cells, lithium-ion batteries, and alkaline batteries thoroughly. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a literature review of thermal comfort. Both rational and adaptive thermal comfort approaches are presented. An overview of the human body thermoregulatory system as well as the mathematical modelling of heat exchanged between human body and its environment in the situations of both awaked and sleeping people is presented. [Copyright &y& Elsevier]

Based on recent developments, hydrogen-based combustion systems have received wide attention, mainly due to increasing awareness of enduring environmental pollutants and restricted access to fossil fuel usage. In the relevant literature, there are evidences of the possibilities on the partial or total replacement of hydrocarbon fuels with hydrogen in power plants and vehicle engines. However, some challenging issues particularly on hydrogen storage are remained to be resolved. This paper reviews and comments on addressing the effectiveness of hydrogen-enrichment on the engines and burners׳ performance includes the chemical kinetic analysis, the flame propagation structures and the effects of inhibitors on global burning velocity of hydrogen–hydrocarbon mixtures in different combustion bombs, chambers and vessels. It is recommended that future researches should aim towards the different application of hydrogen–hydrocarbon i.e. transportation and clean energy carrier. [ABSTRACT FROM AUTHOR]

Municipal sludge from primary settling tanks of the Sewage treatment plant (STP) is a potentially important bio mass for the production of bio gas. Large amount of sludge is daily produced at wastewater treatment plants (WWTPs) where anaerobic digesters are located. Coupling the waste water treatment plant with the micro-algal culture is currently considered one of the most promising avenues towards the production of renewable bioenergy, either in the form of biodiesel or biogas. Research on anaerobic digestion of microalgae and sewage sludge will be important for the future of WWTPs because it could be a key step for recycling nutrients for algal cultivation as well as for energy recovery. Any co-substrate can have a co-effect in the sense that they stimulate enzymatic synthesis that can also improve the anaerobic digestion yield. Studies have shown that co-digestion can increase the anaerobic digestibility of algae by improving the substrate composition. Early studies have shown that due to the difference in anaerobic inocula, waste composition, and the experimental environment the quantity and the quality of the methane production vary widely. Sewage Sludge improves the digestibility of microalgae and enhances the production of methane. Co-digestion of waste paper and algal sludge could efficiently balance the feed stock Carbon–Nitrogen(C/N) ratio between 20–25 likely to benefit the methane production rate. This paper reviews recent experimental findings of the co digestion of algae with sewage and several substrates and the methods to enhance the methane production and the factors affecting the augmentation of the bio gas. [ABSTRACT FROM AUTHOR]

Microalgae biorefineries for the production of biofuels and high-value products have captured the attention of academia and industry. Implementing an anaerobic digestion step can enhance resource recovery from microalgae and microalgae residues. Anaerobic co-digestion, the simultaneous digestion of two or more substrates, is an opportunity to overcome the low biodegradability and the risk of ammonia inhibition associated with microalgae and microalgae residues mono-digestion. Besides, microalgae can also be used as co-substrate in biogas plants, with the aim of increasing the organic loading rate while providing alkalinity, macro- and micronutrients. Sewage sludge is the most researched co-substrate for microalgae since microalgae photobioreactors can be used for secondary, tertiary and anaerobic digestion supernatant treatment in wastewater treatment plants. However, microalgae and microalgae residues have been successfully co-digested with a wide variety of wastes, including crops, energy crops, paper waste, animal manure, vinasse, olive mill waste, and fat, oil and grease. Lipid-spent microalgae and glycerol co-digestion has also been largely researched due to the growing interest on microalgal-derived biodiesel. Most studies have assessed the impact of co-digestion on the methane yield and process kinetics through biochemical methane potential (BMP) tests. However, BMP test is not the most suitable method to assess the impact of co-digestion on other important factors such as supernatant nutrient content, digestate dewaterability, biosolids quality, and H 2 S concentration in the biogas. Overall, more lab-scale and pilot-scale continuous experiments are needed to get a holistic understanding of microalgal anaerobic co-digestion. • Co-digestion overcomes the limitations of microalgae anaerobic mono-digestion. • Ideal co-substrates boost methane production without increasing the nitrogen load. • In WWTPs, sludge can be co-digested with microalgae used for wastewater treatment. • Microalgae as co-substrate also provides alkalinity and macro and micronutrients. • More research is needed to get a holistic understanding of microalgal co-digestion. [ABSTRACT FROM AUTHOR]

Abstract: Coalbed methane (CBM) or coal seam gas (CSG) as it is known in Australia is becoming an increasingly important source of energy around the world. Many countries such as United States, Canada, Australia and China are investing in the CSG industry. A rise in the cost of conventional natural gas and many other energy resources, along with a decline in these conventional resources and issues such as climate change have encouraged a global interest in alternative sources of energy like CSG. The estimated quantity of CSG worldwide is around 1.4×1014 m3, it is clear that coal seam gas is a significant source of energy. The first section of this paper will discuss the production size of CSG worldwide and the future of the industry. The usage of the coal bed seam for the sequestration of CO2 is also an added benefit. The reduction of CO2 released to the environment may help in the future mitigation of global warming. In addition, the re-injecting of the co-produced CO2 enhances the commercial recovery and production of CSG wells. In the second section, the impact of the CSG industry's by-products on the environment, the freshwater ecosystem and human health are analysed. The second section includes issues associated with the large volume of co-produced water with undesirable composition in the CSG industry. The management of this enormous amount of water requires cost effective technologies and methods. Many methods for dealing with water problems are discussed and analysed in this paper. [Copyright &y& Elsevier]

Among all public buildings, on account of their educational purpose, school buildings have a major social responsibility. Therefore energy performance in this type of building is of great importance. The overall purpose of this research is to achieve a functional benchmarking, based on the real operation conditions of school buildings, by the exploitation of the results made public, through an intensive literature survey on energy consumptions in schools. The survey was made to gather data that is relative to energy consumption in school buildings, documented in the most diverse fields and units: global energy consumption values, electrical energy consumption; fuel consumption for heating, energy data consumption of schools expressed in annual cost per unit of heated/cooled surface area ($/m 2 ) or per unit of heated/cooled volume ($/m 3 ) or, finally, as the annual cost per student ($/student). The literature was analyzed to determine if a worldwide comparison among the published data could be established. The results suggest that when attempting to determine an energy benchmark some considerations should not be forgotten: standard indoor environmental conditions (IEC) for classrooms (set-point for indoor operative temperature of 20 °C in winter and 26 °C in summer as suggested in EN 15251:2007), electrical and heating consumption values should be kept separately, different education levels usually require different energy consumption values. A good way to normalize heating energy consumption is going through a climatic adjustment based on Heating Degree Days (HDD). For an impartial data comparison, based either on an operating rating or on a simulation carried out for reference conditions, benchmark reference values should be expressed in terms of billed energy data. [ABSTRACT FROM AUTHOR]

Focal point of this review is to provide a comparative display of qualitative and quantitative methodologies employed for the appraisal of interacting energy and climate policies, underlying their key features while presenting the most critical issues and limitations not addressed so far. Qualitative approaches provide a descriptive explanatory analysis of often non-quantifiable process in policy interactions, whereas modeling approaches provide numerical data estimating the extent of policy interaction impacts. Quantitative methods work best for narrowly specified policy combinations, while contextual implications and cause-impact effects are explained further via qualitative ones. In addition most evaluations so far adopt a rational view of policies and policy interactions leaving out a systemic evaluation of the institutionalism of interacting policies. Research analysis of energy and climate policy interactions is still young in comparison to the broad field of policy evaluation and impact assessment. However infants inherently tend to grow. Endeavors for a methodological framework that would allow for a systematic exchange of data between qualitative and quantitative approaches and would also include the relevance of the context as well as key casual relationships behind policy combinations, would provide the basis for further growth of knowledge in the field. [ABSTRACT FROM AUTHOR]

Abstract: Buildings consume a vast amount of energy during the life cycle stages of construction, use and demolition. Total life cycle energy use in a building consists of two components: embodied and operational energy. Embodied energy is expended in the processes of building material production, on-site delivery, construction, maintenance, renovation and final demolition. Operational energy is consumed in operating the buildings. Studies have revealed the growing significance of embodied energy inherent in buildings and have demonstrated its relationship to carbon emissions. Current interpretations of embodied energy are quite unclear and vary greatly, and embodied energy databases suffer from the problems of variation and incomparability. Parameters differ and cause significant variation in reported embodied energy figures. Studies either followed the international Life Cycle Assessment (LCA) standards or did not mention compliance with any standard. Literature states that the current LCA standards fail to provide complete guidance and do not address some important issues. It also recommends developing a set of standards to streamline the embodied energy calculation process. This paper discusses parameters causing problems in embodied energy data and identifies unresolved issues in current LCA standards. We also recommend an approach to derive guidelines that could be developed into a globally accepted protocol. [Copyright &y& Elsevier]

Abstract: Solar-power based sorption refrigeration systems do not suffer from the problem of greenhouse gas emission and release of ozone layer depleting substances as in the case of conventional vapour compression refrigeration system. Absorption based systems are already commercially available while adsorption based systems are still in research and development stage. Progress and development of solar-powered adsorption cooling systems have been described in this paper. Factors preventing commercialization of this system have been discussed in detail. The state of the ongoing research, to make the system more efficient and cost effective, has been presented. [Copyright &y& Elsevier]

Abstract: Dust accumulation is one of the natural phenomena that adversely affects the performance of solar systems. Since 1942, many efforts have been made to address the severity of deposited particles like dust, water stains, carbon from smoke, pollen in agricultural regions, etc. on the efficiency reduction of solar devices, which results in additional costs either from oversizing the system or from cleaning it. Although various innovative methods have been employed to clean the surface of grimy PVs, a holistic approach needs to show the cleaning mechanism under different climate conditions. This review highlights the findings from several references in three time periods and focusing on their similarities. For scaling up the appropriate mitigation method, four different global zones are explored based on suspended particles in the air. Consequently, the pattern of dust distribution in different parts of the world is assessed and it was found that the Middle East and North Africa have the worst dust accumulation zones in the world. Finally, a set of recommendations and guidelines with regard to the different climatic zones and their characteristics are presented especially for the installers of PV or other solar devices to implement a suitable cleaning system. [Copyright &y& Elsevier]

Recycling lithium-ion batteries (LIBs) has gained prominence in the last decade due to increasing supply chain constraints for critical materials (such as lithium and cobalt) and policy shift toward increased circularity of materials to mitigate environmental concerns. Conventional recycling methods (e.g., pyrometallurgical techniques) are suboptimal because of high-temperature (>1400 °C) processing with recovery yields ranging from 50% to 85%. On the other hand, optimal preprocessing/pretreatment of end-of-life (EoL) LIBs results in a) high (>90%) recovery yield, b) lower temperature processing (lower environmental footprint), c) high potential for commercial returns of materials, and d) lower safety risks. This paper reviews major preprocessing methods, including sorting, stabilization, dismantling and comminution, and separation for spent LIBs. The capabilities of major recycling firms and preferences for preprocessing in recycling methods are also reviewed, highlighting research and development (R&D) initiatives to allow more efficient and cleaner solutions for recycling spent LIBs. The industry-wide state-of-the-art recycling process is also detailed based on global practices, focusing on the highest yields and lowest environmental footprint. Finally, this paper provides policy recommendations to enable sustainable recycling of LIBs on a global scale, consequently reducing the environmental Impact of waste material and addressing the growing need for LIBs as a result of the increased demand for electric vehicles and stationary storage. [Display omitted] • This paper addresses waste management of Li-ion batteries (LIBs). • Outlines the pros and cons of the preprocessing approach in LIB recycling. • Reviews the commercial preprocessing techniques used by LIB recyclers. • Proposes an optimized recycling method to increase element recovery. • Highlights (and proposes) new regulations to make preprocessing viable. [ABSTRACT FROM AUTHOR]

In recent years, the utilization of biomass through advanced power technologies has intensified to achieve carbon neutrality. An oxy-fuel circulating fluidized bed combustor of biomass with higher efficiency supercritical carbon dioxide cycle has been developed with the aim of compensating the penalties for carbon capture and storage. The combustor fuelled with waste paper, waste wood, and cow manure, at an input of 200 ton/day is economically evaluated. Waste paper is on the verge of becoming an economically feasible fuel, more so than the other biomass examined. The use of waste paper led to a positive net present value, an internal rate of return of 3.8%, a benefit-cost ratio of 1.025, and a payback period of 17.7 years. Subsequent sensitivity analyses conducted for the waste paper fuelled power plant indicated that the capital cost is the most influential factor; the boiler, supercritical carbon dioxide cycle, and oxygen fuel combustion system were indicated in descending order of related subdivided sensitiveness. Both renewable energy certificate and carbon credit has contributed to the feasible economic of the system, with former one took precedence over later one. Sensitivity from the technical perspective, improvement in air separation unit is likely to greatly improve the economic feasibility of the proposed system. The power consumption of the air separation unit, as well as that of the carbon dioxide compression and purification unit, were highly sensitive to the implementation cost. [Display omitted] • Integration of oxygen combustion and supercritical carbon dioxide power cycle. • Economic feasibility study of integrated biomass circulating fluidized bed. • Capital cost demonstrated the foremost sensitivity factor. • Waste paper as potential economically feasible fuel. • Innovation in air separation unit improves economic feasibility. [ABSTRACT FROM AUTHOR]

The primary objective of this research was to analyze the technoeconomic feasibility assessment of hybrid WTE processes (i.e., gasification and hybrid renewable systems) by turning the campus waste into clean electricity and thermal energy. More specifically, the proposed WTE process relies on the use of wastes including papers, woods, plastics, green residues, organic wastes, etc. Solid wastes from the UVic campus (University of Victoria) and the neighbouring areas (e.g., MSWs in CRD) were considered for the feedstock. The potential for generation of 400 kW of renewable electricity and 500 kW of clean heat per day was calculated using approximately 3500 tons of feedstock per year based on proposed standalone gasification system, which could reduce about 1130 tCO 2 -eq of annual GHG emissions by avoiding the landfill disposal of the waste feedstock. Finally, the technoeconomic feasibility of a hybrid system - e.g., including solar photovoltaic panel, wind turbine, and a biomass gasifier - for a model campus building (ECS building) was assessed by HOMER simulation software to identify the cost-optimal HRES configuration for ECS building. The final HRES system was composed of 245 kW PV, 175 kW wind, 250 kW biomass gasifier and 46 batteries. Subsequently, the system net present cost and the cost of electricity were 2.3 MCAD, 0.0941 CAD/kWh, respectively. Likewise, the operating cost of the proposed HRES system was estimated 44,731 CAD/year. By implementing the proposed HRES system, UVic will save annually 386,000 CAD along with 1039 tons of CO 2 emissions. [Display omitted] • A hybrid renewable energy system and standalone gasification process for a model campus building are proposed. • Technoeconomic feasibility of representative gasification and hybrid systems are investigated. • Using the hybrid energy systems, GHG emissions due to landfilling are reduced significantly. [ABSTRACT FROM AUTHOR]

This paper analyzes the carbon emission impact of pickup points in last-mile parcel delivery. Pickup points provide customers and delivery companies with an alternative to attended home delivery. The delivery company can drop a parcel off at the pickup point, such as a service desk in a grocery store or a parcel locker, from where the customer collects the parcel. Because of the potential efficiency gains for the delivery vehicle, pickup points are often presented as a sustainable alternative to home delivery. The efficiency gains for the delivery vehicle need to be weighed against customers traveling to the pickup point by car, however. The mathematical analysis presented in this paper integrates continuous approximation techniques to assess the potential for improved delivery route efficiency with multinomial logistic regression for estimating the travel distance and mode choice of customers collecting their parcels. The results challenge the suggestion that pickup points are a universally sustainable alternative to home delivery. The potential for a net positive carbon emission impact is greatest when pickup points are established in urban settings, while in rural settings, the carbon emission benefits derived from improved delivery route efficiency are quickly offset by the carbon footprint associated with customer travel. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper explores opportunities for effective policy intervention for residential energy savings in southern China, by analyzing achievable potential of residential energy savings in the city of Xiamen as a case study. In contrast to static technical and economic potential analyses, the achievable potential analysis is based on dynamic energy consumption projections, which consider two real-world factors: (1) gradual ramping-up adoption process of advanced technical measures; and (2) consumers’ adoption of these measures. A bottom-up type Residential Energy Consumption (REC) projection model specifically tailored for southern China was developed in this paper, based on the general logic and calculation principles utilized in the U.S. EIA’s “National Energy Modeling System (NEMS),” and the adoption theory of advanced technical measures proposed by Kastovich. This REC projection model was then used as a policy analysis tool to quantitatively evaluate the impact of various policies on residential energy savings in the case study city of Xiamen. The analysis of the Xiamen case shows that although there is a significant technical potential for residential energy savings in the city (about 20.9–24.9%), the maximum achievable potential (MAP) in 2020 is only about 8.3–8.4% of that year’s business-as-usual baseline consumption. Moreover, with existing policies only about one-fourth to half of the calculated MAP is likely to be achieved by 2020. These findings indicate that in order to realize a larger share of achievable potential for residential energy savings in China, additional and more effective polices are needed. [ABSTRACT FROM AUTHOR]

Renewable energy sources play a crucial role in the provision of power supply in active distribution networks. In networks that rely on renewable energy sources, it may become imperative to curtail the power generated by such units due to a variety of factors. The curtailment of renewable energy generation can be attributed to various factors such as overgeneration, voltage limitations at the network bus, and power limitations at the network line. As per the specified parameters, it is possible for the power generation of renewable units to exceed the load consumption at certain intervals throughout the operational duration. Hence, it is essential to devise a solution that mitigates the frequency and duration of power generation curtailments of renewable units. It is feasible to redistribute overgeneration of renewable energy sources from periods of excess to periods of insufficient capacity to meet demand. This study demonstrates that the provision of power to loads from the sub-distribution substation experiences a reduction in power supply and cost. It is feasible to transmit surplus power from a single bus to multiple other buses. The term used to refer to the ability to transfer power across different locations and time periods is known as spatiotemporal flexibility. The presence of data centers in distribution networks enables a reduction in costs and the frequency of power interruptions associated with renewable energy sources, through the utilization of spatiotemporal flexibility. The objective of this paper is to present a methodology for achieving temporal and spatial flexibility in data centers, with the aim of minimizing costs and curtailing the output generation of renewable energy units. Undoubtedly, this approach can also be executed by incorporating mobile batteries; however, it is noteworthy that mobile batteries entail additional costs on the network. Consequently, the implementation of the spatiotemporal flexibility approach in data centers has been adopted as a substitute for the utilization of mobile batteries. This approach, also referred to as virtual battery, effectively eliminates the costs associated with the use of mobile batteries. This study examines overgeneration of renewable units, bus voltage limitations, and line power restrictions on the standard IEEE 33-bus network. Three scenarios are considered, each involving changes in data center power in response to varying load profiles. The implementation of equitable power distribution across data centers, both in terms of temporal and spatial dimensions, as well as the adoption of flexible spatiotemporal flexibility scenario for data centers, have been observed. The findings of this study indicate that the approach employed in this paper leads to a decrease in costs and the output power of renewable units in the examined scenarios. The implementation of spatiotemporal flexibility mode has resulted in a reduction of power supply expenses ranging from 12 to 37 percent when compared to the basic case. Ultimately, the sensitivity analysis pertaining to the placement of data centers and the associated uncertainty index is presented. • Implementing a model of spatiotemporal flexibility within data centers to function as a virtual storage device. • The curtailment of power generation in renewable energy units has been executed under three different distinct circumstances. • The robust optimization method has been employed to demonstrate the uncertainties inherent in the operation problem. [ABSTRACT FROM AUTHOR]

The random pore model (RPM) is the most comprehensive model for non-catalytic gas-solid reactions. The application of RPM is critical in some environmental pollutant removal reactions regarding sustainable energy systems. The common examples are flue gas desulfurization (FGD) by various solid sorbents and carbon capture and storage (CCS) systems, including greenhouse gas separation by carbonation reactions. So far, a review paper about the RPM has not been published in the literature. In this review paper, governing conservation equations for the RPM are presented, and RPM applications in various chemical, environmental, and metallurgical reactions are explained. Then, the paper discusses the method of defining the structural parameter, ψ, as the main parameter of the RPM. The RPM various modifications, such as non-linear concentration dependency, bulk flow effects, and predicting changes in pore size distribution (PSD) during the reaction are explained in detail. Kinetic parameters of various reactions, as mentioned above, are also determined comprehensively by applying the RPM on conversion-time experimental results originating from thermogravimetry (TG). In addition, breakthrough curves obtained using the RPM have been observed for some of the studied reactions in a packed bed reactor. Incomplete conversion is considered for the reactions with Z > 1. According to RPM predictions and experimental data, producing large pores by washing them with a weak acid or using a nanostructure pellet can solve this problem. Also, applications of the RPM to other reactions consisting mainly of gasification and combustion are presented. Finally, machine learning applications for multi-scale modeling of gas-solid reactions are discussed. • Random pore model (RPM) applications in some sustainable energy reaction systems were reviewed. • RPM was proved as the most comprehensive and accurate non-catalytic gas-solid reaction model. • Kinetic studies of various chemical, environmental, and metallurgical reactions using RPM were surveyed. • Conversion-time profiles and breakthrough curves were expressed from RPM predictions. • Some modifications and extensions of RPM in complex situations were presented. [ABSTRACT FROM AUTHOR]

The evolution of district heating systems is characterized by a trend towards lower supply temperatures and higher energy efficiencies. The most recent advancement in this field is the fifth-generation district heating and cooling systems (5GDHCS). Current literature identifies three key features of 5GDHCS: operating at near-ambient temperatures, the use of distributed booster heat pumps at end-users, and the capability to provide both heating and cooling services. However, there is ongoing debate on whether 5GDHCS represents a significant technological leap beyond its predecessor, the fourth-generation district heating system (4GDHS). To resolve fundamental questions surrounding the 5GDHCS concept and to highlight its distinctive features, this paper conducts a detailed comparison between 5GDHCS and 4GDHS, examining their functional, technological, and operational differences. Based on this, limitations in existing definitions of 5GDHCS are identified, and a refined definition better characterizing its unique attributes and advancement is suggested. Additionally, considering the 5GDHCS-related studies are growing fast, with over 30 works published each year since 2021, this paper tries to complement previous reviews with an updated perspective on its latest research progress and practical deployment, through a comprehensive state-of-the-art analysis. Results show that while 5GDHCS is a promising technology to decarbonize domestic heating and to promote sector coupling between electric power and district heating systems, it is still in the early stage of development, marked by substantial research gaps in technical, policy, regulatory, and market aspects. Analysis on an exhaustive collection of real-life cases also indicates a long way ahead to achieve its widespread commercialization. • Diverged opinions on the term of "fifth-generation" are summarized and discussed. • A comprehensive comparison between 5GDHCS and 4GDHS is provided. • Distinctive features of 5GDHCS are analyzed and a refined definition is suggested. • An updated review on the research progress and practical development of 5GDHCS. • A collection and analysis of research projects and real-life systems are presented. [ABSTRACT FROM AUTHOR]

Agricultural crop residues are the lignocellulosic biomass left in the field after harvesting valuable crop parts. These pose a significant concern due to the waste generated annually, burdening management and contributing to pollution. Numerous studies carried out over decades have demonstrated some effective utilization through thermochemical conversion as a potential feedstock, there is not a proper account of their trends. This systematic review addresses a critical gap in the literature by analyzing the sustainable management of crop residues thermochemically, offering insights into research trends, technologies, and future directions for their utilization as biofuel and bioactive value-added-product applications, that has been largely overlooked in previous narrative reviews. Studies for review were searched on web of science, scopus, and google scholar through a carefully developed search syntax and backward snowball methods. Total 343 papers published in past 23 year matched the study inclusion criteria were selected and meaningful outcomes from meticulous analysis of these studies have been extracted. Research publications show exponential growth, primarily focused on laboratory-based experiments. The most studied process was pyrolysis, and the product was biochar. There has been significant progress in process optimization, integration, and product diversification, paving the way for diverse applications. Recent trends indicate a shift from conventional pyrolysis and gasification towards sustainability, circular economy, efficiency enhancements, and novel applications, reflecting a broader commitment to environmental stewardship and resource maximization. Additionally, the challenges linked with recent innovations are discussed, along with recommendations for future research endeavors concerning these systems. [Display omitted] • Systematically reviewed 343 papers on crop residue thermochemical conversion. • Research trends, progress, future prospects and challenges have been discussed. • Optimization, integration, product diversification and applications were major focus. • Exponential research growth, mostly lab-based works on pyrolysis to produce biochar. [ABSTRACT FROM AUTHOR]

The miniaturization, portability, and reduction in power consumption of wearable devices have greatly facilitated significant advancements in the field of wearable human energy harvesting systems. Human metabolism results in waste heat production and dissipation to the surroundings via skin radiation, convection, and evaporation. Wearable flexible thermo-electric and moist-electric devices uses skin waste heat harvesting to convert thermal energy into electricity without user involvement. The principle and structure of the device is simple and pollution free with great application potential in generating power supply. Skin waste heat can be dissipated in the forms of both sensible and latent heat. Wearable thermo-electric generators (WTEGs) collects sensible heat, and wearable moist-electric generators (WMEGs) collects latent heat. This paper reviews the mechanism behind the generator of WTEG and WMEG, as well as state-of-the-art research progress made in material properties and structural design of thermoelectric devices. The performance optimization and design of wearable, flexible thermoelectric devices for skin waste heat harvesting at the material and device levels are studied, followed by a breakdown on the fibers and fabrics used in the foundation for future development of WTEG and WMEG's. The research findings provides valuable insight on the future development of WTEG and WMEG's, providing integration into wearable applications for health and physiological monitoring and disease diagnosis. This paper reviews the mechanism behind the generator of WTEG and WMEG, as well as state-of-the-art research progress made in material properties and structural design of thermoelectric devices. The performance optimization and design of wearable, flexible thermoelectric devices for skin waste heat harvesting at the material and device levels are studied, followed by a breakdown on the fibers and fabrics used in the foundation for future development of WTEG and WMEG's. The research findings provides valuable insight on the future development of WTEG and WMEG's, providing integration into wearable applications for health and physiological monitoring and disease diagnosis. [Display omitted] • Explored the theory of thermoelectric energy conversion from skin waste heat. • Overviewed advancements in material properties and structural design of thermoelectric devices. • Studied on improved designs for wearable thermoelectric devices using fiber and fabric materials. • Future directions for wearable flexible thermoelectric devices. [ABSTRACT FROM AUTHOR]

The pinch analysis technique circumvents the drawbacks of local optima in the design of production processes and determines energy targets from a systemic design perspective. It has now evolved into a comprehensive methodology for process industry integration. As research deepens in traditional industrial domains, the exploration of applications in emerging fields is gradually expanding. However, solely relying on the analysis and summarization within a singular domain is insufficient for driving broader applications across diverse fields. Therefore, this paper discusses the pinch analysis techniques across various fields, from energy exchange networks to mass transfer networks. By examining their technical principles and categorizing method types, different technologies are horizontally compared, and their key characteristics are revealed. Subsequently, this paper explores future development directions and imminent challenges of the pinch analysis technique in power systems, aiming to offer new perspectives for expansion and to address existing issues such as load balance analysis, planning rationality, and reliability assessment in power systems. • Pinch analysis methods in various fields are analyzed comprehensively. • Analogous graphic methods and numerical methods of pinch analysis are compared across different fields respectively. • The underlying mathematical structure of pinch analysis techniques and principle of graphical methodology are revealed. • The prospects and a novel approach to applying pinch analysis in power systems are proposed. [ABSTRACT FROM AUTHOR]

The energy sector plays a vital role in achieving a sustainable net-zero future, and the adoption of advanced technologies such as AI, blockchain, quantum computing, digital twin, cloud computing, big data, IoT, and robotics is crucial to this transition. This paper presents a comprehensive review of over 2,000 papers to investigate the potential of these technologies in transforming the energy landscape. The analysis reveals nine main themes that emphasize the importance of these technologies in improving energy management, integrating renewable sources, and facilitating the transition to net zero emissions. The study highlights the need for future research in areas such as enhancing blockchain platforms, improving integration with traditional power systems, and refining regulations and incentives to support the adoption of these technologies. Additionally, the paper addresses the challenges faced in implementing quantum computing and digital twin technology in the energy sector and proposes potential solutions. The findings emphasize the critical role of these technologies in driving the energy sector towards a sustainable net-zero future and the need for continued research and development to align with global sustainability goals. This review provides valuable insights for researchers, policymakers, and industry stakeholders, emphasizing the importance of collaborative efforts in utilizing the potential of these technologies to create a more sustainable and resilient energy system. [Display omitted] • Review of AI, blockchain, quantum computing in enabling smart, secure, sustainable energy. • Analysis of flexible markets and intelligent systems for net-zero transition. • Quantification of digital technologies' impact on decarbonizing energy systems. • Emphasis on ethical considerations and RD&D needs for responsible digital transformation. [ABSTRACT FROM AUTHOR]

To facilitate a successful integration of distributed energy resources into the electricity generation mix, new forms of energy markets must be considered. Concepts such as Peer-to-peer energy trading (P2P), transactive energy (TE) and community/collective self-consumption (CSC) are frequently mentioned as solutions to this challenge. Despite increasing interest from industry, policy, and academia, the field lacks a shared understanding of this class of models. This need is addressed by presenting sets of shared and distinct characteristics which define P2P, TE and CSC. Our analysis is based on a series of expert group interviews with regulators, industry, and academics across 13 countries, and a systematic and targeted literature review of 133 papers. Findings show that P2P/TE/CSC models can be described as sub-markets that operate within or alongside traditional energy markets and enable trading or sharing of energy using an automated approach. They focus on promoting and supporting local energy generation and consumption using price negotiation mechanisms that reflect the aims of the market. The paper also presents sets of characteristics which differentiate P2P, TE, and CSC from one another and sets out guiding definitions to be used as a reference point. The main differences between these models stem from the goal they are trying to achieve and the contexts they are deployed in. Findings from this analysis can support development of a shared understanding of this class of models across multiple disciplinary perspectives and applications. • Decentralised energy trading models lack a unified definition. • Expert interviews and literature review identify defining characteristics. • Decentralised models can operate as sub-markets alongside traditional markets. • Distinctions between models stem from their goal and the contexts they are deployed in. [ABSTRACT FROM AUTHOR]

The paper's state-of-the-art review focuses on an in-depth evaluation of smart home energy management systems which employ reinforcement learning-based methods to integrate energy storages. In order to optimize energy consumption and improve overall sustainability while maintaining technical and economic constraints, the paper first investigates the multi-faceted aspects of integrating energy storages into smart homes. Second, an overview of a smart home system and a theoretical background of reinforcement learning-based algorithms are given and discussed. Consequently, this study delves into the challenges and benefits of integrating energy storage, specifically looking at ways to lessen the impact of renewable sources' intermittency, improve grid stability, and streamline efficient energy storage management. Thirdly, the paper highlights the beneficial features of smart home energy storage integration, including reduced costs, increased system resilience, and improved energy efficiency. Therefore, cutting-edge reinforcement learning-based methods utilized in smart home energy management systems that incorporate energy storage are thoroughly examined by evaluating their effectiveness and adaptability, taking into account both multi-agent and single-agent reinforcement learning-based methods. Finally, the study identifies potential research directions, including the development of hybrid reinforcement learning algorithms, integration of demand-side management strategies, and addressing privacy and security concerns in reinforcement learning-based smart home energy management systems. While some research has made use of single-agent reinforcement learning, smart home energy storage systems that use energy storages seldom use multi-agent reinforcement learning techniques. Researchers, practitioners, and policymakers will be able to use this work as a foundation to build smart, sustainable home energy systems. [Display omitted] • Performance and effectiveness of reinforcement learning in smart homes are examined. • Single and multi-agent systems in smart homes with energy storages are reviewed. • Research directions and gaps are provided for future research directions. [ABSTRACT FROM AUTHOR]

This work presents the first systematic review analysis of potential Power to Gas integrations in blast furnace ironmaking. The primary objective of the paper is to evaluate the PtG technology implementation in both conventional air-blown and full oxygen blast furnaces, considering different BFG recycling routes (upper, shaft or tuyeres), and synthetic gases (SNG, H2 or syngas). Employing a systematic methodology, the paper compares all the studies using 14 Key Performance Indicators (KPI) and elaborates a discussion on the main findings and limitations, proposing areas for future research. PtG application enables air-blown blast furnaces to cut emissions to 1060 kg CO2 /t HM. With PtG and top gas recycling, oxygen blast furnaces achieve a reduction to 747 kg CO2 /t HM , and when combined with geological storage, the reduction further drops to 435 kg CO2 /t HM. Additionally, the authors propose a novel PtG-ironmaking integration based on the findings of this paper. • First systematic review for Power to Gas in blast furnace ironmaking. • Methodical comparison of technologies using 14 KPIs. • Air-blown blast furnaces emissions can be reduced to 1060 kgCO2/tHM. • Oxygen blast furnaces emissions can be reduced to 435–747 kgCO2/tHM. • Novel power to gas integration proposed by the authors. [ABSTRACT FROM AUTHOR]

The massive load of effluents released from the pulp and paper industry has an adverse environmental impact due to the discharge of hazardous materials. These effluents contain mostly recalcitrant compounds like lignin, which are rigid and resilient to degradation. Bioremediation technologies such as biostimulation using nutrients and biological techniques are being used for the biodegradation of hazardous effluents. But they are not up to that level of remediation efficiency. Many enzymes have been used for bioremediation in recent years, which are easy to use, eco-friendly, and adequate to ensure the public safety. Such enzymes, along with their mechanisms, have been well studied for the bioremediation of effluents. This review describes enzyme technologies, including laccase mediated treatment, lignin peroxidase, and manganese peroxidase treatment to reduce effluent load into the environment. The other methods including aerobic and anaerobic treatments utilizing bio-sludge for producing beneficial products such as biofuels, and bio-sorbents for oil peeling are also described in the present review. This review also gives a summarized but unique description of the aspects of the immobilized biocatalysts and biosorbents used to mitigate the production of toxic pollutants from the pulp and paper industry. The strategies based on the advanced enzyme engineering technologies for bioremediation of such contaminants are also briefly described. This review also discusses the techno-economic assessment of enzymatic remediation and future challenges for the bioremediation of these effluents. In conclusion, enzyme-based advanced technologies are crucial 'green technologies' for providing a sustainable solution for bioremediation and reduced environmental pollution. • Advanced enzyme engineering for bioremediation of pulp effluents is described. • The laccase treatment, lignin peroxidase, manganese peroxidase treatment outlined. • A description of the aspects of the immobilized biocatalysts and bio-sorbents. • The aerobic and anaerobic treatment of pollutants utilizing bio-sludge delineated. • Enzyme based technologies are clue to sustainable solution of environment pollution. [ABSTRACT FROM AUTHOR]

The contemporary world faces several energy problems and struggles to balance sustainable energy and steady industrial development. In this context, the existing energy efficiency studies have not unfolded the mysteries surrounding the industrial units' energy-saving potential and the key determinants and impacts of the manufacturing units' energy efficiency levels. Therefore, there is a need to comprehensively study the existing energy efficiency studies and clarify the above. Considering two databases, Scopus and Web of Science, the study uses bibliometric analysis and a systematic literature review to analyze the current energy efficiency literature. The bibliometric analysis is based on 619 published papers and assesses the existing energy efficiency literature to ascertain the evolution of energy efficiency studies from 2001 to 2022. This investigation adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA-2020) framework for a systematic review of ninety-three relevant papers from the existing energy efficiency literature. The systematic literature review (SLR) highlights twenty-seven theories discussed in several dimensions of the environmental and industrial linkages in the manufacturing sector. Subsequently, the study identifies energy efficiency measures and the associated methodological issues. Next, the study addresses the available set of determinants and the impacts of energy efficiency performance on manufacturing industries across the globe. It explores the potential research gap in the existing studies. Finally, the concluding remarks, discusses several policy implications, and suggests avenues for future research in the direction of theory, context, and methodology in energy efficiency domain. [Display omitted] • Bibliometric analysis and systematic literature review are performed to synthesize the current energy efficiency studies. • The study considers 619 energy efficiency papers from Scopus and Web of Science databases over the past 22 years. • The study uses the PRISMA-2020 framework and uses Bibliometrix in R (RStudio) and VOSViewer software for the analysis. • SLR considers 93 papers and identifies 27 existing theories, addresses determinants and impacts of energy efficiency. • The study identifies the research gap, presents several policy implications and provides the scope for future research. [ABSTRACT FROM AUTHOR]

CO 2 sequestration has proven to be an attractive way to combat global warming. However, due to the corrosive nature of CO 2 , chemical reactions between CO 2 and the host rock can happen after the injection. This study reviews the current state of knowledge about chemical reactions and their effects on the mineralogy, structure, mechanical, deformation, and transport properties of different types of rocks from research papers published in 2004–2024. In addition to drawing a comprehensive picture of the research that has been done on the subject and the gaps that need to be filled, this review combined the data from the papers to introduce the relationships between exposure conditions (CO 2 pressure, exposure duration, and temperature) and mineralogy, strength, and elastic properties, and permeability of multiple types of rocks. Results showed that some minerals like quartz are not affected by CO 2 while others like carbonates can easily be dissolved. Datapoints from various papers showed a negative effect of CO 2 pressure and exposure duration, and a positive effect of temperature on the strength properties of rocks. An increase in permeability was another consequence of CO 2 treatment in most cases. This study is one of the first works to gather data from multiple sources in developing relationships between CO 2 treatment conditions and the strength properties of rocks. Results will potentially improve understanding and prediction of the effect of CO 2 on the properties and behavior of rocks. [Display omitted] • Quartz, unlike carbonates, is not impacted by CO 2. • Dissolution/precipitation of minerals leads to increase/decrease in pore volume. • The compressive strength mostly decreases with an increase in CO 2 pressure. • Bulk and elastic moduli of rocks decrease after CO 2 treatment. • CO 2 increases the permeability of most rocks. [ABSTRACT FROM AUTHOR]

There are some problems in the applications of phase change materials, such as liquid leakage during solid-liquid phase change, and low thermal conductivity during heat transfer process. Three-dimensional network (3DN) structural materials stood out among many encapsulation materials of composite phase change materials (CPCMs) due to the advantages of three-dimensional interoperability, high porosity and low density. In this paper, the characteristics, advantages and preparation methods of 3DN-CPCMs were reviewed. Then, the influencing factors on the thermal, photothermal conversion and mechanical properties of 3DN-CPCMs were summarized from three aspects: pore structure, surface properties and chemical composition. Finally, the applications of 3DN-CPCMs in various fields were introduced, and their current challenges and future development were also discussed. This paper systematically discussed and analyzed the inherent relationship among the composition, structure, properties and applications of 3DN-CPCMs, which was helpful for deeper understanding of the latest research progress in 3DN-CPCMs and reasonable design and controllable preparation of the high-performance CPCMs. [Display omitted] • Research progress of 3DN-based phase change composites was reviewed. • Effects of pore, surface and composition on properties were discussed. • Multiple application prospects and development directions were outlooked. [ABSTRACT FROM AUTHOR]

The power transformer is one of the most important and critical assets involved in the grid and, at the same time, one of the most expensive. Several transformer condition parameters allow to assess the degradation of assets. These help in the decision-making process on the operation, repair, refurbishment, or replacement of transformers. Dissolved gas analysis (DGA) is one of the most commonly used methods to manage maintenance and establish the health index of power transformers, as well as to identify the type of fault. This paper examines and explores the studies related to graphical methods for the identification of faults in power transformers that had been developed over the last almost 50 years. The main types of faults and the sub-types presented in the analysed studies are compiled in this paper. The main differences between the methods in terms of their graphical representation, number of gases used, type of data used from the DGA results, and number of faults and sub-faults identifiable in each of them, are also presented. The application of the reviewed methods was carried out using two real DGA results. [Display omitted] • This paper reviews graphical methods for identifying transformer insulation faults. • Twenty-seven graphical methods were developed over the last 50 years. • Nine different shapes of graphical methods were found. • There are five different ways of using DGA results to identify faults. [ABSTRACT FROM AUTHOR]

Hydrogen, as a clean and efficient energy source, is important in achieving zero-CO 2 targets. This paper explores the potential of hydrogen geologic storage (HGS) in China for large-scale energy storage, crucial for stabilizing intermittent renewable energy sources and managing peak demand. Despite its promise, HGS faces challenges due to hydrogen's low density and viscosity, and its complex interactions with geological formations and microorganisms. This review offers a comprehensive overview of the current research status for HGS, with a particular focus on highlighting the main challenges confronting China. These difficulties and challenges primarily arise from complex geological conditions and the absence of fundamental parameters within potential reservoirs, including depleted oil/gas fields, salt caverns, and brine aquifers. Additionally, we have synthesized the current applications of machine learning (ML)as a potential solution. Key challenges are examined, such as the effects of operational parameters (e.g., cyclical injection-production and injection rates) on HGS efficiency, which can influence phenomena such as hydrogen fingering and caprock integrity. This review also looks into the insufficiently understood hydrogen-water-rock geochemical reactions under diverse temperatures and pressures, a gap that hampers the development of predictive numerical simulations and raises concerns about hydrogen leakage due to changes in porosity and permeability. Additionally, the paper addresses the limited knowledge about the metabolic mechanisms of subsurface microorganisms under extreme conditions, highlighting potential risks of hydrogen leakage and groundwater contamination. These microorganisms can metabolize hydrogen, producing gases such as CH 4 and H 2 S, which may cause steel corrosion. Furthermore, the study assesses the distribution and prospects of three primary methods for pure hydrogen storage in China, considering the current state of hydrogen development and relevant government policies. The role of ML in advancing HGS is also discussed, offering insights into future research directions. This review not only scrutinizes the scientific challenges of HGS but also underscores its potential, guiding future simulation and practical engineering applications in this field. • HGS is feasibility in China through policy examination and potential site analysis. • Geochemical and microbial reactions jeopardize to reservoir integrity and H 2 quality. • Elucidating the present application and future prospective for ML in HGS. • Summarizing the key challenges associated with achieving large-scale HGS. [ABSTRACT FROM AUTHOR]

This paper is the editorial for the virtual special issue (VSI) of Renewable and Sustainable Energy Reviews (RSER) dedicated to three Sustainable Development of Energy Water and Environment Systems (SDEWES) Conferences held in 2022, namely: (i) the 5th South East European Conference SEESDEWES 2022 held from May 22 to 26, 2022 in Vlore, Albania; (ii) the 3rd Latin American LASDEWES 2022 held from July 24 to 28, 2022 in Sao Paulo, Brazil and (iii) the 17th SDEWES 2022 held from November 6 to 10, 2022 in Paphos, Cyprus. The VSI collected both high quality review papers and original research articles presented at these conferences, aligning with the aims and scope of RSER. Following a rigorous peer review process, seventeen articles were accepted and published. These articles explore techniques and technologies essential for advancing feasible Renewable and Sustainable Energy Systems. Spanning multidisciplinary topics, many of them address almost all the Sustainable Development Goals, offering feasible solutions for much-needed decarbonization pathways. • The VSI SDEWES 2022 presents the ready solutions for Renewable and Sustainable Energy Systems. • Five clusters for presenting the Renewable and Sustainable energy cutting edge solutions. • The positioning in the scientific context of the Renewable and Sustainable Energy Systems. • Feasible solutions for much-needed decarbonization pathways. [ABSTRACT FROM AUTHOR]

In recent years, vibration signals have been widely applied for the identification of mechanical states in oil-immersed transformers. This paper, following the framework of 'vibration generation – sensing – processing – recognition – evaluation – solution,' introduces the progress in mechanical state recognition of oil-immersed transformers based on vibration signals from a novel sensor-oriented perspective, which covers sensor deployment, sensor specialization, and equipment integration. The advancements in signal processing and feature selection are also discussed and compared with the identification of states in rotating machinery. To Address challenges like limited rule transferability and the weakness in vibration characteristics and models, some emerging technologies such as Operational Modal Analysis and multisource data fusion are introduced, which may bring new prospects. This paper aims to provide scholars engaged in research on the mechanical state identification of transformers and other electrical equipment with some technical references. • Advances in transformer mechanical state recognition via vibration signals are discussed from a sensor-oriented view. • A cross-comparison of vibration characteristics used for diagnostics in transformers and rotating machinery is conducted. • Emerging tech like Operational Modal Analysis and sensor specialization are discussed for rule transfer challenges. [ABSTRACT FROM AUTHOR]

Energy intensive processes are embedded in the socio-economic and political fabric of our societies; therefore a "green industrial revolution" entails major technical achievements and profound social transformations. In this uncertain landscape, businesses face a crucial but difficult position: they need to manage the decline of their legacy assets, are expected to provide stable employment, and must contribute to national energy resilience and security. As such, significant societal risks are associated to business positioning towards decarbonisation. This paper describes "sunset" versus "sunrise" corporate strategies and their interconnections with market developments, citizens, and government's support to low-carbon transitions. Using a qualitative System Dynamics approach, the paper highlights vicious and virtuous feedback mechanisms where accumulations and tipping points may arise. While defensive strategies to preserve fossil-based assets may appear rational in the short-term, they can have deleterious long-term effects for business and society. The main risks stem from the creation of stranded physical, financial, and human assets. On the contrary, incumbents can increase market certainty and generate industry-society co-benefits by engaging in skills transfers and sending clear innovation signals to investors. The findings, synthetised in a Causal Loop Diagram highlighting key variables and delays, constitute a building step towards improving the realism of energy systems modelling. The study also provides a discussion on centralisation and the political power dynamics of national energy transitions. • Industrial decarbonisation is a society-wide transformation • The study elicits interconnections between "sunset" and "sunrise" business strategies, markets, citizens and governments • A System Dynamics approach is used to synthetize feedback mechanisms and key variables in a Causal loop diagram (CLD) • The accumulation of stranded assets and skills may impact stability and delay transitions while clear innovation signals enhance market certainty • Intangible human factors are essential components of strategic decision making. The study discusses political power dynamics and contributes to improved realism in energy transition modelling [ABSTRACT FROM AUTHOR]

Findings on PEMFC designs grew tremendously in the past decade. Commercially, PEMFCs are usually configured in a stack to achieve higher electrochemical output. However, the two-phase fluid transport in a multiple-cell stack raises the complexity of reactant diffusion towards the porous electrodes than a single-cell stack as the higher current generation naturally increases water and heat production. Ensuring optimum hydration with even thermal distribution is critical in maintaining the MEA durability and overall electrochemical performance. Therefore, this review paper provides a comprehensive discussion of how the inconsistencies in water and thermal distribution impact the electrochemical reactiveness within the cell and electrode layers of a multiple-cell PEMFC stack. Targeting the bipolar plate design is not only essential for uniform fluid distribution but it can also be used to maximise the contact surface area to achieve a greater reactant consumption rate. Hence, the effect of varying manifold, flow field and distribution zone designs towardthe fluid and reaction dynamics per cell of a multiple-cell stack were discussed based on available literature. Although the difference in water and heat saturation between single- and multiple-cell stacks could be highlighted clearly in this paper, more research is needed particularly for novel bipolar plate designs. This would be essential knowledge in generating an optimal bipolar plate design that can enhance the durability and performance of PEMFC stacks. • Water and temperature dispersal in multiple-cell PEMFC stacks differ from single-cell units. • Cell dehydration causes higher performance loss in fuel cells compared to flooding. • The fluid dynamics and electrochemical responses across a single-cell stack differ from a multiple-cell stack. [ABSTRACT FROM AUTHOR]

Because of their low computational costs, surrogate models (SMs), also known as meta-models, have attracted attention as simplified approximations of detailed simulations. Besides conventional statistical approaches, machine-learning techniques, such as neural networks (NNs), have been used to develop surrogate models. However, surrogate models based on NNs are currently not developed in a consistent manner. The development process of the models is not adequately described in most studies. There may be some doubt regarding the abilities of such models due to a lack of documented validation. In order to address these issues, this paper presents a protocol for the systematic development of NN-based surrogate models and how the procedure should be reported and justified. The protocol covers the model development procedure sample generation, data processing, SM training and validation, how to report the implementation, and how to justify the modeling choices. The protocol is used to critically review the quality of NN-based SMs in the prediction of building energy consumption. Sixty-eight papers are reviewed, and details of the developed surrogate models are summarized. The reported developing procedures were evaluated using the criteria proposed in the protocol. The results show that the selection of the number of neurons is the best-implemented step with a justification, followed by the determination of model architecture, mostly justified in a discussion way. While greater focus should be given to sample dataset generation, especially input variables selection, considering independence check and clear report of model validation on training and test data. Also, data preprocessing is strongly recommended. [Display omitted] • A protocol for developing and evaluating surrogate models. • A systematic procedure for developing neural-network-based surrogate models. • Overall quality assessment of developed surrogate models in building energy. • Typical configurations used in building energy neural network-based surrogate models. [ABSTRACT FROM AUTHOR]

Rapid growth in population and economic development in Iran and its neighboring countries has resulted in a dramatic increase in electricity demand over the past few years. A substantial amount of electricity must be produced to meet this growing demand in this region. By installing conventional fossil power plants, using renewable energy, and interconnecting with neighboring countries, this growing demand can be accomplished. The main aim of this research is to identify prospects and challenges in the electrical sector around Iran. To this end, this paper evaluates the existing and future state of the electrical sector in Iran and its neighboring countries. Despite the fact that there is still a long way to go in terms of renewable energy in this region, there are some promising targets for the future that will allow fossil fuels to be replaced effectively. Notwithstanding this, we should point out that a number of cross-border interconnection projects are being pursued by Iran and its neighbors in order to integrate their networks and supply this growing demand. Finally, this study presents an overview of the future prospects and challenges of electricity capacity expansion, cross-border interconnections, and electricity transmission corridors in this region. The review results provide comprehensive background knowledge to all the researchers in order to investigate further into the field. This paper assists energy policy makers regarding the development of sustainable energy planning. • •In addition to providing a general overview of the geographical location, population growth, and economic indicators of Iran and its neighboring countries, this paper presents the current state of the Iranian electricity sector and its neighboring countries in light of the trends in electricity production, energy mix, price, and exports and imports. • •This paper explores the existing and future states of electricity capacity expansion in the region, specifically focusing on renewable energy sources. • •The existing and future states of cross-border electricity interconnections are examined to present a comprehensive overview of the cross-border interconnections in this region. • •This region's potential electricity transmission corridors are proposed to create the opportunity to transmit electricity across countries. [ABSTRACT FROM AUTHOR]

The increasing integration of distributed energy resources has led to heightened complexity in distribution network models, posing challenges of uncertainty and volatility to the operation and control of distribution networks. Simultaneously, the widespread deployment of metering and sensing devices has furnished data-driven approaches with copious data sources. As a potent tool for data mining, artificial intelligence (AI) algorithms have the capacity to harness extensive datasets, thus furnishing comprehensive energy services for distribution grids. This paper provides a comprehensive exposition of AI techniques applied in the realm of distribution network voltage control (DNVC). Initially, a brief overview is provided for the four voltage control frameworks and the data calibration of DNVC, serving as the foundation for various voltage control algorithms. Subsequently, in ascending order of algorithmic advancement, the application of improved heuristic algorithms, deep learning (DL) algorithms structured around artificial neural networks (ANNs), and deep reinforcement learning (DRL) algorithms in the DNVC domain are sequentially introduced, and the relationships among the three AI technologies in framework, control principles, and performance are systematically analyzed. Additionally, attention is directed toward the algorithmic progress made in addressing specific challenges within the DNVC process. Lastly, building upon extant research, the paper summarizes four prominent developmental directions for AI in DNVC: safety exploration, information privacy, multi-feeder collaboration, and heightened uncertainty. Corresponding solutions to each of these directions are individually discussed. • The research status and applications of mainly used AI methods in distribution network voltage control is reviewed. • The relationships among the three artificial intelligence methods are systematically analyzed. • The existing algorithms, along with their strengths, limitations, and relationshipsare highlighted. • The research directions of artificial intelligence methods in distribution network voltage control are discussed in detail. [ABSTRACT FROM AUTHOR]

Energy transition requires a high penetration of reliable and flexible renewable energy. To do so, low-cost, efficient, high capacity and environmentally friendly storage technologies to manage the mismatch between energy production and demand are required. Carnot Batteries are considered as promising energy storage solutions tackling these requirements and storing electrical energy as thermal energy and releasing it whenever necessary while operating on reversible thermodynamic cycles. In Carnot Batteries, power is managed through rotating machines, such as compressors and turbines, and energy is stored as heat in thermal energy storages. In recent years, thermal cycles exploiting Carbon Dioxide (CO 2) as operating fluid, in sub-critical, trans -critical and supercritical conditions, are gaining major interest, thanks to their versatility and high performance, especially for large scale applications. This paper provides an in-depth review on the state of the art of global R&D activities on the use of carbon dioxide for large scale Carnot Battery application, while providing preliminary market and technology maturity breakdown. Different studies on CO 2 -Carnot Batteries at industrial and academic levels are discussed in detail while highlighting the novelty and improvement methods. Detailed information on battery parameters of charging, discharging and storage have been listed and critically analysed, finally concluding with SWOT (Strength, Weakness, Opportunity, Threats) and TRL (Technology Readiness Level) analyses for future developments. [Display omitted] • Academic and industrial outlook on CO2-Carnot batteries. • Important design parameters of charging, storage and discharging are tabulated for each study • · Critical analysis of the design parameters and performance • Roadmap for future developments on CO2-Carnot batteries [ABSTRACT FROM AUTHOR]