Freshwater scarcity is a problem that is becoming more and more of a concern over the world, and as a result, the search for solutions has become a race against time. One of the most crucial solutions for this issue is seawater desalination. The simplest and easiest type of desalination technology is seawater desalination using a solar still system. This present study reviews the past/current status of vacuum solar still systems to pave the way for researchers to improve this technology. This paper aims to describe the design specifications and highlight the merits and demerits of various vacuum techniques used in solar stills systems upon which research has been done in the recent past. Also, a discussion on future ideas is given with some recommendations in the field of vacuum solar stills improvement to economically produce sustainable potable water. The current study concludes that lowering the operating pressure of solar still systems improves system productivity and efficiency by roughly 100% and 70%, respectively. According to the research, forced vacuums account for 52% of all vacuums, while natural vacuums account for 48%. Forced vacuum is an ideal method since it combines creating vacuum conditions and evacuating the non-condensable gases, which is not possible in a natural vacuum. The system productivity and efficiency of the forced vacuum conditions are higher by 80% and 25% than that of the natural vacuum conditions. The cost of freshwater produced per liter in natural vacuum conditions is less than that of forced vacuum conditions.

Latent heat thermal storage (LHTS) using phase change materials (PCMs) faces a significant challenge of poor heat transport efficiency. Fortunately, nature has evolved numerous features and functions that can enhance material properties and heat transport efficiency. This paper provides a comprehensive review of bionic studies on LHTS technology, summarizes bionic strategies for improving LHTS performance, and explores in detail the research progress and challenges faced by bioinspired PCMs and LHTS configurations. The review demonstrates that natural morphology, structure, and function can improve heat charge/discharge efficiency. However, current research mainly focuses on simple configurations of morphological and structural bionics, so more attention is needed to develop high-level functional bionics to maximize LHTS performance. The paper also emphasizes the enhancement methods of heat transfer rate in bioinspired LHTS systems, such as synthesizing bionic hierarchical porous and three-dimensional networks, constructing biomimetic shells, extending the heat exchange area, enhancing the convective heat transfer, and optimizing the heat transport path in PCM regions. Importantly, future research should focus on micro/nano-scale bionics to construct bioinspired PCM and LHTS configurations with more advanced performance. Moreover, a complete enhancement mechanism of multiscale phase-change heat transport needs to be investigated for the development of multiscale biomimetic LHTS technology.

Energy communities are a cornerstone of the European energy transition. Small and medium enterprises (SMEs) exhibit a particularly high potential for energy communities due to their energy demand and flexibility volume. However, in contrast to residential consumers, empirical evidence on SMEs' preferences for participating in renewable energy communities is scarce. This study investigates European SMEs' preferences for local and renewable energy procurement in four countries with a choice experiment. Our sample includes decisions by 823 executives for different energy procurement offers with an energy community approach. In the study, in 67% of the choices, SMEs prefer a renewable energy community offer to their current supply option even without a price premium. Cost is the most important factor in SMEs' energy supply decisions. SMEs have marked preferences for local providers, low administration efforts and high interest in demand-side management and peer-to-peer trading. In contrast, SMEs might reject energy procurement models when major time investments are required, or the provider is an international company. Offers that include local companies or electricity providers and provide smart energy management are most likely to win SMEs' consent. The study recommends orienting the business model design of energy communities towards the specific preferences of corporate consumers to leverage their potential. The results suggest that electricity providers are well-accepted players by SMEs as potential providers of energy community solutions. National implementations of the European policy directive are recommended to take into account the role electricity providers can play in the development and operation of energy communities.

Decommissioned wind turbine blades are becoming a significant problem as they are made from composite material that is difficult to recycle. To solve this problem, sustainable end-of-life value chains are needed. Several significant processes of such value chains consist of the sectioning and pre-processing operations of the blades. Thus, the technologies for these operations must be identified and assessed using sustainable selection criteria. The aim of this study is to investigate how a multi criteria decision making analysis approach can assist and improve the process of assessing technologies through the lens of sustainability. For this purpose, this study proposes a three-step framework for sustainable decision making – 3-SuDeM, which presents a structured approach for how to manage the entire process of applying a multi criteria decision making analysis to an industrial case. The developed framework has been applied and validated in cooperation with a Danish waste management company who have years of experience in handling end-of-life waste. Four different technologies for cutting and sectioning end-of-life wind turbine blades are evaluated using the 3-SuDeM framework applying the method of technique for order of preference by similarity to ideal solution, and an excavator with a large diamond saw blade is identified as the preferred technology in the given case. The results conclude that the developed framework is both value adding to the practical selection of sectioning technology for blades and also adds to the literature on sustainable value chains, multi criteria decision making methodology and end-of-life wind turbine blades.

Wireless power transfer (WPT) promises to be an alternative solution for secure and versatile charging of electric vehicles. However, some challenges still exist in this contactless technology, such as electromagnetic safety, low transmission efficiency and power capacity. A vast research literature focuses on improving the design and optimization of WPT systems. This paper provides an in-depth literature review on the current status and potential trends of wireless charging for electric vehicles and brushless excitation technology for drive motors, including the power electronic structure, coupling mechanism, and compensation topology of WPT systems. In addition, several emerging research topics are proposed and highlighted.

The prediction of regional carbon emissions and the optimization of development paths are particularly important. Regional heterogeneity leads to different links between carbon emissions and population, economy, industry, energy, environment, and other factors. However, most of the previous studies carried out the accounting, factor decomposition, prediction, and decision-making of regional carbon emissions alone, which failed to form the sustainable assessment of regional carbon emissions. Therefore, the carbon emissions coefficient, Logarithmic Mean Divisia Index, system dynamics model and Interlink Decision Making Index were selected in this study to establish the regional carbon emissions systems framework. In this study, a mega-city such as Tianjin was taken as an example, the comprehensive assessment and prediction of regional carbon emissions system was carried out. The results show the change in energy intensity had the strongest mitigation effect, reducing carbon emissions by 106.17 million tons in total, and the per capita GDP effect had the strongest promotion effect, with a cumulative contribution of 265.19 million tons of carbon emissions. Among all 13 scenarios in Tianjin, Scenario-12 is identified as the optimal development path and provides policy suggestions. The results of this study not only verify the effectiveness and necessity of the framework, but also provide guidance tools for regional carbon emissions development. The results of this study validate the effectiveness and necessity of the framework to provide guidance for the regional carbon emissions development path. The results of the case also provide help for the optimization of Tianjin's carbon emissions development path.

Abstract not available

In line with an intensified call for reducing greenhouse emissions and curbing the effects of climate change, scientists and experts have looked to information communication technology (ICT) and digitization as critical tools for the more efficient use and production of energy. Consequently, research on ICT/digitization and their impact on environmental sustainability has witnessed exponential growth in the last few decades. This study provides a systematic review of the relationship between ICT/digitization and environmental sustainability over the period from January 2000 to April 2022. It aimed to improve our understanding of the different theories and channels governing the ICT/digitization–environmental sustainability nexus, to provide an in-depth analysis and discussion of the trends and main empirical findings of the reviewed articles, and to highlight key avenues for future research. In total, 166 scientific articles examining 297 associations between ICT/digitization and environmental sustainability were selected for this review. The results revealed that most of the studies have used measures based on climate change and air pollution for environmental sustainability, and traditional ICT/digitization measures, e.g., mobile phone subscriptions and internet users. The results also showed that although most studies found evidence for ICT/digitization improving environmental sustainability, evidence for a negative association is concentrated in studies on the ’Group of’ countries. The results also revealed a scarcity of studies investigating nonlinear relationships between ICT/digitization and environmental sustainability.

The gamut of geothermal energy research encompasses the studies aimed at harnessing the abundant and inexhaustible thermal energy within the Earth, and it ranges from heat transfer to the activity of thermophilic microorganisms, 3D printing, and additive manufacturing and impacts the NET ZERO endeavour of humanity. In this paper, computational social network analysis has been employed to discover the subfield clusters of geothermal energy research and further trace the key evolutionary routes from the research corpus. The development, limitations, and opportunities of each cluster are examined, and it becomes evident that the focus of research ranges from geothermal evaluation, long-term effects of borehole heat exchangers, shallow systems that employ urbanisation’s ground heating, enhanced geothermal systems (EGS) for district heating, combined and hybridised geothermal power generating models, including multi-generation and poly-generation, geothermal fluids, reinjection and their dual nature, environmental effects in geothermal water and mineral scaling, enhanced geothermal systems aiming to increase permeability without causing seismicity, and finally to social acceptability. We address significant questions, such as whether the waste heat is compatible with the idea of green geothermal heat and the elimination of pollutants and find that further R&D and technological advancements are required for this ubiquitous clean energy to get wider acceptance and employment. The future of this energy depends on the rational and scientifically sound exploration and use of the resources, just as in the case of fossil fuels, and thus precludes geothermal energy as a win-all solution to the energy needs of the whole world.

Accurately forecasting solar radiation is of great significance to solar energy utilization. To forecast the spatial and temporal distributions of solar radiation simultaneously, a deep neural network model named MRE-UNet is proposed, the solar radiation data in Heilongjiang province is taken as an example to test the forecasting performance in different periods ahead forecasting cases. According to the evaluation results, an 16 h historical solar radiation data was determined to be the best choice for input, and the minimum of MSE can reach 6.47 × 10−4, 1.38 × 10−3 and 2.69 × 10−3 for 1 h, 3 h and 6 h ahead forecasting cases, respectively. The transferability of the MRE-UNet is tested by performing the solar radiation nowcasting in Hubei province, China using the pre-trained MRE-UNet trained by the solar radiation data in Heilongjiang province. The robustness of MRE-UNet is tested by monitoring the effects of adding different level of noise, and MSE keeps to be 6.27 × 10−4 even though the measuring noise increase to be 50%. For further demonstration on the effectiveness of MRE-UNet in spatiotemporal forecasting, the performance in total cloud cover forecasting is also tested, and satisfactory forecasting results are obtained. Finally, spatiotemporal correlation analysis on solar radiation and total cloud cover data is carried out, a potential reason for satisfying forecasting performance of MRE-UNet is given. From this work, MRE-UNet proposed can be provided as an efficient tool for dealing with further solar radiation spatiotemporal forecasting problem, and the spatiotemporal correlation characteristics can be employed as the basis for further developing effective solar radiation forecasting approach to a degree.

The latest and state-of-art research on biomass waste-derived carbon materials synthesized for air electrodes used in metal-air batteries were succinctly and comprehensively reviewed in this report. This report also aims to provide greater understanding as well as to identify the strength and challenges of metal-air batteries (MAB), biomass wastes as precursor and the synthesis steps of carbon materials from biomass wastes as well as to propose several research routes for the shortcomings of carbon material synthesis from biomass wastes. MAB is a promising energy storage technology, but its commercialization was hindered due to the absence of a stable and active bifunctional electrocatalyst as well as costly air cathode material. The air cathode which is the key component of MAB is desired to have bifunctional catalytic properties and hierarchical porous structure. Carbon materials were known to be able to perform as an electrode material while acting as a catalyst towards the charge-discharge reactions. Due to its abundance and renewability, biomass wastes have great potential as low-cost and sustainable precursors to synthesize carbon materials as the air cathode while achieving waste reduction. The synthesis of carbon electrocatalyst from biomass waste usually include but not limited to pretreatments, carbonization, activation and doping. The synthesis method controls the structure and size, as well as the elemental content of carbon particles. Activation and doping of heteroatoms or metals were proven to enhance the efficiency and stability of the synthesized carbon material. However, each biomass waste have unique properties which requires tailored synthesis method to obtain carbon material with desired properties. Information on the synthesis methods as well as other crucial information were reviewed in this work which can help to spur more research to promote the utilization of biomass waste materials in energy storage application and to accelerate the commercialization of MAB.

Urban areas account for more than 70% of total carbon emissions. This proportion for China is higher, approximately 80%, closely related to human activities in urban energy consumption. In this context, the low-carbon transition of urban energy systems has become an important strategic goal for China to deal with climate change and seek sustainable development. Based on the comparative analysis of the low-carbon transition of urban energy systems in Beijing and Suzhou, this study examines the effectiveness of decarbonization policies on the evolution of urban energy consumption and carbon emissions; provides methodologies for the low-carbon transition of urban energy systems with a macro framework and a comprehensive evaluation system; and reveals the main challenges and analyzes potential solutions from the aspects of technological innovation, policy guidance, and systematic governance. The findings suggest that Beijing should promote terminal electrification and demand-side response, and Suzhou should promote the cleanliness of local generation and external energy. Under the goal of carbon neutrality, urban energy systems can promote green and low-carbon transitions by accelerating the substitution of clean energy in supply systems, promoting electrification of terminal energy consumption, developing digital and refined carbon emission accounting and management, and innovating collaborative governance mechanisms for achieving carbon neutrality.

Global climate change has prompted many national plans for rapid emissions reductions. For example, the United States recently committed to transitioning to 100% carbon-free electricity by 2035 and net-zero emissions economy-wide by 2050. Parallel to conversations surrounding emissions reductions is the call for energy justice, or the demand for more equitable distribution of energy-related burdens and benefits among communities. To date, energy justice has evolved as a mostly academic conversation, which may limit its utility to praxis. In response, we offer an interdisciplinary framework that aims to organize existing knowledge and lessons learned from energy development. Specifically, we developed the Meaningful Marine Renewable Energy (MRE) Development Framework and conducted a literature review using MRE as a case study. MRE was chosen because it is a nascent renewable energy technology in the US with projects mostly in demonstration stages and no commercial deployment, making it a useful case study to apply lessons learned from other energy sectors and other countries. Discussion of current resources being developed among the MRE community and their implications for furthering energy justice priorities are also explored. We conclude the review with a compiled list of questions meant to support stakeholders in translating theoretical concepts of Meaningful MRE Development to practice. Although the Meaningful MRE framework was developed using MRE as a use case, our interdisciplinary theoretical framework can be applied beyond MRE to other sustainable and renewable energy projects.

High penetration of electric vehicles (EVs) has resulted in an increasing need for charging infrastructure and efficient smart charging coordination of EVs. In addition to residential and public charging, destination charging is another important mode of EV charging, and it has the potential to cover residual public charging demand. Understanding of the factors and charging coordination strategies that ensure a sustainable destination charging business is therefore of utmost importance. Literature on the topic of EV smart charging and coordination is growing exponentially, but the terminology used to describe coordination strategies remained ambiguous. Hence, this paper systematically classifies the literature focused on the destination charging. In doing so, various charging tariffs and business models associated with destination charging are reviewed and a comprehensive discussion on their profitability and availability is provided. Recent EV charging coordination strategies are reviewed and categorized to clarify the commonly used terminology. Destination charging coordination strategies are then classified, and real-world charging coordination initiatives are reviewed and summarized. The analysis contained in this paper shows that further research work on charging coordination for destination charging should account for user behavior and the potential obstacles faced by the intended scale of destination charging to determine a suitable coordination strategy. It is also recognized that implicit charging coordination strategies are understudied and should be investigated because they may circumvent problems encountered by real-world EV charging coordination programs.

Fatty acid photodecarboxylase derived from Chlorella variabilis NC64A (CvFAP) is a novel enzyme that can convert fatty acids to corresponding C1-shortened alkanes under blue light illumination, which provides an alternative approach for the production of bio-aviation fuels under mild conditions. To date, the production of bio-aviation fuel using CvFAP is severely limited by an inefficient reactor. Microfluidic reactors have attracted significant attention owing to their high mass-transfer efficiency and low light attenuation in continuous photobiocatalysis. In this study, a microfluidic photobioreactor was proposed for the continuous photoenzymatic decarboxylation of palmitic acid for the first time. The optimal palmitic acid conversion of 96.7% was obtained at a flow rate of 10 μL/min, a blue light intensity of 200 μmol/(m2 s), a reaction temperature of 30 °C, a catalyst concentration of 2.4 mg/mL, a substrate concentration of 12 mM, and a cosolvent volume ratio of 30%. The maximum pentadecane production rate of 59.8 mM/h was achieved. The highest turnover frequency of CvFAP up to 19,186/h, as ever reported, was obtained at a flow rate of 40 μL/min. Meanwhile, the energy yield of 33.6 kJ/g and energy production rate of 533.5 kJ/L/h were achieved in continuous bio-aviation fuels production. Taken together, the continuous photoenzymatic decarboxylation of fatty acids in a microfluidic photobioreactor is a promising approach for bio-aviation fuels production.

Net-zero emission and self-sustaining carbon-neutral have been widely encouraged and intensively explored in wastewater treatment, as the wastewater industry accounts for approximately 1.6% of global greenhouse gas (GHG) emissions. However, how to achieve net-zero GHG emission in wastewater treatment from a biological standpoint is still lacking. In this paper, the status of GHG (i.e. nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2)) production and emission in wastewater treatment was comprehensively reviewed. Generally, N2O emission contributes the majority of the total GHG emissions from wastewater treatment, and the dissolved N2O and CH4 in the effluent should be paid more attention for the further GHG mitigation. Based on the newly identified microbial communities capable of nitrogen removal with less GHG emissions, several alternative integration systems for GHG mitigation were discussed. Coupling denitrifying anaerobic methane oxidation with anammox process shows high nitrogen removal performance and low GHG emissions, which is regarded as a more promising integration system for GHG mitigation. Moreover, the novel strategies to manage N2O and CH4 as energy sources were also demonstrated, aiming to offset certain carbon footprint in wastewater treatment and thus attain net-zero GHG emission. In addition, future challenges and perspectives of above integration systems and strategies were discussed to facilitate the development of environmentally sustainable wastewater treatment. Finally, a prospective hybrid system integrating emission reduction and energy recovery was proposed as an example for achieving net-zero GHG emission from wastewater treatment.

Anaerobic digestion (AD) is one of the paramount technologies for organic wastes treatment. However, there still remain intractable issues including low digestibility and sluggish reaction kinetics in its practical implementation, leading to limited bio-product production. Recently, carbon-based additives (CAs) have aroused great attentions for enhanced AD performance by establishing direct interspecies electron transfer (DIET) and adjusting the functional microorganisms due to their large specific surface area and high conductivity. However, such inherent physicochemical capabilities of CAs and its specific role in AD have not been fully exploited. In this review, we detailedly summarize the research advances of biochar and activated carbon (AC) as additives in AD system, which are combed in terms of structure construction of CAs, macro-behaviors of CAs, micro-mechanisms of CAs and hybrid strategy. Finally, perspectives regarding future modification and application of CAs in AD system are also discussed.

High-temperature heat exchangers are extensively studied today due to their benefits for industrial processes. In most cases, there is a threshold for the maximum operating temperature of heat exchangers. Beyond this temperature level, special design and material considerations are required. This threshold is 600 °C today, which is higher than in the past due to recent advances in heat transfer and materials. This study presents extensive information about various designs of high-temperature heat exchangers, their materials and heat transfer fluids, and the most significant technical issues and scientific gaps in this field. The aim is to shed light on the pathway to improving high-temperature heat exchanger efficiency, economic feasibility, and safety. The research survey shows that i) molten salts, liquid metals, helium, supercritical carbon dioxide, etc. are the most appropriate heat transfer fluids for high-temperature heat exchangers; ii) shell and tube, plate, plate and fin, helical coil, finned tube, printed circuit, double-pipe, and bayonet tube heat exchangers are the most commonly used configurations for high-temperature applications; and iii) iron- and nickel-based alloys, and ceramics are the most commonly used materials. The critical issues in high-temperature heat exchangers are corrosion, material degradation over time, quality degradation, and limited lifetime. The main benchmarks needed for high-temperature heat exchanger design are fluid types, working conditions, required heat transfer rate, and costs. The study represents a brief yet informative state-of-the-art and discusses the gaps for each of these parameters, providing readers with a clear line of future research.

This research discusses the role of neighbourhoods' design in reducing their energy vulnerability during power disruptions. Neighbourhoods’ design includes building types and their role and function, as well as land use and spatial design of the neighbourhood. The architectural design and energy characteristics of specific buildings are analysed to assess their potential to act as local shelters in case of evacuations, and available renewable and alternative energy sources to supply energy during power outage. The neighbourhoods considered in this study are designed according to sustainable practices while reflecting North American practice of urban developments. Several response scenarios are designed and analysed to account for the duration of disruptions, scenarios of evacuations, and type of temporary shelters. The role of neighbourhood design is highlighted under each of these scenarios, and recommendations on practices to enhance resilience are discussed. Building such as schools with shelter energy intensity of 9.5 kWh can be prioritized during the evacuations in power outages. By modifying standard design guidelines for shelters of 5.6 m2/person to 4 m2/person, the shelter to population ratio can be significantly increased (i.e., by 77%–80%) supporting community resilience. The relevance of proximity of shelter building to residential areas as well as role of landscape for additional energy system installation are also discussed in this work.

The rise in energy consumption and non-renewable fossil fuel depletion has sparked interest in finding more sustainable fuel alternatives. Hydrotreated vegetable oil (HVO) is a prime candidate to replace conventional hydrocarbon (HC) fuels as it is renewable and has a high calorific value. However, the existing processes to convert vegetable oil to HVO involve extreme operating conditions and expensive metal catalysts. Recently, photodecarboxylase derived from Chlorella variabilis NC64A (CvFAP) has demonstrated great potential to convert fatty acid (FA) to renewable HC fuel in the presence of blue light. This is a simple one-step process that does not form any intermediates. This review summarized the findings related to CvFAP-catalyzed renewable HC fuel production, including the catalytic mechanism and challenges in scale-up and commercialization. Current studies have demonstrated great potential to produce renewable HC fuel from FA using CvFAP.