Renewable and Sustainable Energy Reviews最新文献

The transition to renewable energy sources is crucial for combating climate change and enhancing energy security. However, along with well-acknowledged benefits, the energy transition may impose overlooked and unintentional risks to sustainability, stemming from patterns of trade between countries. The buildup of solar and wind energy capacity requires critical metals and equipment that are often imported, while too ambitious renewable energy and climate policies may lead to the offshoring of energy- and carbon-intensive industries, resulting in carbon leakage. This study uses principal component and cluster analyses to estimate indicators of trade-related energy security and carbon dioxide emissions embedded in trade of the sixty-four countries. The analysis indicates that wealthier countries, particularly those that are not energy self-sufficient, are more likely to utilize solar and wind energy. Solar and wind energy use is also associated with higher imports of embedded energy and emissions, as well as imports of metals and equipment required for renewable energy production. In contrast, energy-self-sufficient countries, being net exporters of both energy and energy embedded in products, barely use solar and wind for electricity generation and hardly import metals or low-carbon technologies. This study highlights the need to account for possible cross-border dependencies and displaced emissions, which may result from higher reliance on distributed renewable energy sources.

Sustainable insulation is an integral part of energy efficient building design. Buildings have a significant carbon and energy footprint and using sustainable material is key to their decarbonization especially in cladding. In additional traditional cladding materials are not environmentally friendly. In developing countries with constrained construction budgets, limited resources and existing energy poverty using local resources is important to sustainable development, reducing building energy demand and supporting the local circular economy. Hence the aim of this research is to assess the thermal insulation and mechanical properties to identify an optimal mix of clay, cork, and sheep wool in composite bricks to improve energy efficiency in buildings. The novelty is that wool was introduced into the composite via an innovative method in the form of yarn network layers. The obtained results revealed that the thermomechanically optimal composite, which is clay specimen incorporating 12 % of the cork mass percentage with 2 % of wool in one layer (ClW₂Co₁₂) provides a gain of 64 % in thermal conductivity, 49 % in thermal effusivity, and 50 % in thermal diffusivity. Furthermore, the specimen ClW₂Co₁₂ is 14 % higher in flexural and 24 % lower in compressive strength compared to the reference material (clay alone) at the 30-day setting period. This innovative method ameliorates the lightness of the elaborated ClW₂Co₁₂ brick by about 52 %. These findings indicate that the developed composite made with locally available and economically local sustainable materials can be well used as thermal insulator in buildings using a circular economy approach.

Heat storage is becoming increasingly important from the perspective of energy storage. Among the various thermochemical heat storage materials, MgO has garnered interest as a heat storage material at moderate temperatures (200–400 °C) owing to its low price, non-toxicity, and high heat storage density. However, the practical integration of MgO into a thermal energy storage system is challenging because of its low cycling stability, which is largely attributed to the agglomeration of its powder. Although pelletization has been proposed as a solution to cycling instability, structural instability due to volume changes during heat storage cycles remains a concern. In this study, an MgO-based heat storage pellet was successfully developed using a fabrication strategy that involved the direct molding of char, the introduction of a sintering process, and the incorporation of ceramic fibers. Consequently, superior heat storage performance and cycling stability observed in the developed MgO-based heat storage pellet can be attributed to various factors. The hierarchical pore structure and small particle size facilitate efficient material transport and provide a large surface area, leading to superior heat storage performance. Additionally, the necking and toughening effects due to sintering help overcome structural instability during heat storage cycles, resulting in robust structural stability. It is expected that the developed pelletization technology, which allows to overcome the inherent cyclic instability, will contribute significantly to the practical implementation of MgO as a heat storage material.

With the growing concern on climate change, many governments are making efforts to substitute fossil-fuel passenger vehicles in order to meet the urgent need for low-carbon and renewable fuels. Electric and hybrid vehicles reflect the increasing interest in clean and energy-efficient options. Nevertheless, the large-scale adoption of full electric is challenged in some regions due to the higher cost of these vehicles. This research presents a framework to assess the total cost and greenhouse gas (GHG) emissions in three types of technologies currently present in Brazil: fully electric, hybrid, and combustion flex-fuel cars. Brazil's light-duty fleet is a compelling case because it is mainly composed of flex-fuel engine combustion cars. The country also has strong conditions to supply this fleet with ethanol at a large scale with competitive prices. According to our results, full electric can reduce GHG emissions by 85 % if compared to gasoline-powered combustion. Nevertheless, there is a 96 % higher cost per kilometer in comparison to flex-fuel combustion vehicles. Flex-fuel hybrid fueled with ethanol can reduce GHG emissions by 76 %. Combustion flex-fuel vehicles can reduce 59 % of GHG emissions with no additional cost when powered by ethanol. Our findings show that hybrid cars fueled with ethanol are a more cost-viable option for reducing the Brazilian light vehicle fleet carbon footprint in a short time. The methodological approach presented in this study can be replicated in other regions to analyze trade-offs between costs and GHG emissions, thus helping plan the most appropriate path for the light-duty fleet energy transition.

Floating photovoltaic systems are a promising option for renewable energy by mitigating the drawbacks of land-based photovoltaic systems. However, renewable energy systems are designed in a site-specific way, therefore, the performance of renewable energy alternatives substantially depends on the selected site characteristics. In this study, a comprehensive assessment was performed to identify the optimal hydroelectric power plant reservoir for floating photovoltaic system deployment in Turkey using the Geographical Information System and Multi-Criteria Decision Making method. A two-staged methodology was used to evaluate the results of questionnaires including several expert opinions. In the first stage, a nonlinear fuzzy Aczel-Alsina functions based Ordinal Priority Approach method was employed to weigh the fourteen sub-criteria based on technical, environmental, economic and social considerations. In the second stage, fuzzy sine Trigonometric based Additive Ratio Assessment method was used to rank the fifteen hydroelectric power plant reservoirs all across Turkey. Despite the global horizontal irradiation being the most important criterion, Sarıyar hydroelectric power plant reservoir, with one of the lowest global horizontal irradiation values among alternatives, was determined as the most suitable dam reservoir for floating photovoltaic installation in Turkey. Therefore, the findings of this study highlight the importance of comprehensive analysis that considers the several assessment criteria from fundamental aspects to achieve reliable site selection for floating photovoltaic systems.

A perfect combination of weather and a power system backed by battery-based energy storage enabled Ireland to break a renewable penetration record in February 2022, with 96 % of electricity demand covered by wind generation at its peak. In high renewable energy penetration scenarios seen worldwide, ensuring the resilience of power systems against major events has received increased attention. Supplementing traditional generation units with renewables and distributed energy resources (DER) in the energy mix to meet the load demand and net-zero emission goals has affected power system inertia, black-start readiness, service restoration, and operations. Maintaining adequate resources to retain black-start readiness in anticipation of widespread outages is becoming challenging. This study reviews the technical aspect of a 100 % inverter-based resources (IBR) based distributed restart zone (DRZ) to assist black-start. It investigates the feasibility of using a set of IBR control schemes to help restart a non-black start combined cycle unit by aggregated energy storage system and PV via transmission lines. Through assistance from power system operators, common operation practices are incorporated and simulated in a black start cranking path case study. Simulation results are reported and compared against the traditional practices based on hydropower. The results show that the IBR could supplement the traditional black-start resources. The functional requirements identified in this study would be useful for developing GFL and GFM inverter controls in the industry to enable black-start ancillary service by IBR.

Shifting and shedding power demand in buildings can be cost-effective techniques for grids to function reliably and for end users to earn compensation. Grid operators reimburse customers in proportion to the quantity of load shed. Simple data-driven methods are used to quantify this shed, which is the difference between a measured load during the event and modeled “baseline” that would have occurred in absence of the event. These methods have evolved over the years and in many cases have been integrated with building physics, to make them a hybrid between physics based and empirical models. However, there is no comprehensive analysis that provides guidance to building operators, grid operators and researchers in selecting appropriate models based on their specific needs and available data. This work aims to fill this gap by critically assessing the performance of baseline models put forward from the year 2000 through 2023. The literature reviewed includes reports generated by grid operators, reports from national laboratories and academic journal articles.

The work outlines modeling features like the inputs, training period, estimation method, adjustments to fine tune the predictions and metrics to evaluate the performance. A comprehensive list of 50 models has been provided. For each model, the study explores the applicability of the model to weather sensitive buildings, variability in the building profile, timing of the event, and whether the building reduces energy consumption before an event. The work identifies the situations in which a particular model works and draws lessons based on evidence of performance. Finally, recommendations to aid in model selection are given.

Submarine natural gas hydrates (NGHs) are one of the largest methane reservoirs on Earth, offering huge potential as an alternative energy source and serving as a crucial global carbon sink. However, the substantial risk of methane leakage during NGH development seriously threatens marine and global ecological and environmental safety, presenting a major challenge for commercial NGH exploitation. Focusing on the unknown leakage mechanisms, this study employed a new simulation device to construct a stratified environment and to investigate the characteristics of hydrate dissociation and methane leakage during depressurization production, under conditions of varied fracturing in overlying sediment. A movable module was used to dynamically isolate and connect the hydrate reservoir with the overlying layer. The results showed that the intrusion of overlying water decelerated the reservoir depressurization rate, leading to a mass of hydrate reformation. The invasion locations and flow paths of the overlying water were influenced by the fracture scale of the overlying sediment. Benefiting from the additional sensible heat and reservoir space occupation of the overlying water in the later production stages, the methane recovery ratio in the fracture-containing systems were not significantly affected. However, the leakage methane increased as fracture channels enlarged, reaching up to 9.90 % of the total methane content in the hydrate reservoir. The leakage mechanism primarily involved local overpressure, buoyancy effects, and diffusion. The research, for the first time, experimentally revealed the response relationship between methane leakage and hydrate dissociation, providing foundational data and theoretical support for the safe and efficient NGH development.

The photocatalytic hydrogen production from water splitting is considered to be a clean and promising technology of new energy conversion. The low quantum efficiency, the narrow response range of visible light and the low utilization rate of solar energy are still the problems that need to be solved urgently for the industrial application of photocatalytic hydrogen evolution technology. This work provides a comprehensive review of the preparation strategies and hydrogen evolution ability of various photocatalysts in these years and highlights their advantage and disadvantage. Four improvement methods including element doping, vacancy defects, homojunction and heterojunction, self-built internal electric field are reviewed to reveal the effect of molecular structure change on the photocatalytic activity. Moreover, the sacrificial agents or cocatalysts commonly used in photocatalytic H₂ production are also reviewed, analyzing the difference of hydrogen performance under different reaction system. This review also looks forward to the future challenges of this technology in the direction of binding force, crystallinity and electron transfer of photocatalyzed hybrid materials, as well as hydrogen production from seawater splitting. This is conducive to the development of the industrial application of photocatalytic hydrogen evolution technology, which has a great reference significance for solving the freshwater crisis, promoting the development of sustainable renewable clean energy, and meeting the social demand for green hydrogen.

Lithium-ion batteries occupy a place in the field of transportation and energy storage due to their high-capacity density and environmental friendliness. However, thermal runaway behavior has become the biggest safety hazard. To address these challenges, this work provides a comprehensive review of thermal runaway warning techniques. The mechanism and characteristic behavior of thermal runaway are summarized. The characteristic parameters of thermal runaway (thermal, electrical, gas signal, etc.) are the basis of early warning technology. Then, three kinds of early warning technologies are discussed and proposed. Gas sensors have more early warning capability than sensors based on internal signature monitoring, but both lack predictive capability. Fortunately, battery management system technology combined with intelligent algorithms has powerful data processing and prediction capabilities. The innovation of early warning technology cannot be achieved without the synergy of multiple technologies. This review aims to provide a comprehensive overview of the current progress and challenges in the development of LIBs thermal runaway warning technology, providing ideas for potential future areas and directions.