ALBERT

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 113〈/p〉 〈p〉Author(s): S.K. Kim, K.H. Cho, J.Y. Kim, G. Byeon〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents long-term field test results of lithium-polymer and advanced lead-acid battery systems for consumer load management. The battery systems aimed to minimize electricity bills of an industrial consumer by shifting its load to lower priced time-zones and regulating its peak. Annual and daily peak reduction effects and operating revenues are examined under a time-of-use tariff and battery promotional incentive. Capacity degradations of the batteries are calculated to estimate the actual lifetime. Based on actually earned revenue during the field test and predicted service life for the each type of the batteries, total expected revenue per unit installation capacity is estimated and compared with investment cost per capacity to perform the economics of the tested battery systems for consumer load. This analysis found that the profitability cannot be assured under the considered time-of-use pricing alone but can be expected when adequate incentive is provided. It is also revealed that the batteries in real use conditions lose their capacity considerably quicker than suggested by manufacturers. Therefore, it is recommended to consider actual fading pattern of the battery for accurate economic evaluation at the design stage and to reflect the battery degrading cost into the charge-discharge scheduling model to optimize operating revenue.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 112〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 113〈/p〉 〈p〉Author(s): Yifan Yang, Gary Cui, Christopher Q. Lan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Evaporative cooling is a widely employed energy-saving cooling method. It has found applications in a variety of different areas such as HVAC, industrial process cooling, and personal microclimate cooling, as stand-alone cooling processes or in combination with conventional cooling technologies. Evaporative cooling could be classified into different categories such as air-mediated vs water-mediated evaporative cooling and direct vs indirect evaporative cooling. Evaporative cooling could be enhanced by means such as desiccants, membranes, and the combination of desiccants and membranes. This paper strives to provide a comprehensive review on the recent developments and applications of different enhanced evaporative cooling technologies.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 113〈/p〉 〈p〉Author(s): Sujan Ghimire, Ravinesh C. Deo, Nawin Raj, Jianchun Mi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The accurate prediction of global solar radiation (GSR) with remote sensing in metropolitan, regional and remote, yet solar-rich sites, is a core requisite for cleaner energy utilization, monitoring and conversion of renewable energy into usable power. Data-driven models that investigate the feasibility of solar-fueled energies, face challenges in respect to identifying their appropriate input data as such variables may not be available at all sites due to a lack of environmental monitoring system. In this paper, the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite-derived predictors are employed to train three-phase hybrid SVR model for monthly 〈em〉GSR〈/em〉 prediction. Firstly, to acquire relevant model input features, MODIS variables are screened with the Particle Swarm Optimization (PSO) algorithm, and secondly, a Gaussian emulation method of sensitivity analysis is incorporated on all screened variables to ascertain their relative role in predicting 〈em〉GSR〈/em〉. To address pertinent issues of non-stationarities, PSO selected variables are decomposed with Maximum Overlap Discrete Wavelet Transformation prior to its incorporation in Support Vector Regression (SVR), constructing a three-phase PSO-W-SVR hybrid model where the hyper-parameters are acquired by evolutionary (〈em〉i.e〈/em〉., PSO & Genetic Algorithm) and Grid Search methods. Three-phase PSO-W-SVR hybrid model is benchmarked with alternative machine learning models. Thirty-nine model scenarios are formulated: 13 without feature selection (〈em〉e.g〈/em〉., SVR), 13 with feature selection (〈em〉e.g〈/em〉., PSO-SVR for two-phase models) and the remainder 13 with feature selection strategy coupled with data decomposition algorithm (〈em〉e.g〈/em〉., PSO-W-SVR leading to a three-phase model). Metrics such as skill score (〈em〉RMSE〈/em〉〈sub〉〈em〉SS〈/em〉〈/sub〉), root mean square error (〈em〉RMSE〈/em〉), mean absolute error (〈em〉MAE〈/em〉), Willmott’s (〈em〉WI〈/em〉), Legates & McCabe’s 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈mo stretchy="true"〉(〈/mo〉〈msub〉〈mrow〉〈mi〉E〈/mi〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈/msub〉〈mo stretchy="true"〉)〈/mo〉〈/mrow〉〈/math〉 and Nash–Sutcliffe coefficients 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈mo stretchy="true"〉(〈/mo〉〈msub〉〈mrow〉〈mi〉E〈/mi〉〈/mrow〉〈mrow〉〈mi〉N〈/mi〉〈mi〉S〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉) are applied to comprehensively evaluate prescribed models. Empirical results register high performance of three-phase hybrid PSO-W-SVR models, exceeding the prescribed alternative models. High predictive ability evidenced by a low 〈em〉RRMSE〈/em〉 and high 〈em〉E〈/em〉〈sub〉〈em〉1〈/em〉〈/sub〉 ascertains PSO-W-SVR hybrid model as considerably favorable in its capability to be enriched by MODIS satellite-derived variables. Maximum Overlap Discrete Wavelet Transform algorithm is also seen to provide resolved patterns in satellite variables, leading to a superior performance compared to the other data-driven model. The research avers that a three-phase hybrid PSO-W-SVR model can be a viable tool to predict 〈em〉GSR〈/em〉 using satellite derived data as predictors, and is particularly useful for exploration of renewable energies where satellite footprint are present but regular environmental monitoring systems may be absent.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1364032119304472-fx1.jpg" width="313" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Nicolas DeLovato, Kavin Sundarnath, Lazar Cvijovic, Krishna Kota, Sarada Kuravi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With depleting natural resources and the effects of conventional energy sources like coal and petroleum on the environment, clean energy sources have been gaining prominence in recent times. Renewable sources are abundant and improving the efficiency of renewable technologies will provide a viable solution to meet the ever-increasing energy demands of the modern-day world. One of the most effective and practical ways for improving the efficiency of renewable power plants and other possible energy sources is by recovering waste heat (vs. improving the power plant component efficiencies using new designs and materials). However, in many of the existing designs, the waste heat is merely rejected or not effectively utilized. Through a combination of sustainable and hybrid solutions and reusable waste heat methods, a sustainable future for power and advanced technology can be made a reality. Many independent review articles exist in the areas of solar power plants, geothermal power plants, and combined heat and power (CHP) plants. In this article, power generation using solar and geothermal sources when simultaneously operated as CHP plants for waste heat recovery (WHR) is reviewed with the focus on the current state of the art applications for this waste heat. Also, the thermodynamic performance and economics of these power plants when combined with the heat recovery applications are discussed. Finally, the future research direction for the field is suggested based on the current status and findings to pave the way for a more effective waste heat utilization from renewable thermal sources.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Tommaso Barbiero, Carlo Grillenzoni〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Owing to the rapid urban growth of past decades, the refurbishment of buildings has become a central topic of city development. A key aspect of building renovations deals with energy saving, both for economic and environmental concerns. The present literature mainly focuses on technological solutions for buildings, and the related data are studied with descriptive statistics. Instead, this paper aims to evaluate the energy effectiveness of refurbishment interventions from a global sector viewpoint. This implies building representative datasets, developing a synthetic cost indicator, estimating a proper regression model, evaluating the meaning of results and outline proper support policies. Two relevant case-studies are considered: the first is a published dataset of European service buildings, which contains detailed information on the undertaken interventions. The cost indicator is built by averaging standard costs per square meter; next, a Beta regression model is fitted to the data. This belongs to the class of generalized linear models (GLM) and it is suitable when the dependent variable (the saving rate) has an asymmetrical distribution on the interval [0,1]. The second case study is a survey on the retrofitting decisions of households in an urban area of Venice; the related dataset includes information on the cost of investment, the energy saving, and the comfort improvement. Comfort may be a subjective perception, including physical, psychological and economic wellness; however, it is also a drive for housing renovation and for energy saving itself. Statistical analyses show a significant positive dependence between all variables, confirming the energy saving effectiveness of refurbishment interventions. On the base of these results, proper refurbishment policies, both for public and private actors, are finally proposed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Yuekuan Zhou, Sunliang Cao, Jan L.M. Hensen, Peter D. Lund〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Clean power production, buildings, and transportation are key areas for climate change mitigation. Their tighter integration decreases not only the emissions, but also the energy consumption of buildings and transportation. Energy integration and interactions between buildings and vehicles are dependent on the type of building, vehicle, and renewable energy system, as well as the local climatic conditions. The current academic literature does not provide a systematic analysis of this topic. In the study, different energy management systems and advanced energy control strategies have been formulated to study such interactions both from a building and a vehicle perspective. Furthermore, technical solutions have been systematically reviewed in terms of the enhancement of energy interaction capabilities, in particular from the standpoint of renewable energy systems, energy/fuel charging facilities, and control strategies. Assessment criteria employed in the review of solutions include grid interaction, annual operational cost, annual net CO〈sub〉2〈/sub〉 emissions, and annual matching capability. The literature review identifies several technical challenges that need further consideration such as capacity expansion and power fluctuation of the electric grid, low efficiency of heat recovered from electricity generation, and depreciation of vehicles. The future outlook and potential for the energy interaction networks between buildings and vehicles have also been presented.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Chih-Chun Kung, Jianhong E. Mu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Pyrolysis is considered to be an effective technology that not only provides renewable energy but also mitigates climate change. Biochar, one by-product of pyrolysis, can be utilized in multiple ways by different biochar applications, which could result in considerable changes in renewable energy production and carbon sequestration. In existing literature, however, the economic and environmental benefits of pyrolysis and biochar applications are rately discussed, thus, a thorough investigation on conjunctive applications of pyrolysis and biochar should be conducted. This study (1) reviews the pyrolysis outputs from various inputs such as energy crops, crop residuals, animal manures, municipal solid wastes, and sewer sludge; (2) discusses the economic and environmental consequences from pyrolysis and biochar applications through the investigation of a lifecycle assessment; and (3) illustrates the potential climate-induced impacts on agriculture and stability of feedstock supply. To do this, this paper adopts a sector-wide model to compare the effectiveness and efficiency of pyrolysis and biochar applications with and without impacts of climate change for a specific region as a case study; and addresses the influential factors that potentially affect the large-scale development of pyrolysis. The results show that, in the absence of climate change impacts, conjunctive applications of pyrolysis and biochar can reduce more than 2.69 million tons of CO〈sub〉2〈/sub〉 emission and generate electricity of 3,962 MWh annually. In the cases where climate-induced impacts do have influences on crop yields, transitions among pyrolysis technologies and agricultural practice would occur. Under such a circumstance, net electricity generation and emission reduction would decrease by 1.72% and 3.19%, respectively. Thus,taking potential climate change impacts into account is necessary to avoid considerable deviations from the target.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): S. Bell, T. Steinberg, G. Will〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High temperature corrosion of molten salt containment materials is of great interest for thermal energy storage systems used with concentrating solar power. Mitigating this corrosion is critical for the design, life cycle and economics of these systems and requires understanding the mechanisms which drive corrosion. In molten salts these mechanisms are complex, and heavily influenced by factors such as impurities, atmosphere, temperature and metal composition. This review aims to illustrate the mechanisms of molten salt corrosion in thermal energy storage systems and the primary factors which affect them. As these factors are so important for corrosion mechanisms, much of the published corrosion rate data will be not be applicable to many thermal energy storage systems. This means that controlling these conditions and corrosion testing will be an indispensable part of developing cost-effective thermal energy storage systems.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Mohamad Sahban Alnarabiji, Omar Tantawi, Anita Ramli, Noor Asmawati Mohd Zabidi, Ouahid Ben Ghanem, Bawadi Abdullah〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Metal-metal oxide composite materials have been garnering wide attention due to their extraordinary properties and applications in several areas. Ni-NiO is an important composite; its synthesis and properties have been of increased interest with regards to prominent applications in many fields. This article provides for the first time a comprehensive review of the cutting-edge research activities that focus on rational synthesis, characterization techniques, novel properties and applications of the Ni-NiO composite. While the formation mechanism of this composite is still vague, much attention has been given to the reported formation mechanisms using different precursors in one-pot synthesis, and thus, a formation mechanism and green synthesis route have been proposed. All the applications of the Ni-NiO composite in different fields including magnetic materials, ion-lithium battery, supercapacitors and catalytic activities are also emphasized. It was proved from the available literature that metallic Ni was obtained into the skelton of NiO by the reduction process during the calcination through the production of adventitious H〈sub〉2〈/sub〉 via the gasification-like process.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Ana Filipa Esteves, Francisca Maria Santos, José Carlos Magalhães Pires〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Carbon dioxide (CO〈sub〉2〈/sub〉) has been proposed to be used as the geothermal working fluid, as it presents enhanced thermodynamic properties for this application when compared with the water-based system. This paper aims to present an overview of the recent research advances on CO〈sub〉2〈/sub〉-based geothermal systems, particularly CO〈sub〉2〈/sub〉-enhanced systems and CO〈sub〉2〈/sub〉-plume geothermal energy technology. The results of the recent operational projects are also described. This emerging technology can improve the efficiency of geothermal systems and their environmental impact, promoting the process sustainability and helping to tackle some of the most important issues that Humanity is facing: (i) global climate change; (ii) energy availability; and (iii) water scarcity. For deployment of this technology at a large scale, some issues and uncertainties were identified. Special attention was focused on the basic findings achieved in operational projects.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Yee Van Fan, Jiří Jaromír Klemeš, Timothy Gordon Walmsley, Simon Perry〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study introduces a new graphical decision-making tool to facilitate the rapid selection of transportation modes with minimum energy consumption or emissions, indicating the most sustainable transportation mode. Greenhouse gas (GHG) and air pollutants (NO〈sub〉x〈/sub〉, PM and SO〈sub〉2〈/sub〉), together with a composite price-weighted total environmental burden (TEB), are considered in the analysis. The graphical tool, which has a similar appearance to a phase diagram, presents a map of energy use (or emission) of different transportation modes based on the values of the ratio of the transportation distances (R) and the absolute load (L). A freight transportation case study (Rotterdam to Antwerp and Genova) demonstrates the construction and application of the graphical tool. For this case study, the electric train is the transport mode that offers the lowest energy consumption and minimum TEB. The graphical decision tool can also indicate the next-best solutions when one or more options (e.g. electric train) are not available. In this scenario, general cargo shipping achieves the lowest GHG emission, but heavy lorry imposes the lowest TEB. The developed tool further demonstrates the impacts of possible future fuels and technology developments on transportation selection, including renewable biodiesel and transport electrification under different grid mixes (e.g. Latvia, Sweden and EU-28). Further criteria, including economics, can be included for future study using the proposed tool as a foundation. The graphical approach transforms the transport selection problem into an easily understandable format from which arises sound solutions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Wei Feng, Qianning Zhang, Hui Ji, Ran Wang, Nan Zhou, Qing Ye, Bin Hao, Yutong Li, Duo Luo, Stephen Siu Yu Lau〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sustainable development in the building sector requires the integration of energy efficiency and renewable energy utilization in buildings. In recent years, the concept of net zero energy buildings (NZEBs) has become a potential plausible solution to improve efficiency and reduce energy consumption in buildings. To achieve an NZEB goal, building systems and design strategies must be integrated and optimized based on local climatic conditions. This paper provides a comprehensive review of NZEBs and their current development in hot and humid regions. Through investigating 34 NZEB cases around the world, this study summarized NZEB key design strategies, technology choices and energy performance. The study found that passive design and technologies such as daylighting and natural ventilation are often adopted for NZEBs in hot and humid climates, together with other energy efficient and renewable energy technologies. Most NZEB cases demonstrated site annual energy consumption intensity less than 100 kW-hours (kWh) per square meter of floor space, and some buildings even achieved “net-positive energy” (that is, they generate more energy locally than they consume). However, the analysis also shows that not all NZEBs are energy efficient buildings, and buildings with ample renewable energy adoption can still achieve NZEB status even with high energy use intensity. This paper provides in-depth case-study-driven analysis to evaluate NZEB energy performance and summarize best practices for high performance NZEBs. This review provides critical technical information as well as policy recommendations for net zero energy building development in hot and humid climates.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Moslem Yousefzadeh, Manfred Lenzen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Concentrating Solar Power (CSP) plants can make a significant contribution to renewable energy supply in many regions of the world. Several bottom-up engineering performance models for CSP plants have been developed. However, they require the capacity of the plant to be known. In whole-of-grid optimization models, the capacity of the plants is an optimization variable and therefore not known in advance. In this case, researchers have taken a simplified modelling approach that overestimated CSP performance, especially for low-DNI conditions.〈/p〉 〈p〉In this paper, we offer a novel density-based engineering modelling approach in which CSP performance is determined independently of the capacity of the power plant, and which can be used in whole-of-grid optimization models. We investigate a case study of the site of the new Aurora CSP project in Port Augusta, South Australia, to be one of the world's largest solar thermal power plants by 2020. Using a Geographical Information System (GIS)-grid representation of Australia, we compare CSP performance resulting from a simplified model with our new approach.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 113〈/p〉 〈p〉Author(s): C. Ortiz, J.M. Valverde, R. Chacartegui, L.A. Perez-Maqueda, P. Giménez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Energy storage based on thermochemical systems is gaining momentum as a potential alternative to molten salts in Concentrating Solar Power (CSP) plants. This work is a detailed review about the promising integration of a CaCO〈sub〉3〈/sub〉/CaO based system, the so-called Calcium-Looping (CaL) process, in CSP plants with tower technology. The CaL process relies on low cost, widely available and non-toxic natural materials (such as limestone or dolomite), which are necessary conditions for the commercial expansion of any energy storage technology at large scale. A comprehensive analysis of the advantages and challenges to be faced for the process to reach a commercial scale is carried out. The review includes a deep overview of reaction mechanisms and process integration schemes proposed in the recent literature. Enhancing the multicycle CaO conversion is a major challenge of the CaL process. Many lab-scale analyses carried out show that residual effective CaO conversion is highly dependent on the process conditions and the CaO precursors used, reaching values in a wide range (0.07–0.82). The selection of the optimal operating conditions must be based on materials performance, process integration, technology and economics aspects. Global plant efficiencies over 45% (without considering solar-side losses) show the interest of the technology. Furthermore, the technological maturity and potential of the process is assessed. The direction towards which future works should be headed is discussed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 113〈/p〉 〈p〉Author(s): Antonello Ignazio Croce, Giuseppe Musolino, Corrado Rindone, Antonino Vitetta〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The mobility of people and goods represents an essential activity that influences sustainability owing to energy consumption.〈/p〉 〈p〉Generally, electrical mobility problems concern the selection of technology (e.g. electrical vehicles (EVs)), monitoring the ex-post effects of their implementation. However, an ex-ante quantitative assessment of transport services in relation to travel demand is necessary in decision-making processes.〈/p〉 〈p〉The objective of this study is to propose a framework that supports decision-making regarding the optimisation of transport services for people in an effort to minimise renewable energy resources. Transport system models (TSMs) are the core of the framework, adopted to design transport services operated with EVs.〈/p〉 〈p〉TSMs are examined in a practical scenario, represented by the touristic port “Porto delle Grazie”, located in the Città Metropolitana of Reggio Calabria, south of Italy. Clean energy is produced from maritime waves. Transport services are designed considering travel demand by means of TSMs.〈/p〉 〈p〉The novelties of this study are a framework to support decision-making processes aimed at optimising renewable energy consumption, while ensuring the satisfaction of mobility requirements, and an application in a practical scenario where energy is produced by the sea waves to facilitate green transport services for people mobility.〈/p〉 〈p〉The application represents a prototypical experiment aimed at validating the proposed framework. A discussion section presents the main potentialities and limitations of this work, which can be extended to wider geographical scales and over different time periods.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Tong Zhu, John Curtis, Matthew Clancy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉While a rich body of literature has looked at greenhouse gas emissions in biogas production systems and the potential impacts of biogas production on food supply, broader issues relating to the economic, environmental and social pillars of sustainability need to be carefully considered. Drawing upon experiences from European countries, key outcomes associated with large-scale implementation of biogas and biomethane production are identified. Topics of particular interest include policy instruments, farm intensification, and supply chain risks. Conclusions are drawn by recommending policy directions for countries such as Ireland that are at earlier developmental stages for biogas and biomethane deployment.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Michael O. Fagbohungbe, Abiodun O. Komolafe, Uchechukwu V. Okere〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hydrogen technology is essential to the decarbonisation of global economies because it addresses the variability and storage limitation of renewable energy. Several research literatures on hydrogen technology have focused on energy systems with minimum attention given to other fossil fuel driven sectors such as chemical and material production. For effective decarbonisation, the application of hydrogen in global economies must extend beyond the use of energy systems. Renewable hydrogen anaerobic fermentation is a suitable technology for converting the hydrogen substrate into gaseous fuel and precursors for material and green chemical production. The technology leverages on the well-established anaerobic digestion (AD) technology and can be selectively operated for a specific product. Although there are some problems associated with renewable hydrogen anaerobic fermentation, studies show different technological advancements in mitigating these challenges. This review focuses on the technological breakthroughs and limitations associated with renewable hydrogen anaerobic fermentation and provides insights on other products that could be derived from it, especially for a circular economy and the emerging market of green chemicals, sustainable agriculture, and bio-based product development.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1364032119305489-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Hong Li, Zhenyu Zhao, Christos Xiouras, Georgios D. Stefanidis, Xingang Li, Xin Gao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The aim of this review is to discuss the applications of microwave heating to separation and purification processes in chemical engineering from the perspective of its three unique features, namely rapid heating, selective heating and specific microscopic effects. These features render microwaves an alternative clean energy source that can replace or complement the conventional heating in various separation processes. The rapid heating and evaporation of water under the influence of microwaves renders the technology valuable in materials drying and organic extraction. The direct and selective heating of materials with high dielectric loss in a mixture enables energy savings in the treatment of petrochemical products. In adsorption processes, microwave heating can selectively heat solid adsorbent material leading to the formation of micro “hot spots” (localized zones of high temperature), increasing the efficiency in adsorbent regeneration. Finally, a deeper understanding of the impact of microwaves on microscopic structure has led to novel separation methods, such as microwave-assisted pervaporation and microwave-assisted reactive distillation. An overview of the key mechanisms and developments of microwave heating in all these applications during the recent five years is provided and is followed by identification of the associated challenges in scale up. Fundamental research is still required for guiding further industrial application, while numerical simulations considering both heat transfer and distribution of the electromagnetic field in various reactor geometries can be helpful in the design of microwave reactors for large scale applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1364032119305246-fx1.jpg" width="465" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Polona Šprajc, Miroslav Bjegović, Bojana Vasić〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The main objective of the paper is to evaluate the methodological setting of the 〈em〉Energy Trilemma Index〈/em〉 (developed by the respected 〈em〉World Energy Council〈/em〉), which serves as a decision-making support tool in energy policy and governance. The study included 125 countries. Energy security, as part of the national security system, is becoming an increasingly important factor in global geopolitics, thus imposing a need to develop most precise and reliable decision-making support tools as possible in this field. The 〈em〉Energy Trilemma Index〈/em〉 comprises energy security, energy equity, environmental sustainability and country context. Values of Index are, in general, highest in European union and North America. The assessment of the methodological setting of Index reliability was made using a set of statistical methods: 〈em〉Principal Component Analysis〈/em〉 (whose additional interpretation was carried out using the following tests: 〈em〉Pearson Correlation test〈/em〉, 〈em〉Kaiser-Meyer-Olkin Measure of Sampling Adequacy〈/em〉 and 〈em〉Bartlett's Test of Sphericity〈/em〉). The final assessment of reliability was made using the 〈em〉Cronbach's Alpha test〈/em〉. Based on the results of the analysis it has been established that the 〈em〉Energy Trilemma Index〈/em〉 can in no way be considered reliable due to a number of disadvantages, of which the most important is the end indicator of 〈em〉Cronbach's Alpha〈/em〉 value (0.694), which stands at the very margin of reliability (0.600). Bearing in mind the significance of the energy security policy, the research results have a significant policy implication: the 〈em〉Energy Trilemma Index〈/em〉 cannot be considered reliable for energy policy without comprehensive methodological improvements.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Vinod Nandal, Raj Kumar, S.K. Singh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Present day India has tremendous energy requirements, and with each day it is becoming more difficult to meet those needs through conventional power sources. The never-ending demand of population which is growing exponentially has become very tough to fulfill. To enhance its energy security, mitigate carbon emissions and augment its economic development, it becomes an urgent need to implement innovative policies and mechanisms for the adoption of green and clean energy. India because of its demographics has good solar energy potential. This study aims to examine the solar power implementations in thermal power plants situated all across India. This paper contributes to the literature on solar power by identification of barriers for the adoption of solar power in thermal plants. Still, there is some lack of study about solar power implementations in different areas. In this paper, investigating efforts have been made to examine the solar power implementations in thermal power plants within the Indian context by identifying key barriers. In this study, Interpretative Structural Modeling (ISM) has been adopted to find the contextual relationships among key barriers and Matriced’Impacts Croises- Multiplication Applique’ an Classment (MICMAC) analysis has been carried out for validation of the model. Requirement of gigantic investment, longer recovery period, safety implications, environmental implications, and societal concerns emerge at the top level in ISM structure. Lack of adequate government policies and lack of political leadership appears at the bottom of a structured model and these emerged as the most influential barriers. This research also suggested how to mitigate the key barriers by the installation of solar power in electricity generation utilities.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Hou Jiang, Ning Lu, Jun Qin, Wenjun Tang, Ling Yao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To apply deep learning technique for estimating hourly global solar radiation (GSR) from geostationary satellite observations, a hybrid deep network is proposed, relying on convolutional neural network (CNN) to extract spatial pattern from satellite imagery, multi-layer perceptron (MLP) to link the abstract patterns and additional time/location information to target hourly GSR. Its representative advantage lies in the ability to characterize changeable cloud morphology and simulate complex non-linear relationships. The deep network is trained using ground measured GSR values at 90 Chinese radiation stations in 2008 as well as the radiative transfer model simulation at the top of Mt. Everest which serves as constraints of extrapolation for high elevation regions. The extensibility of trained network is validated at 5 independent stations in 2008, yielding an overall coefficient of determination (R〈sup〉2〈/sup〉) of 0.82, and at all stations in 2007 along with an R〈sup〉2〈/sup〉 of 0.88. Comparative experiments confirm that the combination of spatial pattern and point information can lead to more accurate estimation of hourly GSR, achieving a minimum root mean square error (RMSE) of 84.18 W/m〈sup〉2〈/sup〉 (0.30 MJ/m〈sup〉2〈/sup〉), 1.92 MJ/m〈sup〉2〈/sup〉 and 1.08 MJ/m〈sup〉2〈/sup〉 in hourly, daily total and monthly total scales, respectively. Moreover, the deep network is capable of mapping spatially continuous hourly GSR which reflects the regional differences and reproduce the diurnal cycles of solar radiation properly.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Tohid N.Borhani, Meihong Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Solvent selection and design are imperative in the CO〈sub〉2〈/sub〉 capture process. The efficiency and the overall cost of the process are directly affected by the solvent as a consequence of the effect of solvent on factors such as CO〈sub〉2〈/sub〉 absorption capacity, size of equipment, and solvent regeneration energy. This review paper aims to review the most important solvents and mixtures of solvents, absorbing CO〈sub〉2〈/sub〉 via chemisorption, physisorption and chemi-physisoprtion. Characteristic and structure of different solvents are presented with the advantages and disadvantages of each being highlighted. Mixtures of solvents include chemical or physical solvents only, and combinations of physical and chemical solvents are categorised. In addition to common solvents, phase change solvents are also described. Once a comprehensive list of solvents is presented, different methods of solvent selection and design are illustrated, namely methods involving experiments, process and equilibrium models, predictive models, and computer-aided molecular design (CAMD). The importance of integrated solvent and process selection and design is also discussed. The most recent and selected progress studies in each section are reviewed in detail.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Liu Yang, Shuli Liu, Hongfei Zheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Microencapsulated phase change slurry (MPCS) shows remarkable merits especially in narrow temperature range and high energy density for the thermal energy application. It combines the advantages of the carrier fluid and the phase change materials. However, the performance of slurry is limited by the poor thermal conductivity and pumping energy of microcapsules. This paper reviews the extensive research findings of the rheological behaviours, the hydrodynamic properties, the heat transfer characteristics and the heat transfer enhancement for MPCS. The aims are to remark the research progresses about the flow and heat transfer performance, as well as to promote further study in this field. The paper presents the basic thermophysical parameters for MPCS, such as phase change temperature, specific heat capacity, thermal conductivity and sub-cooling. Then, the state of the art in rheological behaviours and hydrodynamic properties for MPCS are analysed. The present work compares the existing literatures towards to the forced convective heat transfer characteristics achieved through experimental and numerical investigations. Furthermore, the melting/solidifying process, the enhancement mechanisms of heat transfer and a plenty of enhanced techniques are elaborated. This paper also reports several representative applications of MPCS in recent years. It is expected that this work can give interesting and valuable insights on the hydrodynamic mechanisms and heat transfer characteristics of MPCS, and promote the further studies in strengthening the comprehensive performance of MPCS.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Katalin Bódis, Ioannis Kougias, Arnulf Jäger-Waldau, Nigel Taylor, Sándor Szabó〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rooftop solar photovoltaic (PV) systems can make a significant contribution to Europe's energy transition. Realising this potential raises challenges at policy and electricity system planning level. To address this, the authors have developed a geospatially explicit methodology using up-to-date spatial information of the EU building stock to quantify the available rooftop area for PV systems. To do this, it combines satellite-based and statistical data sources with machine learning to provide a reliable assessment of the technical potential for rooftop PV electricity production with a spatial resolution of 100 m across the European Union (EU). It estimates the levelised cost of electricity (LCOE) using country-specific parameters and compares it to the latest household electricity prices. The results show that the EU rooftops could potentially produce 680 TWh of solar electricity annually (representing 24.4% of current electricity consumption), two thirds of which at a cost lower than the current residential tariffs. Country aggregated results illustrate existing barriers for cost-effective rooftop systems in countries with low electricity prices and high investment interest rates, as well as provide indications on how to address these.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): F. Penizzotto, R. Pringles, F. Olsina〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Renewable power generation based on solar energy is deemed to be a key instrument to reduce the carbon footprint of modern economies. Collectively, buildings are an energy-intensive consumption sector. Therefore, existing building rooftops are seen as a target for massively deploying photovoltaic (PV) distributed generation. Nevertheless, estimating the benefits and risks of investing in rooftop PV systems is indeed a challenging task due to the large uncertainties that affect tariffs, technology costs, and regulatory policy. After reviewing the literature and identifying the current gaps, this article develops a method based on Real Options theory for appraising investments in PV generation systems to be installed on the rooftop of existing buildings. The option value of differing the investment decision and the problem of the optimal time to invest in irreversible PV assets are addressed by an advanced valuation method based on stochastic simulation, linear regression, and backward dynamic programming. In this work, returns of self-generation PV investments are subjected to uncertainties upon declining investment costs and fluctuating electricity tariffs, which are represented by appropriate exogenous stochastic processes. In order to test the practicability of the proposed decision-making framework, the valuation of an exemplary rooftop PV-system in a government building is considered. Results show that while standard appraisal methods wrongly reject the rooftop PV project now and in the future, the option valuation method finds optimal to hold the opportunity open in order to reconsider to invest later. In addition, the method provides an objective value of the opportunity cost of using the building rooftop for another purpose. The proposed valuation approach would result in better investment allocation and faster development of distributed PV power capacity contributing thereby to enhance the sustainability of current energy systems.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Rakesh Kumar Sinha, Nitin Dutt Chaturvedi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Carbon emission is a prime reason for global warming. There are various industrial processes which discharge significant amount of carbon dioxide to the atmosphere. Carbon emission from industrial process can be controlled by the application of technologies at different stages in industries. This paper reviews the research works carried out for executing energy efficient and low carbon technologies for industries at different stages and classifies these works into inward, in and outward process stages. The review outlines few major approaches that are followed in majority of the research works. Process integration technique and improving energy and matter efficiency are key approaches of inward process stage. Retrofitting of existing industries with best available technique and utilizing energy model tools for predicting energy consumption and carbon emission are key approaches of inward process stage. Incorporating CCUS technology and targeting of CCUS via process integration technique are key approaches of outward process stage. The research works carried out for planning of carbon emission limits are also studied. Further a methodology based on pinch analysis is developed for determining restrictions on the carbon emission on tenure track basis. The emission limits can guide policy maker about the future course of action with respect to process modifications and technological innovations.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S136403211930512X-fx1.jpg" width="347" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Bo Pieter Johannes Andrée, Andres Chamorro, Phoebe Spencer, Eric Koomen, Harun Dogo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The UN's Sustainable Development Goals for 2030 aim on one hand at inclusive growth and eradicating poverty, and on the other at preserving environments. The relation between development and the environment has been studied extensively since the 1990s, documenting inverted 〈em〉U〈/em〉-shaped relations between per capita income and indicators of environmental degradation. This paper revisits the issue with machine learning techniques and novel disaggregate data to model these relationships heterogeneously across economic indicators. Results suggest that development gradually improves the efficiency of consuming the earth's nonrenewable resources, but increased efficiency alone is not sufficient to offset growth in scale. Development shifts reliance on one nonrenewable source to another, and on average we find successive inverted 〈em〉U〈/em〉-shapes in deforestation, air pollution and carbon intensities, followed by a 〈em〉J〈/em〉-shape in per capita carbon output. Local economic circumstances further determine the shape, amplitude, and location of tipping points in environmental output. The general implications of the estimated dynamics are explored by extrapolating environmental output to 2030 under simplistic scenario's. The results are a reminder that immediate, and sustained global efforts are required to preserve our environment.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Nayab Bushra, Timo Hartmann〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Every year a wide range of articles are published on reflective two-stage solar concentrators (TSSCs), that focus on either geometrical designs, performance characteristics, solar energy receivers, or applications. Among previous studies, no review article currently highlights all the aforementioned aspects to observe the overall research development of these systems. Therefore, this paper aims to develop a comprehensive analysis of reflective type TSSCs based on the review of research papers and patents and analyses the presented TSSC technologies along five categories: geometries, concentration ratio, optical performance, receivers, and applications. We found that the most dominant geometries applied in TSSC design were cassegrains and solar furnaces. Our review also shows that most papers focussed on applying TSSCs for power generation using solar cells, and thermo-electric generators. Most studied systems remained at medium, high and ultrahigh concentration level and medium to high optical efficiency. We also found that most studies only validated the proposed systems experimentally. Only a few studies focussing on solar furnaces have also been validated within large scale practical settings. The analytical results help to identify future research initiatives towards a wider spread practical implementation of TSSCs which emphasizes parametric modeling approach. Parametric models can provide a range of design alternatives which can be tested under multiple environmental conditions. Through joint use of receivers, these systems can be deployed for multiple applications. Additionally, development of cost-effective and energy efficient TSSCs further requires detailed feasibility studies, cost-benefit analysis, as well as, environmental impact analysis. Based on the categorization analysis and the proposed research initiatives, future research on TSSCs can proceed on a more solid footing.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Junping Ji, Hua Tang, Peng Jin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Concentrating solar power (CSP), a promising renewable energy technology, requires better policy support for its initial implementation, which, in turn, necessitates accurate forecasting of its economic potential. This study develops a model based on meteorological data and local policies to calculate the levelized cost of electricity (LCOE) in 31 provincial-level divisions in China. Based on land occupation, concessionary loan, and technology mode as the independent variables, the LCOE is estimated to be $142/MWh to $781/MWh in sites with direct normal irradiance above 1,800 kWh/m〈sup〉2〈/sup〉/yr under current local policies and conditions (with and without thermal storage). Thus, this study lays a solid foundation for forecasting power generation and selecting economically feasible sites. It analyzes the CSP learning curve with respect to technologically advanced trends and scale expansion. With the proper optimization of the technology mode, it is reasonable to expect a significant LCOE reduction and grid parity in certain areas. A comparison of the current policies provides a reference for the Chinese government to formulate subsidy policies that would make CSP more competitive.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Jorge-Enrique Zafrilla, Guadalupe Arce, María-Ángeles Cadarso, Carmen Córcoles, Nuria Gómez, Luis-Antonio López, Fabio Monsalve, María-Ángeles Tobarra〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Sustainable development, in its wider sense, i.e., economic, social and environmental, has emerged as one of the key challenges for humankind in the 21st century. Solar photovoltaic (PV) emerges as a key technology to meet not only the climate targets but also those related to social progress and economic growth. This paper's main objective is to capture the momentum and potentialities of the Spanish Solar PV sector using a Triple Bottom Line (TBL) analysis from a broad economic, social and environmental footprint perspective in an MRIO context in 2016.〈/p〉 〈p〉Regarding the economic impact, we find that the Spanish Solar PV sector accounts for 0.19% and 0.31% of GDP in direct and in total terms, respectively; besides, 60% of indirect GDP is created within Spanish economy and 40% is generated abroad, while 86% of induced GDP is generated within domestic economy. By activity, PV manufactures is the only one to generate most of its indirect GDP abroad (68%). In social terms, Solar PV activities are responsible for 5904 direct jobs and 18,377 in total in Spain in 2016, and the most important activity is energy production and distribution (50.2% of total generated employment). In environmental terms, the footprint of the whole Solar PV industry accounts for only 734 ktCO〈sub〉2〈/sub〉, which helps to avoid a great volume of direct emissions in electricity generation, with more than 69% generated beyond Spain's borders.〈/p〉 〈p〉With regard to the potentialities of the Spanish Solar PV sector, and given the forecasted growing deployment of Solar PV in Spain by 2030 and 2050, this industry is set to be one of the leading sectors of the Spanish sustainability transition in the near future. Current policy requires the fast deployment of Solar PV throughout the country to ensure more sustainability-friendly economic, social and environmental development.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 113〈/p〉 〈p〉Author(s): Antonio Sandá, Sara L. Moya, Loreto Valenzuela〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Direct steam generation (DSG) in parabolic-trough collectors (PTC) is one of the most attractive technologies in concentrated solar power plants. Its appeal stems from its ability to reduce the operational and maintenance costs compared with other heat transfer fluids. Modelling and simulation (M&S) tools, together with the development of experimental real-scale set-ups have played a key role in the advancement of this solar technology. The aim of this review is to summarize and analyse the thermohydraulic, thermal and optical models implemented in M&S tools for DSG in PTC in order to identify the contribution that these models could provide towards the improvement of the technology in the future. Thermohydraulic models have been, in most cases, developed under the three-equation homogeneous equilibrium model (HEM) approach, successfully for recirculation mode. The more complete six-equation two-fluid model (TFM) approach, has also been properly applied, to a lesser extent, to modelling the once-through solar field operation mode, considering water/steam two-phase flow patterns. Although these advancements have contributed to the design and operation of the first commercial solar steam power plant with PTC for electricity generation, there are however some technological gaps still to be overcome to consolidate the technology. In recirculation solar field operation mode, the use of HEM has shown to be adequate to model the DSG process in PTC integrated with thermal energy storage systems and into solar hybrid power plants. For once-through operation mode, the distributed-parameter thermohydraulic models, especially under TFM approach, involving a detailed flow pattern map, have demonstrated to be suitable tools for solving the uncertainties related to the two-phase flow, especially at the endpoint of the evaporation section.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Dorte Nørgaard Madsen, Jan Petter Hansen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Solar power production in Europe has raised from about 130 MW to 110 GW of installed capacity (corresponding to 90 GWh to 120 TWh in annual electricity generation) during the present century. Together with wind power, it constitutes the largest growth within renewable energy sources in the last decades. At present however, clear signs of saturation can be observed in the leading areas of solar power in Europe. Here, the development of solar power in Europe is analysed and, for the three leading countries (Germany, Italy, Spain) a logistic growth path at the national level and a proportionality between saturation level of the growth curve of each country and its gross domestic product (GDP) is found. The sum of the next three countries (France, UK, Belgium) is well described by a logistic path with a time offset relative to the first group of three, and the sum of the two logistic paths, representing in total about 85% of European solar power production, describes the growth pattern in the corresponding area very well. Based on this, an estimate of a future saturation level for solar power in Europe is obtained by extrapolation. Finally, a model based on logistic growth patterns and learning curves that links solar power production data to investment data, is proposed. The proposed model is validated and calibrated on historical European data and extrapolated into the future. In a future scenario where European investments continue to decrease, a saturation level that is fully in line with our GDP based 200 TWh/y estimate is found and the application of the findings is discussed in a global context.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Carmen Valor, Carmen Escudero, Victoria Labajo, Rafael Cossent〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Demand-side management is widely considered a key tool to achieving decarbonization in the energy sector. In this regard, providing end users with detailed information about their consumption patterns enables them to make informed decisions to reduce or adapt their energy consumption. This requires the deployment of interactive feedback technologies such as domestic energy displays, dedicated apps/web portals, or ambient interfaces. Extensive research and numerous pilot projects have examined the effects of these technologies on end-user behavior and identified the importance of an appropriate device design to achieve the desired demand response. However, a clear framework for designing these feedback technologies to ensure the desired behavioral change does not exist.〈/p〉 〈p〉To fill this gap, this paper presents an exhaustive review of existing research on feedback, with a particular focus on interactive devices. This review has identified ten key parameters that should be considered by device designers, including the type and form of the information provided (medium, units, disaggregation level, comparisons, goal setting), the design of the interface and devices themselves, the possible inclusion of penalties and rewards, and privacy concerns. Recommendations are provided for implementing these parameters in such a way that end-user interactions and responses are maximized. These recommendations would make domestic displays more effective in creating the desired household behavioral change to maximize energy conservation. Moreover, critical areas are identified where further research is necessary before a prudent recommendation can be made.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): P. Murto, M. Jalas, J. Juntunen, S. Hyysalo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Energy retrofits in households are an important means of reducing energy consumption and mitigating climate change. However, energy retrofit rates have generally been lower than expected. As a key reason behind non-adoption, the complexity of energy retrofits can be challenging for adopters to handle. In this article, we study how suppliers and retrofit adopters seek to manage the complexity of an energy retrofit purchase. Using interview and mystery shopping data, the article analyses how the complexity is managed through a variety of complexity management devices (CMD) and complexity management strategies (CMS). We identify four complexity management devices, concretizations that help deal with energy retrofit complexity: characterisations, projections, comparisons and references. In addition, we identify four complexity management strategies for managing complexity: pre-exposure, choice simplification, outsourcing and championing. The contribution of the study is in highlighting the role of complexity management in energy retrofits and how CMDs and CMSs are involved in structuring energy retrofit offerings, business models and energy information. This, in turn, provides impetus for developing measures to ease the complexity of adoption.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Ghasem Barati Darband, Mahmood Aliofkhazraei, Sangaraju Shanmugam〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Development of new electrocatalysts with high electrocatalytic activity and stability is of great importance in the production of hydrogen fuel. Numerous methods have been established to increase the activity of electrocatalysts, including increasing active surface area and improving intrinsic catalytic activity. However, the electrochemical water splitting is a gas-involving reaction in which hydrogen and oxygen bubbles are formed on cathode and anode surfaces, respectively, which lead to an increase in overpotential of electrochemical reactions. In this review, recent advances have been complied to understand the behavior of hydrogen and oxygen bubbles separation from the surface of electrodes during water splitting. Initially, various types of resistance in water splitting have been discussed, and further progress has been discussed to improve the separation of bubbles and thus improve electrocatalytic activity. These improvements include surface nanostructuring and making superaerophobic surfaces where bubbles can easily be removed from the surface, resulting in lower bubble resistance. Furthermore, the use of magnetic, supergravity and ultrasonic fields are among additional methods for fast separation of bubbles from the surface and improving catalytic activity This paper presents a review of a research pathway for creating 3D nanoarrays to improve the bubble separation behavior on the surface and improve electrocatalytic properties.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 113〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Luca Evangelisti, Roberto De Lieto Vollaro, Francesco Asdrubali〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The need to put in place alternative energy policies stems from the awareness that fossil fuels are exhaustible and harmful to the environment. For this reason, during the last decades the scientific world has focused on systems able to use and convert renewable energy sources, particularly solar radiation. Nowadays, solar thermal collectors use solar energy to distribute low-cost domestic and industrial heating. In this review a comprehensive analysis of peer-reviewed journals and relevant papers on solar thermal collectors is provided. Descriptions of the different types of solar collectors are provided. Theoretical analyses, latest developments related to the functional elements, and hybrid systems have been considered throughout this analysis. Performance test methods for solar thermal collectors and standards are discussed. This cross-review aims to assist researchers, engineers and manufacturers in keeping them abreast of latest developments in the field of solar thermal collectors.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Zhijian Liu, Qingxu Zhou, Zhiyong Tian, Bao-jie He, Guangya Jin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With the rapid development of urbanization and the improvement of living standards of residents in China, the energy consumption and carbon emissions of the building sector is expected to increase in the near future. Nearly or net zero energy buildings have become a hot topic of research to reduce the fossil energy consumption and greenhouse gas emissions in the building sector. As the largest developing country and carbon emitter around the world, China has also made significant efforts on nearly zero energy buildings in recent decades. The central government has approved many demonstration projects on nearly zero energy buildings in different climate zones for more than ten years. This paper summarizes international definitions of zero-energy buildings, analyzes the latest definition and identifies the boundaries of nearly zero energy buildings in China. It provides an overview of the current situation, detailed policies and building codes of nearly zero energy buildings in China. Suggestions were given on the development and promotion of nearly zero energy buildings in China. These findings in this paper will help to guide the government to implement more efficient and effective policies and building codes of nearly zero-energy buildings in order to reduce carbon emissions in the building sector.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Dominik Bucher, René Buffat, Andreas Froemelt, Martin Raubal〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To ensure long-term availability of mobility and to keep the effects of humanity on global climate limited, politics, research, and industry currently search for ways to reduce greenhouse gas (GHG) emissions caused by it. A potential reduction could be achieved by transitioning towards more efficient transport modes, optimally powered by renewable energy. Based on mobility (commutes), population, and weather data from Switzerland, we present a model to compute energy savings due to a (hypothetical) widespread deployment of electric bicycles. In different scenarios, we analyze the dependence of the commuting energy demand on users’ preferences about when to take the bike, such as an aversion to biking on cold and rainy days. Our study shows that GHG emission reductions of up to approx. 10% of the total emissions from diesel and gasoline are possible. In combination with a widespread deployment of electric vehicles, further savings of up to 17.5% could be achieved. In particular, the willingness to drive longer commutes by e-bike influences the potential GHG emission reductions, followed by the willingness to use the bicycle at temperatures below 10°C. Using these results, we identify the spatial energy and greenhouse gas savings potential and thus regions that are particularly suited for e-bike use. The identification of regions with high saving potentials allows for targeted marketing, transition-supporting incentives, or infrastructural changes to maximize the reduction of emissions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 113〈/p〉 〈p〉Author(s): Shibiao Fang, Wenrong Tu, Lin Mu, Zhilin Sun, Qiuyue Hu, Yang Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Solar desalination technology develops slowly in Southern Xinjiang, and salt-leaching method is the most popular measure for improving salinization land, failing to make full use of the local rich solar energy. Therefore, government of China plans to exploit the solar energy for driving the desalination process in Southern Xinjiang to solve the issue of water scarcity and salinization. Firstly, this paper reviews the existing status of salinization, and elaborates traditional treatment measures of salinization in Southern Xinjiang. Secondly, a saline alkali water desalination planning in Southern Xinjiang is demonstrated with detailed explication, showing the necessities and feasible strategy of the desalination project in Southern Xinjiang. Thirdly, a combination of reverse osmosis membrane and solar still is proposed for the desalination project, and current research states and progresses of membrane treatment technology and solar desalination are analysed, pointing out the possible solutions for research challenges in Southern Xinjiang. Finally, the technology of modifications of single basin solar still is studied, and several solar still configurations are selected from reference to conduct the cost analysis using local market price to figure out the optimal type suitable for Southern Xinjiang. Once this desalination project is implemented successfully, remedied saline lands in Xinjiang will become backup land resources to secure the local socio-economic and agricultural development, improving the ecological environment and soil fertility. Other prospective regions in China, such as eastern coastal saline soil, salted soil in North China Plain and Northeast Plain, can benefit from this research.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 114〈/p〉 〈p〉Author(s): Songyan Niu, Haiqi Xu, Zhirui Sun, Z.Y. Shao, Linni Jian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With the growing adoption of electric vehicles (EVs), there is a pressing need for constructing charging infrastructures. In this context, wireless charging technology has been under development for the past few decades. Dispensed with awkward plugs and wires, wireless power transfer (WPT) technology is very safe, convenient and easy-to-use. Researchers have taken sustained efforts to make it an improved technology and automakers also work to provide the wireless charging option for their customers. In this paper, the basic principles of resonant inductive power transfer that is common-used for wireless electric vehicle charging (WEVC) are elaborated. Then, with a different emphasis on WEVC technologies, the key issues in academia and industry are discussed respectively. The core technologies of a fully-function WEVC system in academia are summarized and a comparative study is conducted among the selected WEVC industry standards. In addition, based on the possible technical development and currently valid policies, the author envisions the future of WEVC, followed by some conclusions and helpful advice.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 113〈/p〉 〈p〉Author(s): A. Matallana, E. Ibarra, I. López, J. Andreu, J.I. Garate, X. Jordà, J. Rebollo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉A large number of factors such as the increasingly stringent pollutant emission policies, fossil fuel scarcity and their price volatility have increased the interest towards the partial or total electrification of current vehicular technologies. These transition of the vehicle fleet into electric is being carried out progressively. In the last decades, several technological milestones have been achieved, which range from the development of basic components to the current integrated electric drives made of silicon (〈em〉Si〈/em〉) based power modules. In this context, the automotive industry and political and social agents are forcing the current technology of electric drives to its limits. For example, the U.S Department of Energy’s goals for 2020 include the development of power converter technologies with power densities higher than 14.1 kW/kg and efficiencies greater than 98%. Additionally, target price of power converters has been set below $3.3/kW. Thus, these goals could be only achieved by using advanced semiconductor technologies. Wide-bandgap (WBG) semiconductors, and, most notably, silicon carbide (〈em〉SiC〈/em〉) based power electronic devices, have been proposed as the most promising alternative to 〈em〉Si〈/em〉 devices due to their superior material properties.〈/p〉 〈p〉As the power module is one of the most significant component of the traction power converter, this work focuses on an in-deep review of the state of the art concerning such element, identifying the electrical requirements for the modules and the power conversion topologies that will best suit future drives. Additionally, current WBG technology is reviewed and, after a market analysis, the most suitable power semiconductor devices are highlighted. Finally, this work focuses on practical design aspects of the module, such as the layout of the module and optimum WBG based die parallelization, placement and Direct Bonded Copper (DBC) routing.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 100〈/p〉 〈p〉Author(s): Andrea Antenucci, Giovanni Sansavini〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The recycling of carbon dioxide (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si0009.gif" overflow="scroll"〉〈msub〉〈mrow〉〈mi〉CO〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈/math〉) into synthetic fuels via Power-to-Gas (PtG) could represent an important instrument for achieving the complete decarbonization of the energy sector. To address such issue, this paper calculates the investments in PtG units, grid reinforcements and renewable installations that allow the almost complete recycling of the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si0010.gif" overflow="scroll"〉〈msub〉〈mrow〉〈mi〉CO〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈/math〉 emissions of a countrywide electric power system. Furthermore, this work evaluates the feasibility of gas and electric operations in the new system configuration. The analysis is enabled by coupled gas and electric network modelling. The necessary PtG station installations and overhead line reinforcements are identified via scenario-based cost optimization. Hourly operations of electric power plants are scheduled as a sequence of day-head security-constrained unit commitment problems. A transient gas flow model assesses the capability of the gas network to act as short- and long-term storage of synthetic gas. The developed framework is applied to the electric and gas transmission networks of Great Britain, whose investments and operations are investigated for increasing renewable capacity levels based on the 2030 Gone Green case. Results show that almost complete 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si0011.gif" overflow="scroll"〉〈msub〉〈mrow〉〈mi〉CO〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈/math〉 recycling is achieved if the installed renewable capacity is approximately three times as large as the 2030 Gone Green estimates. The investments comprise 114 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si0012.gif" overflow="scroll"〉〈mi mathvariant="italic"〉GW〈/mi〉〈/math〉 of PtG capacity and the construction of 23 electric parallel lines. Remarkably, gas network operations do not represent a limit to the storage of large amount of synthetic methane. Moreover, PtG stations are preferentially installed at locations with large RES capacity and foster large renewable penetration; only small curtailments occur even for large renewable capacity levels. These results support decision makers by quantifying the techno-economic implications of the presented extensive 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si0013.gif" overflow="scroll"〉〈msub〉〈mrow〉〈mi〉CO〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈/math〉 recycling strategy.〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 100〈/p〉 〈p〉Author(s): Ahmad Fudholi, Muhammad Zohri, Nurul Shahirah Binti Rukman, Nurul Syakirah Nazri, Muslizainun Mustapha, Chan Hoy Yen, Masita Mohammad, Kamaruzzaman Sopian〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents a review of the exergy and sustainability index of solar thermal systems. The review includes exergy analyses of solar collectors, solar drying systems and photovoltaic thermal (PVT) systems. Solar collectors, the most essential components of solar thermal systems, receive solar energy and convert it into thermal energy. The PVT collector is a popular means of harvesting solar energy. A PVT collector can generate electrical and thermal energies simultaneously. Experimental and theoretical approaches for a PVT air collector with a ∇-corrugated absorber are investigated in this study. A steady-state energy analysis of the PVT air collector is performed to predict photovoltaic (PV) and air outlet temperatures. Experimental results are in close agreement with the results of the theoretical study. The percentage errors of PV and air outlet temperatures between experimental and theoretical values are 5.49% and 3.75%, respectively. The PVT exergy efficiency of the PVT air collector with a ∇-corrugated absorber is 13.36% and 12.89% for the theoretical and experimental study, respectively. Furthermore, a sustainability index is proposed. The sustainability index of the PVT air collector is 1.168 and 1.148 for the theoretical and experimental study, respectively.〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 100〈/p〉 〈p〉Author(s): Jan Kočí, Václav Kočí, Jiří Maděra, Robert Černý〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Building energy demands in long-term studies are mostly calculated using the averaged weather data sets, reflecting the changes in environmental conditions over time, thus the different energy consumption each year. This paper reviews and discusses the coupled effects of warming trend in global mean surface temperatures, application of different design weather datasets, and utilization of different methods of building energy assessment on the calculated energy demands. The possible inaccuracies of building energy analyses caused by those three factors are investigated on the example of a residential house in Central Europe. For that purpose eight different weather data sets for Prague, Czech Republic are selected and simulations in two different scales are performed. The analysis of the effect of recent weather data is performed by an improved methodology. First, the simulation brings an increased precision as an advanced hygrothermal model is used for energy calculations. Second, the building performance is assessed, contrary to the Czech national standards, using both heating and cooling energy demands. The simulation results confirm the warming trend in the time period of 2013–2017 as the average heating demands are 3.95% lower and the average cooling demands 3.96% higher in a comparison with the Test Reference Year. In the extreme years, a 12–15% decrease of energy consumed for heating and up to 20% increase of energy necessary for cooling is found. This is in accordance with the presumed warming trend that has been widely discussed during the last few decades. Furthermore, the presented results verify the critical and positive design weather years as suitable for application in the simulation of heating and cooling energy demands in the Czech Republic.〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 100〈/p〉 〈p〉Author(s): Ignacio Mauleón〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Methods to assess global renewable energy investment plans are presented and applied to photovoltaic and wind energy roadmaps recently published by international organizations. Price learning rate effects, uncertainty and derived risk, social discounting, investment depreciation, cost of capital and other factors are dealt with in detail. Some significant empirical results are: a) the roadmaps are market competitive globally, and also economically efficient from an environmental point of view; b) the volume of funds required is significant, but the investments can be financed with moderate carbon taxes; c) more expansive roadmaps yield enhanced results regarding both competitiveness and environmental efficiency; d) risks derived from the uncertainty in estimated Learning Rates may be significant and measures to control them are presented.〈/p〉〈/div〉

Description: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 107〈/p〉 〈p〉Author(s): Aristeides Tsiligiannis, Christos Tsiliyannis〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present work investigates solid biofuel, derived from household food waste (food residue biofuel, FRB) as a potential bioenergy source in cement manufacturing. Up-to-date investigations of household food waste as a solid fuel focused on composition and heating value, yet no results are available regarding impact on plant efficiency and emissions upon utilization. A multidimensional model based on fundamental principles (mass and enthalpy balances) is used together with actual data from fossil fuel operation to identify and quantitatively asses the impacts on plant performance, product quality and atmospheric emissions. Τhe energy needed to prepare low moisture FRBs is determined and suitable processes are singled out. Key issues of cement plant operation are identified and quantitatively assessed via simulation in an actual dry-process plant, when FRBs substitute 20% of thermal energy (provided by petcoke). The facility utilizes 1.65 × 10〈sup〉5〈/sup〉 tpa of fossil fuels to produce 1.5 × 10〈sup〉6〈/sup〉 tpa clinker. It is found that energy efficiency falls and clinker production diminishes by about 0.5 t clinker/t FRB. Refractory thermal rating and main blower capacity constraints remain satisfied. Non-biogenic green-house-gas emissions are reduced by ~60 kg/t clinker. Emitted concentrations slightly increase for several pollutants, mainly nitrogen oxides (NO〈sub〉x〈/sub〉) hydrogen chloride (HCl) and metals; they decrease for sulphur dioxide (SO〈sub〉2〈/sub〉) and particulates. Maximum emission limits are observed for all regulated pollutants but NO〈sub〉x〈/sub〉. Incombustible chlorine and inclusions of alkalis in cement increase by ~9%. To reap the bioenergy benefits and mitigate impacts, blends of FRB (~80%wt) with paper residues (~20%wt) are investigated. Conforming to plant operational constraints and product specifications, the blends ensure production level, environmental compliance and reduced emission rates. The results direct towards customer-tailored FRB blends with lignocellulosic residues, that best suit the design, specific quarry raw materials, operating conditions and individual parameters of the cement plant towards more sustainable cement manufacturing.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 108〈/p〉 〈p〉Author(s): A.B. Kristiansen, T. Ma, R.Z. Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Decreasing prices of photovoltaics (PV) and Lithium-ion batteries are creating a significant momentum for off-grid Zero Energy Buildings (ZEBs). In literature, most researchers have focused on grid-connected ZEBs built on site. This literature review is written with factory-made off-grid ZEBs in mind. High investment costs, poor construction quality and problems to achieve ZEB in real operation are three challenges that ZEB buildings currently face. This article discusses how automated mass production of continually improved standardized modules can overcome those problems. A shipping container is chosen as the modular unit to take advantage of the existing transport infrastructure. Due to the narrow width, the potential for utilizing daylight is better than that of traditional buildings. Off-grid ZEBs mean that the user must achieve ZEB in real operation, including plug loads. The local energy generation is likely to motivate the users to learn more about renewable energy. Plug loads is the largest energy consumer in buildings but are still often overlooked in ZEB definitions. With the Belt and Road initiative and political incentives to increase industrialized construction in China, the premises for exporting container buildings to the main markets in Asia and Africa are improving.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 108〈/p〉 〈p〉Author(s): Omar R. Llerena-Pizarro, Raul Pereira Micena, Celso Eduardo Tuna, José Luz Silveira〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The electricity sector in the Galapagos Islands is heavily dependent on fossil fuels for electricity generation but only a few renewable sources are used for such a purpose in this archipelago. Therefore, this work aims to present the current status of its electricity sector and show estimates for the upcoming years, discuss exploited and unexploited renewable resources, and put forward a proposal for a hybrid system to generate renewable power. Currently, thermoelectric power plants run on diesel are the main source of electricity generation in the archipelago due to supplying 85% of the total power installed in the islands (27.6 MW), and the remaining 15% (7.3 MW) is from renewable sources, such as the wind (10.8%), sun (4.1%), and vegetable oils (0.1%). In the upcoming years, there will be a growth in the use of these renewable resources if an additional capacity of 28.5 MW is installed. The gross electric output generated by this sector in the last twelve months (March 2017 - February 2018) was 53.80 GWh, which has allowed a return on revenues of over five million dollars at an average cost of US $0.10/kWh. Based on the existing renewable resources in the Galapagos Islands, the implementation of a hybrid solar/biogas power generation system is an attractive alternative to support the zero-fossil fuel initiative, diversify the energy matrix, and promote local development. However, sustainable development policies, energy efficiency programs and foreign investment funds to carry out new projects are required to ensure a bright future for the electricity sector in the Galapagos.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 108〈/p〉 〈p〉Author(s): Junpeng Huang, Jianhua Fan, Simon Furbo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Solar thermal has contributed little for space heating in China. In 2014, although China shared 75.8% of the total solar collector installations in the world, only less than 0.3% of the solar collectors were used for space heating. To promote solar district heating (SDH) in China, based on Danish experiences and Chinese clean heating transformation practices, a PEST (policy, economics, social, and technology) analysis and a SWOT (strengths, weaknesses, opportunities, and threats) analysis on SDH development in China were conducted. An extensive survey and on-site investigation were carried out to identify the applicability of SDH in rural areas. SDH development strategies, roadmap, and decision-making process for a SDH project are summarized. SDH has a broad application prospect in China with abundant solar resources and favorable policies. The solar heated floor area can achieve 756 million m〈sup〉2〈/sup〉 with an assumption of 3% coverage of the total heat demand of buildings. Particular areas with low population density, scarce resources, and strict environmental requirements, e.g., Tibet, should be given a high priority for SDH. Rural villages and small towns with better infrastructure, e.g., district heating networks, are the best target market for SDH in the next five years. With the development of seasonal heat storage technologies and the accumulation of practical experience, SDH can be expanded to industrial parks, large residential communities in sparsely populated northwest China. Integration of solar heat with existing heating networks in big cities with central heating will be challenging in the long run.〈/p〉〈/div〉

Description: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 107〈/p〉 〈p〉Author(s): Lei Zhang, Zhiqiao Chen, Jing Su, Jingfa Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉New energy materials that act as clean power sources and data science are developing rapidly in the past decades and the advancement of the two research areas have significantly benefited the development of each other. At the meantime, structural information of materials have been obtained and stored in various structure databases, such as the Cambridge Structure Database (CSD) and the Inorganic Crystal Structure Database (ICSD). Researchers have developed various structure-property relationships of the energy materials, which could be applied to screen the potential suitable materials from structure databases; this has become an efficient route to explore and design new energy materials. In this article, we review recent progresses on the data mining study of new energy materials based on structure databases such as CSD and ICSD, in the context of dye-sensitized solar cells and perovskite solar cells, and also include other energy systems such as water splitting systems, lithium batteries, thermoelectric devices and gas adsorbent materials. The structure descriptors that are more fundamental in the data mining procedure employing the structure-properties relationships are focused; the structural descriptors are complementary to the quantum descriptors and are efficient in the materials design process. We believe that with the successful formulation of more advanced and case-by-case structure-property relationships of energy materials, many new energy materials could be efficiently identified with much lower cost and shorter design period via the data mining process.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 108〈/p〉 〈p〉Author(s): Zhe Dong, Miao Liu, Zuoyi Zhang, Yujie Dong, Xiaojin Huang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To balance the intermittent renewable energy (IRE) and to realize its deep penetration, it is necessary for nuclear power plants (NPPs) to operate with enough flexibility. This necessity leads to the concerned questions such as which types of nuclear reactors are suitable for flexible operation and how to realize the operational flexibility of NPPs. In this paper, based on literature review and related analysis, it is shown that the modular high temperature gas-cooled reactor (MHTGR) is suitable for balancing IRE because of the advanced features such as robust fuel elements, online fuel handling, low power density and full-power-range temperature negative feedback effect. Due to the low power density, the power rating of a single MHTGR is lower than those large commercial pressurized water reactors (PWRs). To balance IRE by MHTGRs in a scalable manner, it is recommended to develop NPPs with high rated power based on multimodular scheme, i.e. multiple MHTGR-based nuclear steam supply system (NSSS) modules providing superheated steam for a common turbine. Further, to realize the flexible operation of MHTGR for deep IRE penetration, the automatic generation control (AGC) of multimodular MHTGR plants should be developed. In this paper, two AGC methods including both the adaptive AGC and extended-state-observer (ESO) based AGC are proposed, where the former one has a simple proportional-integral (PI) structure, and the latter one has an additional feedforward compensating action determined by the ESO. The corresponding control system of multimodular MHTGR plants is also designed, which is composed of the units of NSSS control, multimodular coordination control, turbine speed governor (TSG) and AGC. The AGC methods as well as the plant control system design with AGC function are then applied to two modular MHTGR plant HTR-PM. Numerical simulation results show that the newly-built multimodular control system can well stabilize the grid frequency by properly performing the power-level maneuver and maintenance of NSSS modules, and also show that the ESO-based AGC has a better frequency stabilization performance than the adaptive AGC does.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 108〈/p〉 〈p〉Author(s): Huajing Sha, Peng Xu, Zhiwei Yang, Yongbao Chen, Jixu Tang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Building energy systems, i.e. heating, ventilation, and air-conditioning (HVAC) systems, are essential for modern buildings. They provide a comfortable and healthy indoor environment. Design quality has significant impact on HVAC system efficiency. The typical building energy system design process involving several procedures is repetitive and time-consuming. It is often limited by the engineer's experience, capabilities, and time constraints; thus, the design in most cases barely satisfies building codes. In recent decades, computational intelligence (CI) has achieved substantial improvements in various fields. This paper presents a comprehensive review of using CI for HVAC system optimization design. Firstly, this paper analyzes seven procedures which constitute a typical HAVC system design process and finds that optimization problems encountered during design process can be divided into three categories: model estimation, decision making and uncertainty analysis. Then a brief introduction of CI techniques used to solve HVAC design optimization problems and detailed literature review of application examples are given. Though the design problem varies with each other, this paper outlines a typical workflow which is able to solve most HVAC optimization design problems. At last, a framework of an integrated HVAC automation and optimization design tool is proposed. The framework is developed based on building information modeling (BIM) and extracted typical design optimization workflow. It is able to connect various design stages by implementing structured information transfer between them and ultimately improve design efficiency and quality.〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 108〈/p〉 〈p〉Author(s): Anabel Palacios, Lin Cong, M.E. Navarro, Yulong Ding, Camila Barreneche〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Researchers have sought for standards, methodologies and procedures to properly measure the thermal properties of Thermal Energy Storage (TES) materials. Among them, thermal conductivity plays a key role in the TES system design as it dictates the charging/discharging dynamics of a TES system. The lack of thermal conductivity measurement's standards led to a large extent of discrepancies in terms of measurement method, measurement equipment, and sample preparation as reported in this review. Such discrepancies create uncertainties in the thermal conductivity values, which results in misleading interpretation that will be later used by other researchers for comparison purposes. This is particularly important when thermal properties are strongly linked to complex nano and micro scale materials structure. This review paper was motivated by the need of filling the gap in the literature when assessing the thermal conductivity measurements used for TES media. To that end, steady-state methods and transient methods have been reviewed by its device (commercial or own-developed), sample size, accuracy, repetitions, measurements time, etc. The outcomes of this study are threefold: regarding TES media, not all three TES technologies have been studied at the same extent; just few papers have been reported on thermochemical storage, being phase change materials and sensible the most studied; Regarding thermal conductivity techniques, transient plane source, laser flash apparatus and transient hot wire are the most used, whereas modulated DSC and 3ω the least; And lastly, regarding the measurement procedure, the data is widely spread especially for accuracy, sample size and repetitions within the same material/technique. Overall, TES community have many challenges to face in the future to converge on a common agreement aiming comparable results among studies. That means optimized sample preparation and method procedure across the different techniques achieving high accuracies for the different TES materials.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1364032119301625-fx1.jpg" width="457" alt="fx1" title="fx1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 108〈/p〉 〈p〉Author(s): Ji-Long Chen, Lei He, Hong Yang, Maohua Ma, Qiao Chen, Sheng-Jun Wu, Zuo-lin Xiao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Global solar radiation is a core component of scientific research and engineering application across a broad spectrum. However, its measurement is limited by a small number of stations due to the technical and financial restricts. Estimating solar radiation with the meteorological variables using empirical models is of benefit to obtain solar radiation data at global scale. Yet, there are various options of available empirical models to select the most suitable one. This study conducted a most comprehensive collection and review of empirical models employing the commonly measured meteorological variables and geographic factors. A total of 294 different types of empirical models were collected and classified into 37 groups according to input attributes. Such collection built an empirical model library providing an overall overview of the developed empirical models in literatures. Furthermore, the collected models were calibrated and evaluated at three meteorological stations in the Three Gorges Reservoir Area in China. This study suggests that these model-comparing processes can assist the governments, scientists and engineers in tailoring the most fitted model for specific applications and in particular areas.〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 101〈/p〉 〈p〉Author(s): Riaz Ahmad, Ali F. Murtaza, Hadeed Ahmed Sher〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents a comprehensive overview on various maximum power point tracking (MPPT) techniques, which have been recently designed, simulated and/or experimentally validated in the PV literature. The primary goal of each MPPT technique is to optimize the output of shaded/unshaded photovoltaic (PV) array under static and dynamic weather conditions. Though each MPPT technique has its own pros and cons, an optimized MPPT technique is characterized in many aspects like hardware and software simplicity, implementation, cost effectiveness, sensors required, popularity, accuracy and convergence speed. In this paper the rating of various MPPT methods has been done based on the benchmark P&O method. The rating criteria is separately calculated for the techniques that are capable to work in full-sun and partial shading conditions. A rule based table is set to evaluate the MPPT against the algorithm's complexity, hardware implementation, tracking speed, and steady state accuracy or detection of global maximum. Moreover, special consideration has been given to bio-inspired MPPT algorithms. The bio-inspired algorithms are compared side by side with their specific application in PV system. A tree diagram is also designed to see the emergence of partial shading algorithms over a period of time. The traits presented in this paper are novel and provide bottom-line for the researchers to select and implement an appropriate MPPT technique.〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 101〈/p〉 〈p〉Author(s): Mohammadjavad Raeisossadati, Navid Reza Moheimani, David Parlevliet〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Raceway open ponds are preferred cultivation system for mass algal commodity production. For operational reasons, large-scale raceway ponds must be operated at a depth greater than 20 cm meaning that algal cultures are normally light limited as light cannot penetrate into the depth below 5 cm. For the efficient distribution of light into the culture, different light delivery systems such as temporal and spatial have been proposed. If the proper mixing created, the flashing light effect can be created and that would result in a significant increase in biomass productivity. However, to date, this method has not been achieved in outdoor raceway open ponds. On the other hand, spatial light dilution systems are found to be more effective and economical that temporal light dilution systems. Among spatial dilution systems, luminescent solar concentrator (LSC) panels have a potential to be commercialized for mass microalgae production. Luminescent solar concentrators combine spectrum shifting properties with spatial dilution to channel the light into the culture where it is needed. There is also the possibility of electricity production as well as higher algal biomass production when using LSC panels in open ponds or PBRs. Additionally, compared to other proposed methods, the lower capital cost can be expected when using LSCs in algal cultivation systems as there is no need to use a solar tracking system to track the sun. In this review article, the effects of photolimitation, photosaturation and, photoinhibition in concentrated microalgal cultures, as well as the impact of applying different light distribution systems on the biomass productivity and photosynthetic efficiency as a result of having more uniform distribution of light into the culture, have been outlined.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1364032118307329-fx1.jpg" width="417" alt="fx1" title="fx1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 100〈/p〉 〈p〉Author(s): Junliang Fan, Lifeng Wu, Fucang Zhang, Huanjie Cai, Wenzhi Zeng, Xiukang Wang, Haiyang Zou〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Accurate estimation of global solar radiation (R〈sub〉s〈/sub〉) is essential to the design and assessment of solar energy utilization systems. Existing empirical and machine learning models for estimating R〈sub〉s〈/sub〉 from sunshine duration were comprehensively reviewed. The performances of 12 empirical model forms and 12 machine learning algorithms for estimating daily R〈sub〉s〈/sub〉 were further evaluated in different climatic zones of China as a case study, i.e. the temperate continental zone (TCZ), temperate monsoon zone (TMZ), mountain plateau zone (MPZ) and (sub)tropical monsoon zone (SMZ). The best-performing model at each station and the overall best model for each climatic zone were selected based on six statistical indictors, a global performance index (GPI) and computational costs (computational time and memory usage). The results revealed that the machine learning models (RMSE: 2.055–2.751 MJ m〈sup〉−2〈/sup〉 d〈sup〉−1〈/sup〉; NRMSE: 12.8–21.3%; R〈sup〉2〈/sup〉: 0.839–0.936) generally outperformed the empirical models (RMSE: 2.118–3.540 MJ m〈sup〉−2〈/sup〉 d〈sup〉−1〈/sup〉; NRMSE: 12.1–27.5%; R〈sup〉2〈/sup〉: 0.834–0.935) in terms of prediction accuracy. The cubic model (M3), modified linear-logarithmic model (M5) and power model (M10) attained generally better ranks among empirical models based on GPI. M3 was the top-ranked model in TMZ and MPZ, while general best performance was obtained by M5 and M2 in SMZ and TCZ, respectively. ANFIS, ELM, LSSVM and MARS obtained generally better performance among machine learning models, with the overall best ranking by ANFIS in TCZ and SMZ and by ELM in MPZ and SMZ. XGBoost (8.1 s and 74.2 MB), M5Tree (11.3 s and 29.7 MB), GRNN (12.3 s and 295.3 MB), MARS (14.4 s and 42.6 MB), MLP (22.4 s and 41.3 MB) and ANFIS (29.8 s and 23.1 MB) showed relatively small computational time and memory usage. Comprehensively considering both the prediction accuracy and computational costs, ANFIS is highly recommended, while MARS and XGBoost are also promising models for daily R〈sub〉s〈/sub〉 estimation.〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 101〈/p〉 〈p〉Author(s): Deyou Li, Xiaolong Fu, Zhigang Zuo, Hongjie Wang, Zhenggui Li, Shuhong Liu, Xianzhu Wei〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Over the past decade, the use of conventional one-dimensional numerical-simulation methods has been demonstrated to be inadequate in terms of their usefulness in investigations concerning transient processes in hydraulic machines systems—their theoretical analyses and engineering applications. Consequently, numerous three-dimensional numerical methods capable of accurately simulating transient processes in hydraulic-machine systems have been proposed and improved upon in recent years. Through use of these novel methods and strategies, many researchers have investigated transient characteristics of processes occurring within hydraulic-machine systems along with corresponding formation mechanisms. This study presents a comprehensive review of related experimental studies, novel numerical methods and strategies along with transient characteristics and formation mechanisms in hydraulic-machine systems. Based on this study, suggestions have been made concerning the selection of simulation methods to be used and directions for future research have been proposed.〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 101〈/p〉 〈p〉Author(s): Jiayu Chen, Qiwen Qiu, Yilong Han, Denvid Lau〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Piezoelectric materials are capable of transforming mechanical strain and vibration energy into electrical energy. This property allows opportunities for implementing renewable and sustainable energy through power harvesting and self-sustained smart sensing in buildings. As the most common construction material, plain cement paste lacks satisfactory piezoelectricity and is not efficient at harvesting the electrical energy from the ambient vibrations of a building system. In recent years, many techniques have been proposed and applied to improve the piezoelectric capacity of cement-based composite, namely admixture incorporation (〈em〉e.g.〈/em〉 lead zirconate titanate, barium zirconate titanate, carbon particles, and steel fibers) and physical treatments (〈em〉e.g.〈/em〉 thermal heating and electrical field application). The successful application of piezoelectric materials for sustainable building development not only relies on understanding the mechanism of the piezoelectric properties of various building components, but also the latest developments and implementations in the building industry. Therefore, this review systematically illustrates research efforts to develop new construction materials with high piezoelectricity and energy storage capacity. In addition, this article discusses the latest techniques for utilizing the piezoelectric materials in energy harvesters, sensors, and actuators for various building systems. With advanced methods for improving the cementitious piezoelectricity and applying the material piezoelectricity for different building functions, more renewable and sustainable building systems are anticipated.〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 101〈/p〉 〈p〉Author(s): Anthony J. Slate, Kathryn A. Whitehead, Dale A.C. Brownson, Craig E. Banks〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Research into alternative renewable energy generation is a priority, due to the ever-increasing concern of climate change. Microbial fuel cells (MFCs) are one potential avenue to be explored, as a partial solution towards combating the over-reliance on fossil fuel based electricity. Limitations have slowed the advancement of MFC development, including low power generation, expensive electrode materials and the inability to scale up MFCs to industrially relevant capacities. However, utilisation of new advanced electrode-materials (〈em〉i.e.〈/em〉 2D nanomaterials), has promise to advance the field of electromicrobiology. New electrode materials coupled with a more thorough understanding of the mechanisms in which electrogenic bacteria partake in electron transfer could dramatically increase power outputs, potentially reaching the upper extremities of theoretical limits. Continued research into both the electrochemistry and microbiology is of paramount importance in order to achieve industrial-scale development of MFCs. This review gives an overview of the current field and knowledge in regards to MFCs and discusses the known mechanisms underpinning MFC technology, which allows bacteria to facilitate in electron transfer processes. This review focusses specifically on enhancing the performance of MFCs, with the key intrinsic factor currently limiting power output from MFCs being the rate of electron transfer to/from the anode; the use of advanced carbon-based materials as electrode surfaces is discussed.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1364032118306920-fx1.jpg" width="297" alt="fx1" title="fx1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 101〈/p〉 〈p〉Author(s): F.F. Freitas, S.S. De Souza, L.R.A. Ferreira, R.B. Otto, F.J. Alessio, S.N.M. De Souza, O.J. Venturini, O.H. Ando Junior〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Biomass is a potential energy source for the diversification of the Brazilian energy matrix. In this context, the biogas produced from the anaerobic digestion of residues is a relevant renewable resource that plays a significant role in the mitigation of environmental problems and the local generation of electric energy. This review presents the scenario of the biogas production and electricity distributed generation within the Brazilian context. Firstly, it presents an overview of the electric energy generation from biogas and the Brazilian plants that compose this electric matrix. Secondly, the main technologies to produce biogas and the possibilities of its use, followed by the comparison of technologies for distributed generation of electric energy from biogas in the Brazilian market. To illustrate the application of biogas technology, this paper presents a case study of a biogas plant operation and its connectivity to the grid, the Colombari Farm. The information presented here aims to enhance and to foment the recovering of biomass residues to produce biogas via anaerobic digestion and its utilization to generate electricity. Although the case study considers a specific plant in Brazil, the information and results presented can be applied to others areas of the country or regions of the world, so contributing to promote the expansion of biogas plants to generate electricity. Finally, a future perspectives section describes the practical implications of the biogas production and electricity generation in rural and urban areas and its contribution to the implementation of Brazilian environmental and social policies. This review also is useful to support the research development of biogas for electricity production.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1364032118307391-fx1.jpg" width="274" alt="fx1" title="fx1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 101〈/p〉 〈p〉Author(s): Negin Choubineh, Hamid Jannesari, Alibakhsh Kasaeian〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nowadays, solar energy is harvested in two different ways including the extraction of thermal energy in solar collectors and electrical energy generation in photovoltaic panels. The Photovoltaic panels convert a small fraction of absorbed solar radiation into electrical energy and waste the rest in the form of thermal energy that results in increasing the panel temperature and decreasing the electrical efficiency. Photovoltaic thermal systems (PVT) equipped with phase-change materials (PCM) are capable of benefiting from the storage when phase change happens. In this manuscript, the effect of PCMs deployment on the performance of an air-cooled photovoltaic system is investigated, experimentally. As such, the effect of PCM is deliberated in a setup provided in which the PVT is equipped with a sheet of PCM. Herein, the first case considers a natural convection and the other three cases regard three different forced air convection. The experimental results indicate that using PCM sheets of six millimeters thick leads to reducing the panel temperature to 4.3, 3.4, 3.6 and 3.7 °C in average in a natural flow mode, forced high-velocity, medium and low velocity, respectively. Moreover, decreasing the temperature results in increasing the outlet power and electrical efficiency. Accordingly, it is concluded that using PCMs leads to a significant increase in natural and forced convection situations.〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 101〈/p〉 〈p〉Author(s): Shailesh Sharma, John Waldman, Shahab Afshari, Balazs Fekete〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Despite the considerable contribution of hydropower in driving the American economy for over a century, the rationale for hydropower in the U.S. energy mix needs to be reassessed in the context of advanced science and technology. Other alternative-yet-cheaper energy resources have been identified and hazards associated with aging hydro-dams have escalated in recent years. Furthermore, research has shown more negative environmental consequences associated with hydro-dams—and dams in general. To compare the contribution of hydro-electricity to the total energy production in the U.S., and to identify its regional distribution and contemporary patterns, we conducted a systematic analysis of large-scale multi-year data from U.S. federal agencies and tallied the nameplate capacities of major hydro-dams against their existing energy production values. We found that despite continuous efforts at upgrading hydro-facilities, since 2000 the mean contribution of hydroelectricity has remained less than 10% of the total generated energy in the U.S. and has been declining since then. Based on our results, we conclude that reservoir- and dam-based hydroelectricity may not be an efficient energy resource—at least from the American perspective, and perhaps it is timely to consider promoting other non-conventional renewable resources for energy production.〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 102〈/p〉 〈p〉Author(s): Koenraad Van Meerbeek, Bart Muys, Martin Hermy〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Pathways towards decarbonization of society to limit global warming well below 2 °C heavily rely on bioenergy. The predicted increase in biomass demand raises concerns about the sustainability of large-scale bioenergy deployment. To investigate the diversification of biomass supply this synthesis gives an overview of the underused biomass potential of landscapes beyond croplands and forests: gardens, roadsides, conservation areas, sport fields etc. In Western Europe, their annual biomass production ranges from 2.0 to 9.2 Mg dry matter per hectare, while intensive agriculture can produce 12.0–20.4 Mg dry matter per year under the same climatic conditions. However, the net energy balance (energy output minus energy inputs) of landscape bioenergy has the potential to be higher than that of some of the current bioenergy systems (ranges between 4.9–28.4 and 11.0–68.8 GJ per ha respectively). These landscape elements have in common that biomass is removed for other purposes than bioenergy production and they already provide indispensable ecosystem services to society. The scattered availability of this resource in space and time, however, limits a general implementation of landscape bioenergy. The deployment of landscape biomass is promising in regions where the management is organized, and where it could be combined with the energetic valorization of other organic waste streams. In a case study, the landscape biomass potential of an urbanized region in Western Europe is quantified and the feasibility of integrating landscape biomass together with other waste streams in the bioenergy chain is further explored. Anaerobic digestion of 1087 Gg landscape biomass (fresh weight) together with other organic waste streams could potentially generate 12.7 PJ gross per year, or 20% of the current renewable energy production in the study region. Results of this study show that landscape biomass has the potential to diversify the current biomass portfolio and can effectively contribute to the decarbonization of society.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1364032118308049-fx1.jpg" width="500" alt="fx1" title="fx1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 102〈/p〉 〈p〉Author(s): Danay Carrillo-Nieves, Magdalena J. Rostro Alanís, Reynaldo de la Cruz Quiroz, Héctor A. Ruiz, Hafiz M.N. Iqbal, Roberto Parra-Saldívar〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Agro-industrial lignocellulosic waste, an abundant source of non-food fermentable sugars, represent a potentially negative environmental impact due to unsuitable waste disposal issues, which can be attenuated when transformed to bioethanol. Several alternative processes have been developed for bioethanol production from a large variety of agro-industrial wastes (AIW) but the high economic costs of these technologies and variable substrate composition limit their implementation at commercial scale. Nevertheless, consolidated bioprocessing to produce bioethanol of second generation has been researched increasingly in recent years and it is, so far, the most promising fermentation approach for bioethanol production. Mexico ranks as one of the leading food producing countries worldwide with 818 agro-food products, 71 of which hold the first place by production volume at international level. However, strategies and specific actions for AIW management need to be incorporated. This paper discusses agro-industrial lignocellulosic waste potentials in Mexico for efficient production of second generation bioethanol using consolidated bioprocessing.〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 101〈/p〉 〈p〉Author(s): Rintu Banerjee, S.P. Jeevan Kumar, Ninad Mehendale, Surajbhan Sevda, Vijay Kumar Garlapati〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Biofuels/Bioenergy is renewable in nature by mitigating the greenhouse gas emissions despite rapid economic growth and energy demand. Biodiesel and bioethanol production from renewable sources are gaining much attention but unable to translate the technologies into commercially ventures. Several technical challenges like the screening of algae/yeast for higher lipid accumulation/ethanol production, separation and purification of microalgae from contaminants, harvesting of microalgae, improving transesterification efficiency with meager solvent consumption, energy and time have been addressed using microfluidic devices. Besides, it has shown promising results in microbial fuel cell domain. Microfluidics and microreactors offer miniaturization of experiments by a very little expense of solvents, energy and time with higher precision results. Moreover, it provides 19.2% higher surface to volume ratio when compared with Petri dish (35 mm diameter) and microchannel (50 µm tall, 50 µm wide, and 30 mm long). Higher surface to volume ratio is helpful in the integration of the whole laboratory (i.e., lab-on-a-chip), where efficient screening of ethanol/lipid producer, higher transesterification efficiency could be ascertained. Due to the overwhelming potential of microfluidics in biofuel and bioenergy sectors, the present review article illustrated several examples to depict the importance of microfluidics towards high-throughput analysis of screening the potent microbial/microalgal strain, fabrication of microfluidic bioreactor, quality analysis of biofuel and bioenergy products.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1364032118307949-fx1.jpg" width="333" alt="fx1" title="fx1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Renewable and Sustainable Energy Reviews, Volume 101〈/p〉 〈p〉Author(s): Vladislovas Katinas, Mantas Marčiukaitis, Eugenijus Perednis, Eugenija Farida Dzenajavičienė〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The study presents possibilities to use biodegradable waste, formed in the farms and agro industry, sewage sludge and waste from food plants and trade, for energy generation. Farms were evaluated by relative size and volumes of produced biodegradable waste as well as by type. Also, the waste volumes, efficiency of biogas generation technologies processing various biodegradable organic waste and their mixes were investigated. Farms and agro industry companies gain environmental and economic benefit while implementing the described technologies. It was defined that organic waste from small livestock farms are dissipated sources of pollution. It is technically difficult to assess their impact on the environment, especially its liquid fraction, thus more attention and means should be paid for reduction of this impact. Therefore, the paper also investigates trends defined in Lithuania's agriculture strategy with regard to increase feasibility of farms. The evolution of the Lithuanian energy sector trends and the use of renewable energy sources for energy production growth are given. The development of the biogas production is analysed using the different sources of biodegradable waste. It is found that in Lithuania last year, production of biogas from biodegradable waste show strong growth from 2 thousand tonnes oil equivalent (ktoe) in 2006 to 32.1 ktoe in 2016.〈/p〉 〈p〉Fact-findings disclosed that biogas can replace certain share of conventional fuel for production of heat and power, and it can also be used in transport sector. The biodegradable waste resources and possibility to use it for biogas production have been determined in the country and main factors affecting GHG emission and pathways to reduce it have been discussed. The data given in the investigation can be applied in other countries aiming to reduce conventional fuels use and improve environmental conditions.〈/p〉 〈/div〉