bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of Hydrogen with Solar Energy
Authors: Schoonman Joop 
Published: July 2015

AbstractOne of the main requirements for a future Hydrogen Economy is a clean and efficient process for producing hydrogen using renewable energy sources. Hydrogen is a promising energy carrier because of its high energy content and clean combustion. In particular, the production of hydrogen from water and solar energy, i.e., photocatalysis and photoelectrolysis are methods for both renewable and sustainable energy production. Systems based on a photocatalyst powder suspended in an aqueous solution comprise single particles, layered materials, composite particles, or particle mixtures. The oxidation and reduction reactions take place at the same surface of a single particle. In order to avoid recombination processes, co‐catalysts are deposited on the surface of the photocatalyst to ensure that oxygen and hydrogen evolve at spatially separate surface sites. While water splitting can be carried out with coupled solar cells‐commercial water electrolyzers, the direct photoelectrolysis with a semiconductor photoelectrode is a more elegant and cheaper approach and the direct photoelectrolysis is the Holy Grail of electrochemistry, using the power of light. Here, the photoactive semiconductor is immersed in water and the photogenerated electrons and holes are directly used to reduce and oxidize water, respectively, in a PhotoElectroChemical cell (PEC cell).This article focuses on the materials science and engineering of photocatalysts, co‐catalysts, and photoelectrodes and will illustrate that the activities in the field of solar energy conversion into hydrogen are numerous. The principle of the PEC cell will be presented along with materials requirements for application in a PEC cell. Characterizations of the physical and chemical properties of state‐of‐the‐art and novel materials guide materials scientists to optimal photocatalysts and photoelectrodes. Engineering on an atomic scale is achieved by cation and anion doping effects, deviations from stoichiometry, and, in case of ternary and more complex materials, deviations from molecularity. Defect chemical aspects will be presented. To date, the decreasing length scale to the nanoscale of the functional materials for photocatalytical and photoelectrochemical applications attracts widespread attention. Besides water, also aqueous solutions of hydrobromic acid and hydrogen sulfide have been explored for hydrogen production using solar radiation. The large‐scale conversion of hydrogen sulfide from the Black Sea would be beneficial from an environmental and energy point of view.
Organic Rankine Cycles Including Fluid Selection
Authors: Lemort Vincent , Declaye Sébastien , Quoilin Sylvain 
Published: July 2015

AbstractAn organic Rankine cycle (ORC) is similar to a steam Rankine cycle, except that the working fluid is not water but an organic compound, such as a refrigerant or a hydrocarbon, characterized by a lower boiling temperature (at the same pressure) than that of water. Hence, lower temperature heat sources can be exploited such as solar energy, geothermal energy, and waste heat from many different processes.During the design phase of anORCsystem, the selection of the working fluid must be conducted in parallel with the selection and the sizing of the components (mainly the expansion machine, the pump, and the heat exchangers) and with the definition of the cycle architecture. This approach allows taking into consideration all technical constraints. Relevant properties of working fluids that should be considered during their selection are listed. Major characteristics of available displacement and turbo‐expander technologies are described. The impact of the pump performance on the overall performance is discussed and strategies to increase the available net positive suction head are proposed. Finally, improved cycle architectures are introduced.Major applications ofORCsystems are described: geothermal power plants, biomass combined heat and power plants,WHRin industry, andWHRon internal combustion engines and solar power plants. All these applications differ by the nature of the heat source and heat sink, the integration of theORCwith these sources and sinks, and the range of installed capacities. These differences yield specific designs, which are described. Performance achieved by systems in operation or prototypes are presented.
Kalina Cycles for Power Generation
Authors: Rogdakis Emmanouil , Lolos Periklis 
Published: July 2015

AbstractThe Kalina cycle has been developed by Dr. Alexander Kalina a few decades ago. The Kalina cycle is a further development of the Rankine cycle operating with a binary fluid, such as ammonia–water, instead of one fluid of a pure substance as a working medium. So, the main difference is that the isobaric evaporation and condensation process occur under variable temperature. The mixture composition varies throughout the cycle. The increased efficiency compared to the Rankine cycle is due to the close temperature match between the cycle heat acceptance and the source heat availability and of the high level of recuperation. Furthermore, a Kalina power plant uses the same devices (turbine, pumps, valves, etc.) as a conventional steam power plant, as the molecular weight of the mixture ammonia–water differs slightly from the pure water.The thermodynamic representation of binary cycles is a complex procedure and, for this reason, over a long period of time, was not feasible. The graphical representation of the Kalina cycle in temperature–entropy and temperature–enthalpy diagrams, where all heat quantities are reduced to 1 kg vapor expanded in the turbine, enable quick and reliable estimation of thermal power and heat exchanged between mixture and the environment. This gives the opportunity to scientists and engineers to dimensioning such installations and making further improvements.Kalina cycle‐based configurations have been developed, adjusted to the respective temperature field of the heat source, and parametrically evaluated. Firstly, an application of the Kalina cycle for low temperature heat sources is presented and briefly analyzed. In addition, the application of the Kalina cycle in medium to high temperature heat sources has been examined. The function of the “thermal compressor” has been analyzed. A parametric analysis has been conducted, and those factors that influence its performance have been identified. The superiority of the cycle regarding thermal efficiency and power output has been highlighted through a comparative evaluation with a Rankine cycle operating under the same conditions and using an ammonia–water mixture as a working fluid.An innovative Kalina cycle has been introduced, which uses aLiBr–H2Omixture as a working solution. The cycle has been thermodynamically analyzed and parametrically evaluated.A case study is presented, which concerns an innovative hybrid Kalina cycle for the exploitation of the heat gained through solar flat collectors.An overview of implemented Kalina cycle projects is presented, which includes demonstration‐research power plants and commercial applications.Finally, a list of Kalina patents is reported, and a few of them realized are briefly described.
Fuel Cells for Commercial Applications
Authors: Pratt Joseph W. , Klebanoff Lennie , Harris Aaron , Sookhoo Ryan 
Published: July 2015

AbstractThe use of fuel cell technology offers benefits to many applications beyond light‐duty vehicles, and many of these are currently commercially viable or have the potential to be in the near term. These include material‐handling equipment, construction equipment, handheld and portable power, telecom backup power, airport ground support equipment, aerospace power, and maritime power.In all of these applications, fuel cells can provide immediate benefits in terms of decreased fossil‐fuel use, reduced criteria pollutants and greenhouse gases, and delivery of new capabilities. Just as important, they can also be leveraged to facilitate the eventual introduction of fuel cell light‐duty vehicles by providing experience in both fuel cells and hydrogen that helps to refine products, drive down cost, reconcile codes and standards issues, make hydrogen fuel more available, and introduce familiarity with the technology to the public. In the words of theUS DOE's Fuel Cell Technologies Office Market Transformation subprogram, these near‐term applications “help overcome nontechnical challenges to the expansion of hydrogen and fuel cell technologies into the broader vehicular marketplace.”The applications mentioned earlier are in varying states of commercial viability and development yet all are contributing to these goals. As experience and performance enhancements continue, the opportunity for new applications increases.
Demand Side Management in Power Systems with High Penetration of Non‐Dispatchable Sources
Authors: Shahidehpour Mohammad , Wu Hongyu 
Published: July 2015

Abstract

This article discusses a stochastic optimization model for the day‐ahead scheduling in power systems with a high penetration of nondispatchable sources, that is, renewable energy sources (
RES
). The stochastic model incorporates the flexible ramping up/down capability of thermal generating units and applies energy storage and hourly demand response (
DR
) program as alternatives for firming the
RES
variability in economic and emergency conditions. The stochastic day‐ahead scheduling will consider hourly forecast errors of the system load and
RES
generation, as well as random outages of power system components. The Monte Carlo simulation (
MCS
) is used for creating stochastic day‐ahead scheduling scenarios. A general purpose mixed‐integer linear programming (
MILP
) software is employed to solve the stochastic day‐ahead scheduling problem. Numerical cases that include high
RES
penetrations are studied for a modified 6‐bus system and
IEEE
118‐bus system. The results demonstrate the benefits of applying
DR
as an alternative to flexible ramping in the day‐ahead scheduling model with variable
RES
.
Integration of Electric Vehicles in the Electric Energy System
Authors: Andersen Peter B. , Wu Qiuwei 
Published: July 2015

AbstractSince Scottish inventor Robert Anderson built the first electric vehicle (EV) in 1832, the world has seen several attempts at electrifying the transportation sector. Successful EV introduction represents a challenge of daunting proportions but with an extraordinary potential for society. A challenge that can only be solved through a large set of disciplines spanning fields such as anthropology, politics, business, and technology. In the following, the term “EV integration” is used to cover the technological challenges and describe the solutions that engineers and technicians working within electric components, power system design, informatics, and mathematics have to combine in a number of crossdisciplinary solutions. EV integration research should, for instance, find solutions forinfrastructureroamingnew EV servicessmart grid integrationThe goal of the latter area would be to minimize the adverse effects of introducing EVs as a new load in the power system and, instead, promote them as an active asset. This would ultimately reduce society's cost, monetary as well as environmental, for the electrification of transportation. To achieve this, the EV itself would have to be equipped with capabilities so that it through information and communication technology (ICT) can receive stimuli from its surrounding environment and through logic adjust its charging or discharging behavior.The main EV integration challenge addressed in this article is that of intelligent EV integration into the power system as part of the smart grid concept. The following sections describe the main stakeholders that have to be considered, the integration scenarios that may be pursued, and finally, provide an example on how EV integration was approached by the EDISON project.
Physical Modeling and Numerical Simulation ofCO2Storage Security
Authors: Jiang Xi 
Published: July 2015

AbstractSeveral trapping and leakage mechanisms affect the security of geological carbon storage, which has to be carried out on a large scale, safely, and economically if it were to make a significant contribution in reducing CO2emissions. Modeling and simulation can be used to predict the migration of CO2under storage conditions; accordingly, they can be used to understand the storage security. Darcy's law for describing the multiphase flows in porous media, the mass and energy conservation equations together with geochemical relations constitute the main governing equations for the numerical simulation. Because of the broad range of scales involved, modeling and simulation of geological carbon storage remain a challenging task. To effectively model the large‐scale phenomena in geological carbon storage, upscaling of permeability and other multiphase properties of the porous media as well as that of the geochemistry will be needed. In the meantime, there is a need to further develop and validate simulators for geological carbon storage. New developments on physical modeling and numerical simulation are urgently called for the understanding and predicting of the carbon storage process and the technology development.
Sustainable Energy Indicator System and Its Application in China
Authors: Chen Shaofeng , Su Liyang , Qiu Mingjing 
Published: July 2015

Abstract

Energy is a condition, a foundation, an essential factor, and the key driving force for human socioeconomic development, and the sustainable use of energy is also vital to achieve the objectives of sustainable development. As the world's largest energy producer, consumer, and carbon emitter, China is facing with severe challenges domestically and internationally, which means that China must transit toward a pathway of sustainable energy development as early as possible. Under such context, there is a pressing need for China to establish an indicator system for sustainable energy development, which aims to monitor and evaluate the progress toward the objectives of sustainable energy development and the results of implementing relevant policies, support policymaking, guide and promote the sustainable transformation of energy system. In this article, we firstly explore the challenges of sustainable energy development in China, then redefine the concept of sustainable energy, and then propose the hypothesis of three “inverted U‐shaped curves”, which is the evolutionary relation between economic growth and energy consumption or carbon emission. Then, a policy intervention conceptual model, that is, Policy intervention‐Behavior adjustment‐Process change‐Targets and effects (
PBPT
) for sustainable energy indicator system that links policy actions and performance is established, and the sustainable energy indicator system in China is also developed from the perspectives of energy supply and demand. Finally, this article gives an example of the application of the indicator system with wind power as a case study, and explains the policy implication of the indicator system.
Energy Consumption and Economy Development: An Empirical Case Study forChina
Authors: Yu Hao 
Published: July 2015

AbstractThe researches on the relationship between energy consumption and economic development became increasingly popular after the first oil shock in the early 1970s. This article at first briefly summarizes the academic development in this area in both theoretical and empirical aspects and then the energy consumption–economic development nexus is investigated by utilizing China's actual data as a case study. The empirical estimations indicate that there exists a bilateral Granger causality between China's energy consumption and economic development, both in short and long terms. Besides, the inverted‐U‐shapedEKCrelationship between energy consumption and per capitaGDPis also verified. The important policy implication from these results is that China should pay more attention to keep the balance between the short‐ and long‐run effects when conducting environmental and energy policies. Although in the long run efforts should be paid to control the total amount of energy consumption, in the short and medium terms, more emphasis should be placed on energy efficiency improvement and the development of green and renewable energy industries.
Natural Gas as a Clean Fuel
Authors: Leung Guy C. K. 
Published: July 2015

AbstractThe emergence of a global natural gas industry accelerated at the turn of recent century. While global leaders are perplexed by the “energy dilemmas” that quest for energy security and environment, which often contradict each other, natural gas, the cleanest fossil fuel and globally abundant, appears to be able to provide a temporary leeway to get around these dilemmas. This article seeks to introduce and explore relevant issues of developing natural gas as a clean fuel. It starts by providing a concise introduction to the diverse attributes, subtle meanings, and global trends of “natural gases.” It then summarizes the key arguments of the debate around whether natural gas should be considered a clean energy option. It goes on to investigate the social‐technical conditions of gas trade and production. The article argues that should natural gas, or could it, be developed as a clean fuel is largely dependent on geographical, institutional, and organizational contexts.
Brief Introduction to Solar Energy Utilization
Authors: Boehm Robert F. 
Published: July 2015

Abstract
A brief outline of the application of solar energy is given in this article. Some characteristics of the terrestrial solar flux are described, including a series of maps that show the long‐term values of yearly solar flux. In addition, short descriptions of the various applications used today are given. The article ends with some possible directions that solar research will take in the next few years.
Photovoltaics: Sun Tracking Systems
Authors: Fraas Lewis M. 
Published: July 2015

AbstractSolar electric power generation using standard silicon solar cell modules has seen major cost reductions through volume manufacturing over the past few years. According to a recentNRELstudy, today's system cost for an approximately 200‐MWP DCfixed‐axis utility‐scale ground mount system is about $3.80/WP DC. In Los Angeles without subsidies, this corresponds to an electric power price of about 18 cents/kWh. With evolutionary changes in this technology, NREL predicts that this price can drop to $1.71/WP DCby 2020 or to about 8 cents/kWh. Herein, opportunities are discussed for introducing technical innovations that can potentially reduce this cost to about 5 cents/kWh. All of these innovations involve tracking the sunlight to allow the use of higher efficiency cells and in order to increase the available solar energy incident on the solar photovoltaic modules. One‐axis and two‐axis tracking concentrator systems are discussed, as well as a revolutionary idea of using mirrors in space in a sun‐synchronous dawn–dusk polar orbit to provide sunbeams in the early morning and evening hours for large solar farms distributed around the world extending the available sunlight hours for these production sites from 8 to 14 h/day.
Spark Ignition Engines: State‐of‐the‐Art and Current Technologies. Future Trends and Developments
Authors: Cipolla Giovanni , Bozza Fabio 
Published: July 2015

AbstractThe purpose of this article is to provide fundamental information on spark‐ignited internal combustion engines (SI‐ICEs).In the first section, a general overview of mainSIengines and their peculiarities is given, as well as the foreseen evolution scenario, both from product requirement and technology opportunities points of view.In the subsequent sessions, a deeper analysis of the different specific features ofSIengines is performed, from the peculiar aspects of: air management and charging, fuel mixture preparation, fuel characteristics, combustion process, emissions generation and abatement, mechanical and parasitic losses, thermal management, and their related control aspects.
Offshore Wind Farms
Authors: L. Petersen Erik , Hasager Charlotte B. , Courtney Michael , Natarajan Anand , Larsen Torben J. , Bredmose Henrik , Larsen Gunner C. , Sørensen Poul E. , Cutululis Nicolaos A. , Erik‐Clausen Niels , Buhl Thomas 
Published: July 2015

AbstractThe technology behind constructing wind farms offshore began to develop in 1991 when theVindeby wind farm was installed off theDanish coast (11 Bonus 450kWturbines). Resource assessment, grid connection, and wind farm operation are significant challenges for offshore wind power just as it is for the more traditional onshore wind power, which has been under development since the 1970s. However, offshore projects face extra technical challenges some of which requires in‐depth scientific investigations. This article deals with some of the most outstanding challenges concerning the turbine structure: the rotor, the nacelle, the tower, and the foundation. Further the determinations of the essential environmental conditions are treated: the wind field, the wave field, the sea current, and the soil conditions. The various options for grid connections, advantages, and disadvantages are discussed. Of special concern are the problems associated with locating the turbines close together in a wind farm and the problems of placing several large wind farms in a confined area. The environmental impacts of offshore wind farms are also treated, but not the supply chain, that is, the harbors, the installation vessels, theO&Mships, and the communication and maintenance challenges.
New Electric Transmission Systems: An Overview
Authors: Aabakken Anders , Halonen Mikael , Boström Anders 
Published: July 2015

AbstractThe article gives an overall description of electric transmission systems and the current challenges and changes these systems are facing. Changes are driven by both new commercial and political environment as well as technology changes. This article focuses on the technical aspects that are indirectly driven by the other aspects. This article describes how different technical solutions can be used to manage and mitigate challenges. This covers bothHVDC(high voltage direct current) solutions and a number ofFACTS(flexibleACtransmission system) solutions. Finally, some reflections on the future of electric transmission system are given.
Energy Efficiency of Municipal Energy Systems: An Introduction
Authors: Dahlquist Erik , Wallin Fredrik 
Published: July 2015

AbstractThe energy situation is very different in different parts of the world. In cold areas, the demand for heat is overruling everything else, at least during the winter. In tropic and subtropic countries, it is usually cooling summertime that is the dominating task. When it is dark, lightning is needed, and when it is sunny, we may need sun protection to keep the strong radiation out. In northern countries with high heating demand wintertime, it is usually very economical to have cogeneration systems producing electricity with heat as an important “by‐product.” In hot countries, solar power has significant advantages as the demand for cooling is high when the solar intensity is the highest. Another important municipal task is how to build energy‐efficient buildings. In cold countries, “passive houses” have become popular; however, in hot countries, “smart glasses” and good cooling capacity are important. Transportation is another important factor where public transportation using electric trains and biogas buses has become common and is increasing, and fuel cell vehicles with hydrogen as fuel are commercialized by, for example, Toyota, who was also the first to launch the commercial hybrid cars, setting a new trend. A 4th important task is food and water.