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Improvement of thermal performance of a solar air heater can be obtained by enhancing the rate of heat transfer. Thermal efficiency of matrix solar air heater is higher in comparison to conventional type. Number of studies has been reported in the literature on the performance of matrix air heater with different material packing and elaborated various parameters such as design; heat transfer enhancement, flow phenomenon and pressure drop in the duct. Majority of the studies revealed an increase in the thermal efficiency for matrix collector as compared to conventional plane solar air heater. This review paper presents an extensive study of the research carried out on matrix solar air heater. Based on literature review, it is concluded that the solar air heaters performed well when packed with porous medium and this is due to the geometrical parameters of porous material. In addition double pass porous bed solar air heaters performed better than single pass. Various types of matrix materials used in the literature and correlations developed for heat transfer and friction factor by different researchers have been presented. Much attention has been devoted in this paper to portrait the development of various types of solar air heaters over the years. The merits and demerits of different models evolved by many researchers have been critically analyzed. Finding in a nut shell is that the drawbacks associated with conventional nonporous solar air heaters such as high heat loss to the ambient, decreased convective heat flow from plate to air, etc. can be overcome by the use of an effective design of porous bed solar air heater. [ABSTRACT FROM AUTHOR]

This paper provides a comprehensive review on various maximum power point tracking (MPPT) algorithms based on Perturb and Observe, Incremental Conductance, Soft Computing and other techniques along with the real time hardware implementation of photovoltaic (PV) system. In this review, the complete procedure, the implementation methodology and their effects in the PV output were discussed in detail for each algorithm. Further, MPPT algorithms for PV systems with partial shading condition were reviewed and reported. This paper is intended to serve as a suitable reference for future work in PV based power generation and its related research. [ABSTRACT FROM AUTHOR]

Electric energy transport theories are still a debatable subject regarding their validity and applicability in various aspects. This paper includes a comparative study of the group of theories which are categorized as instantaneous theories as opposed to periodic-averaged ones. As a preliminary review this paper presents first the three apparent power definitions in order to emphasize the difference between them. A discussion regarding their accuracy for energy metering of various conditions such as multiphase and non-sinusoidal environments is presented. Instantaneous theories are then reviewed and compared with periodic averaged theories. The review focuses mainly on p-q theory ( PQT ) and its derivative, instantaneous multi-phase theory. The legacy application of this theory for active filtering is briefly presented and the new idea of using the theory for multi-load and multi-source theory is presented as well. The comparison identifies the similarities and differences between the instantaneous and periodic averaging theories, and their inter-relations. [ABSTRACT FROM AUTHOR]

According to UNDP Policy Note 2014, only 23% of Yemen rural community have access to electricity – having connected to national grid or use small isolated generating units – while the country is one of the richest in solar energy with over 3000 h per year clean blue sky. The objectives of this paper is to concentrate on the utilization and the cost effectiveness of photovoltaic solar energy for electrification of Yemeni rural and desert communities, which will result in enhancing education, culture, science, medical services, and improve the living conditions in rural areas. Otherwise, energy poverty that is a facet of a multidimensional poverty in Yemen will persists because the possibility of connecting rural communities to the national grid, even in the next ten years, is invisible due to major political and financial problems that the country is facing. Moreover, PV energy is environmentally clean and has proved to be one of the best solutions for rural electrification in many countries worldwide due to noticeable drop of PV systems prices with the advance in PV technology. Accordingly, it should be the best solution for rural electrification in Yemeni as well. The paper demonstrates the cost effectiveness and the design procedure of utilization of solar energy for rural and desert communities in Yemen using a number of subsequent cases typical to Yemeni communities and provides also a practical study to support Bedouin backpackers. [ABSTRACT FROM AUTHOR]

Given that the first industrial revolution was based on Steam Engine (coal as energy source), and the second on oil and electricity, where both these revolutions are actually "high carbon" revolutions, it is logical to expect that the third industrial revolution should be based on systems of renewable energy sources (RES), in order to minimize the problems arising from climate changes and to achieve sustainable development. However, the usage of the RES technologies and daily/weekly storage of energy and their connection to smart grids is not enough for the expected third industrial revolution. The start of this revolution would require technologies that have a great potential for further development and ability to supply, at any time, the necessary energy and power to a settlement/city, as well as drinking water, meeting the peak load requirements, continuously throughout the year, and independently of external sources of energy and drinking water. This would be provided from intermittent RES energy (solar, wind, etc.) and sea or other unclean source of water as natural resources. In that context, this paper presents a radically new technological solution: Key Engine which uses only natural resources: the sun, sea and gravity, in order to continuously and simultaneously supply a consumer with energy, power and drinking water. This solution has all the essential features required to start a third industrial revolution. The basic unit of Key Engine consists of the solar thermal (ST) generator with parabolic trough collectors through which sea water flows directly, absorbing thermal energy of solar radiation. After the separation of steam from seawater, the steam drives turbines and generators and produces electricity that is delivered to Pump Storage Hydroelectric (PSH) facility with seawater, which balances the daily and seasonal surpluses and shortages of energy, thus ensuring a continuous supply of electric power and energy to a consumer. At the same time, the water that comes out of the turbine, passes through the water treatment unit and is stored in drinking water reservoir, enabling continuous supply of the same consumer with drinking water. The paper presents theoretical aspects of Key Engine, model for optimal sizing and practical formulas for the calculation of characteristic values of the system, which could be the basis for further scientific research, development and innovative solutions that would help engineers in practice for numerous and diverse applications of Key Engine. In order to verify the derived mathematical relationships and models for optimizing the Key Engine in real conditions, the case study of the island of Vis in the Adriatic Sea, Croatia, has been considered, along with total annual irradiance of 1575 kW h/m 2 a, total annual electric energy consumption of 20 GW h and drinking water consumption of 453,382 m 3 . The obtained results: power of ST generator of 52 MW, working volume of the upper reservoir of 7 hm 3 , total annual electric energy production of 62 GW h/a, and drinking water production of 480,754 m 3 /a, clearly show that the new technology can fully meet the needs of the considered consumer for energy and drinking water. As the basic idea of Key Engine relies on the use of natural resources, i.e. RES energy and sea, the paper presents only the starting solution, whereby, apart from the sun, RES can be wind, or other renewable sources, that can perform separation of vapor from seawater and thus produce drinking water, as well as energy simultanously. Also, energy storage may not be performed solely by the PSH technology, but also by any other technology that can provide seasonal balancing of energy. All this suggests that the Key Engine can be understood as an open-source for RES technology development and thus bring changes in all three aspects of sustainable development: economy, society and environment. [ABSTRACT FROM AUTHOR]

After a three-year low valley caused by Fukushima nuclear accident, China finally restarted the approval of new coastal nuclear projects followed by the gradually matured new generation nuclear reactor technology and increasingly more supporting policies. Under this major shift of policy environment, China׳s nuclear power development would certainly stride on a new stage. This paper simulated the growth rate, development scale and evolvement path of China׳s nuclear power by establishing system dynamics models in the new-round construction. Under the background of changing nuclear power policy, this paper is helpful to master the dynamic development pattern of China׳s nuclear power system. These dynamic analyses also have reference meaning to the prediction of nuclear installed-capacity, nuclear generation, uranium import and other relevant factors. Further, the simulation results of this paper provide the Chinese government with suggestions of planning China׳s nuclear push, and deciding the strategy of uranium supply in order to secure the safe and steady nuclear power supply. [ABSTRACT FROM AUTHOR]

Since 2010 China has faced a worrying phenomenon “wind curtailment” in the development and operation of the wind power industry. This phenomenon has resulted in sharp decline of the utilization hours of the wind power equipment, seriously affected the economic benefits of the wind farms and caused serious energy waste. The wind curtailment in China is seemingly caused by the volatility of the wind power technical characteristics. However, judging from a deep level, the planning, networking management and policies play a critical role. With analysis this paper makes such a conclusion: it is not practical to solve the wind curtailment of China solely with the technical solutions and comprehensive measures must be taken. The paper offers strategies from the planning, policy and technical levels to solve the wind curtailment problem according to the actual situation of China and by referring to experiences of developed countries. [ABSTRACT FROM AUTHOR]

Introduction of renewable energy sources (RES) in insular areas is growing on different islands of various regions in the world and the large-scale deployment of renewables in island power systems is appealing to local attention of grid operators as a method to decrease fossil fuel consumption. Planning a grid based on renewable power plants (RPP) presents serious challenges to the normal operation of a power system, precisely on voltage and frequency stability. Despite of its inherent problems, there is a consensus that in near future the RES could supply most of local needs without depending exclusively on fossil fuels. In previous grid code compliance, wind turbines did not required services to support grid operation. Thus, in order to shift to large-scale integration of renewables, the insular grid code ought to incorporate a new set of requirements with the intention of regulating the inclusion of these services. Hence, this paper discusses grid code requirements for large-scale integration of renewables in an island context, as a new contribution to earlier studies. The current trends on grid code formulation, towards an improved integration of distributed renewable resources in island power systems, are addressed. The paper also discusses advanced grid code requirement concepts such as virtual wind inertia and synthetic inertia for improving regulation capability of wind farms and the application of energy storage systems (EES) for enhancing renewable generation integration. Finally, a comparative analysis of insular grid code compliance to these requirements is presented in the European context. [ABSTRACT FROM AUTHOR]

There is a global consensus on making full use of renewable energy because of human concern for energy security and environmental deterioration. Power generation with large-scale renewable energy such as solar and wind energy has become the trend of modern power systems, and the resulting impacts on power systems are more and more prominent. Therefore, there is great concern from academic and engineering areas of all countries. In China, as the fastest growing country in the photovoltaic (PV) industry in the world, these problems are particularly outstanding. This paper extensively reviews the present research and application status of large-scale PV (LSPV) power generation in China, discusses the modelling and simulation techniques of LSPV, explores impacts of LSPV integration on dynamic and static characteristics of power systems, and describes key technologies about LSPV power generation delivery and consumption from the perspective of power system planning, simulation, dispatching and control. Additionally, this paper also refines academic and engineering problems, and recommendations are proposed for future research and development of LSPV power generation in China. [ABSTRACT FROM AUTHOR]

Development of alternative energy sources has become a necessity as fossil energy resources are declining. At the same time, energy demand is rapidly increasing, putting the world on the verge of a global energy crisis. Moreover, the extensive use of conventional energy sources is polluting the environment and causing global warming. On the other hand, wind and other renewable energy sources are viable and clean alternatives to fossil fuels. Low operating cost and extensive availability make wind one of the most advantageous and effective renewable energy sources. This paper provides an exposure to the necessity for deployment of renewable energy sources and the worldwide installed capacity of wind power as well as a review of various wind technologies in conjunction with their applications and devices of operation. Furthermore, this paper discusses the cost of electric generation in wind power plants as well as the economic and environmental policies that advocate the installation of wind energy systems. [ABSTRACT FROM AUTHOR]

Total energy consumption per capita of any country is a critical input for the economic and social development. But nowadays, the current energy production systems are not sustainable and they are not environment friendly. Increased fossil energy consumptions in manufacturing, transportation and standard of living in the growing population have the highest impact on the environment in terms of global warming potential and air pollution. Also fossil fuel prices are increasing because of shortening of fossil fuel sources. Sustainable development improves standard of life economically and environmentally over the long term in a way that must be supported by the industrial structure of the country. In order to sustain energy availability and keep environment livable for future generations, finding new alternatives is necessary. Increased awareness of society about environmental issues and fossil energy sources depletion support new clean alternatives. These alternatives are one of the important and determinant policy areas for the countries, and should include both short and long term energy policies. This paper discusses the environmental pollution caused by energy consumption, and the role of conventional and renewable energy technologies as one component of the effective sustainable development and solution. Also, renewable energy potential of Turkey for assessment of the green energy systems is investigated in terms of sustainable development, environmental impact and prices. All the given results in this paper will be useful to researchers, engineers, decision and policy makers in industry and government. [ABSTRACT FROM AUTHOR]

Adsorption refrigeration technology has established enhanced significance in last three decades, due to its noiseless, non-corrosive and environment friendly operation by the utilization of low grade heat sources, especially solar energy. A plethora of adsorption cooling systems had been developed but still these cooling systems are not ready to compete with the traditional vapor compression cooling systems. This paper aims to provide fundamental knowledge on the adsorption systems and presents a comprehensive literature review of the past efforts in the field of their solar energy utilization. This paper also presents a brief of various related researches conducted in India. A survey of developments in the market trends is also presented in this paper. It shows that a number of attempts have been made by various companies to enhance the performance of adsorption refrigeration systems and maintain their presence in market but limitations regarding their technical and economic aspects seem difficult to overcome. Nevertheless, adsorption cooling systems driven by solar energy not only lowers down the daily electricity consumption but also reduces the global warming potential due to its environment friendly nature. [ABSTRACT FROM AUTHOR]

Green and renewable, wind is one of the major ways to produce power. However, natural wind used for tunnel ventilation is often neglected. Natural wind is usually regarded as resistance. Every year, unchanging ventilation mode and unreasonable control strategy lead to huge energy consumption and economic loss In China. This paper mainly discusses and analyzes the current situation of energy consumption in extra-long tunnel operation ventilation in China. It proposes the natural wind utilization in extra-long segmented tunnels. Therefore, a scientific and theoretical calculation method for extra-long tunnels located in climate separation zone is presented in this paper. Principles of natural wind in each tunnel section are obtained based on long-term monitored meteorological factors. A feasible optimized energy-saving ventilation strategy is put forward, which utilizes natural wind and will minimize the operation energy consumption. It is concluded that, the results about operation energy consumption from this paper can provide useful technical supports in design, operation and management for tunnels all over the world. [ABSTRACT FROM AUTHOR]

Pakistan is facing increasing power shortage from the last two decades. The Government of Pakistan (GoP) has taken various remedial measures and is offering incentives for private investment to generate electricity at cheap rates. New hydropower dams were proposed in the past, such as Kalabagh Dam, but could not be commissioned to date. Fossil fuels are depleting and oil has to be imported for oil-fired power plants, which is highly expensive and a burden for the country's economy. This scenario has raised serious concerns among citizens. In this frustrating situation, there is dire need for exploration and installation of alternate renewable energy resources, in particular, wind energy and solar energy to augment the existing power generation and distribution apparatus. These then need to be integrated with the national power grid. Pakistan has enormous wind energy potential, especially in three of its four provinces namely, Khyber Pakhtun Khwa (KPK), Sindh and Balochistan. The country's multifarious terrain includes coastal and hilly areas suitable for installation of large wind turbines. The GoP has taken active steps towards measuring wind speed statistics in various parts of the country. In this paper, the authors analyze wind speed data for the mentioned three provinces. The fourth province, Punjab, has very limited wind energy potential and hence is not considered. Wind speed data for Jiwani (a reference site in Balochistan) was obtained from Pakistan Meteorological Department (PMD) as a case study. The paper attempts to assess how much wind energy can be harnessed from the three provinces. It then focuses on Jiwani whose specific power density is estimated for wind turbine sizing. Lastly, a practical scheme is proposed for integration of wind power output (from windy sites) with the national power grid. [ABSTRACT FROM AUTHOR]

Renewable energy hybrid power systems have been proven through their ability to address the limitations of single renewable energy system in terms of power efficiency, stability, and reliability while operating at minimum cost. In this regards many research and practical experiences have been done. The present paper reviews the different hybrid PV–Wind renewable energy hybrid systems used for electrical power generations. Different criteria of sizing the different system components of hybrid renewable energy power plant at the most preferable logistical environmental and economical considerations have been discussed. Also, the paper discussed some of the optimization approaches which are used to compare the energy production cost and performance of different hybrid system configurations using simulation techniques. Based on the fact that, potential of the wind and solar energy is not equal in Oman, this paper will discuss the optimum sizing process of two proposed hybrid PV–Wind plants in Oman. [ABSTRACT FROM AUTHOR]

The use of the two-phase closed thermosyphons (TPCTs) is increasing for many heat transfer applications. This paper reviews the most recent published experimental and theoretical studies on the TPCT. After a description of the TPCT operating principle and the performance characteristics, the heat transfer analysis in condenser and evaporator sections that depends on the complex two-phase process are described. The influence of the affecting parameters on the performance of TPCTs such as the geometry (diameter, shape and length), the inclination angle, the filling ratio (FR), the working fluid, the operating temperature and pressure analyzed by various researchers is discussed. The various operating limits occurring in a thermosyphon includes viscous, sonic, dryout, boiling and flooding are also analyzed. Considering the application of TPCTs, the paper presents a review of experimental tests and applications. This paper can be used as the starting point for the researcher interested in the TPCTs and their renewable energy applications. [ABSTRACT FROM AUTHOR]

This paper assesses competing outlooks for energy mix in the Association of Southeast Asian Nations (ASEAN), highlighting the paradox of its fossil fuel-dominated outlooks when contrasted with its aspirations to move toward a green energy mix, and reviews green energy strategies using the strengths, weaknesses, opportunities, and threats (SWOT) analysis method. The paper argues that despite the looming brown outlooks due to the expected surge of coal, the ASEAN region has many advantages in providing cleaner energy for its green vision. However, reduction of CO 2 emissions has not been explicitly set in the region’s policy agenda and thus green energy potential is underdeveloped. To achieve a greener energy mix, ASEAN needs to make further efforts such as cleaner use and removal of subsidies of fossil fuels, promotion of renewables and energy efficiency, regional market integration and connectivity, and execution of existing plans by nations. Ultimately, each of these strategies will require sustained leadership, political determination, and concrete actions from stakeholders, in particular, national governments across the region. [ABSTRACT FROM AUTHOR]

Renewable lithium batteries are widely used in both hybrid and pure electric vehicles. Graded materials have structural heterogeneity and anisotropy which allows for these materials to have excellent energy storage capabilities. These important capabilities are why these materials are so fundamental in search for safe, renewable energy storage. As the development of graded materials used in battery development has increased rapidly, the effect of degradation on these batteries has emerged as an issue of international concern. In academic settings specifically, research efforts are focused equally on the capacity degradation of lithium batteries and the security of energy storage. This paper will describe recent advancements in understanding lithium battery performance degradation. To accomplish this goal, this paper will include theoretical characterization models and microscale experimental techniques. In the section that outlines our laboratory work, the impact of coupled degradation effect on the safety of lithium battery is highlighted. The theoretical and experimental analysis section will show that the relationship between degradation (such as dislocations, holes and pores) and energy storage safety is reflected so as to deepen the understanding of the issue’s nature. By discussing battery security and predicting battery performance, this paper evaluates the impact of battery degradation and the corresponding control strategies, offering scientific basis and technical support for the development of sustainable energy. [ABSTRACT FROM AUTHOR]

As a good power supplement form of super power and large-scale energy base, distributed energy has the characteristics of less investment and flexible power generation. Facing with the double pressure of the sustainable development of energy use and environmental protection, it has become an efficient solution to meet the demand of load growth, reduce environmental pollution and improve the comprehensive utilization of energy and the reliability of power supply. However, the development of distributed energy starts relatively late in China and confronts many difficulties. So this paper analyzes the present development situation and existing problems of the distributed energy in China. Then it elaborates from the aspects of policies and regulations, technical specifications, price policy and grid-interconnection codes. At last, this paper puts forward relevant policy suggestions of the guarantee mechanism of distributed energy. This paper argues that, with the attention of the development of distributed energy increasing, a series of policies to promote the construction and interconnection of distributed energy will be introduced, and distributed energy will get scaled development in China. [ABSTRACT FROM AUTHOR]

The oil crisis and the successful commercial exploitation of shale gas in America have made shale gas become the focus of global energy industry. Shale gas industry will be developed mainly in the future. Sichuan has natural geographical advantages and becomes the main battlefield of shale gas in China. So it is necessary and urgent to analyze the current situation of Sichuan shale gas. This paper introduces the status quo of shale gas in Sichuan, and systematically analyzes the industrial environment for developing Sichuan shale gas from four aspects of policy, economy, society, technology. Then the issues facing Sichuan are discussed. Finally, the paper puts forward some corresponding recommendations to provide certain references to the development of shale gas industry in Sichuan. [ABSTRACT FROM AUTHOR]

The development and exploitation of sustainable and environmentally friendly energy sources are required in order to resolve global energy shortages and to reduce the reliance of many countries on fossil fuel combustion. Salinity gradient energy has been considered a potential candidate for renewable energy due to the abundance of saline waters that could be combined with less saline solutions across the globe. Pressure Retarded Osmosis (PRO) is one of the technologies to harness salinity gradient energy. Apart from zero carbon dioxide emission, PRO is capable of producing power with less periodicity, abundance and low environmental impacts. One of the preconditions for the technical and financial feasibility of PRO, however, is the development of a PRO-specific membrane—one that meets the conditions that none of the current commercially-available membranes have met so far. The current paper discusses the progress made in PRO membrane development, particularly during the past decade, and analyses the challenges that are still hindering the implementation of PRO at large scales. Also, this paper explores possibilities for the implementation of PRO by analysing various combinations of existent solutions of various salt concentrations. Australia has been chosen to demonstrate some potential applications of PRO. This vast country has extensive reserves of saline waters that could be paired with less concentrated solutions to generate power. For each combination of solutions, a conceptual idea is presented, and an estimate of power production is given. Also, advantages and disadvantages of each scheme are discussed. The ideas and estimates can be easily extrapolated, with minor adjustments, to other countries with similar conditions. It is hoped that this publication will be valuable to those nations that have similar policies as Australia’s, with government incentives for the development and implementation of new technologies to explore new renewable energy sources. [ABSTRACT FROM AUTHOR]

The main goal of this paper is to argue for the necessity and significance of studying the distributional employment impacts of renewable and new energy development (RNE). Based on the comprehensive review of the methodology and conclusions of existing literatures, this paper builds up an extended input–output model to study RNE’s distributional employment impacts on gender and personnel structure. The case study of China׳s power sector in this paper affirmed earlier doubts that RNE development will indeed aggravate the gender inequality problem and add to the level of mismatch between the structure of labor demand and supply, causing structural unemployment problems. The quantitative analysis in this paper outlined here implies that from 2011 to 2020 the development of RNE will bring about 7 million employment gains, but only 81.8% of which can be realized due to the mismatch problem. The study of China may alert other countries to be less-optimistic about RNE’s employment impacts and reaffirm the need to carry out the distributional employment impacts analysis. This paper concludes with policy suggestions such as providing suitable training and equal promotion opportunities for women, offering courses and vocational trainings to RNE-related majors, in order to reduce the structural unemployment problem and further speed up the development of RNE. [ABSTRACT FROM AUTHOR]

China has become a net importer of natural gas as a result of rapidly increasing consumption in recent years. A production peak would exist since natural gas is an exhaustible resource. As conventional natural gas production peak approaches, the development of unconventional natural gas is attracting increasing attention. China׳s unconventional natural gas reserves are abundant, but exploration is still in its infancy stage. Thus, with the increasing quest for low-carbon development and China׳s natural gas price reform, studying the impacts of unconventional gas development on China׳s natural gas supply and price reform under different scenarios has practical significance. In this paper we predict China׳s natural gas production trends in different scenarios and forecast natural gas demand. This paper concludes that the exploitation of unconventional natural gas will greatly improve China׳s annual natural gas production, and delay the production peak year. This is important for China׳s natural gas supply security as it can decrease dependence on imported gas. Furthermore, as the cleanest fossil fuel, it will enable more time and space for renewable energy development given the many costs and controversies surrounding its development in China. [ABSTRACT FROM AUTHOR]

China faced the greatest challenge in balancing its economic growth, energy and resource security as well as environmental pollution. The energy-intensive industries, which used to be the major force driving China׳s economic growth, had seriously exhausted the countries׳ natural resources and energy, and at the same time polluted the environment because of the severe surplus of low-efficiency production capacities. As a result, the Chinese government had initiated multiple economic and administrative policies to eliminate these low-efficiency production capacities intended to improve the energy efficiency of energy-intensive industries. These policies are summarized in this paper, along with export tax rebating rate, resource tax, administrative audit and approvals, differential electric power pricing and shutting down the low-efficiency production capacities. The paper also evaluates the effects of these policies by analyzing several key indicators about the energy-intensive industries, including fixed asset investment growth rate, energy-intensity of industrial added-value, waste gas emission-intensity of industrial added-value. The VALDEX methodology is selected to examine the improving trends of energy-efficiency for energy-intensive industries. The analyzing results show that firstly the development of low-efficiency capacities tends to be more sensitive to the policies, so the policies that China had enacted really exert very important effects on improving the energy-efficiency of energy-intensive industries. However, the effects of economic policies seem more faster and obvious than the fiscal policies. Besides, the results also show that polices which are designed to reserve energy may not necessarily exert the same effects on reducing emissions. There is still large room for improving the energy efficiency of energy-intensive industries, substantial improvement still needs to be done for current policies’ system. Some suggestions for future work are provided. [ABSTRACT FROM AUTHOR]

Plug-in electric vehicles (PEV) are emerging as an efficient and sustainable alternative for private and public road transportation. From the point of view of electric grids, PEVs are currently considered as simple loads due to their low market penetration. However, as the PEV fleet grows, implementation of an intelligent management system will be necessary in order to avoid large capital expenditures in network reinforcements and negative effects on electric distribution networks, such as: voltage deviations, transformers and lines saturations, increase of electrical losses, etc. These issues may jeopardize the safety and reliability of the grid. As a consequence, this topic has been researched in many papers where a wide range of solutions have been proposed. This paper presents a review of different strategies, algorithms and methods to implement a smart charging control system. Also significant projects around the world about PEVs integration are presented. Finally, on the basis of this review, main findings and some recommendations are presented. [ABSTRACT FROM AUTHOR]

Abstract: This paper aims to review the developments and the potentials of organic photovoltaic, which has caught the attention of researchers of optoelectronics. The paper briefly introduces the physics underlying organic photovoltaic devices of donor–acceptor interfaces. It examines a variety of materials and architectures that benefit the performance of the organic photovoltaic cell; along with the important photogeneration factors including the exciton diffusion length as well as charge transport, separation, and collection. The authors have reviewed the recent understanding of the mechanisms that govern these photocurrent generation steps and sketched out the search for alternative materials and device architectures. The review also discusses areas where active researches should be directed for cell efficiency improvement and outlines the issues to be resolved in order to speed up the commercialization. [Copyright &y& Elsevier]

Abstract: Wind Energy is a fast developing source of energy since 1996. Despite its advantages, this energy could never be a primary source of electric power to be integrated into the grid even in high wind areas, such as Great Plains, due to its intermittent behaviour. This intermittency will generate intermittent power to grid, which leads to instability, unreliability and power quality problem onto the grid system. One of the widely accepted methods to overcome this problem is by coupling the wind turbine with the energy storage system. This paper reviews the ability of four different types of the energy storage system to mitigate the power fluctuated into the grid, especially during low wind speed. This paper also explains the operating principles and the different methods of charging and discharging the energy storage. The ability of permanent magnet synchronous generator (PMSG) in dealing with variable wind speed also will be discussed. [Copyright &y& Elsevier]

Abstract: The global demand for energy is currently growing beyond the limits of installable generation capacity. To meet future energy demands efficiently, energy security and reliability must be improved and alternative energy sources must be investigated aggressively. An effective energy solution should be able to address long-term issues by utilizing alternative and renewable energy sources. Of the many available renewable sources of energy, solar energy is clearly a promising option as it is extensively available. Solar power, especially as it reaches more competitive levels with other energy sources in terms of cost, may serve to sustain the lives of millions of underprivileged people in developing countries. Furthermore, solar energy devices can benefit the environment and economy of developing countries. This paper illustrates the need for the utilization of alternative energy sources, evaluates the global scenario of installed generation systems, reviews technologies underlying various solar powered devices, and discusses several applications and challenges in this area. In addition, this paper addresses the costs of deployment, maintenance, and operation, as well as economic policies that promote installation of solar energy systems. [Copyright &y& Elsevier]

Abstract: The subject of heat transfer enhancement has significant interest to develop the compact heat exchangers in order to obtain a high efficiency, low cost, light weight, and size as small as possible. Therefore, energy cost and environmental considerations are going on to encourage attempts to invent better performance over the existence designs. Streamwise vortices can be generated using small flow manipulators or protrusions such as wings and winglets configurations. Single-pair, single row, or two dimensional array of vortex generators (VGs) can be punched, mounted, attached or embedded in the boundary layer of flow channel. VGs generate longitudinal and transverse vortices, while longitudinal vortices are more efficient for heat transfer enhancement than transverse vortices. A dramatic augmentation in thermal performance of the thermal system can be achieved but pressure drop penalty is existed. Several parameters have been overviewed in this paper, which have pronounced effect on the convective heat transfer coefficient and pressure drop penalty. These parameters are: attack angle of VG, geometry of VG, standard and novel types of VG, spacing between the VG tips, number of pairs of VGs in the flow direction, rectangular or circular array arrangement of VGs, common-flow upper (CFU) or common-flow down (CFD) configuration of VG, pointing up (PU) or pointing down (PD) arrangement of VG with flow direction, Re number, channel aspect ratio, number of tubes of fin-tube heat exchanges (HE), circular or oval tubes of fin-tube HE, and location of VG respect to the tube of HE or from leading edge of the channel. This paper gives an overview about the early studies done in order to improve the performance of thermal systems with minimal pressure losses to derive systems with less negative impact on the environment and high level of energy economic. This study also provides an outlook for future work using nanofluids with vortex generators. This article is also summarizes the recent experimental and numerical developments on the thermal conductivity measurements of nanofluids, thermal conductivity enhancement, convection and conduction heat transfer, some applications, main problems and suggestions for future works. [Copyright &y& Elsevier]

The goal of this paper is to analyze recent developments in the renewable energy sector in the Western Balkans – Albania, Bosnia and Herzegovina, Croatia, Kosovo, Macedonia, Montenegro, Serbia, and Slovenia. In order to achieve this goal, existing knowledge gaps regarding the use of renewable energy as a share of the region׳s final energy consumption had to be filled in. This was done by creating a reliable model for the calculation of these shares for the years 2010 and 2011. The results were then put together with the official data for the years 2009, 2012, and 2013, and a linear trend forecast was included based on the combined data. In this way it was possible to make an estimation of the time frame in which the countries with positive linear trend results would reach their renewable energy use targets. The results of the analysis show inconsistent development of renewable energy sources for countries outside of the EU. Combined with political challenges, such as the natural gas crisis of 2009, this creates increased volatility in the proportion of renewable energy in final energy consumption. Additionally, regulatory and market issues ranging from a lack of appropriate legislation and complicated administrative procedures, to poor coordination between various institutions act as barriers to increased investment in renewable energy. [ABSTRACT FROM AUTHOR]

Inter-area low frequency electromagnetic oscillation (LFEO) in inter-connected power systems is one of the major barriers to improve the dynamic performance of power systems, since they could either limit the amount of power transfer on the tie-lines or endanger the dynamic stability of the power systems. With the high penetration of wind and photovoltaic (PV) power plants in power systems, LFEO is becoming a problem worth more attention in renewable energy age and must be better solved in order to accept more wind and PV power in power systems. Wide-area damping control (WADC) has gained popularity in suppression of inter-area LFEO recently. Many control strategies have been developed on WADC design. This paper aims to provide a general review on practical issues, typical WADC off-line and adaptive design methods and engineering cases regarding WADC implementations. These practical issues include design flow, mode analysis, choice of actuator and feedback signal, system identification and the effect of time delay. In terms of designing WADC controllers, both offline and adaptive methods have been reviewed and compared. Finally, WADC engineering cases all around the world are summarized. [ABSTRACT FROM AUTHOR]

The finiteness of fossil fuels implies that future electric power systems may predominantly source energy from fuel-free renewable resources like wind and solar. Evidently, these power systems without fuel will be environmentally benign, sustainable, and subject to milder failure scenarios. Many of these advantages were projected decades ago with the definition of the soft energy path , which describes a future where all energy is provided by numerous small, simple, and diverse renewable sources. Here we provide a thorough investigation of power systems without any fuel-based generation from technical and economic standpoints. The paper is organized by timescale and covers issues like the irrelevance of unit commitment in networks without large, fuel-based generators, the dubiousness of nodal pricing without fuel costs, and the need for new system-level models and control methods for semiconductor-based energy-conversion interfaces. [ABSTRACT FROM AUTHOR]

Interest in the advancement of hydrokinetic energy conversion (HEC) technology has grown substantially in recent years. The hydrokinetic industry has advanced beyond the initial testing phase and will soon install demonstration projects with arrays of full-scale devices. By reviewing the current state of the industry and the cutting edge research this paper identifies the key advancements required for HEC technology to become commercially successful at the utility scale. The primary hurdles are: (i) reducing the cost of energy, (ii) optimizing individual turbines to work in concert considering array and bathymetry effects, (iii) balancing energy extraction with environmental impact, and (iv) addressing socioeconomic concerns. This review is split into three primary sections. The first section provides an overview of the HEC technology systems that are most likely to be installed in commercial arrays. The second section is an in-depth literature review. The literature review is sub-divided into five areas that are positioned to significantly impact the viability of HEC technology: (i) site assessment, (ii) turbine design, (iii) turbine wake modeling, (iv) array performance, and ( v ) environmental impact. The final section presents an outlook for the HEC industry and future research. [ABSTRACT FROM AUTHOR]

The paper analyzes the biomass resulting from the processing of olive oil, in order to evaluate, in terms of economic sustainability, its importance in energy processes and the use of alternative paths other than the normal disposal process of the residues of the oil industry productive chain. Attention has been focused on the manufacturer of “Valdemone DOP” extra virgin olive oil, located in Sicily (Italy), in order to evaluate the possible energy recovery, directly by the farmer, of by-products of the production chain of olive oil, in order to make the whole process more efficient, using the scraps from the mill directly on site. The economic analysis aims at identifying measures for energy recovery from by-products; in order to reduce the incidence of the cost of waste disposal on the cost of the production of the oil; to energy conservation through the use of by-products as renewable fuel. [ABSTRACT FROM AUTHOR]

In search of alternative fuels for CI engines, many experimental studies have been carried out and posted in the literature during the last few decades. This paper presents a comprehensive review on the production, performance and emissions from a compression ignition engine using biodiesel as alternate to fossil based diesel fuel. The properties of biodiesel produced from different sources and their fatty acid composition have also been described. The experimental set up used by different researchers for the investigations and their findings regarding performance and emissions with respect to mineral diesel have been presented in short for a large number of studies. For better illustration of the facts, results of a few experimental studies available in the literature have been presented in the form of different graphs for selective important performance and emission parameters as case studies. The overall impression is that the performance of the engine slightly deteriorates with the use of biodiesel partially or fully instead of diesel, but the environmental aspects are significantly improved. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the social, economic, and environmental aspects of utilizing woody biomass for energy. We first conducted a questionnaire survey to determine which energy utilization methods were preferred in Japan and to collect the data on the cost, workforce, and energy production relevant to each energy utilization method. The results of the survey indicated that energy recovery by direct combustion and combusting wood pellets were the preferred methods. Subsequently, we employed input–output analysis to compare certain factors pertaining to the two preferred energy utilization methods. The factors were compared in relation to energy generation from the unutilized woody biomass in Japan, which amounts to 8.58 million tonne annually. The relevant factors were the social effects of employment creation, the economic effect, and the reduction of CO 2 emissions. As a result, however, as direct burning has advantages on 13.7 million tonne of CO 2 emission reduction, there are few impacts on increase of production and employment creation. In addition, we found that combusting the wood pellets was advantageous because of the increase in production (981 million USD) and the creation of employment opportunities (24,700 jobs). [ABSTRACT FROM AUTHOR]

The Australian electricity industry – like many other countries globally – is currently facing the complex challenge of reforming electricity tariffs. Momentum is growing for transitioning residential consumers toward more ‘cost-reflective’ pricing that better reflects the true costs of generation and supply, and sends a ‘price signal’ that presumably incentivises reduced consumption during peak periods. Under such tariffs, customers pay more for electricity used during times of peak demand – unlike traditional ‘flat-rate’ tariffs where the price remains stable regardless of time or demand. Pilot trials indicate that cost-reflective tariffs might succeed in reducing peak demand, but often only for a small minority of customers, such that population-wide demand response is minimal or insignificant. In this paper, we apply insights from psychology and behavioural economics to identify how cost-reflective pricing can be designed, depicted and delivered to enhance customer uptake and optimal usage –thereby facilitating ‘appropriate’ demand response – for a larger cross-section of the population. By carefully considering the likely impact of relevant cognitive biases and psychological factors –which routinely shape human decision making and behaviour – we are able to propose practical strategies that industry can adopt to maximise the prospect of cost-reflective pricing achieving significant population-level peak demand reductions, while providing shared benefits for customers, retailers, networks and regulators alike. [ABSTRACT FROM AUTHOR]

This paper examines the existence and nature of a causality relationship between clean energy consumption and economic growth for a panel of eleven sub-Saharan African countries over the period 1971–2007. We apply the panel unit root test that accounts for the presence of multiple structural breaks [13] and the newly-developed panel cointegration methodology which allows for cross-section dependence and multiple structural breaks [38] as well as a bootstrap-corrected Granger causality test. The estimation results show that there is cointegration between clean energy consumption and economic growth. Further, the results from the panel causality tests indicate that there is indeed a unidirectional Granger causal flow from clean energy consumption to economic growth. [ABSTRACT FROM AUTHOR]

India has an active participation in global solar energy contribution through the Jawaharlal Nehru National Solar Mission (JNNSM) and its many states are also walking hand in hand with the national government through individual state solar policies. The state of Gujarat, through the ‘Gujarat Solar Power Policy 2009 (GSPP 2009)’, has been leading the country in solar power generation. The feed-in-tariff based GSPP 2009 is a unique experiment of the state to develop individual solar projects as well as public-private partnership based large-scale ‘solar parks’. Of the about 2700 MW (in September 2014) installed solar energy capacity in India, Gujarat occupies a share of more than 900 MW. This paper, through semi-structured in-depth interviews conducted with project developers involved in implementation of the Charanka solar park, Gujarat, investigates the industry perspectives on the GSPP 2009. With an installed capacity of 216 MW (in April 2012), the Charanka Solar Park is the Asia׳s largest solar park. Findings from this study indicate that the attractive fixed feed-in-tariff and strong implementation mechanisms are the key strengths of the policy. On the other hand, the key challenges are lack of trust of financial institutions on solar energy projects, and tradability and bankability of the solar power purchase agreements. [ABSTRACT FROM AUTHOR]

More than a decade ago, in China׳s electric power industry, the investment for generation side and power grids was inadequate and the gap between power supply and demand kept enlarging. In order to relief the problems above, power industry reform has been carried out in 2002 under the guidance of “No. 5 Document” by the Central Government. The reform in 2002 has made a series of achievements, including the enhancement of operation efficiency of power industry and the fulfillment of power demand all over the country. During the past decade, as the rapid development of the society and economy, the external environment of China׳s power industry has changed greatly. However, the pricing and planning mechanism of China׳s power industry still operates following the requirements of “No. 5 Document”, this has led to a number of problems including twisted pricing mechanism, irrational power system planning, inefficient utilization of renewable energy and so on. These problems have not only hindered the development of power industry in China for quite a long time, but also brought negative influence on the business operation of upstream and downstream industries. Therefore, Chinese government has issued “No. 9 Document” in 2015 and launched a new round of power industry reform. Policies were carried out to form new pricing mechanism, new policies about renewable energy generation and power system planning process to solve the problems mentioned above. This paper has reviewed the history of reform in 2002 and summarized the existing problems of China׳s power industry. Besides, the main policies of “No. 9 Document” were deeply analyzed, and their significance as well as backwards were illustrated. At last, solutions were proposed accordingly and these solutions have considerable theoretical and practical significance to China׳s electric power industry reform in the future. [ABSTRACT FROM AUTHOR]

Geothermal energy piles utilize the almost constant ground temperature at shallow depths below the ground surface to heat and/or cool built structures. Heat is extracted from and/or injected into the ground through the use of a heat carrier fluid that flows in pipes attached to the reinforcement cage of the pile foundations. The performance of the energy piles can be improved by enhancing the heat exchange between the heat carrier fluid and the ground. The purpose of this paper is to provide evidence from literature on multidisciplinary methods to improve the thermal properties of elements in a geothermal energy pile. Geometrical optimization such as the number of pipes and their arrangement can be done to reduce the total pile thermal resistance. Nanofluids can be used as the heat carrier fluid to enhance the fluid conductive and convective heat transfer. Highly thermally conductive fillers can be mixed with the pipe material to enhance its thermal conductivity. The thermal properties of the concrete can also be enhanced by adding highly thermo-conductive materials to the concrete mix. [ABSTRACT FROM AUTHOR]

Iran is rich in energy resources and oil has dominated the politico-socio-economic life of this country, but nevertheless Iran has no documented policy and vision for its massive resources. This poses a major challenge to policy makers and the society. It is necessary to have a clear picture of Iran׳s energy status in recent years showing the flow of energy supply, demand, consumption, import and export to know how the energy situation in Iran is and identify its weaknesses and strengths. This paper is the first step in that direction and presents an overview of Iran energy situation and the potential and current state of renewable energy application. The status of energy in Iran is compared to world’s energy status via five key factors, and finally this comparison shows hints for designing roadmap of energy for Iran to attain sustainable and secure energy in long term. The novel contribution of this work is the STEEP analysis of Iran energy situation for designing the long-term supporting mechanisms for sustainable and secure energy for Iran based on Social (S), Technological (T), Economical (E), Environmental (E) and Political (P) criteria. [ABSTRACT FROM AUTHOR]

Wind energy is becoming more important in recent years due to its contribution to the independence of power generation industry from traditional fossil energy resources and availability of continuous harvest-able potential on earth approximately around 10 6 MW . This paper presents a comprehensive overview of grid interfaced wind power generation systems. This is intended to provide a wide spectrum on the status of wind profile, wind potential estimation, configuration/design of wind energy conversion systems, wind generators, power converter topologies used for grid integration of wind power, energy storage systems for wind power applications, power smoothing methods, HVDC links used for wind integration, international grid codes and maximum power point tracking methods to the researchers, designers, manufacturers, and engineers working on the grid interfaced wind power generation. More than 200 research publications on the topic of grid interfaced wind power generation systems have been critically examined, classified and listed for quick reference. This review is ready-reckoner of essential topics for grid integration of wind energy and available technologies in this field. [ABSTRACT FROM AUTHOR]

The technological development and economic of scale for solar photovoltaic (PV), batteries and combined heat and power (CHP) have led to the technical potential for a mass-scale transition to off-grid home electricity production for a significant number of utility customers. However, economic projections on complex hybrid systems utilizing these three technologies is challenging and no comprehensive method is available for guiding decision makers. This paper provides a new method of quantifying the economic viability of off-grid PV+battery+CHP systems by calculating the levelized cost of electricity (LCOE) of the technology to be compared to centralized grid electricity. The analysis is inherently conservative as it does not include the additional value of the heat form the CHP unit. A case study for residential electricity and thermal demand in an extreme worst case environment (Houghton, Michigan) is provided to demonstrate the methodology. The results of this case study show that with reasonable economic assumptions and current costs, PV+battery+CHP systems already provide a potential source of profit for some consumers to leave the grid. A sensitivity analysis for LCOE of such a hybrid system was then carried out on the capital cost of the three energy sub-systems, capacity factor of PV and CHP, efficiency of the CHP, natural gas rates, and fuel consumption of the CHP. The results of the sensitivity provide decision makers with clear guides to the LCOE of distributed generation with off-grid PV+battery+CHP systems and offer support to preliminary analysis that indicated a potential increase in grid defection in the U.S. in the near future. [ABSTRACT FROM AUTHOR]

The development of distributed energy system is one of the important measures to promote energy production and innovation of energy utilization patterns of China. Combined with development status of distributed energy resources in China, this paper introduces the development emphasis and main goals of three distributed generation industries from natural gas, photovoltaic and distributed wind power, then describes the policies about distributed generation from three aspects: subsidy standard, grid connection and electrovalence mechanism. Moreover, it analyzes policy options and management experience in developing distributed generation of several typical developed countries, such as America, Germany, Japan and Denmark. Finally, aiming at further development of distributed generation in China, related recommendations on policy options are put forward from four aspects: policies, regulations, financing channel and development pattern. [ABSTRACT FROM AUTHOR]

This paper examines the causality relations among economic growth, biomass energy consumption, employment and capital in the U.S between 1961 and 2011. Using the ARDL bounds testing approach to cointegration, long and short run relationships among the variables are estimated. Long run and short run coefficients indicate that biomass energy consumption has positive impacts on economic growth for the U.S. In addition, the Granger causality results illustrate that unidirectional causality from biomass energy consumption to real GDP supportive of the growth hypothesis. [ABSTRACT FROM AUTHOR]

The “Hydrogen Office building (HO)” presents a wind–hydrogen energy system, located in Fife/Scotland, which has been set-up to demonstrate the role of hydrogen in reducing the impact of wind intermittency in a grid-tied microgrid. The main components of the system are a wind turbine, alkaline electrolyser, hydrogen storage and a PEM fuel cell. The building demand is met by the wind turbine, while the fuel cell provides back-up power to the ground floor when wind power is unable to meet the demand. Accurate modelling of wind–hydrogen systems allows their successful implementation and operation, however, most of the currently available simulation tools do not provide consistent methods to represent the dynamic behaviour of such systems which is essential for their precise design, control, performance optimisation and economic study. Previous research lacks global methodologies for a whole-system scope simulation. Moreover, experimental validation is missing in most of these models and no guidelines are given for parameter estimation, which are essential for replicability. This paper presents a comprehensive methodology for the modelling, simulation and performance evaluation of wind–hydrogen systems, while including experimental validation and guidelines for parameters estimation. The developed model encompasses usability, adaptability, dominant dynamics accuracy and reliability that makes it able to assess different systems prior and after their installation. The proposed model has succeeded to depict the HO dynamic behaviour accurately with an error of less than 2% in average. The model has also been successfully utilised to evaluate the HO system performance. Evaluation criteria includes: average energy production, stand-alone operation and round-trip efficiency among others. Quantitative analysis has showed how this methodology can contribute to improve the design and performance of such systems. [ABSTRACT FROM AUTHOR]

The increasing need for thermal comfort has led to a rapid increase in the use of cooling systems and, consequently, electricity demand for air-conditioning systems in buildings. Heat-driven ejector refrigeration systems appear to be a promising alternative to the traditional compressor-based refrigeration technologies for energy consumption reduction. This paper presents a comprehensive literature review on ejector refrigeration systems and working fluids. It deeply analyzes ejector technology and behavior, refrigerant properties and their influence over ejector performance and all of the ejector refrigeration technologies, with a focus on past, present and future trends. The review is structured in four parts. In the first part, ejector technology is described. In the second part, a detailed description of the refrigerant properties and their influence over ejector performance is presented. In the third part, a review focused on the main jet refrigeration cycles is proposed, and the ejector refrigeration systems are reported and categorized. Finally, an overview over all ejector technologies, the relationship among the working fluids and the ejector performance, with a focus on past, present and future trends, is presented. [ABSTRACT FROM AUTHOR]

Due to the stark reality of regional development disparities, China has to confront the sustainable development challenges brought about by social inequality. To compensate for these regional differences in natural resource endowments, effective investment in power grid infrastructure (PGI) and improvement of power grids might prove helpful in reducing poverty and narrowing the development gap. This paper constructs a “Peripheral Degree Index” (PDI) of power grid to measure the effective distance between electricity delivering areas and receiving regions. Moreover we discuss how to efficiently locate the investment in PGI and optimize the allocation of limited financial resources. The results show investment in PGI has higher marginal benefit for less developed provinces in energy delivering regions; and more importantly, improvement of the grid infrastructure in central areas which connect energy receiving and delivering regions. Particularly, to improve the grid facilities in the central areas could reduce electricity transmission cost and help to alleviate the railway strain for coal transportation. Therefore, our findings suggest that it is more advisable to locate the investment of power grid infrastructure in the central provinces that are located at strategic conjunctions of the nationwide power grid, including Shanxi, Henan, Hubei and Hebei. [ABSTRACT FROM AUTHOR]

In this paper, the management of PEVs, uncontrolled or controlled (i.e. aggregated), and their ability to use V2G and G2V technologies are first analysed. The electricity markets are then considered; real world applications are discussed and different market types categorised. The interaction of the PEVs with some renewable energy sources (e.g. solar, wind and biomass) is also examined, and the interaction of the PEVs with demand response programs addressed. Finally, the models of PEVs are categorised and multiple types of modules, the related variables, applied methods and the considered parameters are presented. [ABSTRACT FROM AUTHOR]