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[Display omitted] • Various carbon nanotube-based devices are developed for solar energy utilization. • The water evaporation system can generate freshwater (1.28 kg m−2h−1). • The solar-thermoelectric system can output a voltage and charge a cellphone. • The supercapacitor performs an areal specific capacitance of 19.6 mF cm−2. • The hybrid energy system can produce freshwater, generate and store electric power. Nowadays, multi-functional systems driven by solar energy have been explored to alleviate the crisis of energy and freshwater scarcity. However, it remains a great challenge to integrate multi-functions into one hybrid system with a monolithic material, which can harvest, convert and store solar energy synergistically. Here, we firstly propose a multi-functional carbon nanotube paper, which starts from a material level to solve these problems. The carbon nanotube paper is fabricated by vacuum filtration. It exhibits high efficiency of solar-thermal conversion. Secondly, three types of energy conversion/storage systems (e.g., solar-thermal evaporation system, solar-thermoelectric generation system, and supercapacitor) are constructed based on the carbon nanotube paper, which extend the research to a device level. The solar-thermal evaporation system shows an evaporation rate of 1.28 kg m-2h−1 under simulated sunlight irradiation of 1 kW m−2. The solar-thermoelectric generation system demonstrates a stable electric power generation with an output voltage of 100 mV under light irradiation of 1 kW m−2. The supercapacitors perform the energy storage function with an areal specific capacitance of 19.6 mF cm−2. These devices and systems can be used in freshwater generation (0.84 kg m-2h−1, sunlight irradiation of 1 kW m−2), water purification/desalination (inorganic ions rejection larger than 99.9%) and portable solar charging system (maximum output voltage of 5 V). Finally, a hybrid energy system is innovatively proposed from the system level to simultaneously produce freshwater, generate and store electric power. Through the synergetic coupling of solar conversion and storage technologies, the hybrid energy system can supply sustainable freshwater and electricity for remote areas in daily life, highlighting the superiority of multi-energy (thermal energy, electrical energy, and electrochemical energy) complementary. [ABSTRACT FROM AUTHOR]

Several studies calculate the potential of renewable energies throughout the world. However, these studies vary in the underlying assumptions and do not consider several technologies within a uniform methodology, which affects comparability. In this paper, we calculate the worldwide potentials of ground-mounted photovoltaic (PV), concentrated solar power (CSP), and wind onshore and offshore on a 6.5 by 6.5 km grid. The results consist of installable capacity, generated electricity, and specific cost of electricity generation. Our methodology combines high-resolution data for land uses, slope, and hourly weather data with a thorough analysis of different factors for wind power, like hub heights and rotor diameters, and solar power plants, like tilt angle, and temperature-related loss of efficiency. The results show that the summed-up potential capacity of ground-mounted PV surpasses the amount of CSP, wind onshore and offshore combined with 450 TW. Given the cost-potential curve, ground-mounted PV reaches 560,000 TWh at costs below 20 €/MWh, which is twice the projected worldwide primary energy supply of the World Energy Outlook 2022 for the year 2050 with 205,557 TWh. The calculated results can function as input factors for energy system models, which are an important tool to analyse the energy transition. • Model-based global renewable potential calculation. • Calculation of capacity, electricity generation and costs for four technologies. • Results show technical potentials of 662,740 TWh for ground-mounted PV. • Ground-mounted PV shows potentials of 560,000 TWh at costs below 20 €/MWh. • Most cost efficient ground-mounted PV and CSP potentials can be found in Chile. [ABSTRACT FROM AUTHOR]

Traditional building integrated photovoltaic (BIPV) windows face the problems of low efficiency and unsatisfactory daylighting. Given this, this paper proposes a solar louver to harvest solar energy in the vertical building space for on-site electricity and heat generation. The solar louver is composed of concentrating photovoltaic-thermal (CPV-T) modules and allows users to adjust interior daylight according to individual demand. The design scheme of the CPV-T module and the solar louver is introduced. The CPV-T module's optical characteristics are revealed by optical simulations. The results illustrate that the CPV-T module can concentrate sunlight at the incident angle between 5° and 75° and holds the maximum concentration ratio of 3.14. Moreover, its concentration ratio can exceed 2.5 over the range of light incident angles between 15° and 45°. A prototype of the solar louver is manufactured and experimentally studied under actual weather conditions to illustrate its electricity and thermal collection performance. The results show that within the light incident angle of 20°–50°, the solar louver can maintain electrical efficiency above 4.18% and thermal collection efficiency above 55.6%. Additionally, the effective working hour is greater than 6 h, which provides a possibility to be used on buildings. • A solar louver composed of concentrating photovoltaic-thermal modules is proposed. • The louver's concentration ratio can exceed 2.5 in light incident angle of 15°–45°. • The louver allows user to adjust daylighting without reducing solar energy capture. • Its effectiveness is demonstrated by experiment with energy efficiency over 59.7%. [ABSTRACT FROM AUTHOR]

The rapidly growing of population in the developing countries and their lack of access to electricity, especially in the remote or rural areas, is causing huge challenges for on energy production. Energy is an enabler and a reliable energy supply is critical to sustainable socio-economic development for any nation. Most of Chad's people live in villages with no particular power supply system. Exploiting renewable energies is the only means of fostering development and improving people's welfare. This paper attempts at proposing an energy profile and storage model for Chad in vast remote towns. The paper addresses the key energy gap that is hindering on the development of such systems, it models and assess the potential on electricity generation and using hydrogen as surplus power storage system. A techno-econo-environmental survey on a solar-wind hybrid system in 25 towns in Chad is undertaken using NASA data and HOMER Software. Several hybrid scenarios of energy production and storage is analyzed. The results showed that in the electricity generation scenario, the average total NPC for the studied stations was $ 48164 and the average LCOE was $0.573. The lowest LCOE was related to Aouzou station with 0.507 $/kWh and the highest LCOE was obtained for Bol station with 0.604 $/kWh. In the simultaneous electricity and hydrogen generation scenario, the cheapest hydrogen ($4.695/kg) was produced in the "Grid" scenario, which was the same for all of the stations, with a total NPC of $2413770. The most expensive hydrogen ($4.707/kg) was generated in the "Grid-Wind" scenario and Bol stations with a total NPC of $2420186. The paper develops cost effective models for all hybrid systems combination for both electricity and hydrogen generation across Chad. These findings could help policy makers, investors and other developmental agencies make informed choices on energy access for sustainable development for rural communities in Sub Saharan Africa. • The wind turbine alone was the superior choice at no station in Chad. • The lowest LCOE (0.507 $/kWh) was associated with Aouzou station. • The lowest COH (4.695 $/kg) was associated with Grid scenario. • In electricity generation scenario, Abeche has the lowest emission (63.1 kg/year). • In hydrogen generation scenario, Aouzou has the lowest emission (1109 kg/year). [ABSTRACT FROM AUTHOR]

Electricity generation by means of renewable energy such as solar energy has paid great attention over recent decades. In this paper, a comprehensive study on the effect of geometric parameters such as collector roof angle (β), chimney divergent angle (α) and wind velocity on the performance of solar chimney power plant (SCPP) is carried out. A new mathematical model for airflow through all components of SCPP including collector, turbine and chimney is presented. In order to validate the present model, the geometry and operating conditions same as ones in SCPP prototype built in Manzanares are considered in the present model and comparing the obtained results with the measured data of SCPP prototype verifies the accuracy of the present model. The parametric study is carried out at various α and β. Results show that the power output of SCPP increases with decreasing β at a specified α. In addition, it is proposed that the ratio of turbine pressure drop to total pressure potential is chosen in the range of 0.7–0.85 to attain the optimum performance of SCPP. Furthermore, results demonstrate that an increase in wind velocity has a remarkable positive effect on power generation. [Display omitted] • Comprehensive theoretical modeling of SCPP is carried out. • The simultaneous effect of geometric parameters and wind velocity are investigated. • The maximum power output increases as the area of collector inlet increases. • The performance of SCPP enhances with increasing the chimney divergent angle. • Power output becomes higher with increasing wind velocity. [ABSTRACT FROM AUTHOR]

Solar dish (SD) technology is recognized as one of the most efficient solar thermal technologies for electricity generation. Moreover, SD technology has proven its suitability and reliability in solar energy potentials areas that are scarce to have water. In this regard, Egyptian western desert occupies an area of more than 65% of the total area of Egypt. It receives some of the highest solar radiation in the world (up to 3.0 MWh/m2/year), making it a prime location for the exploitation of this technology. Then, it is worth to investigate the opportunities of SD power plant for electricity generation. This paper investigates the techno-economic performance of SD power plant under Egypt desert weather condition. Accordingly, the proposed power plant is modeled and simulated using System Advisor Model (SAM). The annual energy and the levelized costs of electricity (LCOE) are calculated based on the annual simulations of 50 MW installed capacity. The profitability of proposed power plant is assessed based on Egypt's feed in tariff of concentrated solar power (CSP) projects. The proposed location of this power plant is Benban solar power park, near Aswan city in the south of Egypt. This is because the nature of the place is convenient and configured for building solar power plant, as well as its proximity to the Egyptian electricity grid. Furthermore, a sensitivity analysis is conducted to investigate the effect of the main economic variables of the proposed power plant on the LCOE and NPV. The results show that annual energy output of 50 MW is estimated to 105 GWh/year. The LCOE is estimated to 13.38 ¢/kWh. The avoided GHG emissions and fossil fuels usage are equal to about 45 million tons of CO 2 emissions and 21.64 thousand tons of equivalent oil (toe) per year (respectively). Furthermore, the results indicate that LCOE and NPV are very highly sensitive to the collector cost. • A Solar Dish/Stirling power plant is technically and economically investigated. • The solar dish power plant is modeled and simulated in SAM. • The levelized cost of electricity of the power plant estimated to be 13.38 ¢/kWh. • LCOE and NPV are very highly sensitive to the collector cost. [ABSTRACT FROM AUTHOR]

Fault current studies are often required to determine the proper settings for the overcurrent relays. The conventional synchronous generators are known to exhibit high current magnitude during fault, which present an ideal scenario for fault isolation using the cost-effective overcurrent relays. On the other hand, the fault current magnitude from renewable based generation such as solar photovoltaic (PV) is intentionally limited due to the constraints in the power electronic components. Therefore, dispute pertaining to the feasibility of overcurrent relay in inverter based distributed generations (IBDG) applications arises. These disputes mainly arise due to the unavailability of firm understanding of the fault current characteristics from the IBDGs. The problem is further compounded with the availability of numerous possible fault current controls, where various fault current characteristics can be obtained from the IBDGs. In light of this problem, this paper aims to establish the various possible IBDG fault current characteristics, with special attention paid to compliance to the latest grid codes requirements such as low voltage ride through (LVRT) with reactive current injection (RCI). Five different types of RCI controls are analyzed as follows: variable active current control, constant active power control, constant reactive power control, constant active current control, and maximum current control. From the established fault current characteristics in this paper, the disputes pertaining to the feasibility of overcurrent relay for IBDG applications can be resolved and the suitable types of RCI control that allow satisfactory performance of overcurrent relays can be identified. [ABSTRACT FROM AUTHOR]

Electrical energy becomes necessary for human being. Generation of electrical energy mostly depends on fossils fuel, they are limited in nature and also responsible for environmental pollution. Renewable energy resources provides a better alternative for future,In comparison to conventional energy resources economical aspect is a major issue of renewable energy sources with the feasibility and efficiency. These limitations are tried to overcome by deployment hybrid renewable energy resources. There are certain criteria to analyze and implement the sized, optimized and cost efficient system. This paper focus on hybrid energy systems based on solar photovoltaic (PV) and wind resources. This paper shed lights on various parameters of economic feasibility, sizing strategies with logical advancements to enhance their utilization, future prospects, and their arrangement. Strategies to develop an effective storage system is also presented here.A brief review on developments in optimization techniques, reliability index and cost analyzing techniques for hybrid renewable energy systems are also presented. [ABSTRACT FROM AUTHOR]

Long-term solar irradiance prediction can be more effective to plan and manage solar power systems. Existing methods have demonstrated the effectiveness of decomposing time series to enhance solar irradiance prediction models. However, these methods still have limitations in extracting potential sequence information from complex data sources. This makes the long-term prediction of irradiance still uncertain. In this paper, an improved complete ensemble empirical mode decomposition adaptive noise (ICEEMDAN) combined with TimesNet (ICEEMDAN-TimesNet) method is proposed. The ICEEMDAN method decomposes the subsequence features of the original irradiance, and the multidimensional spatial mapping of the data in the TimesNet model ensures that the model can efficiently extract historical information for the week-ahead hourly prediction of irradiance. In order to explore the performance of ICEEMDAN-TimesNet in the solar irradiance prediction task, several multi-step prediction models were established for comparison. Overall, the ICEEMDAN-TimesNet framework can report satisfactory testing results. The prediction curve is fitted to the trend of irradiance change which can play an excellent guiding role in scheduling electricity generation. [ABSTRACT FROM AUTHOR]

Photovoltaic/thermal (PV/T) systems allows for simultaneous electricity and heat generation. The energy output characteristics of PV/T systems are well-suited to complement the proton exchange membrane electrolytic water hydrogen production technology (PEMWE). In this paper, the performance of photovoltaic/thermal powered proton exchange membrane water electrolysis cogeneration system (PV/T-PEMWE) under different connection modes is compared. By establishing the mathematical model of PV/T-PEMWE system under indirect connection mode, direct connection mode and the optimized connection mode based on maximum power tracking, the dynamic performance is compared and analyzed. In addition, the influence of number of PV/T modules on the energy output of the system is also discussed. And the performance of PV-PEMWE and PV/T-PEMWE with the same area and optimized connection mode is compared under identical meteorological conditions. The results indicate that the hydrogen production efficiency of the systems with different connection modes, ranked from high to low, is as follows: indirect connection, optimized connection, direct connection. The operating voltage range of PV/T-PEMWE system is close to that of PV-PEMWE system, while the operating current in PV-PEMWE system is noticeably higher than that in PV/T-PEMWE system. The hydrogen production efficiency of PV-PEMWE system and PV/T-PEMWE reaches peak value at 12:00 and 14:00 respectively. [ABSTRACT FROM AUTHOR]

Solar energy contributes a major share in sustainable energy-based electricity generation. The solar power transfer system (SPTS) has emerged to integrate solar energy into the distribution network. Moreover, the adverse effects and exhaustible nature of fossil fuels have made the control and design of the SPTS significant. This paper presents a novel grid integration control, named frequency adaptive generalized integral (FAGI) algorithm for a three-phase four-wire SPTS to compensate the reactive power, harmonics and DC offset demands of the sinks connected at the common point, and also eliminates the grid neutral current along with maximum PV array power injection to the grid. The narrow bandwidth bandpass filter property of the FAGI algorithm with adaptive corner frequency improves the fundamental component quality without compromising the response time at adverse operating conditions. The two-stage SPTS uses a DC–DC boost converter for peak power extraction. An enhanced incremental conductance (EIC) algorithm is utilized for its control, which gives simple and dynamic performance over other conventional maximum power point tracking techniques. The system control is developed to meet the load requirements, even at zero irradiance by importing the active power from the grid. Therefore, the major objectives of this work are extracting maximum power, meeting the load demands, and maintaining the grid power quality at any operating conditions. Comparison of FAGI with other common controls, is carried out and the results are produced. The system performances are analyzed at PV-side, load-side, and grid-side disturbances in the MATLAB/Simulink model, and examined the grid power quality compliance with the IEEE-519 standard. An experimental prototype of the system is developed in the laboratory and tested rigorously for multiple dynamic scenarios for validating the reported claims. • Novel frequency adaptive generalized integral control for grid integration. • Compensates load reactive power, unbalanced currents, harmonics and neutral current. • FAGI enhances dynamic response at fluctuating loads and rejects input DC offset. • System has bi-directional power transfer capability at the grid coupling point. • Performance confirmed from experimental results on developed prototype. [ABSTRACT FROM AUTHOR]

Accurate and reliable solar irradiance forecasting can bring significant benefits for managing electricity generation and distributing modern smart grid. However, the characteristics of instability, intermittence, and randomness make an accurate prediction of solar irradiance very difficult. To exploit fully solar irradiance by the successful scheduling of electricity generation and smart grid, this work proposes a new CEEMDAN–CNN–LSTM model for hourly irradiance forecasting. Firstly, complete ensemble empirical mode decomposition adaptive noise (CEEMDAN) is employed to decompose original historical data into a set of constitutive series to extract data features. Secondly, a deep learning network based on convolutional neural network (CNN) and long short-term memory network (LSTM) is used to forecast solar irradiance in the next hour. Moreover, in this paper, the various CNN-LSTM-based strategies for solar irradiance forecasts are systemically investigated. Four real-world datasets on different climate types are employed to evaluate the full potential of the proposed model. Multiple comparative experiments show that the proposed CEEMDAN–CNN–LSTM model can accurately forecast the solar irradiance and outperform a large number of alternative methods. An average RMSE of 38.49 W/m2 indicates that CEEMDAN–CNN–LSTM model has a relatively stable prediction performance in different climatic conditions. • A novel deep learning-based model is used to forecast multi-region solar irradiance. • CEEMDAN is used to decompose the original data in different climate regions. • Five types of CNN-LSTM are designed for multiple feature inputs. • The proposed model shows better accuracy than other state-of-the-art models. [ABSTRACT FROM AUTHOR]

Concerns over climate change have led governments around the world to establish a range of renewable, low-carbon energy goals. Plans for meeting these targets vary widely in their ambition, specificity, and time horizons. Wind and solar electricity generation will feature prominently in future energy systems that meet these renewable, low-carbon energy goals. Implementing largescale wind and solar PV infrastructure configurations in a timely fashion will require cooperation between and among electric grid stakeholders and communities that host the infrastructure. This paper presents methods for constructing a diverse range of wind and solar PV energy infrastructure pathways that meet statutory energy goals, measuring their land use impacts, and assessing their performance relative to electricity demand. A case study on the state of Vermont's statutory energy goals from its 2016 Comprehensive Energy Plan is presented as an example. While total wind and solar PV infrastructure requirements would increase several-fold, Vermont's statutory energy goals can be met while occupying less than 1% of the state's land area. Vermont electricity demand was most effectively met by balanced configurations of wind and solar PV similar to the state's present wind and solar PV resources, while 100% wind or 100% solar PV configurations were less effective. • Most statutory energy goals do not prescribe implementation pathways. • Large-scale wind and solar PV deployments will expand electric grid land use impacts. • The state of Vermont can meet its 40% by 2035 goal with less than 1% of its land. • Wind turbines offer attractive performance per unit direct land use versus solar PV. • Direct land use only captures one aspect of the grid's total landscape impacts. [ABSTRACT FROM AUTHOR]

Organic Rankine Cycle (ORC) is promising in utilizing low-medium thermal energy, and solar energy is widely considered as the most attractive renewable energy for the future. Consequently, electricity production by coupling ORC and solar energy can reduce the fossil fuel consumption and lower the CO 2 emissions over the world. However, the intensity of solar radiation keeps changing throughout the daytime, so it is important to study the daytime performance of solar-ORC system to guarantee a proper operation. Based on the discretized parameter model built in Dymola, dynamic performances of a small-scale power plant driven by parabolic trough collector (PTC) under clear sky and cloudy sky conditions are analyzed in this paper, respectively. The results show that degree of super heat, evaporation pressure and output power are relevant to direct normal irradiance (DNI) and follow the variation of DNI from morning to afternoon. Particularly, this paper pays attention to analyze the system's responses to the cloud blockage using the dynamic model. It shows that short period (5 min) of cloud blockage of the sun poses no severe influence, while the cloud occurring at morning can cause the system to break down easily. In addition, a conventional PID control strategy is considered for the PTC-ORC system under the weather condition of cloudy sky. The optimized system can generate 105.54 kWh and the system without control can generate 84.95 kWh. The generation can improve 24% compared to the system without control. [ABSTRACT FROM AUTHOR]

This paper presents a multi-objective model for expansion with a high share of renewable energy. The model considers three objective functions (minimizing the total cost, maximizing generation at the peak load, and maximizing the contribution of non-hydro renewable sources). The model was then applied to the Brazilian case, using the new government targets for renewable energy. The introduction of the objectives regarding peak load and non-hydro renewable generation lead to an increase of solar power generation. In many studies about Brazil, solar power was not considered, or its participation was negligible, but in this paper the results show solar energy as the main non-hydro renewable source in 2030, due to its capacity to meet the peak demand, since its daily curve coincides with the peak load period. In this study, it was possible to meet 90% of the annual load with renewable sources (with 23% being ensured by non-hydro) and the solar power increased from 21 MW to 40000 MW by 2030. [ABSTRACT FROM AUTHOR]

In this paper, an alternative renewable energy concept, i.e. concept of solar power plant with short diffuser (SPD) was investigated through the development of a numerical model with simplifications due to general complexity. The mentioned alternative energy concept is based on the possibility of utilizing an artificially created and maintained convective vortex system in the surrounding atmosphere. Finally, it is assumed that the specific vortex system would able to deliver useful mechanical work which then can be used to produce carbon-free electricity via turbine assembly. Preliminary numerical results were presented as a case study for SPD plants using a solar collector diameter of 600 m with a diffuser of 30 m in maximal and 25 in minimal diameter. According to the obtained numerical simulations, for the considered case, it was found that pressure potential should be below 5 kPa in general (with mass air flow rates less than 31 t/s) in order to enable reasonable operating conditions for commercial wind turbine technologies (a specific pressure potential range was defined in order to provide reasonable parameters related to the vortex system). Namely, for pressure potentials ranging between 3.5 kPa to 5.0 kPa, and mass air flow rates from 26 to 31 t/s, the plant would be able to deliver between 5.17 MW to 16.95 MW of nominal electric power output with an associated range of wind turbine operating air velocities from 30 m/s to 50 m/s. A comparison of the numerical results was obtained by using available observation data and reasonable matching was achieved, i.e. partial validation of the developed numerical model due to the non-existence of an experimental plant. Current research related to SPD concept development is still in the stage of numerically based experiments, which are crucial and important towards the consideration of a prototype plant. Therefore, the gained and presented findings in this paper are certainly valuable for the further development of the herein analyzed alternative renewable energy concept and provide a base for the final experimental realization of a prototype plant. [ABSTRACT FROM AUTHOR]

The continuous aggravation of environmental pollutions and the rapid increase in the conventional sources of energy price advocated scientists to search for solutions such as heat recovery and continual sources of energy. One of the most distinguished types of renewable energy is solar energy which is neat, free and environmentally friendly renewable energy. Indeed, there are several solar energy systems that need to be studied. At the same time, combining solar energy systems is a trend these days which aims to optimize the benefits from solar radiations. Photovoltaic/Thermal (PVT) hybrid solar system is obtained by combining solar thermal collectors and solar photovoltaics to enable a simultaneous generation of electricity and production of heat. The target of this paper is to proffer a review on PVT hybrid solar collectors which comprises the history of PVT hybrid solar systems, main concept, benefits and classifications according to various manners in addition to integration of thermoelectric generators with PVT system. [ABSTRACT FROM AUTHOR]

• A membrane-less μPFC with dual photoelectrodes and lateral design is developed. • Photoanode is formed by coating CdS/ZnS-TiO 2 on the FTO conductive glass. • Air-breathing photocathode is formed by coating CuO on porous carbon paper. • Both the photoanode and photocathode show the visible-light response. • The developed μPFC exhibits good discharging and long-term performance. Photocatalytic fuel cell (PFC) is a promising wastewater treatment technology, which cannot only purify wastewater but also generate electricity using solar energy. In this study, a membrane-less visible-light responsive micro PFC was developed, where the CdS/ZnS-TiO 2 deposited on a conductive glass as a photoanode and CuO deposited on the porous carbon paper as an air-breathing photocathode were laterally arranged. Such design allows for both the photoanode and photocathode to be irradiated simultaneously from one side and enhances photon and mass transport. It was found that the developed micro PFC with dual photoelectrodes well responded to light illumination and exhibited good long-term performance. Experimental results also showed that upgrading the light intensity and methanol and electrolyte concentrations could improve the discharging performance because of larger amount of generated electron-hole pairs and more hole scavengers resulting from the enhanced transport. Besides, it was also found that although the increase of the liquid flow rate from extremely low rate to a moderate one caused the residence time to be lowered, positive contribution resulting from enhanced mass transport was more significant, leading to the improved performance. However, too high liquid flow rate resulted in critical low residence time, which made the discharging performance worse. The feasibility of the developed micro PFC with dual photoelectrodes toward the applications of using solar energy to remove organic pollutants contained in wastewater and simultaneously generate electricity is demonstrated in this work. [ABSTRACT FROM AUTHOR]

Continuous elevation in temperature of photovoltaic (PV) panels results in the decline of PV electric power production. This paper presents the experimental methodology tested outdoors in Taxila, Pakistan to lower PV temperature with the simultaneous use of nanofluid (graphene/water) and phase change material (RT-35HC). Performance of this hybrid PVT system in terms of PV temperature, electrical efficiency, thermal efficiency and overall efficiency, is compared with PVT/PCM system integrated with water flowing through tubes inside PCM, PV/PCM system and conventional PV. Effects of varying volume concentrations (0.05%, 0.1%, 0.15%) of graphene nanoparticles as well as flowrates (20, 30, 40 LPM) are also examined and it is found that the best performance is achieved with 0.1 vol% nanoparticle concentration and 40LPM flowrate. From the experimentation results, maximum reduction in PV temperature is observed to be 23.9 °C, 16.1 °C and 11.9 °C with nanofluid-based PVT/PCM system, water-based PVT/PCM system and PV/PCM system respectively, with maximum enhancement in electrical efficiency of 23.9%, 22.7% and 9.1% respectively as compared to conventional PV. It is also found that nanofluid-based hybrid PVT/PCM system shows 17.5% higher thermal efficiency as compared to water-based hybrid PVT/PCM system, and overall efficiency enhanced by 12%. Thus, results ensure the best performance with hybrid PVT system integrated with nanofluid and PCM simultaneously. • Novel solution for thermal management of PV using nanofluid and PCM simultaneously. • Nanofluid-PCM system was most effective followed by water-PCM and PCM alone systems. • At 0.1 vol% conc. and 40LPM flowrate, nanofluid-PCM system showed best performance. • PV electrical efficiency enhanced by 23.9% as compared to conventional PV. • Nanofluid-PCM PVT system showed 12% higher overall efficiency than water-PCM PVT system. [ABSTRACT FROM AUTHOR]

• An asymmetric concentrator with a large acceptance range of 10°–85° and high optical efficiency has been designed. • An multifunctional asymmetric concentrator-PV type window was designed. • The shading effect was analyzed and an optimization strategy was proposed to reduce the influence of it. • An typical office room integrated with the multifunctional asymmetric concentrator-PV type window was modelled and analysed. • The daylighting performance and concentrating PV performance were analyzed. The development of PV type window for building south wall integration is a promising concept, which provides a solution to the energy crisis and environment pollution problem. Thus in this paper, an asymmetric concentrator is proposed, and through the simple concentrator array optimization process, the asymmetric concentrator-PV type window can be designed, which provides the electricity generation and incorporates the function of daylighting at the same time. The optical models for the concentrator design and daylighting analysis are built and experimentally validated. The optical performance of the asymmetric concentrator has been analyzed. Considering that the incidence angles of sunrays on the building south wall remain at a high level throughout the year, the shading effect should be seriously considered. In order to reduce the shading effect between each concentrator array, the shading effect has been predicted and an arrangement optimization strategy by setting gaps between each concentrator array is presented. It was found that these gaps could alleviate the shading effect, which will also further allow the function of daylighting. Through the simulation analysis, it was found that the asymmetric concentrator can attain a large acceptance range of 10°–85° while maintaining high optical efficiency and the asymmetric concentrator-PV type window can achieve the daylighting efficiency of 4.0% to 21.8%, thus it can confirm good annual concentrating PV and daylighting performance. At last, a typical office room (the length, width and height are 3.4 m × 3.0 m × 3.3 m) installed with the asymmetric concentrator-PV type window is modelled and the illuminance distribution on the ground floor at various incidence angles is determined with the solar irradiance set at 500 W m−2. Besides of that, the energy distribution for the electricity generation and daylighting at various incidence angles is also indicated. Through the analysis, the asymmetric concentrator-PV type window is proved suitable for building south wall integration, which can efficiently use the solar energy for the domestic use, in the forms of electricity and daylighting. [ABSTRACT FROM AUTHOR]

• The design and performance comparison of a novel use of the concentrator to achieve the multifunction of the electricity generation and daylighting;. • The prototype of the concentrators are manufactured and the outdoor overall concentrating photovoltaic/daylighting experiment system was built;. • Optical performance of the concentrator was analyzed through the ray-tracing simulation and indoor experiment under the solar simulator;. • The actual transmittance of the system was investigated through the outdoor experiment under different sky conditions. This paper aims to validate an efficient way to use the low-concentration ratio concentrator for the building integrated concentrating photovoltaic/daylighting system, which is able to collect maximum solar energy for the renewable electricity generation and provide the function of daylighting. A 2-D static concentrator has been designed by leaving the lower portion of the outer parabolas near the base area uncoated to form the "daylighting window", which is named as CPVD (indicating that the concentrator is for the concentrating photovoltaic/daylighting system), while the concentrator with the same structure but can only achieve the onefold function of the electricity generation is named as CPV. In order to address the interaction effects between the concentrating PV performance and daylighting performance, the overall detail comparison is made for the CPVD module and CPV module through the ray-tracing simulation and experimental characterization. It's found that CPVD and CPV have similar optical performance (indicated by concentrating PV performance, optical efficiency, opto-electric gain and flux distribution on the receiver etc.) at various incidence angles, which validates that setting the "daylighting window" have no native effects on the optical performance of the concentrator. At last, in order to quantify the beneficial harvest for the daylighting, the conducive lighting transmittance through the "daylighting window" under two different sky conditions: clear and overcast sky conditions are investigated through the outdoor experiments. The outdoor concentrating photovoltaic/daylighting experiment test rig is built and the transmittance of the CPVD is measured under two different sky conditions. Under the clear sky condition, the daily average transmittance of the CPVD is measured to be 8.73% which is pretty much consistent with the ray-tracing simulation results. Under the overcast sky condition, the transmittance value is lower, the daily average value of which is 7.11%. [ABSTRACT FROM AUTHOR]

• Real case studies of Tazouta and Fez rural area in Morocco. • Hybrid biomass, wind, and solar electricity generation in areas those are rich in renewable energies. • Potential of bioenergy for producing power in rural areas of Fez-Meknes region in Morocco. High dependence of Morocco's energy sector on imported fossil fuels and subsequent associated expensive import bills, as well as global agreements with greenhouse gas emission reduction, has motivated Morocco to utilize renewable energy sources such as hydro, wind, and solar for energy generation. However, in recent years, the use of wind and solar energies in Morocco has accelerated more than hydropower usage because of the reduction in water levels as a result of rainfall drop, global warming, and natural droughts. Morocco has a great potential for electricity generation from solar and wind energies because of many sunny days, vast desert areas, long coastlines, and appropriate wind blow. However, accommodations of wind and solar generating units in electric power systems are difficult because of wind speed variations, solar irradiation uncertainty, and costly energy storage systems. Regarding the huge amounts of biowaste in Morocco, power generation from biomass can resolve this problem and compensate for the decrease in wind and solar energy generation during cloudy, rainy, and/or non-windy moments. Therefore, in the present paper, the capability of hybrid electric energy generation, using biomass, wind, and solar in a Moroccan village of Tazouta and the rural area of Fez city is evaluated. The proposed mixed-integer linear programming model was implemented in A Mathematical Programming Language (AMPL) using a linear solver of CPLEX. The biomass, solar, and wind power plants are biogas units fed by cow manure, 1-kW photovoltaic (PV) modules, and 5.1-kW wind turbines, respectively. The evaluation of the results indicates that hybrid utilization of wind, PV, and biomass energy resources is a more appropriate way for electricity generation in Tazouta and Fez rural areas compared to the individual operation of wind turbines and other combinations of mentioned renewable energy sources. [ABSTRACT FROM AUTHOR]

The use of zeotropic fluid mixtures in refrigeration cycles and heat pumps has been widely studied in the last three decades or so. However it is only in the past few years that the use of zeotropic mixtures in power generation applications has been analysed in a large number of studies, mostly with low grade heat as the energy source. This paper presents a review of the recent research on power cycles with zeotropic mixtures as the working fluid. The available literature primarily discusses the thermodynamic performance of the mixture power cycles through energy and exergy analyses but there are some studies which also consider the economic aspects through the investigation of capital investment costs or through a thermoeconomic analysis. The reviewed literature in this paper is divided based on the various applications such as solar energy based power systems, geothermal heat based power systems, waste heat recovery power systems, or generic studies. The fluid mixtures used in the various studies are listed along with the key operation parameters and the scale of the power plant. In order to limit the scope of the review, only the studies with system level analysis of various power cycles are considered. An overview of the key trends and general conclusions from the various studies and some possible directions for future research are also presented. [ABSTRACT FROM AUTHOR]

Today solar power is still dominantly presented to be expensive source of electricity. However, the profitability of solar and other electricity generation technologies is typically evaluated with the Levelized Cost of Electricity (LCOE) approach. This paper questions the traditional investment evaluation logics of power production (LCOE) in the interesting case of rooftop PVs and based on customer value generation logics presents a new approach for evaluating the profitability of rooftop PV investments. The approach recognizes the value that PVs produce to real estate owners and utilize basic real estate investment models to evaluate the profitability of PVs. The results imply that, if PVs are considered as a part of the underlying property, rooftop PV systems are already today profitable in many European cities and can provide substantial returns on investment for property owners. More interestingly, the results imply that rooftop PV investments are most profitable in the dense urban cores instead of more remote (industrial) locations, and thus the current trend of urbanization seems to further strengthen the profitability of rooftop solar power. This paper points out that spatial locations drive the economic analysis of real estate, and thus it is likely that it will drive the economic analysis of decentralized on-site energy investments as well. [ABSTRACT FROM AUTHOR]

In the present context, energy access to remote rural households through local energy generating systems has been recognized as a cost effective and extent efficient option. With increased emphasis on eco-friendly technologies and high fuel cost associated with conventional energy generation, the use of renewable energy resources (small hydro, biomass, solar, wind energy etc.) are being explored. The present paper is focused on the optimal sizing of a stand-alone Integrated Renewable Energy System (IRES) which comprises the resources of micro hydro power (MHP), biogas, biomass, solar and wind energy. Initially, a demand response (DR) strategy based on energy consumption scheduling of appliances has been suggested and modelled in the paper. This strategy aims to minimize the peak hourly energy consumption of the study area. Further, different combinations of system components without and with DR strategy were considered and optimized for power reliability criteria of 0% and 5% unmet load. It has been found that significant amount of savings in system sizes and costs are obtained with DR strategy compared to system without DR. [ABSTRACT FROM AUTHOR]

India with a fast growing demand for electricity and increasing consideration to emissions reduction is investing strongly in renewable electricity generation. Among renewables, the Central and State Governments have set aspirational targets for on-grid solar electricity and legislated several supporting policies to realise these targets. As a result of the favourable political environment, the development of on-grid solar, in terms of the rate of growth in installed capacity, has been increasing in the recent years, and it is expected to continue in the future. This paper aims to investigate the impact of historical transitions of India's electricity sector on the ongoing development of on-grid solar electricity and to explore the prospect of solar sector development in the future. First of all, we investigate how the historical transformation of governmental intervention's approach intertwined with the gradual shift of the source of generation has paved the way for the current achievements in on-grid solar electricity. Second, we envision the future challenges and opportunities for the development of solar sector by looking ahead and discussing the continuity of government's support and the prospective competitions between different sources. We conclude the paper with some required steps to be taken in order to secure the achievement of the targets in solar electricity in the future. [ABSTRACT FROM AUTHOR]

The utilization of solar energy based technologies has attracted increased interest in recent times in order to satisfy the various energy demands of our society. This paper presents a thorough review of the open literature on solar energy based heat and power plants. In order to limit the scope of the review, only fully renewable plants with at least the production of electricity and heat/hot water for end use are considered. These include solar photovoltaic and solar thermal based plants with both concentrating and non-concentrating collectors in both solar-only and solar-hybrid configurations. The paper also presents a selection of case studies for the evaluation of solar energy based combined heat and power generation possibility in Denmark. The considered technologies for the case studies are (1) solar photovoltaic modules, (2) solar flat plate collectors, (3) a ground source heat pump, (4) a biomass burner, and (5) an organic Rankine cycle. The various cases are compared on the basis of economic profitability and environmental performance. The results from the case studies indicate that it is economically and environmentally beneficial to invest in both small and large capacity solar-biomass hybrid plants for combined heat and power production in the Nordic climatic conditions. The results also suggest that the configuration with an organic Rankine cycle with solar thermal collectors and a biomass burner is particularly attractive for large capacity plants. [ABSTRACT FROM AUTHOR]

Nowadays, renewable energies are more preferable to fossil fuels because of being free, widely available and producing minimal pollution. One of the disadvantages of renewable energy systems is that using only one type of renewable energy cannot guarantee a continuous power generation. To overcome this problem, two or more renewable energy systems should be used simultaneously to compensate for times when one of them is not available or the renewable system should be used aligned with the generator. In addition, another weakness is that they are not accessible in every geographical position and location. It is clear that renewable energy systems can be exploited to their fullest capacity when used in the proper place. Therefore, given the importance of finding suitable places for co-utilization of several renewable energies, present paper attempted to find the ideal locations for construction of hybrid solar-wind power stations in Middle-East using Boolean model in GIS software. The Boolean method is, in a way, a more stringent method compared to the other positioning methods. Therefore, the selected locations will definitely have greater energy potential by using the Boolean method. Data obtained by RETScreen4 software from 400 stations in Middle-East were used for collecting monthly weather information. Results of the current paper may be helpful in creating prospects for sustainable energy development for systems based on natural resources and facilitating the national power transmission and sustainable environmental policies. [ABSTRACT FROM AUTHOR]

In recent years, solar energy has been considered as one of the principle renewable energy source for electric power generation. In this paper, single diode photovoltaic (PV) system and double/bypass diode based PV system are designed in MATLAB/Simulink environment based on their mathematical modeling and are validated with a commercially available solar panel. The novelty of the paper is to include the effect of climatic conditions i.e. variable irradiation level, wind speed, temperature, humidity level and dust accumulation in the modeling of both the PV systems to represent a realistic PV system. The comprehensive investigations are made on both the modeled PV systems. The obtained results show the satisfactory performance for realistic models of the PV system. Furthermore, an in depth comparative analysis is carried out for both PV systems. [ABSTRACT FROM AUTHOR]

The penetration of photovoltaics (PV’s) in electric power generation is continually increasing. Tracking maximum power point in PV systems is an important task and represents a challenging problem. In maximum power point tracking (MPPT), the duty cycle of DC-DC converter is adjusted in a way that maximum achievable power is extracted from PV system. In this paper, the existing MPPT strategies are classified into two main categories and the strategies of each category are reviewed. Based on the conducted review, some directions for future research are recommended. The author strongly believes that this paper will be helpful for researchers and engineers in the field of PV systems. [ABSTRACT FROM AUTHOR]

Abstract Solar updraft tower (SUT) is a simple power plant in which ventilation of heated air inside a channel drives a turbine. This system is recognised as suitable for areas with abundant solar radiation. As a result, there is no extensive research on the performance of SUTs under mild solar radiation. Studies show that strong ambient crosswinds can affect the performance of a SUT. In this paper, the efficiency of SUTs in areas which benefit from strong winds, despite low solar radiation, is investigated through numerical modelling. Comparison is made between the efficiency of a commercial-scale SUT in Manzanares (Spain) with intensive solar radiation, and one of the same size potentially located in the windy and mild climate of Orkney Islands in Scotland. The results show that ambient crosswinds can increase internal air speed and efficiency of a SUT by more than 15% and 50%, respectively. Consequently, such a SUT in Orkney can offer more than 70% of the efficiency of the one in Manzanares. The results show that, for a given power capacity, a wind turbine enclosed in a SUT can be considered as an alternative to a number of conventional wind turbines installed at height in the open air. Highlights • Strong ambient crosswinds can increase the efficiency of SUTs by more than 15%. • A large SUT in a windy climate can have 70% of the efficiency of the one in a sunny climate. • A wind turbine enclosed in a SUT is more efficient than conventional wind towers. [ABSTRACT FROM AUTHOR]

Abstract In this research paper, a novel solar-based integrated energy system with a thermoelectric generator (TEG) is proposed to provide cooling and hydrogen production. The energy integration is performed by establishing a TEG unit instead of the condenser of the double effect LiBr-H 2 O absorption cooling system. The proposed system is comprehensively investigated and compared with the conventional cogeneration system from energy, exergy, and exergoeconomic point of view. To enhance the understanding of the effect of major design parameters on system exergy efficiency, net output work, total cost rate and hydrogen production, a comprehensive parametric study is carried out. In addition, using a developed MATLAB code, multi-objective optimization method based on genetic algorithm is applied to optimize the proposed model and determine the optimal design parameters. The results of exergy and exergoeconomic analysis show that PVT has the highest exergy destruction rate and the cooling set has the lowest exergoeconomic factor. Results of the parametric study indicate that the proposed system with TEG has higher exergy efficiency, higher hydrogen production rate, lower total cost rate, and lower pay back period. Multi-objective optimization results show that, at the optimum point, exergy efficiency and total cost rate of the proposed system are 12.01% and 0.1762 $/h, respectively. Examining scatter distribution, further shows that the high-pressure generator temperature and PV module area are the most sensitive parameters and should be kept at their lowest value. Higher performance indicators and lower economic indicants reveal that the proposed integration method is more suitable from the exergy/exergoeconomic standpoints. Highlights • Developing a new solar based integrated system with thermoelectric generator. • A newly proposed system to provide electricity, cooling and hydrogen. • Comparing performance of the newly proposed model to the condenser based model. • Applying a Multi-objective optimization to determine the optimal parameters. [ABSTRACT FROM AUTHOR]

Abstract Carbon emissions from the Chilean public transport sector have doubled between 2000 and 2013. Thus, the need to find alternative clean-air solutions is becoming increasingly critical. With this in mind, this paper addresses a solution to the aforementioned problem by studying the conversion of both taxis and "colectivos" (public taxis with defined routes) into electric vehicles (EV) to be used in the Chilean public transport sector. In Chile, 80% of taxis are Nissan V16s, meaning that all of these vehicles will be replaced and end up in landfills within the next 5–8 years. This study presents an option to give a second life to these vehicles, addressing environmental and financial issues. It compares emissions from the Nissan V16's conventional internal combustion engine (ICE) with an equivalent electric conversion prototype. Furthermore, it analyses the CO 2 emissions from the EV that has been fully charged by the Chilean grid as well as one that has been charged by a solar photovoltaic system. A solar recharging station for EV taxis is designed, taking advantage of the high levels of solar radiation in Chile. The results show that EV conversion does not lead to real environmental benefits, in comparison to its ICE equivalent, when it is charged with the grid. However, the results also show a considerable decrease in cost and CO 2 emissions per km travelled when using solar energy to charge the batteries. Future challenges include identifying solutions to cope with solar intermittence and minimizing CO 2 emissions during periods of low radiation. Highlights • Conversion of ICE taxis into EVs in Chile. • Comparison of emissions of the Nissan V16 ICE with its electric conversion prototype. • Design of solar charging stations considering solar irradiation available in Chile. • Conversion does not show benefits when EV charged from electricity grid in comparison to ICV. • Results show decrease in running cost and CO2 emissions when EV charged from solar electricity. [ABSTRACT FROM AUTHOR]

Highlights • Developed and validated the detailed model of Photovoltaic/Thermal (PV/T) collector. • New correlations of series resistance and shunt resistance for better accuracy. • Compared the performance of the PV/T collector with or without air gap design. • Integration of PV/T collector with thermochemical sorption storage using SrCl 2 -NH 3. • 26 m2 PV/T collector coupled with storage covers the annual DHT demand of a household. Abstract To maximise the utilisation of solar energy and improve the solar fraction for domestic applications, this paper explored the potential of the hybrid solar Photovoltaic/Thermal (PV/T) collector integrated with a thermochemical sorption thermal storage system. The thermal output was used to provide domestic hot water or stored over seasons in the England city of Newcastle upon Tyne. The performance of the water-cooled PV/T collectors with or without an air insulation layer between the glass cover and the Photovoltaic (PV) cell was compared. The electrical power generation model of the PV cell developed in MATLAB was coupled with a Computational Fluid Dynamics (CFD) model to simulate the simultaneous generation of electrical and thermal energy. The one-diode model was used to simulate the electrical production of the PV cell with the new correlations of the series resistance and the shunt resistance proposed in this work, so that the accuracy of dynamic performance simulation can be improved especially in the cases with relatively higher PV cell temperature. The water outlet temperature was studied at 100 °C to meet the heat supply requirement of the sorption cycle using the working pair strontium chloride-ammonia. It was found that the PV/T collector with air gap could produce 28 L hot water per day per m2 collector (L/(day·m2)) with the electric efficiency of about 10% if the water outlet temperature was required at 100 °C; in contrast, around 133 L/(day·m2) was produced with the electric efficiency of 13% when the water outlet temperature at 40 °C. The PV/T collector without air gap was not competent for the applications studied in this work especially in cold regions. The application case studies suggested that an installation of 26 m2 air-gap PV/T collectors integrated with the strontium chloride-ammonia thermochemical sorption storage system can fully satisfy the annual hot water demand of an ordinary single household in Newcastle upon Tyne with 100% solar sources, and cover at least half of the annual electricity consumption. [ABSTRACT FROM AUTHOR]

Conventional deterministic electric vehicles (EV) charging coordination is performed assuming the EV and grid loads and PV output are known advance. In contrast, conventional probabilistic EV charging coordination takes into account the uncertainties of EV and grid loads and PV output without considering their mutual correlations. The major drawbacks of these methods are that the conventional deterministic charging increases the probability of voltage and current noncompliance (PVCN), while the conventional probabilistic charging decreases the quality of service (QoS). Therefore, this paper proposes a novel correlated probabilistic model for EV charging loads in coordination with a solar photovoltaic (PV)-rich commercial grid. In this model, correlated samples are generated from uncorrelated samples, which contain various random variables associated with EVs, battery energy storage (BES) and PV. The generated samples are subsequently incorporated in the proposed coordinated EV charging method, where the power factors of BES and PV are also controlled, to maximize QoS while minimizing PVCN. The effectiveness and practicability of the developed model are validated on an IEEE 37-bus unbalanced distribution system, which is associated with the real data of vehicles and solar PV collected from a campus of the University of Queensland. [ABSTRACT FROM AUTHOR]

This paper presents an investigation of a 111 MWe linear Fresnel reflector (LFR) plant integrated direct contact membrane distillation (DCMD) system. Both the technologies are synergized by using seawater as cooling fluid in the condenser, and then utilizing heated seawater from the condenser into the DCMD unit. The performance analysis of the LFR plant and DCMD unit has been conducted mainly in regard to direct normal irradiance (DNI) and feed water temperature, respectively. For the LFR plant, electricity generation increased with increasing DNI. The highest and the lowest energy production was 38.33 GWh and 14.08 GWh in June and December, respectively. The real levelized cost of energy was found to be 0.34 ¢/kWh. For DCMD unit, the evaporation efficiency increased from 39.13% to 50.01% corresponding to a feed temperature increase from 30 °C to 45 °C. The average freshwater production capacity of the DCMD unit was found to be 31,844.6 L/day with a water production cost $0.425/m 3 . The investigations revealed that the performance of the proposed system is quite satisfactory, and the low unit production cost of electricity and freshwater make it competitive to eradicate energy and freshwater crises. [ABSTRACT FROM AUTHOR]

Abstract Fuel cells and solar energy are promising candidates for electricity generation. It is forecast that fuel cells and solar power systems will play an important role in reducing the greenhouse gas footprint and replacing fossil fuels. Therefore, the limitations of fuel cells and solar power systems, such as low efficiency, high cost, and low reliability, must be addressed appropriately to enable their full potentials. Metal foam is a new class of material that has gained immense attention due to its excellent properties suitable for a wide range of applications. Its unique characteristics distinguish it from typical solid metals. The properties of metal foam can be modified during the fabrication stage by manipulating its physical structure. The goal of this paper is to review the application of metal foam in fuel cells and solar power systems. Besides, the performance of metal foam in fuel cells and solar systems is also discussed. Metal foam has been applied to the electrodes, gas diffusion layer and flow field of fuel cells to enhance performance, especially in regard to current density and flow distribution. Furthermore, metal foam is a heat exchanger for the solar energy harvesting system to improve its efficiency. Superior performances in experimental testing allows the possibility of commercialization of metal foam products in the renewable energy field. Highlights • This article reviews the past research on metal foam in fuel cell and solar power systems. • Metal foam applications on bipolar plates, electrodes and the gas diffusion layer in a fuel cell. • Metal foam as a thermal management system in solar power systems. • Barriers and future perspectives of metal foam applications in fuel cells and solar power systems. [ABSTRACT FROM AUTHOR]

Abstract Compared with wind and solar power, biomass power has grown relatively slowly in China. With abundant biomass resources, the development of biomass electric power in China has potential advantages. This paper analyzed the environmental impact of biomass power in the construction and operation stages in comparison with wind and solar power. The results showed that biomass power produced relatively less emissions in the system construction stage at around 1700 ton CO 2 -e/MW. In the operation stage, biomass power projects achieved an average of 131462 ton CO 2 -e per year, which is greater than wind and solar power of equal installed capacity. Biomass power plants could achieve net emission reductions in a shorter time (0.39 year) after operation. The life cycle GHG emissions of biomass power projects are between 42 and 85 g CO 2 -e/kWh. The evidence pointed out that biomass power is worth supporting in China, from the perspective of environmental performance. Local governments should promote the sustainable supply of biomass materials and the development of renewable energy industry should depend on local conditions. Highlights • The unit emissions of biomass power from construction is around 1700 ton CO2-e/MW. • Biomass power projects achieved net emission reductions less than half year. • The life cycle GHG emission of biomass power projects are between 42 and 85 g CO2-e/kWh. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Use of solar chimney can reduce the semi-transparent PV temperature by up to 38 °C. • Use of solar chimney results enhances the PV generated power by around 30%. • There is an optimum packing factor that maximizes the power generation. • There is an optimal chimney height at which the best cooling effect is achieved. Abstract Semi-transparent photovoltaic (STPV) system’s performance strongly depends on its surface temperature. To provide a mechanism that decrease the temperature of STPV can improve the power generation significantly. This cooling mechanism will be more interesting if it needs no additional energy. In this paper a novel solar chimney system is proposed to cool a STPV system. The STPV is employed as a roof for the solar chimney and an air flow generated by the solar chimney cools the STPV. Based on the energy balance for three main components: STPV, air and ground, a theoretical model is developed for the proposed system. Convection heat transfer coefficients are calculated precisely for the heat transfers taking place in the system and the obtained results for the solar chimney are compared with the existing experimental data in literature. Results of proposed model have a good agreement with the previous data. It’s shown that there is an optimum packing factor that maximizes the generated power for each radiation intensity. It is observed that the proposed system effectiveness depends on the radiation intensity as well as on the structural parameters. The proposed system can reduce the average temperature of the STPV up to 15 °C. It is concluded that, by cooling the STPV power plant with the solar chimney for a solar radiation of 500 W/m2, an enhancement of about 29% in power generation is gained. [ABSTRACT FROM AUTHOR]

As Iran is rich in oil and gas resources, renewable energy was known as a luxurious source of electric power generation for a long time. New policies and targeted subsidy reform plan for fossil fuel products have changed the view of decision-makers and energy sector investors toward renewable energy resources. According to the climatological studies, two-thirds of Iran's land has three hundred sunny days which indicates great potentials for providing solar energy. This paper deals with small-scale solar energy potentials in different cities of Iran. The considered solar systems are based on the combination of photovoltaic panels in order to obtain the nominal values of 1, 5 and 10 kW for 15 selected cities of Iran. Design of the photovoltaic (PV) systems is carried out based on optimum fixed tilt angles of the panels and efficiency variation due to the temperature changes of different locations. The final decision on financial assessment of the mentioned solar PV projects is based on different concepts of engineering economy such as rate of return (ROR), present worth of benefit and cost (PWB, PWC), extra investment analysis, levelized cost of energy (LCOE). The amount of calculated income and the expected benefit are also investigated under certainty and uncertainty of guaranteed solar electricity purchase tariff in a 30-year project lifetime. [ABSTRACT FROM AUTHOR]

This paper investigates a novel solar driven multi-stage flash (MSF) desalination plant in UAE. UAE achieved major progress in utilizing solar energy for power production. The desalination plant simulated in this work investigates the use of parabolic trough collectors (PTC) and a solar pond to completely satisfy the energy requirements for a multistage flash desalination. The plant is designed to be located in Sharjah, UAE; a region that receives a high level of solar radiation. The process was equipped with a fire tube boiler to satisfy energy requirements when the sunlight is not available. Aspen HYSYS V8.8 simulation software was used to conduct this study. The objective was to satisfy the water demand for a small community with a total population of around five thousand. The simulation aimed at producing 1880 m 3 /day of desalinated water, out of 40,000 m 3 /day of seawater processed. The results showed that two PTCs of a total aperture area of 3160 m 2 can provide about 76% of the MSF energy requirements. The remaining part is provided by a solar pond of 4 meter depth and a surface area of 0.53 km 2 . [ABSTRACT FROM AUTHOR]

The objective of this paper is to investigate the effect of simultaneous using of nanofluid and selective absorber on the improvement of work extraction by a solar flat-plate collector (FPC). Applying a precise model for the exergy factor of solar incident, it is found that the maximum power generation is higher and lower than that by the Petela-Landesberg-Press (PLP) and Carnot model, respectively. Results showed that the influence of temperature ratio ( a ) and geometry factor ( f ) on the exergy efficiency is not such significant when a FPC is working on the Earth's surface. It is also revealed that the key role of the ratio of the absorber plate's emittance to its absorptance must be given attention since only the values lower than 0.174 are allowed by the second law requirements. Furthermore, the exergy efficiency and energy efficiency would experience 10.5% and near 8% enhancement for a 7.5% increase in collector's optical efficiency. Boosting the exergy efficiency by almost 4.1% at 4% volume concentration, demonstrated that nanofluid exploitation instead of plain water would be capable of improving the power generation by the collector. [ABSTRACT FROM AUTHOR]

Highlights • A novel procedure (PCT) is proposed to reconfigure partially shaded PV arrays. • The proposed procedure finds both optimal reconfiguration and absolute MPP. • This procedure is based on removal of right-hand local peaks of MPP using PCI index. • Due to removal of right-hand peaks of absolute MPP, it is impossible to fall in local MPPs. • This procedure is simple and easy-to-implement. Abstract This paper presents a new reconfiguration procedure, named power comparison technique (PCT), to extract maximum power from photovoltaic arrays. PCT introduces optimum configuration and maximum power point (MPP) of photovoltaic arrays in partial shading conditions. PCT finds absolute MPP and its corresponding configuration via comparing whole peaks of power-voltage (P-V) curve of a photovoltaic (PV) array. This will ensure that the right-hand peaks of absolute MPP have been removed. This logic comes to help algorithm of MPP tracking to identify the absolute peak. This approach is applicable for any topology of PV arrays (series-parallel and total-cross-tied, here). Simulations show better (or at least equal) reconfiguration results by the proposed method in comparison to the previous works reviewed. Results represent about 8% increase in mean output power based on the studied cases. [ABSTRACT FROM AUTHOR]

Utilizing the dissipated thermal energy by photovoltaic cells working as the heat source of thermoelectric module to generate extra electricity is an optional way to further improve the photoelectric conversion efficiency of concentrating photovoltaic system. However, there exists a confrontation between the efficiency temperature characteristics of the photovoltaic cell and the thermoelectric module. The photovoltaic efficiency decreases with the rise of its temperature while the thermoelectric efficiency increases with its temperature difference augmenting, which makes the design of the concentrating photovoltaic-thermoelectric hybrid system crucial. In this paper, the selection principle of the coupling devices and a novel optimal design method for the concentrating photovoltaic-thermoelectric coupling system are proposed. The minimum figure of merit of the thermoelectric generator that enables the efficiency of the concentrating photovoltaic-thermoelectric hybrid system to be larger than that of the concentrating photovoltaic system is calculated and regarded as the reference of evaluating the feasibility and selecting the coupling devices. For the optimal designs, the temperature distribution where the concentrating photovoltaic-thermoelectric hybrid system has the highest electric efficiency is firstly calculated. Then, the optimum thermal resistance of the thermoelectric generator, which keeps the photovoltaic-thermoelectric hybrid system operating at the optimal temperature distribution, is calculated. Once the thermoelectric thermal resistance is obtained, the optimal structure of the thermoelectric generator can be determined. The effects of reference efficiency, the efficiency temperature coefficient of the photovoltaic cell, the figure of merit of the thermoelectric module and the convective heat transfer coefficient of the cooling system on optimal designs of the concentrating photovoltaic-thermoelectric hybrid system are also discussed. [ABSTRACT FROM AUTHOR]

Flexible District Energy plants providing heating and cooling to cities have an important role in the transition to a renewable energy system. They may become major actors in integrating wind and solar power, when equipped with a combination of combined heat and power units, heat consuming absorption chillers, heat pumps producing both heating and cooling and large thermal energy stores. However, often electricity prices do not create sufficient feasibility for these to be installed thus calling for support schemes. The societal resources dedicated to support should be minimised while ensuring the establishment of an adequate amount and right ratio between these units. This paper presents a method for determining the capacities different support schemes will promote as a function of dedicated resources. The method is used in a comparison of two support schemes promoting combined heat and power; a premium on top of hourly wholesale electricity prices and a fixed Feed in Tariff. The comparison shows that the premium scheme requires a little less total support than the Feed In Tariff scheme for promoting a given amount of electrical capacity, but promotes a five-times larger thermal energy store capacity, thereby promoting substantially increased flexibility for integrating intermittent power production. [ABSTRACT FROM AUTHOR]

Multi-criteria decision making (MCDM) methods are becoming increasingly popular in solving energy selection problems because these problems involve multiple and often conflicting criteria. This paper presents comparative analysis of ranking renewable energy sources (RES) for electricity generation in Taiwan using four MCDM methods - WSM, VIKOR, TOPSIS, and ELECTRE. The Shannon entropy weight method is used to assess the importance of each criterion for the ranking of RES. After that, four MCDM methods are utilized for quantitative evaluation to rank all available RE alternatives. From the weights estimation results, efficiency is the first priority in all evaluation criteria, followed by job creation, operation, and maintenance cost. The purpose of this study is to rank the priorities of various RES and propose recommendations for Taiwan's RE development. The ranking results show that hydro is the best alternative in Taiwan, followed by solar, wind, biomass and geothermal. Furthermore, sensitivity analysis of the weights was conducted considering the ranking results heavily depend on the criteria weight. The results of sensitivity analysis indicated that when financial or technical aspects are focused upon, hydropower is the best RES because its technology is the most mature and the cost is the lowest in Taiwan. In addition, from an environmental perspective, wind energy is the best choice, and from the social perspective, solar PV is the best choice. The findings of this study can provide useful information to energy decision makers and serve as a reference for Taiwan's energy policy. [ABSTRACT FROM AUTHOR]

In present day scenario, the focus is reallocating towards integration of small and medium scale power plants based on renewable energy sources into the power distribution system. Solar is the fastest growing form of renewable energy and a single phase voltage source inverter is used to interface photovoltaic based plants with the distribution system. The grid integrated inverter has stringent control requirements. A current controller is employed to mitigate the harmonics in the current injected into the grid and regulate the power exchange between the plant and the grid. This paper presents a review of the current control strategies implemented for a single phase grid tied photovoltaic inverter. A comparative performance evaluation of the current control techniques is also presented through simulation and experimental results. [ABSTRACT FROM AUTHOR]

Highlights • Grasshopper optimization algorithm (GOA) is applied to reconfigure the partially shaded PV array optimally. • Proposed objective function representing the sum of raw powers is presented. • Four different shadow patterns are studied and comparison with TCT, Su Do Ku and GA configuration are done. • The obtained results confirm the superiority of the proposed GOA. Abstract When solar radiation striking the PV modules inserted in PV array is non-homogeneous; then the partial shading operation is taken place. This phenomenon has negative effects on the efficiency of the PV array as the generated power is reduced, hot spots are generated; one solution to get rid of these negatives is the reconfiguration of modules such that distributing the solar radiation in regular form as much as possible. Therefore, this paper proposed a new methodology based on recent meta-heuristic optimization algorithm named grasshopper to be applicable in solving the reconfiguration process of the partially shaded PV array optimally. The main purpose of such action is to maximize the power extracted from the array via proposed objective function presented in this work. The PV array arrangement obtained via the proposed approach incorporated recent meta-heuristic grasshopper optimization algorithm (GOA) is compared with those obtained via total cross tied connection (TCT), Su Do Ku connection and genetic algorithm (GA) configuration. Additionally, different shadow patterns during a day are studied and reconfiguration arrangement is obtained at each hour. The obtained results confirm the reliability and the efficiency of the proposed GOA in evaluating the global maximum power point (GMPP) extracted from the partially shaded PV array. [ABSTRACT FROM AUTHOR]

Highlights • A probabilistic PV forecast model tailored for EMS applications is presented. • The model showed its capability to forecast using only the commonly available data in buildings. • Different evaluation metrics were used to validate the reliability and accuracy of the model. Abstract The photovoltaic (PV) generation forecast is a key element to an efficient building energy management system (EMS) operation. The forecast’s uncertainties and generation variabilities expose the loads to misplanning, and hence decrease building autonomy, self-sufficiency, and potential costs savings. In this paper, a novel approach for a day-ahead PV power generation probabilistic forecast is proposed that is especially optimized for building EMS applications. The model consists of several modules to develop the probabilistic forecast. Initially, a clear sky model is tuned to incorporate the system and temperature losses and partial shading. The deviation of the PV power from the clear sky power is used to train a bagging regression tree, which produces a deterministic point forecast. The probabilistic forecast is developed based on the probabilistic analysis of the point forecast and regenerating it based on the given weather conditions. The model is developed based on the available data in buildings such as the historic PV measurements acquired from the inverter and the weather forecasts. The probabilistic forecast was validated over a complete-year data set of a rooftop PV system in Munich, Germany, where the results showed its capability to provide an accurate and reliable forecast for EMS applications. [ABSTRACT FROM AUTHOR]

Highlights • A guide is proposed to design and verify a reliability of the MPPT algorithm. • The verification is in accordance with the automotive development process standards. • A modified Perturb and Observe MPPT method is appliedand its optimized C-code is tested. • A low cost solution for the hardware implementation of the controller is proposed. • A good performance in term of tracking factor and speed. • A compliance during the verification steps MIL, SIL and PIL. Abstract This paper presents the design and verification process of the Maximum Power Point Tracking Controller in accordance with the automotive development process standards, which could be used in Photovoltaic charging stations or in on-board chargers of electric vehicles. Considered as an automotive embedded software, the designed MPPT controller follows a sequence of three tests of the Model-based design MBD Approach to be verified and validated. The ultimate aim is to present a road map to design, test and validate an embedded software of the MPPT algorithm in vehicle based software. We design a modified Perturb and Observe P&O algorithm, then we generate optimized C code for a 32 bit ARM cortex microcontroller. Next, the algorithm is simulated through Model-in-the loop MIL, Software-in-the loop SIL, and finally co-simulated through Processor-in-the-loop PIL technique in the low cost STM32F429 discovery development board. During all the different tests, the designed embedded software shows a high accordance with MPPT requirement and high performances. [ABSTRACT FROM AUTHOR]