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Summary: Nowadays, microgrids are emerging as an invaluable framework for the integration of renewable energy sources and demand response programs. In such systems, energy storage facilities are also frequently deployed to properly manage surplus energy from renewable sources on pursuing more efficient management of the system. Hybrid storage systems in which various storage facilities are combined may result in a more effective solution than only considering one storage technology. This way, the good features of the different technologies may be jointly exploited while their drawbacks are minimized. Due to the large‐scale integration of renewable energies in this kind of grid, coping with uncertainties becomes a critical issue. Moreover, the operation of microgrids frequently deals with other kinds of uncertainties related to energy pricing from the upscale grid (in the case of grid‐connected mode) or local demand. This way, proper modeling of uncertainties is essential for adequately operating these systems. This paper contributes to this pool by developing a novel interval‐based formulation, for optimal scheduling of microgrids considering battery and pumped‐hydro storage systems. To achieve this goal, the optimal scheduling of a microgrid with pumped‐hydro and battery energy storage considering demand response is modeled, firstly. Then, the new interval‐based formulation is used to cope with the uncertainties. Finally, the suggested model is verified using simulations in various cases, and the results confirm the effectiveness of the novel interval‐based formulation for the optimal scheduling of microgrid with pumped‐hydro and battery energy storage under uncertainty. [ABSTRACT FROM AUTHOR]

Summary: This paper is concerned with innovative approaches to renewable energy sources computation methodologies, which provide more refined results than the classical alternatives. Such refinements provide additional improvements especially for replacement of fossil energy usages that emit greenhouse gas (GHG) into the atmosphere leading to climate change impact. Current knowledge gap among each renewable energy source calculation is rather missing fundamentals of plausible, rational, and logical explanations for the interpretation of results. In the literature, there are rather complicated and mechanically applicable methodologies, which require input and output measurement data match with missing physical explanations. The view taken in this review paper is to concentrate on quite plausible, logical, rational, and effectively applicable innovative energy calculation methodologies with simplistic fundamentals. For this purpose, a set of renewable energy methodological approaches is revisited with their innovative structures concerning solar, wind, hydro, current, and geothermal energy resources. With the increase in the renewable energy utilizations to combat the undesirable impacts of global warming and climate change, there is a need for better models that will include physical environmental conditions and data properties in the probabilistic, statistical, stochastic, logical, and rational senses leading to refined and more reliable estimations with application examples in the text. Finally, new research directions are also recommended for more refined innovative energy system calculations. [ABSTRACT FROM AUTHOR]

Summary: Increased green energy presence in distribution power networks can resolve rising energy demands while also reducing fossil fuel consumption, as well as providing economic and technical merits. However, the quantity of power delivered to customers cannot be allowed to take precedence over the quality of that electricity. This is because the high penetration of the renewable‐based power generation comes at the cost of power quality (PQ) deterioration, especially at the point of common coupling (PCC), owing to nonlinear characteristics of renewable‐based distributed generation (DG) systems and pre‐contamination of modern distribution grids. So, the function of PQ improvement technologies unavoidably comes into the picture when the hosting capacity (HC) of renewable energy systems is constrained by any of the grid PQ performance indices. This paper investigates the application of a hybrid active power filter (HAPF) to improve the harmonic‐constrained HC (HC‐HC) of renewable DG systems in harmonically polluted distribution systems. A shunt type HAPF designing to achieve maximum HC‐HC is considered as an optimization problem and solved by the firefly algorithm under several constraints the system particularly related to individual and total harmonic distortion limits in line current and voltage at PCC, harmonic currents overloading of distribution feeder. Aside from harmonics, constraints related to voltage rise and drop limits, as well as power factor, are also taken into account to ensure the optimal use of the HAPF as a compensator. The proposed HAPF‐based HC‐HC improvement approach's findings and efficacy are compared to those acquired from one of the literature's recently proposed techniques. Besides, the study is extended for HC‐HC enhancement by HAPF, under changing the utility‐side's background voltage distortion and the load‐side's nonlinearity level conditions. The performed extended investigation of the system shows that HC‐HC enhancing the effectiveness of the proposed approach is rather less susceptible to utility or customer side contribution to background distortion at the PCC. Highlights: Hybrid harmonic filtering is investigated for enhancing the harmonic‐constrained hosting capacity of distributed generation in distorted grid conditions.A hybrid filter has been found as a better alternative to achieve an advanced level of renewable energy penetration in distorted distribution grids.Along with increasing the penetration level of distributed generation the harmonic distortion is also substantially reduced instead of being at the verge of the standard limit.With the increase in background voltage distortion, the percentage enhancement in HC‐HC degrades.High load‐side's nonlinearity also results in a relatively lower enhancement in HC‐HC.Background nonlinearity negatively influences the percentage of HC enhancement more than the load‐side's nonlinearity.Though the utility, as well as customer‐side nonlinearity, affect the performance of the hybrid filter also yet the variation is significantly lesser than the purely passive filtering‐based approach. [ABSTRACT FROM AUTHOR]

Summary: Growth in global energy demand, with major fossil fuel consumption, has induced detrimental environmental and social impacts. Therefore, in recent years, technologies focused on renewable energy utilization, including biomass energy, have evolved to meet the energy requirements. Bioenergy‐based power generation systems are among the best‐unutilized configurations to diminish reliance on fossil fuels. However, it is difficult to select a biomass‐based configuration for economical, sustainable, and reliable power generation. Understanding different possible configurations of biomass‐based energy systems, design parameters, system research gaps, and integration challenges in biomass‐based energy systems are important for further development and propagation. This paper presents a critical review of biomass‐based different hybrid configurations with solar, wind, fuel cell, micro‐hydro, geothermal, and diesel generator, and various designing parameters, challenges, and gaps with future scope. To restrict the scope of the review, only the gasification and anaerobic digestion related biomass electricity generation systems are considered. The analysis indicates that the biomass‐based hybrid energy systems can provide an eco‐friendly and cost‐effective solution, especially for off‐grid rural electrification. The solar radiation, load demand, fuel price, capacity shortage, interest rate, wind speed, biomass quantity, and electricity rate are among the most critical designing parameters in biomass‐based energy systems. The study provides valuable information to designers, researchers, and policy makers on the latest design constraints and relevant policies relating to biomass‐based hybrid energy systems. [ABSTRACT FROM AUTHOR]

Summary: In this paper, a novel system to enhance the performance of a solar‐driven finite speed alpha‐type Stirling engine is proposed and evaluated. Part of the concentrated solar energy is used to drive an ejector refrigeration system. The cooling produced in the ejector cooling cycle is used to cool the Stirling engine to enhance its efficiency. Model equations to describe the systems are proposed and solved numerically. The results indicate that the new system produces averagely 3.3 times electrical power more than the conventional one. Moreover, the proposed system improves the Stirling engine efficiency by up to 46% in comparison with 19.15% for the conventional Stirling engine under solar radiation intensity of (1 kW/m2). Also, the results showed that the solar radiation intensity and wind speed are the most influential parameters that affect the proposed system efficiency. The new system is recommended to use in desert climates where high average daily solar radiation intensity, low wind speeds, and water shortage exist. Economic analysis is carried out to determine the feasibility of the proposed system under different economic parameters. It is found that, for instance, the simple payback period is 4.64 years for the new system when the selling price of electricity is 0.35 $/kWh. [ABSTRACT FROM AUTHOR]

Summary: Wind energy conversion system, aiming to convert mechanical energy of air flow into electrical energy has been widely concerned in recent decades. According to the installation sites, the wind energy conversion system can be divided into land‐based wind conversion system and offshore wind energy conversion (OWEC) system. Compared to land‐based wind energy technology, although OWEC started later, it has attracted more attentions due to its significant advantages in sufficient wind energy, low wind shear, high power output and low land occupancy rate. In this paper, the principle of wind energy conversion and the development status of offshore wind power in the world are briefly introduced at first. And then, the advantages and disadvantages of several offshore wind energy device (OWED), such as horizontal axis OWED, vertical axis OWED and cross axis OWED are compared. Subsequently, several major constraints, such as complex marine environment, deep‐sea power transmission and expensive cost of equipment installation faced by offshore wind conversion technology are presented and comprehensively analysed. Finally, based on the summary and analysis of some emerging technologies and the current situation of offshore wind energy utilization, the development trend of offshore wind power is envisioned. In the future, it is expected to witness multi‐energy complementary, key component optimization and intelligent control strategy for smooth energy generation of offshore wind power systems. [ABSTRACT FROM AUTHOR]

Summary: In today's world striving for efficiency in every sector, especially power generation and distribution, smart grids emerge as the solution for efficiently meeting the increasing demand. They adjust themselves to optimally deliver energy at the lowest cost and highest quality possible. The grid successfully makes use of renewable energy resources, electric vehicles, and smart pricing techniques in its attempt to achieve energy efficiency. It also promotes a greener environment by striving to reduce greenhouse gas emissions. Information communication technology (ICT) helps the grid in collecting consumption data from the consumers and in sharing tariff information. ICT also helps to gather information about the status of the grid with regard to aspects like power quality, faults etc. The purpose of this paper is to review recent literature with a view to comprehensively present the technologies employed in the smart grid for achieving energy efficiency and the challenges involved therein. [ABSTRACT FROM AUTHOR]

Summary: Delhi has been experiencing a dramatic surge in pollution levels, especially in the past decade. Renewable energy sources emit negligible carbon pollutants compared to conventional energy sources. However, they are fundamentally intermittent, necessitating a robust storage system. In recent times, hybrid systems have proven to be breakthrough solutions for mitigating electrical energy shortages while also enhancing overall system dependability. This study focuses on hydrogen energy storage which can help overcome variable output power issues for an electric vehicle charging station in Karampura, Delhi. The framework is proposed for three vehicles charging simultaneously, all the while at the charging station, with normal energy utilization of 2100 kWh/day. The most optimum system is found by simulating results from three different combinations (namely photovoltaic [PV]‐Hydrogen, Wind‐Hydrogen, and PV‐Wind‐Hydrogen) using HOMER software. The Levelized cost for the Hybrid combination is most viable, whereas the Wind system costs 7.19% more and the PV combination costs 12.12% higher. In a similar manner, the net present cost (NPC) of a solar PV system and a wind turbine system is $1.80 million and $1.63 million, respectively, whereas the NPC of a hybrid system is $1.52 million. The cost of operating a PV solar system is $79 767, a wind turbine system is $46 078, and a hybrid system is $35 926. These findings suggest that a hydrogen‐based hybrid renewable energy system is an economically feasible combination. [ABSTRACT FROM AUTHOR]

Summary: The EU countries are facing a burning debate with regard to the nature and amount of decarbonized energy used within the supply mix. This study highlights the role of nuclear power and renewable energy use in achieving economic growth in Europe. Capital, labour, exports, and trade openness series are included within a multivariate framework spanning the 1986 to 2019 period and a two‐step methodology is implemented. First, a panel causality analysis over the top 10 nuclear energy‐consuming EU countries is conducted using the panel non‐causality test from Juodis, Karavias and Sarafidis (2021), robust under large cross‐sectional and time‐series dimensions, as well as heterogeneous coefficients. Second, a sub‐set of three states (Germany, Spain, and France) that are different in terms of long‐run nuclear energy policies is selected and a single‐country time‐series assessment is performed using the vector error correction model, causality tests, as well as impulse response functions. Panel EU results support the "conservation hypothesis" for both nuclear and renewable resources, without feedback effect. The country‐level estimates fail to provide homogeneous results since no causal link is found between economic growth and renewable energy use for Spain and France (confirmation of "neutral hypothesis"). A weak causality from renewable energy use to output growth is observed for Germany, while economic growth enhances the nuclear energy consumption in Spain. [ABSTRACT FROM AUTHOR]

Summary: The aim of the work is the analysis of a novel integrated energy system for small‐scale combined heat and power (CHP) generation. The system consists of a topping biodiesel‐fired internal combustion engine (ICE) and a bottoming transcritical organic Rankine cycle (TORC) for waste‐heat recovery. Specifically, the engine exhaust gas provides energy to the TORC sub‐system, while the energy contribution of the ICE cooling circuit assures low‐temperature heat generation. Furthermore, a thermal energy storage (TES) unit for the exploitation of the thermal surplus and an auxiliary boiler are present. A mathematical model is developed to evaluate the main performances at full and partial load in terms of thermal and electric production, efficiency, fuel consumption, and primary energy saving. A preliminary analysis is carried out to find the proper organic working fluid for the TORC sub‐system. Afterwards, the biodiesel ICE‐TORC combined system is adopted to satisfy thermal and electric requests of a commercial centre. To this purpose, hourly energy balances are evaluated, and a techno‐economic analysis is performed on an annual basis. The investigated system guarantees a 16.7% primary energy saving and an 8.4 years payback time. [ABSTRACT FROM AUTHOR]

Summary: The urge for Electrical Power is escalating regularly at an increased rate due to the internationalization and progression of civilization. However, proper economic consumption of additional energy produced from the Islanded Hybrid Microgrid System (IHMS) that has not been consumed by the load is a major challenge globally. To overcome the above mentioned summon, this research focuses on a multi‐optimal combination of stand‐alone IHMS for Tioman Motel located at Tioman Island, Malaysia with an efficient exertion of redundant energy. To avail of this excess energy efficiently, an electrical heater along with a storage tank has been designed concerning diversion load having proper energy management. Furthermore, the system design has adopted the improved hybrid optimization by genetic algorithms (IHOGA) software for profitable and practical analysis of the designated configuration. Moreover, the optimal size of every module has been tested and analyzed through MATLAB Simulink and stabilized the whole system by representing the values of 1297 and 15 096 kW have been determined as the approximated peak and average load per day for the Motel, respectively. Moreover, the optimized IHMS is comprehended of Photovoltaic (PV) cells, Diesel Generator, Wind Turbine, Battery, and Converter. Adjacent to this, the optimized system ensued in having a net present cost (NPC) of $19.77 million, Renewable Fraction (RF) of 23%, cost of energy (COE) of $0.175/kWh, CO2 of 1 726 825 kg/year and excess energy of 532.26MWh per annum. Whereas, the system involved with the diesel generator lead a COE of $0.315/kWh, CO2 of 6 213 353 kg/year and NPC of $22.12 million. Additionally, this design alone with diesel generator has a higher CO2 emission rate, COE and NPC compared to optimized IHMS. On the other hand, the amount of excess energy is effectively utilized with an electrical heater as a diversion load. [ABSTRACT FROM AUTHOR]

The renewable energy hybrid generation system in the area with renewable energy and land source plays a key role in improving the application of the renewable energy in China, with the rapid development of the extra high voltage (EHV) and ultra‐high voltage (UHV) grids to transmit the electricity. The suitable plan and decision‐making mechanism has a significant influence on the utilization of the renewable energy. The output of thermal power, wind power and photovoltaic are respectively simulated in the plan period of a hybrid generation system, and then all the output are comprehensively studied with the consideration of some constrains. However, the experience of the applications of the renewable energy hybrid generation system with thermal power revealed an obvious disadvantage that to maintain the competitiveness of the power output without the guidance of the price signals in the electricity market is difficult. The dispersed areal distribution and discontinuous power output of the renewable energy may be responsible for this disadvantage. The investigation to improve the consumption of the renewable energy hybrid generation system is meaningful to solve the renewable energy curtailment problems. In the present study, the investigation to the operation of a thermal‐wind‐photovoltaic hybrid generation system with market mechanism was conducted to optimize the consumption of the renewable energy. These results are beneficial to the operations of the similar hybrid generation systems. [ABSTRACT FROM AUTHOR]

Summary: A renewable energy based integrated system is developed to meet the total energy demands of a house located off‐grid, and a thermodynamic analysis through energy and exergy methodologies is conducted for analysis, evaluation, and performance assessment. The present novel multigeneration system is mainly driven through the animal residues produced at the farm house. The proposed novel system is composed of nine main units namely, a biomass combustor, photovoltaic (PV) panels, parabolic solar trough collectors, thermoelectric generators, organic Rankine cycle, electrolyzer, homogeneous charged compression ignition (HCCI) engine, absorption chiller, and reverse osmosis (RO) unit. Biomass combustor runs an organic Rankine turbine for additional power during peak loads. The exhaust of gas turbine generates cooling to meet the cooling demand of the residential area of the farm house. PV panels are incorporated to generate hydrogen through electrolyzer. A HCCI engine generates power to compensate peak load as well as charging the farming vehicles of the farm house. The RO unit with energy recovery Pelton turbine produces fresh water for farming and residential use. The advanced integration of subsystems, thermoelectric generators and efficient utilization of waste, improves significant amount of energetic and exergetic efficiencies of overall multigenerational system. The energy and exergy efficiencies are enhanced in the order of 4.8% and 6.3%, respectively, after incorporating innovative cooling system to the PV modules. The overall energy and exergy efficiencies of the proposed multigeneration system with and without thermoelectric are found to be 67.6% and 57.1%, and 68.9% and 58.4%, respectively. [ABSTRACT FROM AUTHOR]

SUMMARY This article develops the concept of renewable-energy-based multigeneration options for producing a number of outputs, such as power, heat, hot water, cooling, hydrogen, fresh water, and so forth; and discusses their benefits. Such multigeneration options obviously lead to improved system performance and reduced environmental impacts. First, single-generation (power generation only) and cogeneration systems are compared with respect to the energy utilization efficiency, exergy efficiency, green house gases (GHG) mitigation, and payback period. It is found that the cogeneration increases GHG mitigation about 2 to 4 times, whereas the payback time decreases about 2.8 times with respect to the single-generation case. Exergy efficiency is found to be between about 55% and 65%, depending on the degree of cogeneration. The exergy efficiency shows the maximum values for certain source temperatures. For the case studied here, the optimum source temperature is taken as 200°C for analysis purposes. The results show that multigeneration of energy systems helps increase both energy and exergy efficiencies, reduce cost and environmental impact, and increase sustainability. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]