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Integrated polygeneration systems have emerged as an effective and sustainable solution for maximizing the utilization of renewable fuels, and offer multiple economic and environmental advantages. This work proposes a new polygeneration system to produce hydrogen, heat, and power based on integrating biomass gasification, solid oxide fuel cell, gas turbine, organic Rankine cycle, and supercritical CO 2 Brayton cycle. The proposed system is simulated in Aspen Plus, and the performance is evaluated based on energy, exergy, economic, and emergy analyses. The overall energy and exergy efficiencies attain 76.82% and 60.64%, respectively. The levelized cost of hydrogen is 4.06 $/kg, comparable to those reported in the literature, and the yearly income generated through revenue sales of hydrogen, heat, and electricity can reach up to 58.42 M$. The emergy analysis showed that the system depends on purchased inputs but can efficiently use the available resources to generate valuable products. The hybrid system has low environmental impacts in the long term. It can serve as a low-cost, low-carbon, and profitable polygeneration system of hydrogen, heat, and power, with a good quality of energy conversion. • A conceptual system is proposed to produce hydrogen, heat, and power and evaluated. • The biomass gasification, SOFC, gas turbine, ORC, and supercritical CO 2 Brayton cycle are integrated. • The emergy analysis is performed to assess the system's sustainability and environmental effect. • The influence of multiple parameters on the performance of the system is clarified. • The system's overall exergy efficiency is 60.87%, and the levelized cost of hydrogen is 4.06 $/kg. [ABSTRACT FROM AUTHOR]

A solid oxide fuel cell (SOFC) hybrid system with an inter-cooled-recuperated gas turbine(ICRGT) and organic Rankine cycle (ORC) was designed to address exergy destruction in the burner of a conventional SOFC and gas turbine (GT) system. In unfired mode of this system, SOFC acts as the GT heater and reheater instead of burners; burners are used only to aid load regulation in fired mode. In unfired mode, the system electrical efficiency is 69.86 % and the overall efficiency is 82.22 %. The total exergy destruction of the system is 21.93 % lower than that in fired mode by exergy analysis, which indicates the effectiveness of reducing afterburner exergy destruction, and the superior energy efficiency of this mode. For the design analysis, we analyzed the influence of different factors on the system, including the number of SOFC modules, turbine outlet temperature, burner exhaust into the turbine, oxidant utilization of SOFC cathode(OUC), and fuel utilization of SOFC anode(FUA) on the system. For the sensitivity analysis, we determined the variation rules of the components and system parameters for fuel proportions of 70–105 %. This work provides a reference for optimizing the design and operation of SOFC-GT and other SOFC hybrid systems. • An SOFC-ICRGT-ORC system is designed with an electrical efficiency of 69.86 %. • Multistage SOFC modules are proposed to reduce exergy destruction by 21.93 %. • Intercooling and regenerative cycle ensures high efficiency of partial-fuel condition. • Energy utilization is improved by deep coupling of ORC, SOFC, and ICRGT system. [ABSTRACT FROM AUTHOR]

In this paper, an integrated liquefied natural gas (LNG) production process, carbon dioxide separation and liquefaction, and fresh water production is proposed and analyzed. The hybrid system consists of three sections: power and heat generation by the process of combustion with pure oxygen, natural gas liquefaction with a two-stage refrigeration cycle (absorption refrigeration cycle and multi-component refrigerant), and multiple-effect distillation (MED) desalination. This integrated process produce 593.3 ton/h LNG, 84.62 ton/h carbon dioxide, and 74.58 ton/h fresh water. Exergy analysis shows that the highest exergy destruction is related to the shell and tube heat exchangers, which is about 38.8% and the lowest exergy destruction is related to the air coolers, 0.84%. Integrated process has an overall electrical efficiency (LHV Base) of 36.3%, a specific power of 0.179 kWh/kg LNG. Also the amount of energy consumed for producing carbon dioxide is 0.005 kWh/kg CO 2 , and gained output ratio (GOR) of 2.87 is achieved by three-stage MED desalination. A sensitivity analysis is done to investigate and identify the important parameters affecting the integrated process performance. [ABSTRACT FROM AUTHOR]

The performance of a solid oxide fuel cell (SOFC) is subject to inherent uncertainty in operational and geometrical parameters, which can cause performance variability and affect system reliability. Operating conditions such as current demand, cell temperature and fuel utilization play an important role on the degradation mechanisms, which affect typical SOFCs. In previous work, a deterministic empirical degradation model of a SOFC was developed as a function of such operating conditions. By the nature of experimental data and regression fitting, this model was not deterministic. The aim of this work is to evaluate the impact of the uncertainties in the degradation model through a stochastic analysis. In particular, the Response Sensitivity Analysis (RSA), an approximate stochastic method based on Taylor series expansion, is applied to a standalone SOFC model and a fuel cell hybrid system model both subjected to cell degradation. The attention is principally focused on the impact on the fuel cell lifetime. To provide an indication of degradation effect and resulting lifetime uncertainty on economic performance, a cursory economic analysis is performed. [ABSTRACT FROM AUTHOR]

Distributed energy resources DERs are small scale energy system which could provide local supply when placed at customers' premises. They aggregate multiple local and diffuse production installations, consumer facilities, storage facilities and monitoring tools and demand management. The main challenges when assessing the performance of an off-grid hybrid micro-grid system HMGS are the reliability of the system, the cost of electricity production and the operation environmental impact. Hence the tradeoff between three conflicting objectives makes the design of an optimal HMGS seen as a multi-objective optimization task. In this paper, we consider the optimization and the assessment of a HMGS in different Swedish cities to point out the potential of each location for HMGS investment. The HMGS consists of photovoltaic panels, wind turbines, diesel generator and battery storage. The HMGS model was simulated under one-year weather conditions data. A multi objective particle swarm optimization is used to find the optimal system configuration and the optimal component size for each location. An energy management system is applied to manage the operation of the different component of the system when feeding the load. The techno economics analysis shows the potential of HMGS in the Swedish rural development. [ABSTRACT FROM AUTHOR]

Determining the economic feasibility and optimal capacity scheme of a hybrid system is the premise of its development. This study proposed a framework for capacity configuration and economic evaluation of the hydro-solar/photovoltaic-wind power system. First, a hydro-solar-wind power system capacity configuration and economic evaluation mathematical model aiming at the maximum net present value was presented. Then, an economic dispatch model of cascade hydropower plants considering flood control level and water supply demand was established, and its target is to maximize the hydropower annual electricity revenues. Finally, the framework was examined by a practical project in China. The results indicated that (1) the hydro-solar-wind power system in Qinghai Province is economically feasible; (2) the hydro-solar-wind complementation leads to the increase of multi-year average water abandonment rate and transmission line utilization hours. Through the regulation of cascade reservoirs, the multi-year average water abandonment rate can be obviously reduced and the hydropower annual electricity revenues can be increased; (3) the hydro-solar-wind power system capacity configuration and economic evaluation model is most sensitive to feed-in tariff, social discount rate, and annual average utilization hours of solar/wind. Thus, this study has important guiding value for the economic development of the hydro-solar-wind power system. • A model for power system capacity configuration and economic evaluation is proposed. • An economic dispatch model for cascade hydropower plants is established. • The influence of hydro-solar-wind complementation on reservoir dispatch is analyzed. • Sensitivity analysis of capacity configuration and economic evaluation model is done. [ABSTRACT FROM AUTHOR]

This paper construct a CCHP and renewable energy based hybrid energy system driven by distributed energy resources (DERs CCHP). Then, the paper constructs performance indexes from energy, economic and environment. Thirdly, the paper proposes a multi-objective optimization model for DERs CCHP system under four optimization of energy rate (ER), total operation cost (TOC), carbon dioxide emission reductions (CER) and joint optimization. Finally, Guangzhou Higher Education Mega Center (GHEMC) in China is taken as the object for comparatively analyzing the operation performance of DERs CCHP system and CCHP system driven by natural gas (NG CCHP system). Results show: Joint optimization mode could balance the results of different optimization modes. DERs CCHP system shows better operation performance. ER of ER optimization, CER optimization and joint optimization are higher than that of NG CCHP system. NPV of all optimization modes is positive, IRR are bigger than the expected yield rate. DERs CCHP system could reduce CO 2 emission by utilizing wind energy and solar energy to replace NG. The sensitivity analysis indicates the performance of the DERs CCHP system will become better with the increase of chiller COP, decrease of NG price and wind-photovoltaic equipment cost. [ABSTRACT FROM AUTHOR]

HOMER software is a powerful tool for modeling and optimization of hybrid energy system (HES). The main two default control strategies in HOMER are load following (LF) and cycle charging (CC) strategies. In these strategies, the decision to use the generator or battery at each time step is made based on the lowest-cost choice. Therefore, these strategies are difficult to be implemented in practice especially in countries with continuous fuel price fluctuations. In this study, a new dispatch strategy based on HOMER-MATLAB Link Controller for an isolated wind/diesel/battery HES is proposed to overcome the limitations of the default HOMER strategies. A detailed technical, economic, and greenhouse gas emission analysis is presented for the system under LF, CC, and the proposed dispatch strategies. Besides offering more realistic optimization, the results show that the proposed strategy offers the best economic and environmental performance with a net present cost of $56473 and annual CO 2 emissions of 6838 kg. Furthermore, the sensitivity analysis reveals that the proposed strategy is not affected by the fuel price variation, in opposite to LF, and CC strategies which is affected dramatically by this variation. The findings are of paramount importance towards more realistic and efficient energy management strategies. • A new dispatch strategy for wind/diesel/battery hybrid energy systems using HOMER-MATLAB Link Controller is proposed. • Overcome HOMER default strategies limitation in dealing with continuous fuel price fluctuations. • The proposed strategy is compared with HOMER default strategies in terms of techno-economic and environmental performance. • Sensitivity analysis is conducted by considering variations in critical parameters. • The proposed strategy is more realistic and has better economic and environmental performance than HOMER default strategies. [ABSTRACT FROM AUTHOR]

The present work intends to develop a rural hybrid renewable energy system and examines the techno-financial, and social viability of the same system for rural sites in northern India. This work analyses the performance of Solar Photovoltaic-Wind hybrid renewable energy system for a residential load demand of 51.54 kWh/day with 11.51 kW peak in standalone application. In this paper, a nine parameter based multi-target optimization and sizing scheme is executed by HOMER PRO software. This work sequentially addresses the techno-economic and socio-environmental indicators for optimization analysis. The specification of technical and financial fields are availed from the Indian local market. Seven feasible combinations of different resources are analysed for designing parameters and the optimized combination is selected by multi criteria analysis. The solar Photovoltaic-wind-diesel generator-battery storage is found best combination for consistent power supply. The net present cost and cost of energy are obtained as $ 0.179 and $31,439 respectively. Sensitivity analysis is performed for macro-economic factors and components cost to obtain better opportunity. Moreover, the technical and commercial viability of the proposed system is assured by robustness check for satisfying the consumer demand. • The techno-economic and socio-environmental feasibility is carried-out for hybrid energy system for rural consumer. • Optimal design and assessment is performed for the nine different parameters related to the four different domains. • The Net-Present Cost, Cost of Energy, Capital Cost, Energy Generated, Excess Energy, and Unmet Load, are considered. • A unique social aspect has been addressed in terms of human development index, and Job formation. • The Life Cycle Emission, Renewable Penetration and Particulate Matters are also considered as environmental factors. [ABSTRACT FROM AUTHOR]

Reliable access to electricity is still a serious problem for remote villages, however, abundant solar radiation and biomass have the potentials to provide energy supply in a sustainable way. This paper focuses on the optimal design and techno-economic analysis of the stand-alone hybrid energy system for a typical rural village in the northwest of China. Based on the estimation of local renewable energy potential and the investigation of heat and power consumption patterns, a mixed-integer linear programming optimization model is presented with the aim of minimum total annualized cost. The techno-economic analysis of different system configurations is conducted and compared. Particularly, the levelized cost of energy production and levelized cost of energy consumption is proposed to evaluate the economic-cost of energy from both supply and demand-side respectively. Furthermore, sensitivity analysis and scenario analysis is conducted to demonstrate the influences of the variations and uncertain environmental policy on total system cost and performance. The results demonstrate that the PV/biomass-CHP/diesel generator/gas boiler/battery/thermal energy storage hybrid energy system is the most economical option with a total annualized cost of 652 × 103 $. The levelized cost of energy consumption (0.355 $/kWh) is greater than that of energy production (0.275 $/kWh), implying a great potential for local electrification and more flexible heat/power output equipment. • Stand-alone hybrid energy system with biomass-CHP for remote areas. • Novel levelized cost of energy evaluated from both supply and demand perspectives. • Techno-economic analysis of hybrid energy systems with different configurations. • Sensitivity analysis to investigate the impacts of market price variations and environmental policy uncertainty. [ABSTRACT FROM AUTHOR]

A new hybrid system coupled an absorption heat transformer to a photovoltaic module is put forward to capture the sunlight transmitted through photovoltaic module for heat upgrading. Taking account of multiple irreversible losses within the hybrid system, mathematic expressions for performance indicators of photovoltaic module, absorption heat transformer and hybrid system are formulated. Whether the proposed hybrid system is effective or not is evaluated. The maximum power output density and maximum energy efficiency of hybrid system are, respectively, enhanced by 99.05% and 99.01% compared with that of stand-alone photovoltaic module. Moreover, comprehensive sensitivity analyses are conducted to study how the hybrid system is affected by various designing parameters and operating conditions. Numerical calculation results indicate that the operating temperature of photovoltaic module, diode ideality factor, solar irradiance and various heat-transfer coefficients of absorption heat transformer have positive influence on the hybrid system performance. However, the environment temperature and heated space temperature have negative influence on the hybrid system performance. Furthermore, a practical case study has been conducted to show the performance limits of such a hybrid system. The present study may offer some new insights into the photovoltaic module performance improvement. • A solar-driven electricity generation and heat upgrading hybrid system is proposed. • Photovoltaic module and absorption heat transformer are mathematically described. • Performance indicators for the proposed system are mathematically obtained. • Effectiveness and feasibility of the proposed hybrid system are demonstrated. • Effects of some decisive designing parameters and operating conditions are revealed. [ABSTRACT FROM AUTHOR]

This paper aims to develop a rural energy system design framework and analyzes the techno-economic feasibility of potential hybrid energy systems (HES) for rural electrification of a village in district Dera Ismail Khan, Pakistan. At first, a comprehensive resource assessment is carried out. Subsequently, system size optimization and techno-economic viability is conducted using a standard software tool HOMER PRO to fulfil the peak-load demand. Due to the deficiency of wind power and biomass resources at the targeted site, the results indicate that a community power system based on solar PV as a primary energy source, batteries as a storage, diesel generator as a backup, and a time-constrained availability of national grid is the most feasible solution. Sensitivity analysis using macro-economic variables and derating factor of PV has been opted to ensure robustness and commercial applicability of the proposed HES. The study finds that levelized cost of electricity (LCOE) in grid-integrated systems (0.072$/kWh and 0.078$/kWh) is economical than the off-grid systems (0.145$/kWh and 0.167$/kWh). The obtained results indicate commercial efficacy of the grid-integrated configurations, where LCOE is lower than the existing government tariff. Most importantly, this hybrid energy system is capable of providing a 24/7 continuous electricity to the site under consideration. • A novel framework for rural energy system design is provided. • Time-constrained grid-integrated systems are found economical than off-grid systems. • Both off-grid and grid-integrated systems can provide 24/7 continuous electricity. • Commercially efficacy and additional sensitivity analyses are carefully examined. • The lowest per unit cost, 0.072 $/kWh, is found technically and financially viable. [ABSTRACT FROM AUTHOR]

This paper carries out a multi-objective optimization of a solar hybrid combined cooling, heating and power (CCHP) system, based on the objective functions of annual cost saving ratio (CSR) and primary energy saving ratio (PESR). The system is modeled in three modes: 1) following electrical load (FEL); 2) following thermal load (FTL) and 3) following thermal load and selling power to grid (FTL-S). Non-dominated Sort Genetic Algorithm- II (NSGA-II) is adopted to find the Pareto front solutions of the potentially optimal configuration and corresponding criteria. The results show a conflict between cost saving and fuel saving. By selecting the compromised optimal point, the CSR increases to 25.04% and the PESR increases to 37.86% on average. The system in FEL mode performs best in energy saving and the system in FTL-S mode performs best in economy. The solar hybrid CCHP system is also compared with other three systems: 1) conventional CCHP system; 2) CCHP system with photovoltaic assisted only and 3) CCHP system with solar collector assisted only. In the end, the sensitivity analysis is implemented and the results present that energy prices and the efficiency of major equipment have varying degrees of impact on system performance. • A multi-objective optimization of solar hybrid CCHP system is implemented. • Performances in three operation modes are compared and analyzed. • FTL-S mode is better than other modes in cost saving. • Proper allocation of PV and SC installation area can improve the system performance. [ABSTRACT FROM AUTHOR]

This paper analyzes the impact on an off-grid renewable hybrid system composed of photovoltaic energy, hydrokinetic turbines, batteries and biomass gasifiers, using various types of biomass in order to determine the optimal configuration of the system located in southern Ecuador. Three types of energy dispatch, charge cycle, load following and combined cycle have been proposed with the objective of determining new patterns on the behavior of sources with respect to electric demand. The biomass used as an energy resource produces electricity through a biomass gasifier that feeds a microturbine. Considering the types of biomass consumed by the gasifier, the items such as net present cost and cost of energy have been analyzed for the different types of control. Sensitivity studies indicate the increase in the cost of the system by increasing the minimum state of charge in the batteries. However, this increase reduces biomass consumption and CO 2 emissions. Finally, the variation of the cost in the components influences the total cost of the system, being the fuel and the photovoltaic system the systems that have the highest sensitivity, the results have shown that the renewable system is able to supply the demand without violating any norm. • Off-grid renewable hybrid system including biomass gasifiers in Ecuador. • Three types of energy dispatch, charge cycle, load following and combined cycle. • Electricity through a biomass gasifier that feeds a microturbine. • Net present cost and cost of energy have been analyzed. • The biomass and the photovoltaic systems have the highest sensitivity. [ABSTRACT FROM AUTHOR]

The integration of renewable energy technologies (solar, wind, biomass, ocean, geothermal energy) is gaining importance in the United Arab Emirates owing to the high energy demand and greenhouse gas (GHG) emissions. This paper presents the analysis and results of the performance and optimization of a stand-alone solar PV power system with single-axis (horizontal and vertical) and dual-axis solar trackers and a diesel generator (DG) for the city of Khorfakkan, Sharjah. The modeling, simulations, and optimization analysis of the hybrid energy system (HES) were performed with the HOMER software based on the daily energy consumption of 37.75 MWh in the study area. The simulation results show that employing an HES with dual-axis solar trackers is the best power system architecture considering the renewable fraction (48.55%) and levelized cost of energy (LCOE; 0.25 $/kWh). The proposed HES meets the annual energy demand of the city (13,778 MWh) without shortages and with an electricity excess of 9.81%. In addition, the sensitivity analysis shows that the HES with dual-axis solar PV tracking system provides lower electricity costs (250 $/MWh) and the highest GHG emission reduction (69.6%, which is equivalent to the GHG emission reduction of a diesel engine consuming 682,279 gallons of diesel fuel). • Design and modeling hybrid energy system (HES) consisting of tracking solar PV and diesel generator for Khorfakkan in UAE. • Compare different cases of solar PV tracking system based on the levelized cost of energy (LCOE) and renewable fraction. • Optimize the component size of HES to meet the AC primary load for Khorfakkan. • Perform optimization and sensitivity analysis for HES at the actual environmental conditions. [ABSTRACT FROM AUTHOR]