System Size Optimization Research Articles

A feasibility study on Balarbhita for advancing rural electrification with a solar—Micro-hydro hybrid system

The study analyzed the techno-economic feasibility of a village in the Indian state of Assam and designs a framework for a rural hybrid energy system. Through an extensive resource evaluation, techno-economic feasibility analysis and system size optimization are carried out using HOMER Pro software. Batteries are being used as a form of energy storage in the community power system, which is based on solar PV and micro-hydro as its principal energy sources. Macro-economic variables and resource variations have been considered in sensitivity analysis to ensure the robustness and commercial viability of the proposed hybrid energy systems. A reliable and economical design can provide 279861 kWh of electricity for the village at a modest cost of energy (COE) of $0.0953/kWh using 118 kW of solar power, 11 kW of hydropower, and 261 kWh of battery storage. Furthermore, solar energy systems account for about 62.5 percent, while micro-hydro turbines account for 37.5 percent. In addition, the suggested system does not pollute the local environment caused by carbon emissions. Most importantly, this hybrid energy system is capable of providing 24/7 continuous electricity to the site under consideration.

Numerical investigation and feasibility study on MXene/water nanofluid based photovoltaic/thermal system

Nanofluid is increasingly adopted in solar collectors as they play a significant role in enhancing the heat transfer process. In this study, a 3D numerical simulation of a nanofluid-based photovoltaic/thermal (N-PV/T) system with MXene nanofluid as heat transfer fluid, was conducted using the finite volume method (FVM). A feasibility analysis was performed on the proposed N-PV/T system. Enviro-economic analysis was also performed from an energy and exergy perspective. The numerical simulation model was validated with experimental and numerical data in the literature and has a minimal error of about 2.75% and 8.9%, respectively. Results indicated that MXene nanofluid of 0.2 wt% achieved a percentage enhancement of 3.5% and 17% electrical efficiency and thermal efficiency, respectively, over water. The 0.2 wt% MXene nanofluid achieved the highest heat transfer coefficient (HTC) of 261.95 Wm−2K−1 at a mass flow rate of 90 kgh−1. Also, 0.2 wt% nanofluid produced a significant HTC improvement of about 21.42% over water at a flow rate of 40 kgh−1. The study showed that MXene nanofluid could effectively reduce the PV surface temperature by 10% compared to water. System size optimization study proved that a 4.5 - 14.5% reduction in the size of PV/T could be achieved with MXene nanofluid. Enviroeconomic analysis showed that the 0.2 wt% nanofluid generated the least emission rate and emission cost according to energy (0.42 kgCO2/day, and 0.028224 $/day) and exergy-based analysis (0.48 kgCO2/day, and 0.032 $/day).

Techno-economic assessment of microgrid in rural India considering incremental load growth over years

<abstract> <p>India, being a developing country with a fast-growing economy, experiences ever increasing electrical energy demand. Industrial and economic development in rural India is impeded by inadequate, erratic and unreliable grid supply. This has resulted in underperformance of small-scale manufacturing and service industries. Dependency on fossil fuel-based sources as an alternative increases the operation costs and carbon emissions. Migration to cleaner energy ensures sustainable solution and addresses the issues of depleting fossil fuels, global warming and environmental hazards. In this regard, hybrid renewable energy systems have gained wide acceptance as optimum solution. Hence, authors have optimally designed hybrid energy system for power deprived rural Indian villages. Authors have heeded to the vital element of incremental load growth over years while designing the microgrid to sustain the increasing load demand of emerging economy of developing country. HOMER Pro Software is utilized to accomplish system size optimization and authors have gained comprehensive insights into techno-financial feasibility for different dispatch strategies of the proposed energy system. The levelized cost of electricity of the optimal off-grid system catering to multiyear incremental load growth is 0.14$/kWh indicating that proposed system is promising in terms of commercial efficacy. The study performs a detailed analysis of the results obtained during different phases of the project to ensure robustness and supply continuity of the proposed system. The paper also includes comparison of the carbon footprint in the proposed system with that of existing system.</p> </abstract>

A techno-economic assessment of hybrid energy systems in rural Pakistan

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.

Virtual-battery based droop control and energy storage system size optimization of a DC microgrid for electric vehicle fast charging station

DC microgrid is supposed to be a feasible solution to reduce the negative impact of electric vehicle (EV) fast charging on the electric grid and improve the penetration of photovoltaics (PV) generation. In this paper, an improved decentralized Virtual-battery based droop control with the capability of bus voltage maintenance, load power dispatch and SOC balance of the energy storage system (ESS) is proposed to ensure the autonomous and stable operation of the DC microgrid. The reference output voltage and virtual resistance in the droop control loop are altered dynamically based on the Virtual-battery model of the ESS. The coordinated control among the PV-ESS-Grid integrated system is realized through the primary Bus-Signaling control, where the reference voltages at which the control modes of the PV array and the grid are switched are designed based on the VirtualOCV of the ESS. The effectiveness of the proposed control strategy is validated in MATLAB/Simulink environment with an equivalent bus capacitance-based model where the EV charging profile is obtained from real-world charging data of a fast charging station. The merits of the control strategy including higher PV utilization, less frequent connection of the grid and more precise voltage tracking are highlighted in comparison with the conventional droop control strategy. Finally, the sizing of the ESSs is optimized based on the total cost of the DC microgrid, including the daily electricity cost purchased from the grid and the depreciation cost of the ESSs based on the expanded capacity degradation model of Li-ion batteries.

Renewable hybrid system size optimization considering various electrochemical energy storage technologies

The main objective of the proposed article is the establishment of rules and tools for energy management optimization as well as the sizing of an autonomous wind and solar production system using an electrochemical storage device. The optimization criterion is techno-economic in order to minimize the energy produced cost, while considering the reliability level required by the consumer. Four most recent nature inspired algorithms have been employed to solve this complex optimization problem. This included ant lion optimizer algorithm (ALO), grey wolf optimizer algorithm (GWO), krill herd algorithm (KH) and JAYA algorithm, which is used for the first time in renewable systems sizing. Thus, the conducted methodology permits to determine the optimal system configuration, by minimizing the unit electricity cost (UEC) for a specified loss of power supply probability (LPSP) while counting the excess energy. Three electrochemical battery technologies including, lead-Acid (LA), lithium-ion (Li-ion) and Nickel-Cadmium (Ni-Cd) have been considered in this study. In order to predict the future performance of the studied system, various sensitivity analyzes have been carried out taking into account, the impact of the lifetime, the depth of discharge (DOD) and the relative cost of divers battery technologies on the UEC. The simulation results demonstrate the supremacy of the JAYA algorithm against the other algorithms. JAYA converges towards the optimal solutions for three battery technologies. It also shows that a 50% reduction in battery cost will reduce the cost of EUC by 30%, which would allow Li-ion batteries to become as competitive as LA batteries in terms of cost. Other similarly interesting results on the effect of DOD on UEC have been found. For DODs of 50% and 80% corresponding respectively, to Ni-Cd and Li-ion technologies, the UEC produced by the PV/Wind/Ni-Cd and PV/Wind/Li-ion systems becomes as attractive as that produced by the PV/Wind/LA system.

Analysis of techno-economic viability with demand response strategy of a grid-connected microgrid model for enhanced rural electrification in Uttar Pradesh state, India

This paper presents an economic and enhanced technological solution for rural electrification of a village Jalalabad, in Ghaziabad District, Uttar Pradesh state, India. The considered system concentrates on optimal sizing of an integrated renewable energy system (IRES) with grid provide a more continuous power supply with respect to the existing system. The different available sources Solar Photo Voltaic (SPV), Battery Energy Storage System (BESS), and a time constrained grid are considered in designing of the system. The system size optimization, sensitivity analysis and techno-economic viability has been done by using a standard software tool HOMER to fulfil the demand of the study area under consideration. A demand response strategy has been applied for the different load profiles. The configuration with the lowest Levelized Cost of Electricity (LCOE) and Total Net Present Cost (TNPC) with maximum value of renewable fraction (RF) has been considered as optimum. This ensures the minimization of the Carbon dioxide (CO2) emission. A comparative analysis has been presented showing the impact of the demand response on the LCOE and NPC as well as the system size. The economic analysis has been done according to four different cases obtained by varying the fraction (βNELS) of non-essential load shifting. It has been observed that the value of LCOE with the strategy of demand response and optimal resource management under which βNELS = 0.25 is reduced Rs. 11.23/kWh and Rs. 8.36/kWh with the grid tariff Rs.10/kWh and Rs.6/kWh respectively while the value of TNPC Rs. 1.99 × 107 and Rs. 1.48 × 107 respectively with the maximum renewable fraction of 31.06. An exhaustive performance analysis has been done and the obtained results show the effectiveness of proposed resource and demand management to provide 24 × 7 supply with limited, time constrained grid availability.

Techno-Economic Performance Evaluation and Enhancement for a PV – Diesel Hybrid System

In this research paper, an illustration for system size optimization for a stand-alone PV – diesel hybrid system is obtained. The requirement is to obtain an optimal size that can meet energy demand at an optimized cost for a given lifetime period of the project, this will be achieved using HOMER software to further improve the system parameters like performance ratio, renewable energy fraction, MATLAB will be used. This research study will be done basing on a system currently installed at the School of Renewable Energy, Naresuan University (SERT), this system has a capacity of 120 kW, and it is a hybrid system with PV array, Diesel generator and battery storage system. The cost parameters that will be addressed are; - Net present cost (NPC), Cost of Energy (COE), Capital cost (CC). The initial size of the hybrid system is PV-120kW, Diesel generator -100kW and battery storage of 200kWh after modelling and simulation with HOMER software using special models to show the predicted performance of the final outcome, the optimal size created has a PV size of 100kW, diesel generator with a size of 100kW and battery storage of 100kWh and compared to the initial system COE od 1.01$/kWh, the optimal size has a COE of 0.934$/kWh.

Hybrid energy system size optimization and sensitivity evaluation for sustainable supply in a remote region in India

This paper illustrates the size optimization of a hybrid energy system designed for a remote region in India. This sustainable system combines a solar photovoltaic system and a wind turbine as a small-scale alternative source, where conventional generation is not practical. This alternative supply option includes the diesel generator as the backup source and the battery as the storage device. HOMER software obtained from the National Renewable Energy Website has been applied for simulation and evaluation purposes. The optimal system obtained in this way will be the one having the least net present cost (life-cycle cost). Furthermore, sensitivity analysis has been carried out on feasible systems for two variables, that is, diesel price and annual real interest rate, to examine the effect of variation of these variables on the type of the system. This futuristic situation leads to more favourable conditions for sustainable supply option with much reduced life-cycle cost of the system.

Epitaxial Transition from Gyroid to Cylinder in a Diblock Copolymer Melt

An epitaxial transition from a bicontinious double gyroid to a hexagonally packed cylinder structure induced by an external flow is simulated using real-space dynamical self-consistent field technique. In order to simulate the structural change correctly, we introduce a system size optimization technique by which emergence of artificial intermediate structures are suppressed. When a shear flow in [111] direction of the gyroid unit cell is imposed, a nucleation and growth of the cylinder domains is observed. We confirm that the generated cylindrical domains grow epitaxially to the original gyroid domains as gyroid $d_{\{220\}}$ $\to$ cylinder $d_{\{10\}}$. In a steady state under the shear flow, the gyroid shows different reconnection processes depending on the direction of the velocity gradient of the shear flow. A kinetic pathway previously predicted using the self-consistent field theory where three fold junctions transform into five fold junctions as an intermediate state is not observed.