Multi-objective optimal design of hybrid renewable energy systems using PSO-simulation based approach

Recently, the increasing energy demand has caused dramatic consumption of fossil fuels and unavoidable raising energy prices. Moreover, environmental effect of fossil fuel led to the need of using renewable energy (RE) to meet the rising energy demand. Unpredictability and the high cost of the renewable energy technologies are the main challenges of renewable energy usage. In this context, the integration of renewable energy sources to meet the energy demand of a given area is a promising scenario to overcome the RE challenges. In this study, a novel approach is proposed for optimal design of hybrid renewable energy systems (HRES) including various generators and storage devices. The ε-constraint method has been applied to minimize simultaneously the total cost of the system, unmet load, and fuel emission. A particle swarm optimization (PSO)-simulation based approach has been used to tackle the multi-objective optimization problem. The proposed approach has been tested on a case study of an HRES system that includes wind turbine, photovoltaic (PV) panels, diesel generator, batteries, fuel cell (FC), electrolyzer and hydrogen tank. Finally, a sensitivity analysis study is performed to study the sensibility of different parameters to the developed model.     

H2 Optimization and Fuel Cells Application on Electrical Distribution System and Its Commercial Viability in Australia

Conventional energy technologies are not environmentally friendly, are not renewable, and also the cost of using fossil and nuclear fuels will go higher and higher (anecdotal evidence suggests that consumers will be paying three times their current bill 5 years from now). Therefore, renewable energy sources will play important roles in electricity generation. This paper highlights the advantages of renewable technologies, like future prospects for the poor population, being environmentally friendly, and also available in abundance. This paper points outs the factors seeking hydrogen energy and fuel cell technology to eradicate environmental disasters. This paper is significant as it looks into optimal utilization of renewable energy sources with major emphasis on H₂ optimization and fuel cells application utilizing cogeneration technology. This paper discusses the multiple hydrogen production pathways from different sources, including renewable and nonrenewable sources, H₂ safety, and also barriers to use of hydrogen energy. This paper recommends different types of quantitative and qualitative methods for optimal energy planning, and different types of fuel cells are also discussed. This paper explains a hybrid system inclusive of renewable energy, with its types and benefits. Finally, this paper concludes that Australia could switch from conventional fossil fuel technology to hybrid energy inclusive of renewable energy.     

Pre-feasibility study of stand-alone hybrid energy systems for applications in Newfoundland

A potential solution for stand-alone power generation is to use a hybrid energy system in parallel with some hydrogen energy storage. In this paper, a pre-feasibility study of using hybrid energy systems with hydrogen as an energy carrier for applications in Newfoundland, Canada is explained. Various renewable and non-renewable energy sources, energy storage methods and their applicability in terms of cost and performance are discussed. HOMER is used as a sizing and optimization tool. Sensitivity analysis with wind speed data, solar radiation level, diesel price and fuel cell cost was done. A remote house having an energy consumption of 25 kW h/d with a 4.73 kW peak power demand was considered as the stand-alone load. It was found that, a wind–diesel–battery hybrid system is the most suitable solution at present. However, with a reduction of fuel cell cost to 15% of its current value, a wind–fuel cell system would become a superior choice. Validity of such projection and economics against conventional power sources were identified. Sizing, performance and various cost indices were also analyzed in this paper.     

An integrated system framework for fuel cell-based distributed green energy applications

The environmental pollution and diminishing conventional fuel sources and global warming problems make it more attractive for considering renewables as alternative energy sources, such as solar, wind and micro hydro, etc. Recent advances in hydrogen and fuel cell technologies further facilitate these energy options to supply electrical power to various communities. Hydrogen fuel cell systems coupled with renewable energy sources stand out as a promising solution. This paper presents an integrated system framework for fuel cell-based distributed energy applications. Five components are included in this framework: a physical energy system application, a virtual simulation model, a distributed coordination and control, a human system interface and a database. The integrated system framework provides a means to optimize system design, evaluate its performance and balance supplies and demands in a hydrogen assisted renewable energy application. It can either be applied to a distributed energy node that fulfills a local energy demand or to an energy-network that coordinates distributed energy nodes in a region, such as a hydrogen highway. The proposed system framework has been applied in the first phase of our multi-phases project to investigate and analyze the feasibility and suitability of hydrogen fuel assisted renewable power for a remote community. Through integration with an available renewable energy profile database, the developed system efficiently assists in selecting, integrating, and evaluating different system configurations and various operational scenarios at the application site. The simulation results provide a solid basis for the next phase of our demonstration projects.     

Techno-economic analysis of PEM fuel cells role in photovoltaic-based systems for the remote base stations

Expansion of telecommunication networks even to the most remote areas where connection to the utility grid could never be justified, especially in touristic regions, has led to the increasing need for stand-alone power systems. In Adriatic coastal area employment of hybrid photovoltaic-based systems is straightforward due to high sun potential. Inherent intermittent nature of renewable sources is especially not compatible with telecommunication system who require uninterrupted power supply. This leads to the need of not only energy storage, but also a “back up” solution in the case of primary system failure. Emphasis is put on the system reliability and simplicity while system price is not necessarily top priority. Usual approach of using diesel generators as a “back up” has been challenged by the introduction of PEM fuel cells. Even with hydrogen technologies market development still lagging behind some comparable advantages such as high energy conversion efficiency, silent operation and no emissions make PEM fuel cells a legitimate candidate for replacing traditional oil burning generators. Techno-economic analysis of various stand-alone power systems for the remote base station on an Adriatic island is made. At the moment, levelized cost of electricity point of view still gives slight advantage to the diesel generators. Though, uncertain petroleum market and fast developing hydrogen technology market could reverse this trend in the near future. Long term reliability of PEM fuel cells system still needs to be examined in practice, as this combined with pro-environmental characteristics of fuel cells can make the difference especially in pristine and protected areas.     

Multi-stage stochastic optimization framework for power generation system planning integrating hybrid uncertainty modelling

In this paper, a multi-stage stochastic optimization (MSO) method is proposed for determining the medium to long term power generation mix under uncertain energy demand, fuel prices (coal, natural gas and oil) and, capital cost of renewable energy technologies. The uncertainty of future demand and capital cost reduction is modelled by means of a scenario tree configuration, whereas the uncertainty of fuel prices is approached through Monte Carlo simulation. Global environmental concerns have rendered essential not only the satisfaction of the energy demand at the least cost but also the mitigation of the environmental impact of the power generation system. As such, renewable energy penetration, CO_2,eq mitigation targets, and fuel diversity are imposed through a set of constraints to align the power generation mix in accordance to the sustainability targets. The model is, then, applied to the Indonesian power generation system context and results are derived for three cases: Least Cost option, Policy Compliance option and Green Energy Policy option. The resulting optimum power generation mixes, discounted total cost, carbon emissions and renewable share are discussed for the planning horizon between 2016 and 2030.     

Design of isolated renewable hybrid power systems

Isolated electrical power generating units can be used as an economically viable alternative to electrify remote villages where grid extension is not feasible. One of the options for building isolated power systems is by hybridizing renewable power sources like wind, solar, micro-hydro, etc. along with appropriate energy storage. A method to optimally size and to evaluate the cost of energy produced by a renewable hybrid system is proposed in this paper. The proposed method, which is based on the design space approach, can be used to determine the conditions for which hybridization of the system is cost effective. The simple and novel methodology, proposed in this paper, is based on the principles of process integration. It finds the minimum battery capacity when the availability and ratings of various renewable resources as well as load demand are known. The battery sizing methodology is used to determine the sizing curve and thereby the feasible design space for the entire system. Chance constrained programming approach is used to account for the stochastic nature of the renewable energy resources and to arrive at the design space. The optimal system configuration in the entire design space is selected based on the lowest cost of energy, subject to a specified reliability criterion. The effects of variation of the specified system reliability and the coefficient of correlation between renewable sources on the design space, as well as the optimum configuration are also studied in this paper. The proposed method is demonstrated by designing an isolated power system for an Indian village utilizing wind-solar photovoltaic-battery system.     

Technico-economic analysis of off grid solar PV/Fuel cell energy system for residential community in desert region

A technico-economic analysis based on integrated modeling, simulation, and optimization approach is used in this study to design an off grid hybrid solar PV/Fuel Cell power system. The main objective is to optimize the design and develop dispatch control strategies of the standalone hybrid renewable power system to meet the desired electric load of a residential community located in a desert region. The effects of temperature and dust accumulation on the solar PV panels on the design and performance of the hybrid power system in a desert region is investigated. The goal of the proposed off-grid hybrid renewable energy system is to increase the penetration of renewable energy in the energy mix, reduce the greenhouse gas emissions from fossil fuel combustion, and lower the cost of energy from the power systems. Simulation, modeling, optimization and dispatch control strategies were used in this study to determine the performance and the cost of the proposed hybrid renewable power system. The simulation results show that the distributed power generation using solar PV and Fuel Cell energy systems integrated with an electrolyzer for hydrogen production and using cycle charging dispatch control strategy (the fuel cell will operate to meet the AC primary load and the surplus of electrical power is used to run the electrolyzer) offers the best performance. The hybrid power system was designed to meet the energy demand of 4500 kWh/day of the residential community (150 houses). The total power production from the distributed hybrid energy system was 52% from the solar PV, and 48% from the fuel cell. From the total electricity generated from the photovoltaic hydrogen fuel cell hybrid system, 80.70% is used to meet all the AC load of the residential community with negligible unmet AC primary load (0.08%), 14.08% is the input DC power for the electrolyzer for hydrogen production, 3.30% are the losses in the DC/AC inverter, and 1.84% is the excess power (dumped energy). The proposed off-grid hybrid renewable power system has 40.2% renewable fraction, is economically viable with a levelized cost of energy of 145 $/MWh and is environmentally friendly (zero carbon dioxide emissions during the electricity generation from the solar PV and Fuel Cell hybrid power system).     

A review on fuel cell technologies and power electronic interface

The issue of renewable energy is becoming significant due to increasing power demand, instability of the rising oil prices and environmental problems. Among the various renewable energy sources, fuel cell is gaining more popularity due to their higher efficiency, cleanliness and cost-effective supply of power demanded by the consumers. This paper presents a comprehensive review of different fuel cell technologies with their working principle, advantages, disadvantages and suitability of applications for residential/grid-connected system, transportation, industries and commercial applications. Development of mathematical model of fuel cell required for simulation study is discussed. This paper also focuses on the necessity of a suitable power-conditioning unit required to interface the fuel cell system with standalone/grid applications.     

Power flow control of grid connected hybrid renewable energy system using hybrid controller with pumped storage

This paper presents a grid-connected HRES using a hybrid controller with PHS for optimal power flow control and minimizing the production cost. The novelty of the proposed approach is the joined execution of the SSA and CSA named as SSA-CS are apparently a very new metaheuristic algorithm. Moreover, the proposed method is the cost-effective power production of the microgrids and effective utilization of renewable energy sources without wasting the available energy. Here, the energy sources in particular PV system, WT, MT and battery with PHS are utilized to generate the power of the MG system. In the proposed approach, the required power demand of the energy system is predicted by the ANN technique. After that, the production cost minimization is done in view of the anticipated load demand by utilizing the optimization approaches to be a specific SSA-CS algorithm. The result of the proposed approach is actualized in the MATLAB/Simulink working platform. The performance of the proposed approach is examined by comparing the current methodologies such as SSA and PSO with the proposed SSA-CS approach. The simulation results show that the proposed method generates maximum power and furthermore the proposed framework has less production cost in light of the power demand.     

The role of renewable fuel supply in the transport sector in a future decarbonized energy system

Battery electric vehicles (BEVs) and fuel cell electric vehicles (FCEVs) have been identified as two electromobility options which can help to achieve GHG emission reduction targets in the transport sector. However, both options will also impact the future energy system characterized by integration of various demand sectors and increasing intermittent power generation. The objective of this paper is to examine the optimal mix of both propulsion systems and to analyze the cost for renewable fuel supply. We propose a generic approach for dimensioning of fast charging and hydrogen refueling stations and optimization of the fuel supply system. The model is applied in a case study for passenger cars on German highways. The results indicate that a parallel build-up of stations for both technologies does not increase the overall costs. Moreover, the technology combination is also an optimal solution from the system perspective due to synergetic use of hydrogen but limited efficiency losses. Hence, BEVs and FCEVs should jointly contribute to the decarbonization of the future energy system.     

Sustainable electricity generation fuel mix analysis using an integration of multicriteria decision-making and system dynamic approach

To achieve a national energy access target of 90% urban and 51% rural by 2035, combat climate change, and diversify the energy sector in the country, the Zambian government is planning to integrate other renewable energy resources (RESs) such as wind, solar, biomass, and geothermal into the existing hydro generation–based power system. However, to achieve such targets, it is essential for the government to identify suitable combination of the RESs (electricity generation fuel mix) that can provide the greatest sustainability benefit to the country. In this paper, a multicriteria decision-making framework based on analytic hierarchy process and system dynamics techniques is proposed to evaluate and identify the best electricity generation fuel mix for Zambia. The renewable energy generation technologies considered include wind, solar photovoltaic, biomass, and hydropower. The criteria used are categorized as technical, economic, environmental, social, and political. The proposed approach was applied to rank the electricity generation fuel mix based on nine sustainability aspects: land use, CO₂ emissions, job creation, policy promotion affordability, subsidy cost, air pollution reduction, RES electricity production, RES cumulative capacity, and RES initial capital cost. The results indicate that based on availability of RESs and sustainability aspects, in overall, the best future electricity generation mix option for Zambia is scenario with higher hydropower (40%) penetration, wind (30%), solar (20%), and lower biomass (10%) penetration in the overall electricity generation fuel mix, which is mainly due to environmental issues and availability of primary energy resources. The results further indicate that solar ranks first in most of the scenarios even after the penetration weights of RES are adjusted in the sensitivity analysis. The wind was ranked second in most of the scenarios followed by hydropower and last was biomass. These developed electricity generation fuel mix pathways would enable the country meeting the future electricity generation needs target at minimized environmental and social impacts by 2035. Therefore, this study is essential to assist in policy and decision making including planning at strategic level for sustainable energy diversification.     

A green hydrogen energy storage concept based on parabolic trough collector and proton exchange membrane electrolyzer/fuel cell: Thermodynamic and exergoeconomic analyses with multi-objective optimization

With the continuous penetration of renewable energy plants into energy markets and their surplus power generation during off-peak periods, the need for utility-scale energy storage technologies is globally prioritized. Among the existing large-scale energy storage technologies, hydrogen storage has appeared as a powerful alternative due to its environmental benefits and the ability to store a large amount of energy for several hours to months. The major objective of the proposed research is to introduce a novel configuration of green hydrogen production for power generation during peak demand periods. In this regard, an innovative hybridization of a solar unit based on a parabolic trough collector with a proton-exchange membrane electrolyzer and a fuel cell is introduced and analyzed from the thermodynamic and exergoeconomic perspectives. Moreover, a sensitivity analysis and a multi-objective optimization based on the combination of neural network and grey wolf optimization algorithms are conducted to select the best working fluid of the solar unit and ideal operating conditions according to the minimum cost rate and the maximum exergy efficiency. The results indicate that Dowtherm? A synthetic oil is the best working fluid, and the proposed system can generate 9, 14.9, and 20.1 MW of power during off-, mid-, and on-peak times, respectively. The results also show that the proposed system operates with an exergy efficiency of 17.6% and a cost rate of 492.4 $/hr under the optimal conditions.     

Analysis of Ontario's hydrogen economy demands from hydrogen fuel cell vehicles

The ‘Hydrogen Economy’ is a proposed system where hydrogen is produced from carbon dioxide free energy sources and is used as an alternative fuel for transportation. The utilization of hydrogen to power fuel cell vehicles (FCVs) can significantly decrease air pollutants and greenhouse gases emission from the transportation sector. In order to build the future hydrogen economy, there must be a significant development in the hydrogen infrastructure, and huge investments will be needed for the development of hydrogen production, storage, and distribution technologies. This paper focuses on the analysis of hydrogen demand from hydrogen FCVs in Ontario, Canada, and the related cost of hydrogen. Three potential hydrogen demand scenarios over a long period of time were projected to estimate hydrogen FCVs market penetration, and the costs associated with the hydrogen production, storage and distribution were also calculated. A sensitivity analysis was implemented to investigate the uncertainties of some parameters on the design of the future hydrogen infrastructure. It was found that the cost of hydrogen is very sensitive to electricity price, but other factors such as water price, energy efficiency of electrolysis, and plant life have insignificant impact on the total cost of hydrogen produced.     

Energy storage based MG connected system for optimal management of energy: An ANFMDA technique

This paper proposes an efficient hybrid technique for the system modeling and the optimal energy management of the MG with low cost. The novelty of the proposed approach is the combination of the ANFIS and MDA named as ANFMDA that performs the decision making with the multi-objective problem. Moreover, the proposed method is the cost-effective power production of the microgrids and effective utilization of renewable energy sources without wasting the available energy. The strategy is worried about the mathematical optimization problems that include in excess of one objective function to be optimized at the same time. The MDA algorithm optimizes the MG configuration at minimum fuel cost to take care of the required load demand by using the inputs of MG like WT, PV array, MT, and ESS with corresponding cost functions. In the proposed approach, the ANFIS learning phase is employed to predict the load demand. Based on the predicted load demand the minimum annual fuel cost characteristics, the operation cost and also the replacement cost is decreased with all the subsequent points of the MDA. The performance of the proposed method is examined by comparison with the other techniques such as ABC algorithm, DA, and HOMER. The comparison results demonstrate the superiority of the proposed technique and confirm its potential to solve the problem.     

Multi-objective assessment of rural electrification in remote areas with poverty considerations

Rural electrification with renewable energy technologies (RETs) offers several benefits to remote areas where diesel generation is unsuitable due to fuel supply constraints. Such benefits include environmental and social aspects, which are linked to energy access and poverty reduction in less-favored areas of developing countries. In this case, multi-objective methods are suitable tools for planning in rural areas. In this study, assessment of rural electrification with renewable energy systems is conducted by means of goal programming towards fuel substitution. The approach showed that, in the Non-Interconnected Zones of Colombia, substitution of traditional biomass with an electrification scheme using renewable energy sources provides significant environmental benefits, measured as land use and avoided emissions, as well as higher employment generation rates than diesel generation schemes. Nevertheless, fuel substitution is constrained by the elevated cost of electricity compared to traditional biomass, which raises households’ energy expenditures between twofold to five times higher values. The present approach, yet wide in scope, is still limited for quantifying the impact of energy access improvements on poverty reduction, as well as for the assessment of energy system's technical feasibility.     

Greenhouse gas emissions reduction by use of wind and solar energies for hydrogen and electricity production: Economic factors

This study addresses economic aspects of introducing renewable technologies in place of fossil fuel ones to mitigate greenhouse gas emissions. Unlike for traditional fossil fuel technologies, greenhouse gas emissions from renewable technologies are associated mainly with plant construction and the magnitudes are significantly lower. The prospects are shown to be good for producing the environmentally clean fuel hydrogen via water electrolysis driven by renewable energy sources. Nonetheless, the cost of wind- and solar-based electricity is still higher than that of electricity generated in a natural gas power plant. With present costs of wind and solar electricity, it is shown that, when electricity from renewable sources replaces electricity from natural gas, the cost of greenhouse gas emissions abatement is about four times less than if hydrogen from renewable sources replaces hydrogen produced from natural gas. When renewable-based hydrogen is used in a fuel cell vehicle instead of gasoline in a IC engine vehicle, the cost of greenhouse gas emissions reduction approaches the same value as for renewable-based electricity only if the fuel cell vehicle efficiency exceeds significantly (i.e., by about two times) that of an internal combustion vehicle. It is also shown that when 6000 wind turbines (Kenetech KVS-33) with a capacity of 350 kW and a capacity factor of 24% replace a 500-MW gas-fired power plant with an efficiency of 40%, annual greenhouse gas emissions are reduced by 2.3 megatons. The incremental additional annual cost is about $280 million (US). The results provide a useful approach to an optimal strategy for greenhouse gas emissions mitigation.     

Analysis of a fuel cell micro-grid with a small-scale wind turbine generator

If electric power is supplied using an independent micro-grid connected to renewable energy, it can flexibly match the energy demand characteristics of a local area. And an independent micro-grid is expected to be effective in cutting greenhouse gas discharge and energy costs, as well as in eliminating the need for an emergency power supply system. Since the output of renewable energy is unstable, other energy equipment needs to cover the stability of output. Thus, the operating conditions of an independent micro-grid that supplies power with natural power sources and fuel cells are investigated. The operation conditions of a fuel-cell independent micro-grid with wind power generation were investigated by numerical analysis. Step loads and an apartment house power load model were analyzed using the dynamic characteristics of a fuel cell obtained from experiments. The output of wind power generation and fuel cells is controlled by proportional-integral control of an independent micro-grid for rapid power demand change.     

MATLAB-based simulator of a 5 kW fuel cell for power electronics design

In the last few years, renewable energies have been encouraged by worldwide governments to meet energy saving policies. Among renewable energy sources, fuel cells have attracted much interest for a wide variety of research areas. Since combined heat-power generation is allowed, household appliances are still the most promising applications. Fuel cell-based residential-scaled power supply systems take advantage by simultaneous generation of power and heat, reducing the overall fossil fuel consumption and utilities cost. Modelling is one of the most important topic concerning fuel cell use. In this paper, a measurement-based steady-state and dynamic fuel cell model is presented. The parameters identification procedure is analyzed and the MATLAB/Simulink implementation is shown. The proposed modelling approach is implemented on a 5 kW Proton Exchange Membrane Fuel Cell. As shown by the comparison between experimental and simulation results, the model error is restricted to ±1%, corresponding to a maximum absolute model error of 0.6 V.     

一种计及无功补偿的分布式电源优化配置方法

可再生能源以分布式电源的形式接入配电网是消纳可再生能源的重要手段,为进一步提高可再生能源的利用率,本文在分布式电源优化配置过程中考虑无功补偿设备以及储能系统的配置,建立了分布式电源、储能系统、无功补偿设备建设成本最小,系统网络损耗最小,系统电压稳定指标最优的多目标优化模型,并提出基于概率分布策略的改进遗传算法用于优化模型的求解。最后,以IEEE-33节点配电网系统为例,表明本文提出的配置方法可以改善分布式电源的波动性对配电网的不利影响,在保证系统稳定的前提下,进一步提高可再生能源利用率。