Sizing methodology for hybrid systems based on multiple renewable power sources integrated to the energy management strategy

This work presents a design methodology for a hybrid energy system based on multiple renewable power sources and bioethanol. The new concept of generation consists on having multiple power sources such as a PEM fuel cell system fed by the hydrogen produced by a bioethanol reformer and wind-solar sources working all together supervised by the energy management system. The necessary heating for the bioethanol reforming reaction can be provided by the renewable sources to enhance the efficiency of the hydrogen production. It is worth noting that, from the power balance as well as backup point of views, the hybrid system is equipped with energy storage devices. An optimal sizing methodology integrated with the energy management strategy is proposed here for designing the overall hybrid system. The suggested approach is based on genetic algorithms, using historical climate data and load demands over a period of one year. Several simulation results are given to show the methodology performance in terms of loss of power supply probability (LPSP), costs and bioethanol consumption.     

Modeling of integrated renewable energy system for electrification of a remote area in India

Over the years, renewable energy based power generation has proven to be a cost-effective solution in stand-alone applications in the regions where grid extension is difficult. The present study focused on the development of models for optimal sizing of integrated renewable energy (IRE) system to satisfy the energy needs in different load sectors of four different zones considered in Chamarajanagar district of Karnataka state in India. The objective of the study is to minimize the total cost of generation and cost of energy using genetic algorithm (GA) based approach. Considering optimization power factor (OPF) and expected energy not supplied (EENS), optimum system feasibility has been investigated. Based on the study, it has been found that IRES is able to provide a feasible solution between 1.0 and 0.8 OPF values. However, power deficit occurs at OPF values less than 0.8 and the proposed model becomes infeasible under such conditions. Customer interruption cost (CIC) and deficit energy (DE) for all zones were also computed to quantify the reliability of the systems.     

Development of IREOM model based on seasonally varying load profile for hilly remote areas of Uttarakhand state in India

An Integrated Renewable Energy Optimization Model (IREOM) model has been developed for sizing and optimization of renewable energy systems based on seasonal variation in the load profiles of the study area. An attempt has been made to develop correlations between renewable energy system sizes and their capital cost for the user specified system sizes. The developed correlations were used for the analysis of IREOM model using user specified system sizes and compared with manufacturer specified system sizes. The cluster of seven unelectrified villages having micro-hydro power, biomass, wind and solar energy resources in the state of Uttarakhand, India has been considered for the implementation of IREOM model. Based on the results obtained from the proposed model, suitable sizes of renewable energy systems have been suggested.     

Modelling an off-grid integrated renewable energy system for rural electrification in India using photovoltaics and anaerobic digestion

This work describes the design optimisation and techno-economic analysis of an off-grid Integrated Renewable Energy System (IRES) designed to meet the electrical demand of a rural village location in West Bengal – India with an overall electrical requirement equivalent to 22 MWh year⁻¹. The investigation involved the modelling of seven scenarios, each containing a different combination of electricity generation (anaerobic digestion with biogas combined heat and power (CHP) and photovoltaics) and storage elements (Vanadium redox batteries, water electrolyser and hydrogen storage with fuel cell). Micro-grid modelling software HOMER, was combined with additional modelling of anaerobic digestion, to scale each component in each scenario considering the systems' ability to give a good quality electricity supply to a rural community. The integrated system which contained all of the possible elements – except hydrogen production and storage presented the lowest capital ($US 71 k) and energy cost ($US 0.289 kWh⁻¹) compared to the scenarios with a single energy source. The biogas CHP was able to meet the electrical load peaks and variations and produced 61% of the total electricity in the optimised system, while the photovoltaics met the daytime load and allowed the charging of the battery which was subsequently used to meet base load at night.     

Reliability based socio economic optimal renewable energy model for India

Renewable energy sources such as solar, wind and biomass have to play a vital role in the developing countries like India in order to meet the growing energy demand. In the last five years, some renewable energy sources had emerged as technically and economically viable alternatives in the energy sector, as a result, more ambitious plans for their dissemination were being launched. In this situation, development of an energy model exclusively for renewables will help in the allocation of appropriate renewable energy systems for different end-uses in the future. An attempt has been made to develop a reliability based socio economic optimal renewable energy model for India in the year 2020–2021. The effect of social acceptance variation in OREM model was analysed. The lighting end-use would be met by solar PV and biogas system to an extent of 0.5198×10¹⁵ kJ and 0.75×10¹⁵ kJ, respectively. Similarly, the renewable energy utilisation is found for other end-uses.     

海上可再生能源开发评价指标体系与实证研究

开发海上可再生能源对于优化能源结构具有重要意义。文章在对海上可再生能源主要开发形式调查分析的基础上,从技术、经济、资源、环境、安全5方面构建了海上可再生能源开发评价指标体系,在此基础上,从能源转换效率、技术成熟度、投资成本等方面对潮汐能、潮流能、波浪能等海上可再生能源开发形式进行分析。以大连为例进行实证研究,利用构建的指标体系对大连地区的海上风能开发进行分析评价,提出了大连地区海上可再生能源开发的建议。     

Development of an integrated data-acquisition system for renewable energy sources systems monitoring

Data-acquisition systems are widely used in renewable energy source (RES) applications in order to collect data regarding the installed system performance, for evaluation purposes. In this paper, the development of a computer-based system for RES systems monitoring is described. The proposed system consists of a set of sensors for measuring both meteorological (e.g. temperature, humidity etc.) and electrical parameters (photovoltaics voltage and current etc.). The collected data are first conditioned using precision electronic circuits and then interfaced to a PC using a data-acquisition card. The LABVIEW program is used to further process, display and store the collected data in the PC disk. The proposed architecture permits the rapid system development and has the advantage of flexibility in the case of changes, while it can be easily extended for controlling the RES system operation.     

A new integrated renewable energy system for clean electricity and hydrogen fuel production

In this paper, a new renewable energy-based cogeneration system for hydrogen and electricity production is developed. Three different methods for hydrogen production are integrated with Rankine cycle for electricity production using solar energy as an energy source. In addition, a simple Rankine cycle is utilized for producing electricity. This integrated system consists of solar steam reforming cycle using molten salt as a heat carrier, solar steam reforming cycle using a volumetric receiver reactor, and electrolysis of water combined with the Rankine cycle. These cycles are simulated numerically using the Engineering Equation Solver (EES) based on the thermodynamic analyses. The overall energetic and exergetic efficiencies of the proposed system are determined, and the exergy destruction and entropy generation rates of all subcomponents are evaluated. A comprehensive parametric study for evaluating various critical parameters on the overall performance of the system is performed. The study results show that both energetic and exergetic efficiencies of the system reach 28.9% and 31.1%, respectively. The highest exergy destruction rates are found for the steam reforming furnace and the volumetric receiver reforming reactor (each with about 20%). Furthermore, the highest entropy generation rates are obtained for the steam reforming furnace and the volumetric receiver reforming reactor, with values of 174.1 kW/K and 169.3 kW/K, respectively. Additional parametric studies are undertaken to investigate how operating conditions affect the overall system performance. The results report that 60.25% and 56.14% appear to be the highest exergy and energy efficiencies at the best operating conditions.     

An opinion survey based assessment of renewable energy technology development in India

India has a very large potential for harnessing renewable energy sources. However, there is a large gap between the estimated potential and the cumulative achievements made so far. A variety of reasons are attributed to the current low levels of dissemination of renewable energy technologies in India as against their respective estimated potentials. Several of these attributes could, one way or the other, be related to the current status of development of the technology, its appropriateness and dissemination strategies adopted for their diffusion and deployment. Results of an attempt to assess the current status of some renewable energy technologies in India are briefly presented in this paper. The main findings of a structured questionnaire based survey undertaken for eliciting views of different categories of stakeholders on various issues affecting dissemination of renewable energy technologies in India are presented in this paper.     

A renewable source based hydrogen energy system for residential applications

In this study, both concentrated solar power and wind energy systems are integrated with electrolyser, fuel cell and absorption cooling subsystems to supply power, cooling, heating and hydrogen to residential applications in an environmentally benign and efficient manner. These subsystems are integrated in a unique way to manage the excess power through water electrolysis to produce and store hydrogen. Integrated systems are thermodynamically analyzed, and their performance is assessed comparatively. Solar radiation intensity, inlet temperature and wind velocity are taken into account, and hence their effects on the system performance are investigated. The results of this study show that the present system appears to be efficient, environmentally friendly and hence sustainable.     

Hybrid renewable energy‐based distribution system for seasonal load variations

In recent scenario, there is abundant availability of renewable energy resources to satisfy the significant increase in residential, industrial, and commercial demand. This paper presents a novel framework to determine the preeminent size of renewable distributed generators (RDGs) by optimizing the system components such as area required for solar‐photovoltaic modules, swept area occupied by wind turbine blades, and area used by fuel cell. A microgrid with hybrid RDG (h‐RDG) is integrated in distribution system to minimize the distribution loss, substation energy requirement, and improve the voltage level of the load. The power loss minimization is formulated as a nonlinear problem and optimized by the proposed Hybrid Nelder Mead‐Particle Swarm Optimization algorithm. The microgrid location is identified by voltage stability index to improve the stability of system. Further, the system is analyzed for energy flow in different seasonal loading conditions with mixture of residential, industrial, and commercial load. The effective performance of the proposed technique is applied to standard 12‐bus, 69‐bus, and a practical Tamil Nadu (TN) 84‐bus radial distribution system (RDS) for different hybrid combinations of h‐RDG in microgrid. The result proves that the proposed method provides a simple and efficient tool for optimal and flexible use of h‐RDG in microgrid under different climatic changes by simultaneously reducing distribution energy loss and improving voltage profile.     

Performance of a stand-alone renewable energy system based on energy storage as hydrogen

Electrolytic hydrogen offers a promising alternative for long-term energy storage of renewable energy (RE). A stand-alone RE system based on energy storage as hydrogen has been developed and installed at the Hydrogen Research Institute, and successfully tested for autonomous operation with developed control system and power conditioning devices. The excess energy produced, with respect to the load requirement, has been sent to the electrolyzer for hydrogen production. When energy produced from the RE sources became insufficient, with respect to the load requirement, the stored hydrogen was fed to a fuel cell to produce electricity. The RE system components have substantially different voltage-current characteristics and they are integrated through power conditioning devices on a dc bus for autonomous operation by using a developed control system. The developed control system has been successfully tested for autonomous operation and energy management of the system. The experimental results clearly indicate that a stand-alone RE system based on hydrogen production is safe and reliable.     

考虑碳捕集利用与可再生能源的低碳综合能源系统配置优化研究

为实现传统工业部门的低碳转型,构建了集成可再生能源、电锅炉、储热以及碳捕集利用与封存（CCUS）装备的低碳综合能源系统,并提出了经济和低碳双重导向下的系统配置优化方法。应用粒子群优化算法求解获得各设备的最优配置容量及典型场景下的最优调度方案,并选取乙烯工业进行案例分析。结果表明：通过引入CCUS和可再生能源装备,系统碳排放减少了57.50%,年总成本增加15.92%;当碳价高于109.61元/t时,低碳综合能源系统具有经济和低碳双重优势。     

A novel renewable energy-based integrated system with thermoelectric generators for a net-zero energy house

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.     

多种形式可再生能源集成互补供暖供冷系统在农村地区的应用

介绍了三种可在农村地区利用的可再生能源状况,提出了一种利用地热能、太阳能、生物质能三种形式可再生能源集成互补供暖供冷系统,并对此系统进行简要的热力学分析。     

可再生能源供热系统在农村建筑的应用研究

农村建筑普遍存在保温性能差、体形系数大、采暖系统能耗高等问题,不仅消耗了大量化石能源,而且造成了严重的环境污染。因此,在建筑采暖领域,尤其是农村这类高能耗建筑,推广可再生能源的应用是十分必要的。单一形式的采暖系统具有不稳定、效率低等缺陷,通过掌握可再生能源互补系统在建筑和工业领域的应用研究历程,对其在农村建筑中的应用可行性和前景进行了创新性分析。     

Decoupling optimization of integrated energy system based on energy quality character

Connections among multi-energy systems become increasingly closer with the extensive application of various energy equipment such as gas-fired power plants and electricity-driven gas compressor. Therefore, the integrated energy system has attracted much attention. This paper establishes a gas-electricity joint operation model, proposes a system evaluation index based on the energy quality character after considering the grade difference of the energy loss of the subsystem, and finds an optimal scheduling method for integrated energy systems. Besides, according to the typical load characteristics of commercial and residential users, the optimal scheduling analysis is applied to the integrated energy system composed of an IEEE 39 nodes power system and a 10 nodes natural gas system. The results prove the feasibility and effectiveness of the proposed method.     

The state of renewable energy harnessing in Tanzania

This paper details the state of renewable energy development in Tanzania and biomass energy supply and consumption. It also highlights the various levels of renewable energy programmes in the country and the Government strategy to improve renewable energy production and utilization technologies. A number of problems hindering the development of renewable energy technologies have been identified and discussed. Biomass accounts for 92% of final energy consumption in Tanzania and will continue to dominate the national energy balance. For example, fuelwood and agricultural residues used to meet domestic energy needs account for 80% of the domestic energy requirements, while commercial energy such as kerosene, electricity and liquefied petroleum gas account for 1%. Total biomass resources for 1990 was 27 million tonnes of oil equivalent (TOE) from the natural forests. Other major industrial biomass energy sources include sawmill industry, sugarcane plantations, sugar industry by-products, cashew nut industry, coffee industry and sisal industry. The major biomass consumers include woodfuel for domestic use, tobacco production, brick making, tea drying and fish smoking. While there are efforts to develop other renewable sources of energy such as solar, wind and minihydros, there are also problems hindering their development. They include the lack of adequate data on the actual energy potential of these sources as well as the lack of local capability to design and manufacture energy related equipment and spare parts.     

Discrete harmony search based size optimization of Integrated Renewable Energy System for remote rural areas of Uttarakhand state in India

In the recent years, decentralized power generation using locally available renewable energy resources has been recognized as a cost effective alternative of uneconomical grid extension. The present paper deals with the size optimization of Integrated Renewable Energy System (IRES) for a cluster of villages of Uttarakhand state in India. The proposed IRES consists of locally available renewable energy resources of Micro Hydro Power (MHP), biogas, biomass, wind and solar energy in order to meet the electrical and cooking demands of the study area. A system operation strategy has been developed in the paper for size optimization of IRES. Also, the loss of power supply probability (LPSP) has been used as the reliability criteria in order to ensure the continuous supply of power without any failure problems. Further, in order to utilize renewable energy resources in different contributions, four different resource scenarios are considered for the study area. Finally, the total net present cost (NPC) of the considered scenarios has been optimized using discrete harmony search (DHS) algorithm. Among different scenarios, MHP-biogas-biomass-wind-solar-battery based IRES offers the lowest net present cost of INR 49.0309 million at the estimated LCOE of INR 5.47/kWh.