Modelling of solar/diesel/battery hybrid power systems for far-north Cameroon

Solar/diesel/battery hybrid power systems have been modelled for the electrification of typical rural households and schools in remote areas of the far north province of Cameroon. The hourly solar radiation received by latitude-titled and south-facing modules was computed from hourly global horizontal solar radiation of Garoua using Hay's anisotropic model. Using the solar radiation computed for latitude-tilted and south-facing modules, the average daytime temperatures for Garoua and parameters of selected solar modules, the monthly energy production of the solar modules was computed. It was found that BP solar modules with rated power in the range 50–180 Wp produced energy in the range 78.5–315.2 kWh/yr. The energy produced by the solar modules was used to model solar/diesel/battery hybrid power systems that could meet the energy demand of typical rural households in the range 70–300 kWh/yr. It was also found that a solar/diesel/battery hybrid power system comprising a 1440 Wp solar array and a 5 kW single-phase generator operating at a load factor of 70%, required only 136 generator h/yr to supply 2585 kWh/yr or 7 kWh/day to a typical secondary school. The renewable energy fraction obtained in all the systems evaluated was in the range 83–100%. These results show that there is a possibility to increase the access rate to electricity in the far north province without recourse to grid extension or more thermal plants in the northern grid or more independent diesel plants supplying power to remote areas of the province.     

Field analysis of solar PV-based collective systems for rural electrification

This article analyses the long-term performance of collective off-grid photovoltaic (PV) systems in rural areas. The use of collective PV systems for the electrification of small medium-size villages in developing countries has increased in the recent years. They are basically set up as stand-alone installations (diesel hybrid or pure PV) with no connection with other electrical grids. Their particular conditions (isolated) and usual installation places (far from commercial/industrial centers) require an autonomous and reliable technology. Different but related factors affect their performance and the energy supply; some of them are strictly technical but others depend on external issues like the solar energy resource and users’ energy and power consumption. The work presented is based on field operation of twelve collective PV installations supplying the electricity to off-grid villages located in the province of Jujuy, Argentina. Five of them have PV generators as unique power source while other seven include the support of diesel groups. Load demand evolution, energy productivity and fuel consumption are analyzed. Besides, energy generation strategies (PV/diesel) are also discussed.     

The delivery of low-cost,low-carbon rural energy services

The provision of both electrical and mechanical energy services can play a critical role in poverty alleviation for the almost two billion rural users who currently lack access to electricity. Distributed generation using diesel generators remains a common means of electricity provision for rural communities throughout the world. Due to rising fuel costs, the need to address poverty, and consequences of global warming, it is necessary to develop cost efficient means of reducing fossil fuel consumption in isolated diesel microgrids. Based on a case study in Nicaragua, a set of demand and supply side measures are ordered by their annualized costs in order to approximate an energy supply curve. The curve highlights significant opportunities for reducing the costs of delivering energy services while also transitioning to a carbon-free electrical system. In particular, the study demonstrates the significant cost savings resulting from the implementation of conventional metering, efficient residential lighting, and electricity generation using renewable energy sources.     

Experimental investigation of power management and control of a PV/wind/fuel cell/battery hybrid energy system microgrid

This paper presents an experimental study of a standalone hybrid microgrid system. The latter is dedicated to remote area applications. The system is a compound that utilizes renewable sources that are Wind Generator (WG), Solar Array (SA), Fuel Cell (FC) and Energy Storage System (ESS) using a battery. The power electronic converters play a very important role in the system; they optimize the control and energy management techniques of the various sources. For wind and solar subsystem, the speed and Single Input Fuzzy Logic (SIFL) controllers are used respectively to harvest the maximum power point tracking (MPPT). To maintain a balance of energy in the hybrid system, an energy management strategy based on the battery state of charge (SOC) has been developed and implemented experimentally. The AC output voltage regulation was achieved using a Proportional Integral (PI) controller to supply a resistive load with constant amplitude and frequency. According to the obtained performances, it was concluded that the proposed system is very promising for potential applications in hybrid renewable energy management systems.     

Study of hybrid energy system coupling fuel cell,solar thermal system and photovoltaic cell

The present work examines the combination of solar energy systems with Fuel cell. Indeed, fuel cells are green storage systems without any pollution effects. They are supplied by oxygen and hydrogen to produce electricity. That is why it is inescapable to find a source of hydrogen in order to use fuel cell. Several techniques can be adopted to produce hydrogen depending on the availability and the cost of the sources. One of the most utilized techniques is electrolysers. They allow to obtain hydrogen from water by several technologies among them proton exchange membrane (PEM) which is considered in this work. On the other hand, electrolysers need electrical power to operate. A green-green energy system can be constructed by using a renewable energy source to supply fuel cell trough electrolysers. A comparison between two solar systems (Photovoltaic and Parabolic Trough) coupled to fuel cell is performed. A case study on the Lebanese city of Tripoli is carried out. The study shows the performance of each of both combined systems for different parameters and proposes recommendations depending on the considered configuration.     

Potential application of renewable energy for rural electrification in Malaysia

Energy poverty and lack of electricity in rural areas exacerbate the poverty of the developing countries. In Malaysia, 3.8% of the population lives below the poverty line and most of them are settled in rural areas. The electricity coverage in poor states is about 79% in comparison with 99.62% in Peninsular Malaysia. The renewable energy sources can be considered the best alternative to reduce the energy poverty of the rural areas where the grid extension through a difficult terrain and thick jungle is not possible or economic. In this study, the potential for applying renewable sources – solar, wind and hydropower – for rural electrification is investigated, especially in the poorest States. A comparative study on rural electrification policies, in order to have community approval, appropriate siting and financial benefits for the rural community, while considering the three categories of social, institutional and economic issues, is also examined. Finally, the Malaysian policies of rural electrification by applying renewable sources are explained. It is found that in Malaysia, with a maximum solar radiation of about 6.027 kWh/m² per day in Sabah and 5.303 kWh/m² per day in Sarawak, the potential for applying solar energy for electrification is too high. However, the potential for micro-hydropower in Sabah and Sarawak is found to be 3182 kW and 6317 kW through 18 and 22 sites, respectively.     

An optimal method of the energy consumption for fuel cell hybrid tram

Energy conservation running for vehicle has been a promising research hotspot in the many universities and research institutions. In order to improve the energy utilization rate in the vehicle running process, an optimization method of the energy consumption and recycle based on fuel cell (FC)/supercapacitor (SC) hybrid tram is proposed in this paper. In the method, a tram operation energy management strategy based on Pontriagin's minimum principle (PMP) can effectively was proposed what adjusts the output power of FC and SC and decreases hydrogen consumption. In addition, a tram breaking velocity curve with maximum energy recovery and the allocation strategy between regenerative force and mechanical braking force be also studied in this paper. According to the simulation results, it could be obtained that the Energy conservation rate is about 5% higher than the un-optimized, it will effectively decrease hydrogen consumption.     

Prospects of key technologies of integrated energy systems for rural electrification in China

Owing to increasing environmental concerns and resource scarcity, integrated energy system shave become widely used in communities. Rural energy systems, as one of the important links of the energy network in China, suffer from low energy efficiency and weak infrastructure. Therefore, it is particularly important to increase the proportion of electricity consumption and build an integrated energy system for rural electrification in China (IESREIC) with a rural distribution network as the core, in line with national conditions. In this study, by analyzing the Chinese regional differences and natural resource endowments, the development characteristics of the IESREIC are summarized. Then, according to the existing rural energy problems, key technologies are proposed for the IESREIC, such as those for planning and operation, value sharing, infrastructure, and a management and control platform. Finally, IESREIC demonstration projects and business models are introduced for agricultural production, rural industrial systems, and rural life. The purpose is to propose research concepts for the IESREIC, provide suggestions for the development of rural energy, and provide a reference for the construction of rural energy systems in countries with characteristics similar to those of China.     

Economic analysis of PV/diesel hybrid system with flywheel energy storage

This paper analyzes a hybrid energy system performance with photovoltaic (PV) and diesel systems as the energy sources. The hybrid energy system is equipped with flywheel to store excess energy from the PV. HOMER software was employed to study the economic and environmental benefits of the system with flywheels energy storage for Makkah, Saudi Arabia. The analysis focused on the impact of utilizing flywheel on power generation, energy cost, and net present cost for certain configurations of hybrid system. Analyses on fuel consumption and carbon emission reductions for the system configurations were also presented in this paper.     

The potential of renewable energy technologies for rural development in Lesotho

The potential and utilization of renewable energy technologies (RETs), and energy analysis in Lesotho with emphasis on the contribution of solar energy technologies (SETs) is presented. The heavy reliance of the country on imported fossil fuel coupled with the growing demand for electricity and declining wood fuel supplies call for alternative sources of energy. Taking the average global solar radiation that ranges from 15 to 20 MJ/m² and cognizant of the short falls of other renewable energy sources in Lesotho, this paper focuses on the application of solar energy and associated developmental issues. The paper provides a statistical analysis of the energy demand and identifies areas of further growth for SETs. Various application areas of solar energy and their contribution to development in Lesotho together with future prospects for use of solar energy are also discussed. An analysis of the relative merits of using photovoltaic (PV) devices over other renewable energy sources in Lesotho is presented. It is argued that with proper economic support and utilization of efficient RETs, developing countries like Lesotho can meet their basic energy demands and alleviate the problems of energy shortages.     

Modeling and control of a wind fuel cell hybrid energy system

This paper describes a hybrid energy system consisting of a 5 kW wind turbine and a fuel cell system. Such a system is expected to be a more efficient, zero emission alternative to wind diesel system. Dynamic modeling of various components of this isolated system is presented. Selection of control strategies and design of controllers for the system is described. Simnon is used for the simulation of this highly nonlinear system. Transient responses of the system for a step change in the electrical load and wind speed are presented. System simulation results for a pre-recorded wind speed data indicates the transients expected in such a system. Design, modeling, control and limitations of a wind fuel cell hybrid energy system are discussed.     

Simulation of a small wind fuel cell hybrid energy system

This paper describes simulation results of a small 500 W wind fuel cell hybrid energy system. The system consists of a Southwest Wind Power Inc. AIR 403 wind turbine, a Proton Exchange Membrane Fuel Cell (PEMFC) and an electrolyzer. Dynamic modeling of various components of this small isolated system is presented. Simulink is used for the dynamic simulation of this nonlinear 48 V hybrid energy system. Transient responses of the system to a step change in the load current and wind speed in a number of possible situations are presented. Analysis of simulation results and limitations of a wind fuel cell hybrid energy system are discussed.     

Comparative study of energy management systems for a hybrid fuel cell electric vehicle - A novel mutative fuzzy logic controller to prolong fuel cell lifetime

Hybrid fuel cell battery electric vehicles require complex energy management systems (EMS) in order to operate effectively. Poor EMS can result in a hybrid system that has low efficiency and a high rate of degradation of the fuel cell and battery pack. Many different types of EMS have been reported in the literature, such as equivalent consumption minimisation strategy and fuzzy logic controllers, which typically focus on a single objective optimisations, such as minimisation of H₂ usage. Different vehicle and system specifications make the comparison of EMSs difficult and can often lead to misleading claims about system performance. This paper aims to compare different EMSs, against a range of performance metrics such as charge sustaining ability and fuel cell degradation, using a common modelling framework developed in MATLAB/Simulink - the Electric Vehicle Simulation tool-Kit (EV-SimKit). A novel fuzzy logic controller is also presented which mutates the output membership function depending on fuel cell degradation to prolong fuel cell lifetime – the Mutative Fuzzy Logic Controller (MFLC). It was found that while certain EMSs may perform well at reducing H₂ consumption, this may have a significant impact on fuel cell degradation, dramatically reducing the fuel cell lifetime. How the behaviour of common EMS results in fuel cell degradation is also explored. Finally, by mutating the fuzzy logic membership functions, the MFLC was predicted to extend fuel cell lifetime by up to 32.8%.     

Rural energy survey and scenario analysis of village energy consumption: A case study in Lao People’s Democratic Republic

In developing countries, providing all citizens an access to modern forms of energy is among the central energy policy objectives, as the linkages between modern energy services and human development are widely recognized. This paper presents in a scenario analysis of rural energy consumption, how energy services in different sectors of a village economy contribute to the achievement of the UNDP Millennium Development Goals. In a rural village in Lao People’s Democratic Republic, household energy demand and energy uses were surveyed immediately prior to the electrification of the village. Based on the situation preceding electrification of the village, the development of village electrification was studied by simulating the village energy system, accounting for all village energy uses but transportation. To study the potential development of electricity demand in the village, three scenarios were constructed using the LEAP model: “residential demand”, “income generation” and “public services”. Energy demand in each scenario was analyzed with reference to the Millennium Development Goals.     

A robust online energy management strategy for fuel cell/battery hybrid electric vehicles

Traditional optimization-based energy management strategies (EMSs) do not consider the uncertainty of driving cycle induced by the change of traffic conditions, this paper proposes a robust online EMS (ROEMS) for fuel cell hybrid electric vehicles (FCHEV) to handle the uncertain driving cycles. The energy consumption model of the FCHEV is built by considering the power loss of fuel cell, battery, electric motor, and brake. An offline linear programming-based method is proposed to produce the benchmark solution. The ROEMS instantaneously minimizes the equivalent power of fuel cell and battery, where an equivalent efficiency of battery is defined as the efficiency of hydrogen energy transforming to battery energy. To control the state of charge of battery, two control coefficients are introduced to adjust the power of battery in objective function. Another penalty coefficient is used to amend the power of fuel cell, which reduces the load change of fuel cell so as to slow the degradation of fuel cell. The simulation results indicate that ROEMS has good performance in both fuel economy and load change control of fuel cell. The most important advantage of ROEMS is its robustness and adaptivity, because it almost produces the optimal solution without changing the control parameters when driving cycles are changed.     

An energy demand model for a fleet of plug-in fuel cell vehicles and commercial building interfaced with a clean energy hub

This paper presents an energy demand model for a fleet of plug-in fuel cell vehicles and a medium-sized commercial/office building interfaced with a clean energy hub. The approach taken is to model the architecture and daily operation of every individual vehicle in the fleet. A simplified architecture model was developed, with daily operation divided into two periods: charging and travelling. During the charging period, the vehicle charges its batteries and refills its compressed hydrogen tanks. During the travelling period, the vehicle depletes the batteries and hydrogen tanks based on distance travelled. Daily travel distance is generated by a stochastic model. The modeling of the clean energy hub is also presented. The clean energy hub functions as an interface between electricity supply and the energy demand (i.e. hydrogen and electricity) of the vehicle fleet and the commercial building. Finally, a sample case is presented to demonstrate the use of the models.     

Review on health-conscious energy management strategies for fuel cell hybrid electric vehicles: Degradation models and strategies

Considering the overwhelming pressure on worldwide demand of fossil fuels and the climate change caused by air pollution, hybrid electric vehicles have seen a promising future thanks to the development of renewable energy sources. Among various kinds of energy sources that have been used in hybrid electric vehicles, lithium-ion battery and proton exchange membrane (PEM) fuel cell exist to be the most favorable ones owing to their high energy density and power density. However, the degradation issues of the energy sources tend to be neglected when designing the energy management strategies for the hybrid electric vehicles. Concerning existing literature, degradation modelling methods of lithium-ion batteries and PEM fuel cells are reviewed and the possibility of integrating them into health-conscious energy management is discussed. Besides, a variety of energy management strategies that have taken the influence of degradations into consideration are reviewed and classified. The contribution of this paper is to investigate the possibility of developing a health-conscious energy management strategy based on accurate estimation of degradation to improve the durability of the system.     

A hierarchical energy management strategy for fuel cell/battery/supercapacitor hybrid electric vehicles

In this paper, a hierarchical energy management strategy (EMS) based on low-pass filter and equivalent consumption minimization strategy (ECMS) is proposed in order to lift energy sources lifespan, power performance and fuel economy for hybrid electrical vehicles equipped with fuel cell, battery and supercapacitor. As for the considered powertrain configuration, fuel cell serves as main energy source, and battery and supercapacitor are regarded as energy support and storage system. Supercapacitor with high power density and dynamic response acts during great power fluctuations, which relives stress on fuel cell and battery. Meanwhile, battery is used to lift the economy of hydrogen fuel. In higher layer strategy of the proposed EMS, supercapacitor is employed to supply peak power and recycle braking energy by using the adaptive low-pass filter method. Meantime, an ECMS is designed to allocate power of fuel cell and battery such that fuel cell can work in a high efficient range to minimize hydrogen consumption in lower layer. The proposed EMS for hybrid electrical vehicles is modeled and verified by advisor-simulink and experiment bench. Simulation and experiment results are given to confirm effectiveness of the proposed EMS of this paper.     

A control architecture to coordinate energy management with trajectory tracking control for fuel cell/battery hybrid unmanned aerial vehicles

Fuel cell/battery hybrid energy storage system (HESS) powered unmanned aerial vehicle (UAV) has the outstanding advantage of long endurance time. Trajectory tracking motion is a commonly used task execution mode of UAVs, especially in autonomous UAVs. This study aims at developing a control architecture to coordinate energy management with trajectory tracking control for fuel cell/battery hybrid UAVs. Its position tracking control adopts model predictive control (MPC) and an extended state observer to eliminate the modeling errors and effect of interference. The attitude tracking control adopts an auto-disturbance rejection controller having a quick response. The obtained control parameters are given as an input to the energy management block. Energy management strategies (EMSs) based on online dynamic programming and hierarchical MPC have been proposed. The results obtained from a simulation show that the proposed trajectory tracking control architecture can track the target trajectory stably with a small tracking error. The tracking performance is stable under interference. Experimental results show that dynamic programming is solved online with good control performance. Compared to ordinary EMSs, dynamic programming and hierarchical MPC can increase endurance time by 2.69% and 1.27%, respectively. The proposed control architecture verifies the coordination of energy management and trajectory tracking control, and prospected the advantages of the combination of fuel cell and autonomous driving for long endurance UAVs in the future.     

A new hybrid solar photovoltaic/ phosphoric acid fuel cell and energy storage system; Energy and Exergy performance

Present work investigates the performance of a combined solar photovoltaic (PV) and Pumped-Hydro and Compressed-Air energy storage system to overcome the challenges of using solar energy systems. This energy system, which is one of the newest hybrid systems, is able to generate electricity and store energy. To examine the solar PV performance the climatic conditions of Shiraz (in Iran) and Abu Dhabi (in UAE) are considered. The results revealed that, the required pump work, which must be supplied by PV system, is equal to 2.85 and 2.62 MJ/m³ for isothermal and isentropic processes, respectively. Furthermore, the total system efficiency is equal to 76.5%. In addition, the total exergy destruction of hybrid system for isentropic process is 8.91% less than that isothermal process. In addition, instead of the solar PV system, a phosphoric acid fuel cell is coupled to the storage system and the results are compared with the main system.