Stand-alone Photovoltaic Energy System Research Articles

Design of a Stand-Alone Photovoltaic Energy System for Small-Scale Business Outlets (Case Study of Arogbo Community in Ondo State)

This paper designed a stand-alone photovoltaic energy system for small-scale business outlets in rural areas, using Arogbo Community in Ese-Odo Local Government Area of Ondo State, Nigeria as a case study. Structured questionnaires were administered to 150 business outlets for energy audit. Total energy estimate and consumption for 8 hours daily operation were estimated from obtained information. Total energy demand of the outlets based on their appliances used per day with power factor of 0.8 and 15% tolerance for a maximum load of 355.228 kW was 1,894.844 kWh. The specific energy required for a typical outlet (Barbing Salon, Computer Centre and Hairdressing Shop) were (0.938, 9.04 and 10.87) kWh, and their photovoltaic equivalence were estimated as (1.266, 12.211 and 14.67) kWh respectively. The solar components for the outlets were estimated as (0.317, 3.053 and 3.66) kW solar modules on installation areas of (3, 28.4 and 34) m2. Inverter ratings of (0.22, 4 and 6) kVA were selected for the respective outlets. (1, 4, and 4) numbers of 12 V deep cycle batteries of (100, 150 and 150) AH were selected. Electricity generator capacities selected were (1, 4 and 6) kVA respectively.

Comparison of Economic Performance of Lead-Acid and Li-Ion Batteries in Standalone Photovoltaic Energy Systems

Standalone renewable energy systems usually incorporate batteries to get a steady energy supply. Currently, Li-ion batteries are gradually displacing lead-acid ones. In practice, the choice is made without previous comparison of its profitability in each case. This work compares the economic performance of both types of battery, in five real case studies with different demand profiles. For each case, two sets of simulations are carried out. In one of the sets, the energy demand is supplied by a standalone photovoltaic system and, in the other one, by a standalone hybrid photovoltaic-diesel system. Through optimization processes, the economic optimum solutions are obtained. In addition, sensitivity analyses on various parameters have been carried out, seeking the influence in favor of one or another type of battery. The results show that if the type of battery is changed, to achieve the economic optimum the entire system must be resized. In some cases, the economic optimum is reached with Li-ion and in others with lead-acid batteries, depending on the demand profiles. Thus, both types of batteries can be profitable options in standalone energy systems, with a greater tendency to lead-acid in fully photovoltaic systems and to Li-ion in hybrids. The price reductions that would make Li-ion the only choice is quantified.

Design of an Ultra-Low Powered Data-Logger for Stand-Alone PV Energy Systems

This paper presents an open-source, ultra-low powered data-logger for off-grid photovoltaic (PV) energy systems. Deep-sleep mode of ESP32-S2 microcontroller is used along with voltage, current, and light sensors for logging the data of PV energy system to an external micro SD card. A toggle switch is used to switch the operational modes of data-logger between deep-sleep and web-server modes. Real-time PV data can be monitored in a local web-portal programmed in the microcontroller. The same web-portal is also used to check and download the historical data of a PV energy system. The energy consumption of the designed system is 7.33mWh during deep-sleep mode and 425mWh during the web-server mode. The total cost of the designed data-logger is C$ 30.

Multi-criteria approach in solar urban water supply systems

An innovative method for sizing solar photovoltaic (PV) pumping systems in urban water supply systems (UWSSs) is presented. The methodology is based on various critical period approaches (the critical period method). A multi-criteria analysis was carried out to evaluate the effects of the critical period duration on the system characteristics. It was found that the critical period length is a design variable that significantly affects the economic, environmental and social aspects of the solution, with a lengthening of the critical period resulting in improvement of the overall sustainability of the solution. The results obtained indicate that a solar PV system is a promising solution to the energy sustainability of UWSSs. This form of energy supply does not emit greenhouse gases and furthermore the ‘social cost’ of carbon dioxide estimates decrease. The concept of a stand-alone PV energy system is a particularly promising sustainable energy solution.

A Single-Stage Stand-Alone Photovoltaic Energy System With High Tracking Efficiency

A single-stage flyback PV inverter with maximum power point tracking (MPPT) high-speed capability is presented in this paper. The proposed stand-alone photovoltaic energy system (SAPES) incorporates the use of hybrid MPPT to ensure peak energy harvesting under all weather conditions. The proposed hybrid MPPT method combines the conventional short current pulse (SCP) MPPT method and the perturb and observe (P&O) methods. Measurement of the offline parameter [short-circuit current of PV module ( ${I}_{\rm sc}$ )] for SCP is made on the basis of the difference between the offline parameter and the instantaneous current of PV module ( ${I}_{\rm pv}$ ). Use of a single power conversion stage is achieved by employing a modified flyback inverter operating in a discontinuous-conduction mode. The control structure of the conventional flyback inverter is also modified to incorporate the hybrid MPPT algorithm. The proposed SAPES method is tested using computer-aided simulations and real-time hardware in the loop experimentation using the dSPACE DS1104 board. The results obtained using the proposed systems are better than those for the conventional algorithms under the environmental conditions tested.

A novel MPPT algorithm based on optimized artificial neural network by using FPSOGSA for standalone photovoltaic energy systems

Maximum power point tracking (MPPT) algorithms are used to maximize the output power of the photovoltaic (PV) panel under different temperature and irradiance conditions in photovoltaic energy sources (PVES). In this paper, a novel MPPT method based on optimized artificial neural network by using hybrid particle swarm optimization and gravitational search algorithm based on fuzzy logic (FPSOGSA) is proposed to track the operation of the PV panel in maximum power point (MPP). The performance of the proposed MPPT approach is tested by doing the simulation and experimental studies under different environmental conditions. The proposed method is compared with the conventional perturb and observation (P&O) method for standalone PVES. The results of the comparison the obtained from the simulation and experimental studies demonstrate that the proposed MPPT method provides the reduction oscillations around the MPP and the increased maximum power yield of the PV system in the steady state.

Design of a Stand-Alone Photovoltaic Model for Home Lightings and Clean Environment

This paper gives a well-documented health risks of fuel-based lighting (kerosene lamps and fuel-powered generators) and proposed a design of a stand-alone solar PV system for sustainable home lightings in rural Nigerian area. The design was done in three different patterns of electricity consumptions with energy efficient lightings (EELs) using two different battery types (Rolls Surrette 6CS25PS and hoppecke 10 OpzS 1000) on; i) judicious power consumption, ii) normal power consumption, iii) excess power consumption; and compared them with the incandescent light bulb consumption. The stand-alone photovoltaic energy systems were designed to match the rural Nigerian sunlight and weather conditions to meet the required lightings of the household. The objective function and constraints for the design models were formulated and optimization procedure were used to demonstrate the best solution (reliability at the lowest lifecycle cost). Initial capital costs as well as annualized costs over 5, 10, 15, 20, and 25 years were quantified and documented. The design identified the most cost-effective and reliable solar and battery array among the patterns of electricity consumption with energy efficient lighting options (judicious power consumption, normal power consumption, and excess power consumption).

Feasibility Analysis and Simulation of a Stand-Alone Photovoltaic Energy System for Electricity Generation and Environmental Sustainability – Equivalent to 650VA Fuel-Powered Generator – Popularly Known as “I Pass My Neighbour”

Photovoltaic (PV) power system can be used to replace wholly 650VA generator for electricity generation for household use in Nigeria. This paper presented the feasibility analysis of load data and simulation study of a stand-alone PV power system that produced the electrical needs of a household. This study is based on designing of PV energy system for household use. The patterns of load consumption within the household were studied and suitably modeled for simulation. The simulation study indicates that energy requirements to provide electricity which is equivalent to 650VA generator for household use in Nigeria can be accomplished by 520W solar PV array, 2312 Ah nominal capacity battery, and a 1kW DC/AC inverter. This would be suitable for deployment of 100% clean energy for environmental sustainability and uninterruptable power performance in the household. The results of this research show that, with a low-power consuming appliances, it is possible to meet the entire annual electricity demand of a single household solely through a stand-alone PV energy supply. Installing solar panels by most Nigerian home can significantly reduce home reliance on government power thereby reduce the strain on the current capacity of our power generation infrastructure. A detailed design and description of the system were presented in this paper.

Feasibility and Optimal Design of a Stand-Alone Photovoltaic Energy System for the Orphanage

Access to electricity can have a positive psychological impact through a lessening of the sense of exclusion, and vulnerability often felt by the orphanages. This paper presented the simulation and optimization study of a stand-alone photovoltaic power system that produced the desired power needs of an orphanage. Solar resources for the design of the system were obtained from the National Aeronautics and Space Administration (NASA) Surface Meteorology and Solar Energy website at a location of 6°51′N latitude and 7°35′E longitude, with annual average solar radiation of 4.92 kWh/m2/d. This study is based on modeling, simulation, and optimization of energy system in the orphanage. The patterns of load consumption within the orphanage were studied and suitably modeled for optimization. Hybrid Optimization Model for Electric Renewables (HOMER) software was used to analyze and design the proposed stand-alone photovoltaic power system model. The model was designed to provide an optimal system configuration based on an hour-by-hour data for energy availability and demands. A detailed design, description, and expected performance of the system were presented in this paper.

Modeling and Simulation of Closed Loop Controlled Buck Converter for Solar Installation

The stand-alone photo-voltaic energy system requires storage to meet the energy demand during period of low solar irradiation and night time. Storage batteries account for the most PV system failures and contribute significantly to both initial and the eventual replacement cost. Switch mode DC to DC converters are used to match the output of a PV generator to a variable load. This paper deals the design of DC to DC converter which makes voltage is maintained at a specified value. Digital simulation of open loop and closed loop controlled buck converter for solar installation is discussed. The simulation results are compared with the theoretical results. This converter has advantages like improved power factor, fast response and reduced hardware.

A battery management system for stand-alone photovoltaic energy systems

It is estimated that about 80% of all photovoltaic (PV) modules are used in stand-alone applications. Continuous power is obtained from PV systems by using a storage buffer, typically in the form of a lead acid battery. Batteries used in PV applications have different performance characteristics compared with batteries used in more traditional applications. In PV applications, lead acid batteries do not reach the cycle of lead acid batteries used in other applications such as uninterruptible power supplies or electric vehicles. The shortened battery life contributes significantly to the costs of a PV system. In some PV systems the battery accounts for more than 40% of the life cycle costs. An increase in the lifetime of the battery will result in improved reliability of the system and a significant reduction in operating costs. The life of a lead acid battery can be extended by avoiding critical operating conditions such as overcharge and deep discharge. This paper presents a battery management system for such applications.

The effect of day-to-day correlation in solar radiation on the probability of loss-of-power in a stand-alone photovoltaic energy system

This paper extends a method previously developed by the author for evaluating the probability of loss-of-power of stand-alone photovoltaic solar energy systems. As before, the method treats the energy capture, storage and dispersement process as a random walk in the storage domain. Correlation in day-to-day levels of solar insolation is now taken into account in the derivation of an expression for the probability of depleting storage.

An Overview Of Control Aspects Of A Village Stand-Alone Photovoltaic Power System

As stand-alone photovoltaic (PV) energy systems have increased in size and diversity of loads, the importance of controls cannot be overstated. These systems represent "mini utilities" with the commensurate control requirements, albeit with the added complexity of not only the loads being variable, but also the energy source (sunlight received) being an uncontrollable variable. The first village stand-alone photovoltaic power system in the world, located in the remote Indian village of Schuchuli, Arizona, U.S.A., is used here as an example to show that stand-alone photovoltaic energy systems employing load management control are feasible and could play an important role in solving energy problems in developing areas of the world. The major components and control concepts of this photovoltaic energy system are reviewed. Performance considerations are briefly discussed along with research topics related to such systems. The foundation is thus laid for future generations of renewable energy system controls.