Off-grid Solar System Research Articles

Desempenho econômico de sistemas fotovoltaicos off-grid para irrigação

ABSTRACT Renewable energies are alternatives to replace fossil fuels and are crucial for the sustainability of the agricultural sector, besides being an important alternative for pumping water in irrigation. Thus, understanding revenues and expenses is fundamental in economic feasibility. Therefore, the aim of this study was to assess the behavior of economic indicators in off-grid solar energy system for irrigation based on different scenarios. Photovoltaic projects were developed for different irrigation powers ranging from 0.736 to 22.1 kW, and the costs for implementation and operation, as well as the occurrence of economy of scale were evaluated, and the levelized cost of energy for each power analyzed was determined. In addition, sensitivity analyses were performed, considering the variation in product price and investment cost, to demonstrate the responses in relation to economic indicators. Photovoltaic energy projects showed increasing costs with the increase in power, and the normalized cost per kW followed an economy of scale, while the levelized cost of energy showed feasibility, except for the power of 22.1 kW. The sensitivity analyses showed profitability for the analyzed configurations.

A new technique in reducing self-power consumption in the controller of off-grid solar home system

Reducing the self-power consumption of an off-grid solar home system is an economic model in which consumer employs photovoltaic (PV) system for its own electrical requirements. The latch-based clock gating approach has been employed in existing solar charge controllers to reduce integrated circuit (IC) power being used in the low-powered intended mode, although the reducing power is limited. This paper presents a self-power reduction technique based on wake-up power and latch-hold time; which minimize power supply during idle time for a solar home system. Wake-up power introduces a push-switch mechanism using typical transistor technology. Latch-hold time function is designed using an operational amplifier and negative-positive-negative (NPN) transistor. A technique with dynamic self-supply mechanism is also introduced for decreasing self-power consumption. The self-power consumption is identified via simulation studies where the result shows that the power usage is 70% lower than traditional approaches. This is determined using a simulated wave-shape analysis.

Modelling and analysis of green hydrogen production by solar energy

Abstract In the article, the viability of adopting photovoltaic energy systems to convert solar energy into hydrogen in Iraqi four main cities are examined. A 22 kWp off-grid solar system, an 8 kW alkaline electrolyzer, a hydrogen compressor, and a hydrogen tank were modeled for an entire year in order to produce hydrogen. Using hourly experimental weather data from 2021 to 2030, MATLAB/Simulink is used to create a mathematical model of the recommended system behavior. The results revealed a range of annual hydrogen production from 1713.92 to 1891.12 kg, annual oxygen production from 1199.74 to 1323.78 kg, and annual water consumption from 7139.91 to 7877.29 L. Each kilogram of hydrogen costs $3.79. The results indicate that the optimal location for solar hydrogen production systems might be constructed in the central region of Iraq and in other regions with comparable climatic characteristics, particularly those with high radiation levels.

Effect of Dust Accumulation on Performance of the Photovoltaic Panels in Different Climate Zones

With the increasing demand for energy globally and the need to reduce fossil fuels, paying attention to renewable and clean energy sources is necessary. Solar systems are viable among renewable energy sources for heat and electricity generation. In this study, an Off-grid solar system was investigated by considering the effect of climate conditions and environmental factors such as dust on the performance of PV panels. Performance and efficiency of PV system using PVsyst software in four cities of Iran (Mashhad, Abadan, Rasht, and Sanandaj) with different climates were presented. This study shows that most of the loss occurs in Sanandaj, with the cold and humid climate, which results show an 11.19% efficiency reduction. On the other hand, with its hot and humid climate, Abadan has an 8.33% loss due to the geographical location of this city in the vicinity of desert areas. With a temperate and humid climate, Rasht has a 2.27% decrease, and Mashhad, with a cold and dry climate, has a 2.19% decrease in yield.

Return on Investment (ROI) Analysis of OFF-Grid Solar Photovoltaic System in Residential Sector of Pakistan

Pakistan being a developing country is observing a rapid rise in electricity demand and currently the big cities such as Karachi, Quetta, Rawalpindi and Lahore are most severely affected by the recent power crises. Therefore, at this time it is important to explore and investigates the alternate and renewable power sources in the country. This study investigates the significance in terms of economic feasibility of off-grid solar photovoltaic systems in the residential sector of Pakistan. Study area comprises the rural and urban residential sector of all four provinces of Pakistan. The return on investment and project payback periods are calculated using the NEPRA defined electricity tariff inclusive of tax so that a concrete conclusion of investing in off-grid solar could be drawn. Results of this study show that most selected areas in Pakistan have sufficient solar radiation potential for electricity generation. Study finds that solar electricity in Pakistan is one of the cost effective and environmental and social friendly forms of electricity. Payback periods of photovoltaic system in Sindh, Baluchistan, Punjab and KPK have been calculated 3.98, 2.33, 3.99 & 6.78 years, respectively. Results of this study may be useful for collective as well as individual consumers while calculating the economic viability of an off grid solar system.
 Keywords: Photovoltaic System, Solar potential, Electricity, Off-Grid Solar System, Return on investment, economic feasibility, Pakistan.

Managing e-waste from off-grid solar systems in Kenya: Do investors have a role to play?

Over the past decade, the market for off-grid solar (OGS) systems providing affordable sources of energy has seen a remarkable expansion in many developing countries where coverage by the electricity grid is limited. The observed market growth has been fuelled by the provision of finance by a variety of foreign investors to private suppliers of such systems. The development of the OGS market plays an important part in meeting the development imperative of ensuring access to sustainable and affordable sources of energy for all. However, increasing awareness and criticism have emerged about the generation of electronic waste (e-waste) from solar products as an unintended negative side effect of their diffusion. In this paper, we explore whether and how investors of dominant OGS system providers in Kenya, a country that has experienced rapid growth in its OGS market, have reacted to concerns about solar e-waste by changing their funding modalities and practices. Our analysis is based on in-depth interviews carried out with a diverse sample of international investors and industry experts. We find that most investors have not incorporated requirements for managing e-waste beyond a mere box-ticking exercise in their due diligence and monitoring and compliance mechanisms. Hence, e-waste is currently not seen as a priority for investors, which raises questions about the overall environmental sustainability of such investments. To the extent that some investors have devoted attention to improving e-waste management, such efforts appear to have been motivated by the potential risks to their reputations. We also find that the Global Off-Grid Lighting Association – a global industry association for the off-grid solar sector – plays an important role in making investors aware of the link between their investments and the adverse environmental impacts of e-waste. Since most of the solar supplier firms are start-ups that are concerned with developing viable businesses, we find that investors do not want to impose another cost burden on them by requiring the introduction of elaborate e-waste management as part of their investment criteria. Furthermore, our interviews highlight the lack of adequate waste transport and recycling infrastructures and the lack of pressures from waste management regulation as key barriers to the management of e-waste. We discuss the relevance of these findings for strategies on how best to tackle the emerging problem of e-waste from OGS devices.

Standalone photovoltaic and battery microgrid design for rural areas

The remote location and many islands in Africa are experiencing a big power shortage and blackouts and they greatly necessitate electric power from standalone photovoltaic microgri­d. In Rwanda, off-grid solar systems are at their infancy level and their affordability for the rural population requires thorough support and incentives. In this process, the Government of Rwanda (GoR) has set a program to subsidize the cost of the system in a rural household power access projects suit to their socio-economic metric known as ‘Ubudehe’ which would determine the required financial support from other poverty reduction programs in a country. The design of a standalone photovoltaic microgrid is aimed to find the cheapest way to go for either a single rural house or a group of 200 rural houses with similar load demand as a long-term solution to their local energy challenges. The models resulted in a Levelized cost of energy, least cost of energy (LCOE) of 1.51US$/kWh for a single home while the LCOE for the group of houses load equals 1.45US$/kWh. The net present cost (NPC) for a single home and multi-user load are respectively equal to 5,625US$ and 1,079,210US$. These results conclude the efficacy of the group sharing load demand model design to provide green energy solutions to the mid-and low-income rural population in Rwanda.

Design and Realization of Solar-powered IoT-based Flood Early Warning System with Telegram Messaging, Auto-restart Watchdog, and Power Management

A Flood is inevitable in some regions in Indonesia during rainy season. Flood can cause problems ranging from simple problem such as lightly flooded street to a complex one such as water that enters the house. For community living at river side, the flood often comes from excessive water due to rain in the upstream that outflows the river as drainage which can happen unnoticeably. An early warning system is needed to detect flood so that people who lived in a flood-prone area can be warned and be prepared to mitigate the flood. With the help of internet of things (IoT) technology, such a system can be made. In this work, an early warning system was developed using off-grid solar system as power source, ultrasonic sensor to detect water level, NodeMCU as microcontroller, and 4G modem to connect to the internet. The system uses Blynk as its IoT platform and sends alarm messages to locals using Telegram so they are vigilant. The system can detect how much the water level and categorizes it into preset alarm levels. Lab. experiments on the proposed system was performed using power from PV-module installed on the lab.’s rooftop. The system functionality works well for 3 weeks of experiments with battery voltage monitored to vary from 12 V at dawn to 13.7 V at daytime. The experiments show that the system exhibits water level measurement average relative error of 2.22% and accuracy of 97.78%. The system is also furnished with power management and auto restart self-healing functionality which were also observed to work well during the test. Measurements show that the system only consumes energy of 11.52 Wh/day which is equivalent to 8% of battery depth of discharge, hence the system can operate for 3.75 days without charging during successive rainy and cloudy days and has sufficient solar energy harvesting margin to cope with site imperfections like shading and soiling of the PV-module.

Application of Off-Grid Solar Panels System for Household Electricity Consumptions in Facing Electric Energy Crisis

At this time the cost of electricity is very expensive which is felt by the community because the government is still exploring oil and natural gas which is the need for non-renewable energy sources that are running low. This non-renewable energy still dominates for power generation in the thousands of Mega Watts. To anticipate the problem of non-renewable energy that is so big, you can use the On Grid-Tie System, sunlight is converted into DC voltage through the Solar Module, a pure DC voltage that comes out of the solar module. And Off Grid-Tie System namely sunlight is converted into DC voltage through the Solar Module, pure DC voltage generated from the solar module. Then the pure DC voltage uses a DC to DC regulation module or is called a DC regulator. DC regulator which aims to regulate the storage of DC current into the battery. Then the battery is used to supply power to the inverter. The method used in this study uses an off-grid solar home system as a power supply for households that are far from the electricity network or save electricity consumption due to expensive electricity rates. For settings for the intensity of sunlight using a portable holder, the solar panels are shifted manually in order to get the optimal light intensity to produce large output power. In off-grid application testing at household loads, from a load test of 93.5 watts to 750 watts, it shows that the load current is getting bigger and the discharging current is also large so that the duration of using the off-grid system from a load of 93.5 watts is 6 hours long and at a load of 750 watts. up to 15 minutes. This is because the condition of the lead-acid battery is maintained from 13.56 to 11.5 Volt DC, the battery should not be forced below the 11.5 Volt voltage because it will cause damage to the battery. For the use of loads that respond to very high instantaneous currents such as electric irons, dispensers, rice cookers should use more batteries and use an off-grid system voltage higher than 12 Volt DC.

Standalone and Minigrid-Connected Solar Energy Systems for Rural Application in Rwanda: An In Situ Study

In recent years, several factors such as environmental pollution, declining fossil fuel supplies, and product price volatility have led to most countries investing in renewable energy sources. In particular, the development of photovoltaic (PV) microgrids, which can be standalone, off-grid connected or grid-connected, is seen as one of the most viable solutions that could help developing countries such as Rwanda to minimize problems related to energy shortage. The country’s current electrification rate is estimated to be 59.7%, and hydropower remains Rwanda’s primary source of energy (with over 43.8% of its total energy supplies) despite advances in solar technology. In order to provide affordable electricity to low-income households, the government of Rwanda has pledged to achieve 48% of its overal electrification goals from off-grid solar systems by 2024. In this paper, we develop a cost-effective power generation model for a solar PV system to power households in rural areas in Rwanda at a reduced cost. A performance comparison between a single household and a microgrid PV system is conducted by developing efficient and low-cost off-grid PV systems. The battery model for these two systems is 1.6 kWh daily load with 0.30 kW peak load for a single household and 193.05 kWh/day with 20.64 kW peak load for an off-grid PV microgrid. The hybrid optimization model for electric renewable (HOMER) software is used to determine the system size and its life cycle cost including the levelized cost of energy (LCOE) and net present cost (NPC) for each of these power generation models. The analysis shows that the optimal system’s NPC, LCOE, electricity production, and operating cost are estimated to 1,166,898.0 USD, 1.28 (USD/kWh), 221, and 715.0 (kWh per year, 37,965.91 (USD per year), respectively, for microgrid and 9284.4(USD), 1.23 (USD/kWh), and 2426.0 (kWh per year, 428.08 (USD per year), respectively, for a single household (standalone). The LCOE of a standalone PV system of an independent household was found to be cost-effective compared with a microgrid PV system that supplies electricity to a rural community in Rwanda.

A Design of a Robust Analog PWM Solar Charge Controller for the Off-Grid Solar Home System: Fixed Frequency Current Control Mode

Solar Home System (SHS) is a stand-alone power solution in an isolated area where the national power grid connection is not accessible. Presently using the off-grid solar home system has one solar panel, one lead-acid batter, one PWM Solar charge controller, and 12V DC power operated lamp solutions, fan, television, radio. Various solar home system packages have been introduced so far, which have offered different product features with price variations. Solar home system size is small, so producing energy is insufficient to fulfill the customer's demand. This research paper presented a novel feature analog PWM solar charging techniques through the algorithm of the fixed frequency current mode controller, which also satisfy the requirements of existing off-grid solar home system users to reduce self-power consumption thus purchasing at an affordable cost. This design set up four periods voltage threshold points as a safeguard for the battery to consider battery voltage level, cable length resistance, battery internal resistance, and EMI (Electromagnetic Interference) effects. PWM solar charging improves the charging strategy by protecting against surge voltage and lightning. The study is divided into three sections: solar charging, regulating signals, and voltage comparator. Accordingly, high-sophisticated fixed-frequency current mode controllers are a noise-free switching gate drive signal with simulation data. The design feature also ignores the EMI (Electromagnetic Interference) noise impact on digital IC's input signals.

Beyond technical standards: Creating an ecosystem for quality and repair in Kenya's off-grid solar sector

Kenya’s national electrification plan now promotes the use of off-grid solar home systems as a long-term energy access solution in rural regions of the country, suggesting that these technologies may no longer be viewed as stop-gap solutions for households awaiting the centralized grid. The quality of these off-grid solar systems is governed by technical standards that require specific information is disclosed on labels to communicate quality measures to consumers, but who uses this information? We argue that there are four audiences that “consume” this information: international organizations and actors working to harmonize standards across countries, port-of-entry conformity assessors, agents or electricians and technicians/installers, and end users. Using qualitative data from interviews and focus group discussions, we illustrate that labels alone do not sufficiently educate end users about solar quality. Rather, end users rely on local sales agents, technicians, and electricians for guidance on purchases, repairs, and e-waste, as these actors are better positioned to help end users interpret the technical information required by standards. International programs and Kenyan policies that address solar quality will benefit from rebalancing the resources (capacity and financial) expended on information campaigns and labeling with efforts that support a more sustainable ecosystem of on-the-ground solar services.

System for performance assessment of solar home systems

This article is the product of the investigation "Development of a photovoltaic pilot system for performance assessment of isolated systems in the Renewable Energy Laboratory at UNAB" developed at the Universidad Autónoma de Bucaramanga (UNAB) in 2019, considering off-grid solar home systems (SHS) are a feasible alternative in rural remote areas, where access to electric power is limited due to their power grid lack. The objective is to develop a PV test system for off-grid solar home system (SHS) performance assessment. For the development, a case study is analyzed based on the behavior of a user's daily demand in Hato Corozal, Casanare. Design aspects of the system are also elaborated. Key performance parameters identified to be monitored are solar irradiance, power generation, energy consumption and battery charge status. Two scenarios of daily demand behavior are analyzed to evaluate the influence of load shifting on the performance of the system. The applied design criteria were validated obtaining that the sized system satisfied the energy requirement without a battery’s depth of discharge (DOD) deeper than specified, showing the capacity of the system to make studies in longer periods with the possibility of generating different demand behavior scenarios. The designed system presents a performance ratio of 0,77 when a daily consumption is considered, while when shifting loads to coincide them with the higher irradiance the PR was 0,95. In both cases, the SoC was higher than 79%, maintaining a DOD of the battery bank according to the specified in the sizing. The system presents excess energy that can be used by expanding the capacity of the battery bank. Findings suggest that a higher performance ratio is obtained when coinciding consumption peaks with the hours of higher solar radiation.

Energy, exergy, and economic analysis of an off-grid solar polygeneration system

Sustainable development goal 13 emphasizes on climate change, due to which there is an urgent need for a transition towards sustainable energy technologies. There are two key issues on the commercialization of renewable energy technologies viz. performance (efficiency) and economic viability. This paper conducts a 3E (Energy, Exergy, Economic) analysis for a novel off-grid solar polygeneration energy technology producing electricity using the solar PV and hot water along with hot air using the solar thermal system. The analysis has been carried out across four Indian provinces such as Andhra Pradesh (AP), Madhya Pradesh (MP), Uttar Pradesh (UP), and Uttarakhand (UTK) located in four climatic zones. For the solar PV unit, the amount of annual electricity production in kWh are 1748, 1799, 1629, 1434 in mentioned four states, and the annual Levelized Cost of Electricity (LCOE) in ₹/kWh are 9.8, 9.6, 10.5, 12 for AP, MP, UP, and UTK respectively. The values of annual average energy efficiency of the solar thermal system in percentage are 64.6 for AP, 64.5 for MP, 64.2 for UP, and 58.3 for UTK, while exergy efficiency are found to be 1.3, 1.4, 1.2, and 0.7 in percentage for the mentioned states. For the solar thermal unit, the values of payback period in years are obtained to be 5.2, 5.5, 7.5, 9.4 and the values of Benefit-Cost ratio (BCR) are 1.32, 1.25, 0.90, 0.73 for AP, MP, UP, and UTK respectively. An innovative business model coupled with utility policy is required for large-scale deployment of these sustainable energy technologies.

ECONOMIC FEASIBILITY ANALYSIS OF OFF-GRID PV SYSTEMS FOR REMOTE SETTLEMENTS IN BHUTAN

Through rigorous rural electrification projects, over 99.97% of Bhutan’s households now have access to electricity, which is predominantly generated from run-of-the-river hydropower plants. Despite this achievement, around 5% of the rural households still do not have access to electricity to meet their cooking load demands and, therefore, they extensively rely on firewood, LPG, and kerosene for cooking purposes. Apart from hydropower, penetration of other renewable sources such as solar and wind power in the country is negligible. Thus, an attempt was made to determine the investment costs of installing PV systems for off-grid households in remote settlements by studying their economic feasibility. The study shows that the initial cost of investment for an off-grid Solar Home System for a rural household is US$1.42 per Wp using polycrystalline PV modules and US$1.55 per Wp using monocrystalline PV modules. The average cost of installing SHS is determined to be US$ 2342.67 per household. The results of analyses indicate that standalone SHS for remote rural households is not financially viable with the current price of electricity supply in Bhutan. However, SHS provides a more cost-effective option than a grid-line extension, which is estimated to cost about US$ 6700 per household for the remaining off-grid settlements.

Demand-side management for off-grid solar-powered microgrids: A case study of rural electrification in Tanzania

This work proposes a novel and sustainable energy development strategy for addressing the energy shortages in rural areas and the low energy efficiency of off-grid solar power systems. This study combines the analysis of power consumption type with consumption anomaly detection to characterize households’ power consumption habits and ensure the safety of a system. Specifically, the proposed anomaly detection method is a hybrid nonintrusive model. The home power usage data are collected and processed by auto-data-binning without manual labeling, and thus, the training cost is reduced to enable the application of machine learning technologies in underdeveloped areas with limited computational resources. With the premise of limited energy sources in off-grid areas, the proposed power consumption analysis method divides home power usage habits into four different types. Different feedback mechanisms are adopted to extend the microgrid’s supply time according to the analysis results. The proposed method significantly increases the utilization of local renewable energy and improves residents’ experience. The proposed method is implemented in a rural village in Tanzania; after long-term monitoring, the validity of the proposed method is demonstrated.

Assessing the opportunities and challenges facing the development of off-grid solar systems in Eastern Africa: The cases of Kenya, Ethiopia, and Rwanda

With the world's lowest electrification rate, Africa is repositioning to offer its citizens a brighter future. Global renewable energy agencies and international financing to expedite rural electrification fueled by off-grid solar systems are attracting worldwide attention. Currently, 770 million people lack access to electricity on the continent, and more than 60% live in poor rural areas where the national power grid is non-existent. The challenge herein is how to supply electricity to rural population, living on $1.5 a day, at a reasonable power tariff. Although there are opportunities for off-grid solar energy to keep growing in sub-Saharan countries, it is impossible to ignore particular challenges in these countries. This paper focuses on three sub-Saharan counties: Kenya, Ethiopia, and Rwanda. Rwanda, Kenya, and Ethiopia foster off-grid solar systems as the primary solution through rural electrification programs. This paper provides a comparative analysis of the electrification experiences of these countries in terms of sources of funding, the challenges and opportunities they have been experiencing as well as an analysis of policy implications. The results show that off-grid solar systems improve health, ICT, and micro-enterprises in rural areas. However, governments should generate more robust developmental schemes that provide income to rural people that pushes them above the poverty line and enables them to afford off-grid solar products.

Rwanda’s Off-Grid Solar Performance Targets

The United Nations Statistical Commission’s Inter-Agency and Expert Group on Sustainable Development Goals (IAEG-SDG) settled on 230 guidelines to assess the 17 SDGs and 169 Targets. The clause of “Leave No One Behind” and scarcity of data in most deserving countries made the UN 2030 Agenda agree on 169 Targets. Recently in Energy Policy, Bisaga et al. used synergies and trade-offs of SDG7 to assess Rwanda’s off-grid solar energy sector performance against the 169 Targets of the UN 2030 Agenda.

The Electrical Energy Modeling of the Modular Off-Grid PV System for Aquaculture Application in the EEC Region

Renewable energy as a solar photovoltaic system represents an essential role in improving and promoting energy sustainability in agricultural/aquaculture-related activities. The “Crab Bank” is the program on practicing the caught gravid females of Blue Swimming Crab (BSC) in supporting conditions, allowing them to spawn and then release the zoea and young crabs back to the sea where are in the Eastern Economic Corridor (EEC). Onward with the project, many scientific studies assess the BSC stocks condition, evaluate the fishing habitat, and other relevant issues as the energy used in a micro-indoor system as Recirculating Aquaculture Systems (RAS). The off-grid solar photovoltaic system is used in the system cause the installed location was near the seaside area. The system’s large size was operating, including solar panels, inverter, charger, and batteries to maintain the AC motor pump, affecting much energy loss in the system. The off-grid solar system design for modular systems is represented in this paper to describe the new structure of the micro modular RAS that reduces cost and increases the solar system’s efficiency in modular concepts comparing the traditional system. The new structure model represents the calculation result in the term of electrical energy and experiment to scale for replacement in the aquaculture area in Rayong or Jantaburi in the EEC region. This research is a cooperation between KMUTNB Rayong and the Provincial Energy Office Of Rayong.

Environmental and Economic Impacts of Lighting Highways Using Photo-Voltaic Panels

The renewable energy sources in power generation globally increases rapidly over time. This paper presents a novel technique of street lighting by using off-grid solar energy system. The electrical power is generated from solar panels at the day time and stored in batteries and consequently, discharged in the street lamps at night. The charging, discharging and their rates rate are controlled obviously by charger controller. Highway road is selected in this study. Several aspects are optimized in this study. Number of columns, columns types, lamp arms, columns distance and the backup storage limits are studied. The sizing of the individual solar stations in terms of economic and environmental feasibility are optimized. New power saving technique will apply advanced methods to reduce the storage capacity and power consumption to enhance the economic feasibility of the suggested system. In addition, the life time of storage batteries is increased. The most appropriate technique is selected in terms of economic and environmental feasibility by comparing all the different cases suggested in this study. Finally, the best case for solar street lighting project is compared to the normal or conventional system to show the economic and environmental potentiality of using renewable energy, especially solar energy. Experimental solar energy street lighting system with power saving is implemented in this study.