Photovoltaic System Owners Research Articles

The impact of different PV system grid integration approaches on voltage profile, grid losses and behaviour of PV system owners

Distribution grids in individual countries inside the European Union have different properties, while the grid operators use different approaches to integrate photovoltaic (PV) systems into the grid, which influences the voltage profile, grid losses and grid’s hosting capability. This work deals with a 0.4 kV distribution gird characteristic for the Slovenian countryside. The grid users are relatively sparsely distributed in the space. The distances between them are relatively long, while the load distribution among individual phases is unbalanced. Three different approaches to the integration of PV into the grid are discussed. The one used before 2012 with the concentrated larger PV units placed close to the transformer busbars, the one introduced with a net-metering scheme where larger PV units are randomly distributed in the grid, and the one where smaller PV units are evenly distributed throughout the grid. The case study discusses the impacts of the three approaches on the proper voltage profile provision, network losses and behaviour of the PV system owners.

Development and Evaluation of an Arduino-Based Data Logging System Integrated with Microsoft Excel for Monitoring On-Grid Photovoltaic Systems

This paper presents the development and evaluation of an Arduino-based data logging system integrated with Microsoft Excel for monitoring on-grid photovoltaic (PV) systems. The system combines open-source hardware and software to enable real-time data acquisition, logging, and analysis of key performance metrics such as solar irradiance, temperature, voltage, and current levels. Leveraging the versatility of Arduino microcontrollers and the accessibility ofMicrosoft Excel, the proposed system offers a cost-effective and user-friendly solution for PV system monitoring. The integration of the MS Data Streamer add-in for Excel facilitates seamless data logging and visualization, empowering PV system owners, researchers, and practitioners with actionable insights for optimizing system performance and contributing to a sustainable energy future. Experimental validation of the system demonstrates its effectiveness in accurately measuring and logging sensor data, highlighting its potential for widespread adoption in renewable energy monitoring applications.

A Study of Households’ Perception towards Solar Panel Installation Case Study: Villagers of Techno-park nearby Faculty of Technology, University of Sri Jayewardenepura

In Sri Lanka, energy demand has been exponentially increasing with the outage of non-renewable energy sources. There is significant solar intensity in most of the areas in Sri Lanka. This study focused on the domestic solar power system since domestic solar panel usage (700 MW) is the country's highest contributor to solar energy usage. A photovoltaic (PV) system can supply electric energy to loads by directly converting solar energy through the photovoltaic effect with a flexible structure. This study aimed to analyze households' perceptions of solar panel installation. The study was conducted within a 5 km radius around the Faculty of Technology, the University of Sri Jayewardenepura, to analyze the awareness of solar-related technologies. A systematically developed questionnaire was used for the survey to collect the peoples' awareness based on environmental, social & economic beliefs. Thirty residential places (30) were interviewed. According to the results, a residential house's average monthly electricity consumption is 137.67 kWh. The mean monthly income in the area is sixty-eight thousand one hundred and sixty-six rupees and sixty-seven cents. Moreover, most people had solar energy knowledge (93.33%). Among them, 53.57% of the majority were willing to install Domestic Solar PV systems for residential places. From the consumers, 76.66% of the majority had an average level of awareness of the Environmental benefits of using renewable energy and 70.00% of the majority had an excellent awareness of government intervention in rooftop solar energy projects such as "Soorya Bala Sangramaya‖. From the defined awareness levels, further analysis was done on the lowest level of Awareness of Solar Energy to identify their characteristics. The majority of them were those who had lower energy consumption, were over the age of 60 and had a monthly income below twenty thousand rupees. According to the consumers, the best strategy for promoting Solar PV Systems was to lower the prices of existing Solar PV systems. Regulating the efficiency of the Solar PV system was identified by the existing Solar PV system owners. 
 Keywords: Solar PV system, Techno-park, Photovoltaic panels

Reactive power management in photovoltaic installations connected to low-voltage grids to avoid active power curtailment.

Photovoltaic (PV) inverters are traditionally designed to operate with unity power factors. In order to use reactive power capabilities of smart inverters, in this work two strategies are analysed: limiting the amount of active power delivered or oversizing the inverter. The first of these options implies a reduction in the PV production and therefore, it would lead to reduced earnings for the PV system owner. On the other hand, oversizing the PV inverter allows having reactive power compensation capabilities, while delivering full power output from its PV field.

Photovoltaic System Protection Against Lightning

Lightning strikes pose a significant threat to photovoltaic (PV) systems, which are increasingly utilized for renewable energy generation. This paper presents a comprehensive overview of the potential risks associated with lightning strikes on PV systems and explores various protection measures to enhance their resilience. The study delves into the characteristics of lightning and its interaction with PV installations, identifies vulnerabilities within the system, and discusses the principles and techniques for effective lightning protection. The paper emphasizes the importance of comprehensive risk assessment, surge protection devices, grounding systems, and maintenance practices to mitigate the damaging effects of lightning strikes. By implementing appropriate protection strategies, PV system owners and designers can safeguard their installations and ensure the longevity and reliability of their renewable energy infrastructure.

Planning and Operation of an Intelligent Power Electronics Series Voltage Regulator for PV-Rich Distribution Feeders

The connection of photovoltaic systems on weak electrical distribution networks can lead to the occurrence of excessive overvoltages or undervoltages that lead toward unsatisfactory operating conditions for renewable energy producers. In such critical situations, where electrical parameters are outside standard regulatory levels, the untimely tripping of electrical protections can lead to losses of renewable energy production and thus to the reduction of producers’ economic revenues. In this context, this article describes aspects related to the planning and operation of an intelligent voltage regulator capable of solving voltage regulation problems in PV-rich low-voltage networks. The results achieved with the application of the power electronics device in electric distribution networks are shown with a real case study in a network with a high penetration of photovoltaic-type renewable energy installations. The results show the effectiveness of the application of the device considering both technical and economic aspects; these results are also compared with traditional distribution network planning strategies, highlighting the advantages for the distributor and the owners of photovoltaic systems.

How an Integration of Home Energy Management and Battery System Affects the Economic Benefits of Residential PV System Owners in Thailand

Although home energy management systems (HEMS) and batteries are part of the Thailand Smart Grid Master Plan, the financial feasibility and attractiveness of installing residential solar rooftop photovoltaic (PV) systems with integration of the HEMS and battery have never been investigated. This study develops three scenarios comprising of an installation of only solar PV system, solar PV system with the HEMS, and solar PV system with integration of the HEMS and battery under the current net billing solar program for households and analyzes their financial feasibility and attractiveness by using economic measures. In addition, sensitivity analysis is performed to analyze the impacts of critical parameters on the feasibility of these three scenarios. Findings indicate that the installation of a solar rooftop system with the HEMS provides the highest customer economics. Although the implementation of HEMs leads to an increase in energy exports, benefits from bill savings of lower electricity consumption by using the HEM are relatively high compared to the loss from energy exports. Therefore, in the short term, the government should promote the integration of HEMS with a PV system; however, the installation of a PV system with HEMS and battery in the residential sector should be promoted when battery cost decreases.

Selling the sun: A critical review of the sustainability of solar energy marketing and advertising in Germany

This paper looks at the messages by solar installers (SI) on rooftop photovoltaic (PV) systems to households in Germany (representative sample of n = 109 randomly selected websites). It examines the motivations they are aiming at in their online communications to convince potential buyers and how they describe living with a PV system. Economic benefits of PV systems are mentioned most frequently. Environmental arguments are also put forward, mainly to signal that buyers are making a valuable contribution to protecting the climate if they invest in PV. Only small parts of the online communication directly relate to energy consumption behaviour in the usage phase. Following this analysis, we discuss how the way PV systems are framed by SI could influence the expectations of households regarding electricity use. This is important with regard to climate mitigation strategies that assume a reduced energy demand in addition to increasing renewable energy sources. Therefore, our discussion focuses on possible rebound effects i.e. an increased electricity consumption by owners of PV systems. We hypothesise that the arguments provided by SI could instigate moral licensing, i.e. support the perception that with a PV system, households have fulfilled their environmental duties and therefore are free to use more electricity. Furthermore, the strong emphasis on economic arguments could weaken other motivations. This leads to the conclusions that (i) further research is needed concerning the influence of sales communications on actual consumption as well as (ii) the recommendation that communication strategies around PV systems should address the usage phase more carefully.

Joint Storage: A Mixed-Method Analysis of Consumer Perspectives on Community Energy Storage in Germany

In this paper, we analyze consumer attitudes toward and interest in community energy storage (CES) in Germany, based on five focus group discussions and an online survey of private owners of photovoltaic (PV) systems, as well as written surveys and workshops with the residents of two residential developments where CES has been installed. We find that owners of PV systems are generally receptive to the idea of CES but are unfamiliar with it. They assume that CES is more resource- and cost-efficient than residential storage and appreciate the idea of professionally managed operation and maintenance, but are skeptical of whether fair and transparent distribution and billing can be realized. Consumers express a need for ancillary services, such as monitoring, information or energy management, but the interest in such services, however, is strongly dependent on their perception of the costs versus potential savings.

PV System Predictive Maintenance: Challenges, Current Approaches, and Opportunities

Within the United States solar energy industry, there is a general motto of “set it and forget it” with solar energy. This notion is derived from much of the research and reliability studies around the photovoltaic (PV) panels themselves, not necessarily the PV system as a whole (including the inverter and other components). This implies that maintenance and regular monitoring is not needed. Yet many things can go wrong to cause the actual performance to deviate from the expected performance. If failures and/or unanticipated degradation issues go undetected, they will lead to reduced energy generation (and associated electricity credits) and/or potential loss of component warranty because of manufacturer turnover. Given the size of the problem and gaps with current solutions, the authors propose that PV system owners need an unbiased third-party off-the-shelf system-level predictive maintenance tool to optimize return-on-investment and minimize time to warranty claim in PV installations. This paper reviews the literature highlighting challenges, current approaches, and opportunities for PV predictive maintenance. The paper concludes with a call to action for establishing a collaborative agenda toward prioritizing PV predictive maintenance.

Performance of roof-top PV systems in Germany from 2012 to 2018

The photovoltaic (PV) sector is a central pillar for the global energy transition process which aims to reach the climate change mitigation goals. Roof-mounted systems in particular can make a significant contribution to greenhouse gas-free energy generation. By the end of 2018, more than 1.5 million rooftop systems have been installed in Germany. The yield data measured by monitoring systems and provided by web-based online systems from 2012 to 2018, as well as the configuration information of 23,944 PV systems, are evaluated in this publication. Long-term indicators are derived from the spatial and temporal distribution of the yield data. The yield analysis shows a typical south-north gradient in Germany. 2018 was the year with the highest yield, 2013 the year with the lowest. The annual specific yield varies between 816 kWh/kWp in 2017 at the Baltic Sea and 1049 kWh/kWp in 2018 in Bavaria. If analysis of data evaluation is narrowed to one to two years, a deviation of five percent and more from the long-term yield can be observed. In order to obtain detailed information on the quality of PV systems, at least five years of data are required. The yield data evaluation can be used by PV system operators and owners to identify an undersupply of their PV system and to initiate countermeasures.

Ensemble Approach of Optimized Artificial Neural Networks for Solar Photovoltaic Power Prediction

The use of data-driven ensemble approaches for the prediction of the solar Photovoltaic (PV) power production is promising due to their capability of handling the intermittent nature of the solar energy source. In this work, a comprehensive ensemble approach composed by optimized and diversified Artificial Neural Networks (ANNs) is proposed for improving the 24h-ahead solar PV power production predictions. The ANNs are optimized in terms of number of hidden neurons and diversified in terms of the diverse training datasets used to build the ANNs, by resorting to trial-and-error procedure and BAGGING techniques, respectively. In addition, the Bootstrap technique is embedded to the ensemble for quantifying the sources of uncertainty that affect the ensemble models' predictions in the form of Prediction Intervals (PIs). The effectiveness of the proposed ensemble approach is demonstrated by a real case study regarding a grid-connected solar PV system (231 kWac capacity) installed on the rooftop of the Faculty of Engineering at the Applied Science Private University (ASU), Amman, Jordan. The results show that the proposed approach outperforms three benchmark models, including smart persistence model and single optimized ANN model currently adopted by the PV system's owner for the prediction task, with a performance gain reaches up to 11%, 12%, and 9%, for RMSE, MAE, and WMAE standard performance metrics, respectively. Simultaneously, the proposed approach has shown superior in quantifying the uncertainty affecting the power predictions, by establishing slightly wider PIs that achieve the highest confidence level reaches up to 84% for a predefined confidence level of 80% compared to three other approaches of literature. These enhancements would, indeed, allow balancing power supplies and demands across centralized grid networks through economic dispatch decisions between the energy sources that contribute to the energy mix.

A global monitoring system for electricity consumption and production of household roof-top PV systems in Madeira

This paper describes recent work on the development of a wireless-based remote monitoring system for household energy consumption and generation in Madeira Island, Portugal. It contains three different main sections: (1) a monitoring system for consumed and produced energy of residencies equipped with photovoltaic (PV) systems, (2) developing a tool to predict the electricity production, (3) and proposing a solution to detect the PV system malfunctions. With the later tool, the user (owner) or the energy management system can monitor its own PV system and make an efficient schedule use of electricity at the consumption side. In addition, currently, the owners of PV systems are notified about a failure in the system only when they receive the bill, whereas using the proposed method conveniently would notify owners prior to bill issue. The artificial neural network was employed as a tool together with the hardware-based monitoring system which allows a daily analysis of the performance of the system. The comparison of the predicted value of the produced electricity with the actual production for each day shows the validity of the method.

Extreme Learning Machines for Solar Photovoltaic Power Predictions

The unpredictability of intermittent renewable energy (RE) sources (solar and wind) constitutes reliability challenges for utilities whose goal is to match electricity supply to consumer demands across centralized grid networks. Thus, balancing the variable and increasing power inputs from plants with intermittent energy sources becomes a fundamental issue for transmission system operators. As a result, forecasting techniques have obtained paramount importance. This work aims at exploiting the simplicity, fast computational and good generalization capability of Extreme Learning Machines (ELMs) in providing accurate 24 h-ahead solar photovoltaic (PV) power production predictions. The ELM architecture is firstly optimized, e.g., in terms of number of hidden neurons, and number of historical solar radiations and ambient temperatures (embedding dimension) required for training the ELM model, then it is used online to predict the solar PV power productions. The investigated ELM model is applied to a real case study of 264 kWp solar PV system installed on the roof of the Faculty of Engineering at the Applied Science Private University (ASU), Amman, Jordan. Results showed the capability of the ELM model in providing predictions that are slightly more accurate with negligible computational efforts compared to a Back Propagation Artificial Neural Network (BP-ANN) model, which is currently adopted by the PV system owners for the prediction task.

BESS-Sizing Optimization for Solar PV System Integration in Distribution Grid

Abstract Although renewable energies are beneficial to reduce carbon emissions, its intermittent characteristics may result in power-supply issues in distribution grid. Battery energy storage system (BESS) is generally regarded as an effective tool to deal with these problems. However, the development of BESS is limited due to its high capital cost. This paper proposes an optimization method for sizing and scheduling BESS and smart inverter (SI) of photovoltaic (PV) system. Scheduling optimization of related facilities is taken into account to ensure PV system owner’s investment returns and assist distribution system operator (DSO) to adjust the voltages. Besides, different electricity tariffs are compared to discuss their impacts on BESS investment. In the proposed method, the sizing and scheduling optimizations are coupled with thus increased dimension and complexity of the optimization problem. A revised electrons drifting algorithm (e-DA) is proposed and applied to the proposed optimization problem for improving the performance of method. The proposed method provides an incentive way to encourage PV system owners to invest BESS voluntarily, which not only raises the operational profits of PV system owner, but also improves power-supply quality of distribution system.

Self-consumption enhancement and peak shaving of residential photovoltaics using storage and curtailment

Increasing the self-consumption of photovoltaic (PV) power is an important aspect to integrate more PV power in the power system. The profit for the PV system owner can increase and the stress on the power grid can be reduced. Previous research in the field has focused on either self-consumption of PV power in individual buildings or PV power curtailment for voltage control. In this paper self-consumption of residential PV power in a community of several single-family houses was investigated using high-resolution irradiance and power consumption data. Cases with individual or shared battery energy storages for the houses were examined. PV power curtailment was investigated as a method to reduce feed-in power to the grid, i.e. peak shaving. Results indicated that the self-consumption ratio increased when using shared instead of individual storage. Reducing the feed-in power from the community by almost 50% only led to maximum 7% yearly production losses due to curtailment and storage losses. The economics for shared storage are slightly better than for individual ones. These results suggest that residential PV-battery systems should use (i) shared energy storage options if local regulations allow it and (ii) PV power curtailment if there are incentives to lower the feed-in power.

Investigation of Methods for Reduction of Power Fluctuations Generated From Large Grid-Connected Photovoltaic Systems

Photovoltaic (PV) systems are presently allowed to inject into the grid all the power they can generate. However, in the near future, utilities are expected to impose additional regulations and restrictions on the power being injected by large centralized PV systems because of their possible adverse impacts. One of the main issues associated with large PV systems is the fluctuation of their output power. These fluctuations can negatively impact the performance of the electric networks to which these systems are connected, especially if the penetration levels of these systems are high. Moreover, the fluctuations in the power of PV systems make it difficult to predict their output, and thus, to consider them when scheduling the generating units in the network. The main objective of this paper is to investigate some methods that can be used to reduce the fluctuations in the power generated from a large customer-owned PV system, in the order of megawatts. This paper focuses on three methods: 1) the use of battery storage systems; 2) the use of dump loads; and 3) curtailment of the generated power by operating the power-conditioning unit of the PV system below the maximum power point. The emphasis in the analysis presented in this paper is on investigating the impacts of implementing these methods on the economical benefits that the PV system owner gains. To estimate the maximum revenues gained by the system owner, an linear programming optimization problem is formulated and solved. Moreover, the effect of varying different parameters of the problem is investigated through sensitivity analysis.

The Role of Policies in Supporting the Diffusion of Solar Photovoltaic Systems: Experiences with Ontario, Canada’s Renewable Energy Standard Offer Program

Traditionally, high initial capital costs and lengthy payback periods have been identified as the most significant barriers that limit the diffusion of solar photovoltaic (PV) systems. In November, 2006, the Ontario Power Authority (OPA) introduced the Renewable Energy Standard Offer Program (RESOP), offering owners of solar PV systems with a generation capacity under 10 MW a 20 year contract to sell electricity back to the grid at a guaranteed rate of CAD $0.42/kWh. While it is the intent of incentive programs such as the RESOP to begin to lower financial barriers in order to increase the uptake of solar PV systems, there is no guarantee that the level of participation will in fact rise. The "on-the-ground" manner in which consumers interact with such an incentive program ultimately determines its effectiveness. This paper analyzes the relationship between the RESOP and solar PV system consumers. Experiences of current RESOP participants are presented, wherein the factors that are either hindering or promoting utilization of the RESOP and the adoption of solar PV systems are identified.

96/03901 A low-cost method of evaluationg saving from lighting retorfits

Photovoltaic (PV) power generation is an important component for the future energy system. High penetration of PV power in a power distribution system might however lead to problems with overvoltage and overload. In this study, a method for PV power curtailment and placement of decentralized energy storage is developed to control voltage, feeder currents and distribution substation overloading. The method determines an individual feed-in power limit for each PV system owner based on a voltage-power relationship. Measured data from a 10 kV/400 V three-phase distribution grid in the Swedish municipality of Herrljunga with more than 5000 end-users and simulated PV electricity production data are used for a case study to verify the model. The method is evaluated for yearly PV electricity production of up to 100% of the yearly electricity consumption. The results show that the method is able to prevent overvoltage for all penetration levels in the studied distribution grid, reduce the number of feeders affected by overcurrent and lower the maximum load on the two substations.

Financial Transactions Between the Electric Utility and the Solar Photovoltaic System Owner

Because of the expected increase in conventional technology fuel cost, reduction in the cost of some solar equipment, and other incentives, residential solar photovoltaic (RSPV) energy system as an onsite technology seems a promising technology of the future. Residential customers with surplus solar photovotaic (SPV) energy in excess of their load have the option of either selling that energy or storing it in batteries and consume it later. Their choice of the option depends on the financial transaction contract between such households and the electric utility. Buy-back ratio can be used to characterize the financial transactions between the utility and the SPV owner. This paper addresses the issue of buy-back ratio and its implications. It describes how buy-back ratio is going to affect the transaction between the SPV owner and the utility. Many components that affect the buy-back ratio are discussed from the electric utility perspective. A range of buy-back ratio is determined from the utility point of view.