Solar Photovoltaic Penetration Research Articles

Transient response of a megawatt-scale solar photovoltaic in an electric distribution utility

There is an increasing trend among customers of an electrical distribution utility to adopt grid-tied solar photovoltaic systems. This shift offers multiple benefits to consumers, including lower monthly electricity bills and a contribution to the development of green energy. For the electrical distribution utility, various impacts may arise due to varying levels of solar energy penetration. This study investigates the effects of integrating varying levels of solar photovoltaic penetration into the commercial consumer network of Cagayan de Oro Electric Power and Light Company (CEPALCO) in the Philippines. Utilizing PowerWorld simulator, the research evaluates 11 different scenarios with solar penetration levels adjusted according to the percentage of load demand. Key findings include alterations in solar megavolt ampere of reactive power output, bus voltage levels, transformer power loading, and transmission line ampacity, with frequency levels remaining stable across scenarios. The optimal solar penetration level was identified at 70%, balancing the benefits of solar energy integration with the need to maintain grid stability and operational limits. This optimal level ensures the effective utilization of renewable energy sources without compromising the performance of CEPALCO’s electrical infrastructure. The research concludes with recommendations for maintaining grid stability and operational limits at the optimal solar penetration limits.

Comprehensive Analysis of the Integration and Advanced Control of Photovoltaic Systems for Grid-Connected Applications

In-depth examination of photovoltaic (PV) system integration and enhanced control for grid-connected applications is presented in this study. It examines the difficulties, methods of control, and cutting-edge technologies needed to raise the dependability and effectiveness of PV systems in contemporary power networks. The study explores innovative Maximum Power Point Tracking (MPPT) algorithms, dynamic modeling methodologies, and different adaptive control strategies, emphasizing their importance in PV system performance optimization. It also looks at how high solar PV penetration affects grid stability and talks about creative ways to deal with these issues so that we can have robust and sustainable energy sources in the future. Key Words: photovoltaic Systems, pv integration, pv control strategies, energy storage systems, smart grid technologies, MPPT.

Robust microgrids for distribution systems with high solar photovoltaic penetration

Robust microgrids for distribution systems with high solar photovoltaic penetration

Comparative Analysis of Smart Grid Solar Integration in Urban and Rural Networks

Solar photovoltaic (PV) power, a highly promising renewable energy source, encounters challenges when integrated into smart grids. These challenges encompass voltage fluctuations, issues with voltage balance, and concerns related to power quality. This study aims to comprehensively analyze the implications of solar PV penetration in Malaysian power distribution networks predominantly found in urban and rural areas. To achieve this, we employed the OpenDSS 2022 and MATLAB 2022b software tools to conduct static power flow analyses, enabling us to assess the effects of solar PV integration over a wide area under two worst-case scenarios: peak-load and no-load periods. Our investigation considered voltage violations, power losses, and fault analysis relative to the power demand of each scenario, facilitating a comprehensive evaluation of the impacts. The findings of our study revealed crucial insights. We determined that the maximum allowable power for both urban and rural networks during no-load and peak-load situations is approximately 0.5 MW and 0.125 MW, respectively. Moreover, as the percentage of PV penetration increases, notable reductions in power losses are observed, indicating the potential benefits of higher smart grid PV integration.

Volt-Var Control for Utility-Scale Solar PV Plants to Downsize SVCs and Curtailment Effects

One way to increase solar photovoltaic penetration in the grid is the management of voltage fluctuations. This is because a photovoltaic plant cannot be interconnected to the grid if it causes voltage violations. Voltage violation is where voltage exceeds the acceptable range. Often, grid operators request photovoltaic plant owners to regulate voltage sufficiently with expensive and space-consuming static Var compensators. Unfortunately, this sometimes makes the project less feasible. This paper argues that there are better ways to regulate voltage. It also asserts that these ways must be sought before blindly procuring a static Var compensator or seeking battery storage. We simulated with a 70-MW photovoltaic plant as an addition to the grid. Without voltage regulation, voltage violations in Spring were found to be particularly significant. However, the proposed reactive power compensation removed all voltage violations smartly. Furthermore, the study results demonstrated that the operator-induced curtailment effectively reduced the necessary amount of reactive power compensation, leading to a smaller size of SVC, as it occurred specifically at certain overvoltage points. This paper argues that the economic and spatial efficiency of reactive power compensation devices is key to increasing photovoltaic penetration. It argues that one-sided bearing of the cost of reactive compensation devices is inefficient.

Evaluating the impact of wildfire smoke on solar photovoltaic production

There are growing needs to understand how extreme weather events impact the electrical grid. Renewable energy sources such as solar photovoltaics are expanding in use to help sustainably meet electricity demands. Wildfires and, notably, the widespread smoke resulting from them, are one such extreme event that can impair the performance of solar photovoltaics. However, isolating the impact that smoke has on photovoltaic energy production, separate from ambient conditions, can be difficult. In this work, we seek to understand and quantify the impacts of wildfire smoke on solar photovoltaic production within the Western United States. Our analysis focuses on the construction of a random forest regression model to predict overall solar photovoltaic production. The model is used to separate and quantify the impacts of wildfire smoke in particular. To do so, we fuse historical weather, solar photovoltaic energy production, and PM2.5 particulate matter (primary smoke pollutant) data to train and test our model. The additional weather data allows us to capture interactions between wildfire smoke and other ambient conditions, as well as to create a more powerful predictive model capable of better quantifying the impacts of wildfire smoke on its own. We find that solar PV energy production decreases 8.3% on average during high smoke days at PV sites as compared to similar conditions without smoke present. This work allows us to improve our understanding of the potential impact on photovoltaic-based energy production estimates due to wildfire events and can help inform grid and operational planning as solar photovoltaic penetration levels continue to grow.

GIScience can facilitate the development of solar cities for energy transition

The energy transition is increasingly being discussed and implemented to cope with the growing environmental crisis. However, great challenges remain for effectively harvesting and utilizing solar energy in cities related to time and location-dependant supply and demand, which needs more accurate forecasting- and an in-depth understanding of the electricity production and dynamic balancing of the flexible energy supplies concerning the electricity market. To tackle this problem, this article discusses the development of solar cities over the past few decades and proposes a refined and enriched concept of a sustainable solar city with six integrated modules, namely, land surface solar irradiation, three-dimensional (3D) urban surfaces, spatiotemporal solar distribution on 3D urban surfaces, solar photovoltaic (PV) planning, solar PV penetration into different urban systems, and the consequent socio-economic and environmental impacts. In this context, Geographical Information Science (GIScience) demonstrates its potent capability in building the conceptualized solar city with a dynamic balance between power supply and demand over time and space, which includes the production of multi-sourced spatiotemporal big data, the development of spatiotemporal data modelling, analysing and optimization, and geo-visualization. To facilitate the development of such a solar city, this article from the GIScience perspective discusses the achievements and challenges of (i) the development of spatiotemporal big data used for solar farming, (ii) the estimation of solar PV potential on 3D urban surfaces, (iii) the penetration of distributed PV systems in digital cities that contains the effects of urban morphology on solar accessibility, optimization of PV systems for dynamic balancing between supply and demand, and PV penetration represented by the solar charging of urban mobility, and (iv) the interaction between PV systems and urban thermal environment. We suggest that GIScience is the foundation, while further development of GIS models is required to achieve the proposed sustainable solar city.

Voltage stability assessment for solar photovoltaic penetration using Reactive Power–Voltage and Active Power–Voltage modal analysis

The assessment of voltage stability in a power system is crucial to ensure all buses in the network can maintain the desired voltage or avoid maximum loadability when subjected to load disturbance. Current research has tended to concentrate on developing new voltage stability assessment tools rather than identifying the best location for the penetration of solar photovoltaic (SP) generation in the network. This paper examines and evaluate the power systems voltage stability with increasing SP penetration levels by employing both the Active Power–Voltage (PV) and Reactive Power–Voltage (QV) modal analysis. The effect of load flow study by penetrating SP at the weakest and the strongest load bus has been investigated in this work. Furthermore, the analysis in this work was carried out in the modified Brunei Darussalam Department of Electrical Services (DES) power system. The main contribution of this paper is to assess and identify the best and worst locations for SP penetration in the simplified DES power system network in Brunei Darussalam using both the QV and PV modal analysis. The load flow results show that the penetration of SP generation is much better at the strongest bus due to it does not influence other load buses as compared to the least reliable bus in the network.

Effect of Nuclear Energy Flexibility on Integrating Large-Scale Distributed Solar PV in an Existing Power Network

This paper estimates the maximum integration level of residential rooftop solar photovoltaic (PV) capacity within the power network of the Duke Energy Progress (DEP) and Duke Energy Carolinas (DEC) under two scenarios embodying different assumptions about the flexibility of nuclear power plant (NPP) operations. A mixed-integer optimization model was constructed and simulated to find out the maximum solar penetration level under each scenario and to calculate the expected total system’s electricity generation costs, energy mix, atmospheric emission reductions, and emission abatement costs. Analysis reveals that improving NPP operation maneuverability would increase the maximum solar PV penetration level in the DEP and DEC power networks by 39%, from 8.9% to 12.4% of the total system’s electricity generation. Consequently, it would further improve the electricity generations’ unit costs and CO2 emission reductions by 3% and 8% points, respectively. On the other hand, increasing the solar PV penetration limit under high flexible NPP operation scenario leads to increase in the CO2 emission abatement costs by 8% points. The results of the study indicate that the flexibility of existing power system resources may present a barrier for a large uptake of solar energy.

Affinely Adjustable Robust Volt/VAr Control Without Centralized Computations

This paper proposes a completely non-centralized Volt/VAr control (VVC) algorithm for active distribution networks which are faced with voltage magnitude violations due to the high penetration of solar photovoltaics (PVs). The proposed VVC algorithm employs a two-stage architecture where the settings of the classical voltage control devices (VCDs) are decided in the first stage through a distributed optimization engine powered by the alternating direction method of multipliers (ADMM). In contrast, the PV smart inverters are instructed in the second stage through linear Q(P) decision rules - which are computed in a decentralized manner by leveraging robust optimization theory. The key to this non-centralized VVC routine is a proposed network partition methodology (NPM) which uses an electrical distance metric based on node <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$Q-|V|^{2}$</tex-math></inline-formula> sensitivities for computing an intermediate reduced graph of the network, which is subsequently divided into the final partitions using the spectral clustering technique. As a result, the final network partitions are connected, stable, close in cardinality, contain at least one PV inverter for zonal reactive power support, and are sufficiently decoupled from each other. Numerical results on the UKGDS-95 and IEEE-123 bus systems show that the non-centralized solutions match closely with the centralized robust VVC schemes, thereby significantly reducing the voltage violations compared to the traditional deterministic VVC routines.

Optimal fractional steam governor damping controller with variable solar penetrations

When the gains of steam turbine governor are properly tuned with modification in control parameters, it can impart effective damping torque to low frequency oscillations in power system. Here a fractional steam governor control action is proposed to provide damping action whose parameters are tuned by Sail Fish Algorithm (SFA). The system oscillations are generated by variable Solar Photo Voltaic (SPV) integrations. The additional steam governor damper employs fractional lead-lag based control action. The low frequency model of steam generator with SPV penetration has been examined with step and random solar power generation for justifying proposed steam governors damping control action. The system eigen values have been analyzed for different solar penetrations.

Comprehensive Approach to Mitigating Solar Photovoltaic Power Penetration Effects in a Microgrid

High solar photovoltaic (PV) penetration in the electrical grid can result in undesired effects on the voltage quality, leading to line loss and voltage magnitude increases. One of the main criteria to ensure the safe penetration of high-power solar systems in the main grid is maintaining an acceptable voltage magnitude when a disturbance occurs (e.g., 0.95 and 1.05 per unit) with respect to total installed power generation capacity of PV power plants. This manuscript analyzes the effects of high solar PV penetration per unit of voltage stability using the Fast Voltage Stability Index and total power loss. Moreover, we investigate the flexibility benefits of coordinated voltage control based on a smart inverter of solar PV capacitor banks (SI-CBs) under five cases in a typical microgrid (MG) test model. For the test of the SI-CBs, MG modeling is developed on a modified IEEE 123 test feeder, which includes 11 building load solar PVs with smart inverters and capacitor banks with real-time data from an area in Los Angeles, California, USA. The simulation results are presented to validate the effectiveness of the proposed approach using a real-time MATLAB interface to the Open Distribution System Simulator (OpenDSS).

Optimal Dynamic Operation of Grid-Integrated Hydrogen Energy System: A Techno-Economic Analysis

Rapidly decreasing costs of solar energy and policies that encourage decarbonization are driving solar photovoltaic (PV) farms to be paired with large scale and longer duration energy storage. Hydrogen generation from renewable energy can provide long-term, clean energy storage and can be used in the power industry through fuel cells or combustion turbines, used as chemical feedstock for industry, or as a fuel for transportation. Production costs of hydrogen via electrolytic methods mainly depends on the electricity price, capital costs, and equipment capacity factors. To be cost effective with other types of energy storage, a desired hydrogen price of $1/kg by 2030 will be needed. This study focuses on a techno-economic analysis of a grid-integrated microgrid that includes hydrogen systems (i.e. electrolyzer, compressor, storage tank, and stationary fuel cell), high penetration of solar PV, and battery energy storage systems. The microgrid is operated in a way to minimize the total operation and investment costs and maximize the revenue of the microgrid owner by exchanging power with the grid. While previous work [1] (one hour steady-state time steps) considered a fixed conversion efficiency for the electrolyzer, this study focuses on dynamic operation of the electrolyzer using polarization curves and non-linear conversion efficiency (modeled based on actual cell voltage, cell current, and Faraday efficiency) for more realistic results.Simulation results show that the hourly conversion efficiency of the electrolyzer highly depends on stack operating conditions (cell voltage and current density, the size of the electrolyzer, the temperature, hydrogen demand, etc.). This results in different microgrid optimization and scheduling of energy assets, and consequently the hydrogen production cost. Sensitivity analysis on the PV penetration, current density of the electrolyzer, and changes in asset capital costs will be presented.[1] Hamed Haggi, Paul Brooker, Wei Sun, James M. Fenton, “Hydrogen and Battery Storage Technologies for Low-Cost Energy Decarbonization in Distributed Networks”, arXiv, 11 (2022). https://doi.org/10.48550/arXiv.2202.02711

Solar Irradiance Nowcasting System Trial and Evaluation for Islanded Microgrid Control Purposes

The rapid increase in solar photovoltaic (PV) integration into electricity networks introduces technical challenges due to varying PV outputs. Rapid ramp events due to cloud movements are of particular concern for the operation of remote islanded microgrids (IMGs) with high solar PV penetration. PV systems and optionally controllable distributed energy resources (DERs) in IMGs can be operated in an optimised way based on nowcasting (forecasting up to 60 min ahead). This study aims to evaluate the performance under Perth, Western Australian conditions, of an all-sky imager (ASI)-based nowcasting system, installed at Murdoch University in Perth, Western Australia (WA). Nowcast direct normal irradiance (DNI) and global horizontal irradiance (GHI) are inputted into a 5 kWp solar PV system with a direct current (DC) power rating/alternating current (AC) power rating ratio of 1.0. A newly developed classification method provided a simplified irradiance variability classification. The obtained nowcasting system evaluation results show that the nowcasting system’s accuracy decreases with an increase in lead time (LT). Additionally, the nowcasting system’s accuracy is higher when the weather is either mostly clear (with a recorded LT15 mean absolute deviation (MAD) of 0.38 kW) or overcast (with a recorded LT15 MAD of 0.19 kW) than when the weather is intermittently cloudy with varying cloud conditions (with a recorded LT15 MAD of 0.44 kW). With lower errors observed in lower LTs, overall, it might be possible to integrate the nowcasting system into the design of IMG controllers. The overall performance of the nowcasting system at Murdoch University was as expected as it is comparable to the previous evaluations in five other different sites, namely, PSA, La Africana, Evora, Oldenburg, and Julich.

Capture or curtail: The potential and performance of direct air capture powered through excess renewable electricity

• Discussion of the potential and costs of direct air capture powered using excess solar electricity. • Historic and forecasted values of excess electricity show tangible and scalable potential. • Use of excess solar electricity exhibits appealing environmental and economic performance in evaluated case study. • Direct air capture could offer carbon dioxide removal and excess electricity management alongside other discussed technologies. The widespread deployment of direct air capture is impeded by technology and scalability challenges, particularly resulting from high capital costs and energy demands. This paper posits that it is not possible to effectively evaluate the economic and environmental impacts of direct air capture without accounting for the spatial and temporal contexts in which it will be operated. Accordingly, the analysis aims to evaluate the near-term and medium-term (2030–50) potential of using excess renewable energy to power flexible deployment of direct air capture in California. Current systems would be able to sequester almost 1 million tonnes of carbon dioxide per year, an important benchmark target. For future systems, increased solar photovoltaic penetration could lead to potential carbon sequestration of 20–140 million tonnes during 2030–50. The environmental efficacy of excess electricity powered direct air capture is also estimated, which exhibits lower upstream energy consumption and net greenhouse gas emissions compared to the average range of carbon dioxide removal technologies. In terms of economic performance, the studied system is appealing across a wide range of capacity factors, thus showing large operational flexibility. Beyond this, the current study discusses a more fundamental premise, which is that different carbon dioxide removal approaches are uniquely suitable for different contexts that should be explicitly accounted for when evaluating their anticipated costs, benefits, and potential.

Integration of Solar Photovoltaic Systems into Power Networks: A Scientific Evolution Analysis

Solar photovoltaic (PV) systems have drawn significant attention over the last decade. One of the most critical obstacles that must be overcome is distributed energy generation. This paper presents a comprehensive quantitative bibliometric study to identify the new trends and call attention to the evolution within the research landscape concerning the integration of solar PV in power networks. The research is based on 7146 documents that were authored between 2000–2021 and downloaded from the Web of Science database. Using an in-house bibliometric tool, Bibliometrix R-package, and the open-source tool VOSviewer we obtained bibliometric indicators, mapped the network analysis, and performed a multivariate statistical analysis. The works that were based on solar photovoltaics into power networks presented rapid growth, especially in India. The co-occurrence analysis showed that the five main clusters, classified according to dimensions and significance, are (i) power quality issues that are caused by the solar photovoltaic penetration in power networks; (ii) algorithms for energy storage, demand response, and energy management in the smart grid; (iii) optimization, techno-economic analysis, sensitivity analysis, and energy cost analysis for an optimal hybrid power system; (iv) renewable energy integration, self-consumption, energy efficiency, and sustainable development; and (v) modeling, simulation, and control of battery energy storage systems. The results revealed that researchers pay close attention to “renewable energy”, “microgrid”, “energy storage”, “optimization”, and “smart grid”, as the top five keywords in the past four years. The results also suggested that (i) power quality; (ii) voltage and frequency fluctuation problems; (iii) optimal design and energy management; and (iv) technical-economic analysis, are the most recent investigative foci that might be appraised as having the most budding research prospects.

Hybrid energy storage design and dispatch strategy evaluation with sensitivity analysis:Techno‐economic‐environmentalassessment

AbstractInternational Energy Agency reported the net‐zero carbon target by 2050 in its recent annual report. The global energy landscape is expected to anticipate an energy transition with an increase in renewable energy share from 12% to 35% for electricity sector by 2050. Most of the countries in the world had pledged to be become net‐zero or carbon neutral countries by 2050. Solar photovoltaic (PV) and wind energy will contribute 50% of energy mix in this context. Solar PV and wind energy are intermittent resources that highly depending on the weather and climate conditions. The intermittency issues caused mismatch between electricity generation and demand profiles. This will greatly affect the requirement of meeting the daily load profile, satisfying the peak demand and resulting in generation of surplus, and so on. Energy storages play a vital role in this scenario by allowing this excess energy to be stored and used to meet the demand during low energy production. Previous literature evaluated the feasibility of utilizing battery energy storage in large‐scale solar PV plant in Malaysia using load following dispatch strategy, which can be further enhanced by utilizing a hybrid energy storage system. This study aims to develop an optimized hybrid energy storage system utilizing battery and supercapacitors to complement a large‐scale solar PV system. This study also evaluates two dispatch strategies that are load following and cycle charging for three different power system configurations. Subsequently, a market leading battery is modelled with parameters such as nominal voltage, capacity, round‐trip efficiency, minimum and maximum state of charge, and maximum and minimum charge and discharge current in four different scenarios utilizing two dispatch strategies. These studies are conducted using power system and energy storage modelling tools with localized energy data for the Malaysia context. The proposed hybrid energy storage system demonstrates an improvement of about 30% in annual throughput under the load following dispatch strategy. The hybrid power system also increases the renewable energy fraction by 5% in the system. This study creates an optimized framework in the development of energy storage for grid integration that permits high level of solar PV penetration in the transmission and distribution network.

Solar PV Penetration Scenarios for a University Campus in KSA

The Kingdom of Saudi Arabia (KSA) is committed to transition its fossil fuel-driven electricity generation to that from renewable energy technologies, such as solar photovoltaic (PV) and wind. The need to reduce greenhouse gas emissions has led it to announce an ambitious target of 40 GW of PV power capacity by 2030. The deployment of such a capacity needs to be augmented with analyses to overcome the challenges faced in terms of the technical capability of the country. This work contributes to this goal by investigating the utilisation of solar photovoltaic PV systems to supply medium-size entities such as universities with clean power, displacing the current fossil fuel power supply. Currently, such considerations are not fully addressed in KSA. The study used the University of Jeddah campus electrical load profile, taking into account future power needs. The methodology encompassed modelling the installation of multi-MW PV systems for the university by considering weather conditions, actual university consumption, load segregation, and economics under different development scenarios informed by surveys with decision makers at the university. The results showed that air conditioning loads alone were responsible for 79% of the campus electrical load and that a 4.5 MW PV system is able to supply half of the total campus annual electrical energy consumption of the year of 2019. The optimum scenario showed that utilising grid-connected PVs would decrease the total cost of electricity over the next two decades by 28 to 35 percent and would result in halving the current campus carbon emissions. The analysis concludes that the business-as-usual case is no longer the cheapest option for the campus.

Solar photovoltaic potential and diffusion assessment for Pakistan

AbstractIn Pakistan, around 58% of current electricity is generated from fossil fuels and only 2.4% is generated using renewable energy (RE) resources even though country is blessed with enormous RE potential. Among other RE resources, Pakistan's geographical location offers high solar energy potential, which implies that actual potential assessment should be undertaken. This study, as such, undertakes a comprehensive assessment of solar energy potential and prospects of solar photovoltaic (PV) systems for both off‐grid and grid‐connected systems. This study also estimates the future available capacity of rooftop and rural off‐grid solar PV capacity. Three different types of solar PV modules of the same size, that is, thin‐film, premium, and standard were modeled to compare energy outputs. NREL's System Advisor Model (SAM) is used to estimate the geographical and technical potential of solar PV considering updated data and geographical information. SAM results suggest that an average of 4.5 kWh/kWp/day is obtained from an installed capacity of 1 KWp. The logistic modeling equations are further used to forecast the solar PV penetration over a period until 2090. The research investigation concludes that 2.8 × 106 GWh of electricity can be generated annually in Pakistan. The estimated results prove that solar PV has the potential to meet the present as well as future energy needs of Pakistan.

Redirecting solar feed in tariffs to residential battery storage: Would it be worth it?

Government subsidies and premium feed in tariffs (PFiTs) have been effective in driving Australia’s high uptake of residential solar photovoltaic (PV) systems. PFiT policies have reduced bills for solar customers and the total greenhouse gas emissions associated with electricity generation. However, solar penetration is approaching technical limits in some areas of Australian distribution networks. Distributed batteries can overcome these limits allowing for a greater penetration of residential solar PV and a reduction in overall network costs through improvements in capacity utilisation. It is important for policies to align the interests of individual consumers with a reduction in total system costs. In this article we demonstrate how redirecting ongoing feed-in tariff payments towards residential battery storage has the potential to reduce overall system costs. We present some of the challenges associated with unlocking these benefits and provide a list of policy principles that can be utilised to guide policy development .