Michael Emmanuel - Academia.edu (original) (raw)

Papers by Michael Emmanuel

2020 47th IEEE Photovoltaic Specialists Conference (PVSC)

This article presents the impact of battery energy storage system's (BESS) control triggers o... more This article presents the impact of battery energy storage system's (BESS) control triggers on its performance during peak shaving application. With the increasing deployment of BESS for load leveling and grid capacity relief, the sensitivity of BESS performance to its set-points is yet to be investigated. Most utilities have defined thresholds to activate BESS discharging for peak demand leveling and baseload BESS charging. However, this study shows that without using optimal set-points for control applications, the BESS can remain under-utilized. In this work, simulation results of the peak shaving algorithm implementation in 30-minute time step over a period of 10 years show the impact of different BESS control set-points on distribution transformer loading, line and system losses.

2020 47th IEEE Photovoltaic Specialists Conference (PVSC)

This paper presents a modeling framework for realworld distribution systems to enable large-scale... more This paper presents a modeling framework for realworld distribution systems to enable large-scale transmission-and-distribution (T&D) cosimulation. The modeling methodology includes three major steps: utility feeder model conversion, feeder load modeling, and model validation. The feeder models obtained from the utility are converted to the format that is more flexible for analysis and algorithm development. The load profile of each medium-voltage bus is modeled based on the data obtained from advanced metering infrastructure and the supervisory control and data acquisition (SCADA) system. Then the converted feeder models are validated by comparing the simulated feeder-head voltage results to the measured voltage data from SCADA. Last, the modeled real-world large-scale distribution systems are integrated into a T&D cosimulation framework to perform the system simulation from the bulk system down to the medium-voltage buses in the distribution system.

2021 IEEE 48th Photovoltaic Specialists Conference (PVSC)

This paper models the sensitivity of dynamic hosting capacity analysis to the spatial distributio... more This paper models the sensitivity of dynamic hosting capacity analysis to the spatial distribution of distributed PV scenarios, random, close and far from substation deployments, at various penetration levels on a real distribution feeder, in a quasi-static time series (QSTS) power flow simulation using high resolution time-aware metrics. These spatial distribution scenarios were chosen to capture a wide range of potential operation impacts of these deployments using a set of thermaland voltage-based metrics such as instantaneous violations and moving averages for both thermal and voltage constraints. This study uses actual load and PV data up-scaled from 1-hour time step to 1-minute resolution to fully characterize the interaction between the daily changes in load and PV output, and their impacts on distribution system operations.

Soft Matter, 2022

Lithium phosphate tubular structures grow in two stages around a liquid jet despite their linearl... more Lithium phosphate tubular structures grow in two stages around a liquid jet despite their linearly increasing volume.

2018 IEEE Symposium on Computers and Communications (ISCC), 2018

The need to add intelligence to the existing power grid in order to operate as a cognitive, self-... more The need to add intelligence to the existing power grid in order to operate as a cognitive, self-monitoring and selfhealing system has become imminent. The monolithic energy value chain comes with a lot of constraints such as elongated outage, electricity theft and low equipment optimization. The next-generation grid is a data-centric network with heterogeneous hierarchical interconnected layers. Network devices in the emerging grid need a standard platform for proper integration, monitoring and control. In this paper, a holistic smart grid architectural landscape that clearly separates the power and communication domains to enable "evolving smart grid" engineers provide efficient networking solutions is presented. The communication routes and device topologies for the six smart grid applications are described based on the IEEE Guide for Smart Grid Interoperability and National Institute of Standards and Technology frameworks. Also, the deployments of intelligent electronic devices for microgrid control, monitoring and islanding operations are highlighted. Index Terms-self-healing, distributed energy resources, intelligent electronic devices, islanding, smart grid.

2018 Australasian Universities Power Engineering Conference (AUPEC), 2018

The effect of global warming is expected to increase the number of lightning strikes with the cap... more The effect of global warming is expected to increase the number of lightning strikes with the capacity to alter the operations of power lines and voltage regulating devices. This problem is exacerbated by the rapid proliferation of wind power generation in the distribution system, which increases the propagation of lightning strikes in the network. This paper presents the impact of lightning generated over-voltages on voltage regulating devices of the IEEE-34 feeder with utility-interactive centralized wind turbine generators (WTGs). Three deployment scenarios are considered: centralized WTG close to the feeder source, midpoint and end. Results show the occurrence of over-voltages and high fluctuations across the voltage regulators and fixed capacitors regardless of where the WTG is deployed. However, the WTG deployed closest to the feeder end resulted in higher over-voltages and fluctuations than the other two scenarios. This analysis is critical to network planners concerned about lightning protection and risk assessment.

2016 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), 2016

One of the value attributes of photovoltaic distributed generation (PV-DG) is the offset of feede... more One of the value attributes of photovoltaic distributed generation (PV-DG) is the offset of feeder currents which in turn reduces the overall feeder loading. In addition, for remote nodes at the end of the distribution network with high voltage unbalance tendency, PV-DG can be used to reduce this unbalance factor and its associated adverse impacts. This paper discusses the impact of distributed PVs on the equipment loading and voltage unbalance factor of the distribution network. Impact analysis has been carried out on the IEEE-13 distribution bus at different penetration levels using the Open-source Distribution System Simulator (OpenDSS). The results showed that for such highly loaded distribution network, PV-DG can be used to offset feeder current, active power demand, equipment loading and voltage unbalance. In addition, we use typical localized average temperature, solar irradiance and load demand profiles in this interconnection study.

Steel corrosion is a major and costly problem to industrialists and construction workers. The inh... more Steel corrosion is a major and costly problem to industrialists and construction workers. The inhibiting effect of dioctyl phthalate on the corrosion of mild steel was carried out in 1.0 M solution of HCl as the corrosion medium using the weight loss method. The adsorption of the dioctyl phthalate on the surface of the mild steel in 1.0 M HCl was found to follow the physisorption mechanism and also follow the first order rate law. The corrosion rate was found to be di-rectly proportional to the temperature of the medium, and inversely proportional to the concentration of the inhibitor in solution. The activation energy increases with increase in the concentration of the inhibitor. Values of standard free energy change, are consistently below ﹣20 kJmol﹣1. This solidly established that the adsorption mechanism of the dioctyl phthalate on mild steel surface is physisorption. Langmuir and Freundlich adsorption isotherms were used, with Freundlich isotherm as best fit for the modelling o...

As the solar PV technology continues to evolve as the most common distributed generation (DG) cou... more As the solar PV technology continues to evolve as the most common distributed generation (DG) coupled with increasing interconnection requests, accurate modelling of the potential operational impacts of this game-changer is pivotal in order to maintain the reliability of the electric grid. The overall goal of this research is to conduct an interconnection impact analysis of solar PV systems at increasing penetration levels subject to the feeder constraints within the distribution network. This is carried out with a time series power flow analysis method to capture the time-varying nature of solar PV and load with their interactions with the distribution network device operations. Also, this thesis analyses multiple PV systems scenarios and a wide range of possible impacts to enable distribution system planners and operators understand and characterize grid operations with the integration of PV systems. An evaluation of the operational and reliability performance of a grid-connected...

CrystEngComm, 2020

Flow-driven asymmetric growth of lithium phosphate in the presence of concentration gradients in ... more Flow-driven asymmetric growth of lithium phosphate in the presence of concentration gradients in a microchannel.

2019 IEEE Power & Energy Society General Meeting (PESGM), 2019

Main case Standard modeling assumptions Cost sensitivities Low cost wind High cost solar/storage ... more Main case Standard modeling assumptions Cost sensitivities Low cost wind High cost solar/storage High cost solar/storage + low cost natural gas Other sensitivities Eastern Interconnect has similar CO 2 targets (70% in 2030, net-zero in 2050) Duke able to secure firm capacity outside of the Carolinas All fossil fuel must retire as part of net-zero 2050 target NREL | 8

Solar Energy, 2020

Abstract This article reviews power system flexibility assessment, which is necessary to ensure b... more Abstract This article reviews power system flexibility assessment, which is necessary to ensure both instantaneous stability and long-term security of supply under high penetrations of variable, uncertain, and asynchronous renewable energy resources, such as solar photovoltaics. This article reviews the concept of flexibility and summarizes metrics for evaluating power system flexibility, which is not yet available in the literature. Power system planning and operational models applicable for flexibility assessment, including net load analysis, capacity expansion, production cost, and dynamic models, are reviewed in a comprehensive literature survey, with a focus on high solar and other variable renewable energy penetrations. Each of these models applies different methodological approaches and feasibility criteria appropriate at different timescales. Finally, this article presents a conceptual integrated framework to combine these models for a holistic assessment of power system flexibility requirements across all timescales, from multiyear to sub-cycle.

The United States Agency for International Development (USAID) has had a long and fruitful partne... more The United States Agency for International Development (USAID) has had a long and fruitful partnership with the Ministry of Power (MOP), Government of India (GOI) through several bilateral initiatives to modernize the energy sector. A key initiative under the U.S-India bilateral engagement is the Greening the Grid (GTG) program under the U.S. government's Asia EDGE (Enhancing Development and Growth through Energy) initiative. This 5-year program supports the GOI in its efforts to manage large-scale integration of renewable energy into the Indian power grid. A primary component of this initiative is the collaboration between the U.S. Department of Energy (DOE) national laboratories India's power system stakeholders, to explore solutions for successfully integrating renewable energy and enabling technologies. These collaborations build robust analytical capabilities within India's institutions through joint research efforts between the DOE laboratories and key actors in India's power sector. In addition to capacity building, the research outcomes will be used by Indian institutions and the global energy community to better prepare for a rapidly changing energy sector. One of the most essential institutions in India's power sector are the distribution utilities. Distribution utilities play a critical role in managing the electric grid, and their ability to evolve with the changing needs of their customers is important to catalyze modernization. Significant changes in the makeup of the demand, including the introduction of electric vehicles (EVs), is likely to take place as India seeks to achieve the ambitious goals set out by the GOI. Utilities will play a large role in enabling this growth by building charging infrastructure and learning to manage the additional demand. Additionally, energy storage has emerged as a new asset that utilities will use for various purposes; but high capital costs matched with limited experience from both utilities and regulators make the decision to invest in this technology challenging. To address these challenges, the National Renewable Energy Laboratory (NREL) partnered with BSES Rajdhani Power Ltd. (BRPL) to analyze the impact that EVs could have on its service territory and to understand the benefits that could be had from installing battery energy storage systems (BESS). NREL and BRPL developed an advanced power distribution system impact analysis framework of BRPL's distribution system to evaluate distributed photo voltaic (PV), BESS, and EVs. BESS are evaluated for their effectiveness on the grid to mitigate present and future feeder overloading scenarios and are analyzed for their costs compared to the costs of traditional upgradation measures. Scenarios include assessing the effects of EV density on grid infrastructure upgrades and interlinking EV management with BESS integration. The report "Preparing Distribution Utilities for Utility-Scale Storage and Electric Vehicles: A Novel Analytical Framework" provides both key insights for BRPL and a framework that will be useful to many of India's distribution utilities. The solution framework is built entirely on open-source platforms and programming languages, and therefore it could be replicated by other utilities and built upon as new questions arise in the planning of India's distribution grid. Ultimately, the outcomes from this report and the potential outcomes from the future use of this framework by utilities will provide policymakers and regulators with data-driven guidance on the impacts of their decisions. I would like to thank our bilateral partner, the MOP, for playing a key role in the effort to modernize India's electric grid and provide an enabling environment for renewable energy integration. I would also like to thank Mr. Amal Sinha, CEO and Abhishek Ranjan, AVP, System Operation, BRPL, for his leadership and support in bringing together NREL and BRPL engineers to produce a sound framework that could act as a template for distribution grid analysis in India. I would also like to congratulate team at NREL and BRPL for their excellent work in producing this framework and report. I hope that the findings of the report will be useful for a broad set of stakeholders across India. Thank you Michael Satin Director, Clean Energy & Environment Office USAID/India ACKNOWLEDGMENTS USAID's Greening the Grid (GTG) is a 5-year program implemented in partnership with India's Ministry of Power (MOP) under the USAID's ASIA EDGE (Enhancing Development and Growth through Energy) Initiative. The program aims to support the Government of India's (GOI) efforts to manage the large-scale integration of RE into the grid. This study was supported by the USAID/India, as part of the its Greening the Grid program. The study was undertaken in close collaboration with BSES Reliance Private Limited (BRPL), and the authors thank the Hon. CEO of BRPL Mr. Amal Sinha, and his team-including Abhishek Ranjan, Naveen Nagpal, and Sugandhita Wadhera-for their timely support and help regarding the data sets used in this report. The authors also thank USAID's GTG-RISE (implemented by Deloitte) team for their feedback and coordination. We also thank The Energy and Resources Institute for their support in reviewing and help making this report better. We are finally thankful to Ministry of Power for their support and review.

This report presents a net load analysis, geospatial analysis, and a web application for the Duke... more This report presents a net load analysis, geospatial analysis, and a web application for the Duke Energy Carbon-Free Resource Integration Study. In this collaborative engagement, the National Renewable Energy Laboratory (NREL) provides research support to Duke Energy to analyze the impacts of integrating significant amounts of new solar photovoltaic (PV) power into its service territory under a variety of scenarios. This analysis covers Duke Energy's territories in North Carolina and South Carolina, including two balancing authorities-Duke Energy Progress (DEP) and Duke Energy Carolinas (DEC)-with detailed assessments and discussions of the operations of the existing fleet, particularly nuclear generation, under high-penetration scenarios of solar PV. In addition to quantifying the solar potential, NREL is working with Duke Energy to identify possible opportunities for wind, storage, demand-side resources, and other technologies. Scenario Analysis This analysis looks at a variety of solar power penetration levels in Duke Energy's service territory in the Carolinas-compared to load and system-wide minimum generation levels-that best represent potential challenges and opportunities for renewable generation integration. An example of this includes an analysis of balancing solar and load for typical days during different seasons and extreme days, such as minimum and peak net load days. Net load is defined as the customer load less wind power and solar power generation. This analysis is performed by comparing estimated hourly solar, wind, net load, and system minimum generation time series for the different scenarios. The overall aim is to help Duke Energy understand initial estimates of possible curtailment, key periods of ramping, and load-following requirements. Further, this analysis captures net load impacts across different seasons and operational issues related to generation flexibility limit during periods of low load with high penetrations of solar energy.

IET Renewable Power Generation, 2020

The widespread deployment of autonomous inverter-based solutions for mitigating voltage and frequ... more The widespread deployment of autonomous inverter-based solutions for mitigating voltage and frequency excursions caused by high-penetration photovoltaic (PV) systems has drawn increased attention due to their potential impact on PV production. It is now important to quantify the amount of solar energy curtailed as a result of the activation of inverter-based grid support functions (GSFs). This study proposes a methodology for estimating the impact of volt-watt on customer PV energy curtailment using smart meter voltage data. This method estimates maximum possible curtailment for a given volt-watt curve based on the customer smart meter voltage during the time period of interest. This study compares the proposed methodology with field measurements using irradiance and customer inverter data from Hawaii as well as with results from a previous simulation-driven study on the impact of advanced inverter GSF activation on PV energy curtailment. Results show that the proposed method for estimating lost PV production caused by volt-watt control aligns reasonably well with field measurements and computer simulations for hundreds of customers. The proposed method could be used to estimate customer energy curtailment, which could inform future compensation mechanisms for utilities leveraging customer-sited resources to mitigate high voltage and defer infrastructure upgrades.

OALib, 2019

The research was aimed at the antibacterial studies and cytotoxicity of aqueous trona extract of ... more The research was aimed at the antibacterial studies and cytotoxicity of aqueous trona extract of Sclerocarya birrea (marula) stem bark. Extraction of the stem bark was carried out using decoction method from the dried stem bark of marula. The extract was subjected to phytochemical screening, antibacterial and cytotoxicity test. The extract indicated the presence of tannin, saponins and alkaloids with the absence of flavonoids, steroids and glycosides. An antimicrobial study of the extracts was carried out against Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae using agar-well diffusion method. The extracts with trona have higher zone of inhibition at 100 mg/ml, Escherichia coli, (zone of inhibition = 16), Staphylococcus aureus (zone of inhibition = 14) and Klebsiella pneumoniae (zone of inhibition = 9). The cytotoxicity tests were carried out on the extracts using brine shrimp lethality assay, the extract showed a mortality with 9 nauplii dead upon exposure at 1000 ppm, and had an LC 50 value of 63.1 ppm. The FTIR characterization carried out on the extract indicates the presence of functional groups such as: O-H, C=O, C-N and C-C(O)-C indicating peak of alcohols, carbonyl group amine and ester.

2020 47th IEEE Photovoltaic Specialists Conference (PVSC)

This article presents the impact of battery energy storage system's (BESS) control triggers o... more This article presents the impact of battery energy storage system's (BESS) control triggers on its performance during peak shaving application. With the increasing deployment of BESS for load leveling and grid capacity relief, the sensitivity of BESS performance to its set-points is yet to be investigated. Most utilities have defined thresholds to activate BESS discharging for peak demand leveling and baseload BESS charging. However, this study shows that without using optimal set-points for control applications, the BESS can remain under-utilized. In this work, simulation results of the peak shaving algorithm implementation in 30-minute time step over a period of 10 years show the impact of different BESS control set-points on distribution transformer loading, line and system losses.

2020 47th IEEE Photovoltaic Specialists Conference (PVSC)

This paper presents a modeling framework for realworld distribution systems to enable large-scale... more This paper presents a modeling framework for realworld distribution systems to enable large-scale transmission-and-distribution (T&D) cosimulation. The modeling methodology includes three major steps: utility feeder model conversion, feeder load modeling, and model validation. The feeder models obtained from the utility are converted to the format that is more flexible for analysis and algorithm development. The load profile of each medium-voltage bus is modeled based on the data obtained from advanced metering infrastructure and the supervisory control and data acquisition (SCADA) system. Then the converted feeder models are validated by comparing the simulated feeder-head voltage results to the measured voltage data from SCADA. Last, the modeled real-world large-scale distribution systems are integrated into a T&D cosimulation framework to perform the system simulation from the bulk system down to the medium-voltage buses in the distribution system.

2021 IEEE 48th Photovoltaic Specialists Conference (PVSC)

This paper models the sensitivity of dynamic hosting capacity analysis to the spatial distributio... more This paper models the sensitivity of dynamic hosting capacity analysis to the spatial distribution of distributed PV scenarios, random, close and far from substation deployments, at various penetration levels on a real distribution feeder, in a quasi-static time series (QSTS) power flow simulation using high resolution time-aware metrics. These spatial distribution scenarios were chosen to capture a wide range of potential operation impacts of these deployments using a set of thermaland voltage-based metrics such as instantaneous violations and moving averages for both thermal and voltage constraints. This study uses actual load and PV data up-scaled from 1-hour time step to 1-minute resolution to fully characterize the interaction between the daily changes in load and PV output, and their impacts on distribution system operations.

Soft Matter, 2022

Lithium phosphate tubular structures grow in two stages around a liquid jet despite their linearl... more Lithium phosphate tubular structures grow in two stages around a liquid jet despite their linearly increasing volume.

2018 IEEE Symposium on Computers and Communications (ISCC), 2018

The need to add intelligence to the existing power grid in order to operate as a cognitive, self-... more The need to add intelligence to the existing power grid in order to operate as a cognitive, self-monitoring and selfhealing system has become imminent. The monolithic energy value chain comes with a lot of constraints such as elongated outage, electricity theft and low equipment optimization. The next-generation grid is a data-centric network with heterogeneous hierarchical interconnected layers. Network devices in the emerging grid need a standard platform for proper integration, monitoring and control. In this paper, a holistic smart grid architectural landscape that clearly separates the power and communication domains to enable "evolving smart grid" engineers provide efficient networking solutions is presented. The communication routes and device topologies for the six smart grid applications are described based on the IEEE Guide for Smart Grid Interoperability and National Institute of Standards and Technology frameworks. Also, the deployments of intelligent electronic devices for microgrid control, monitoring and islanding operations are highlighted. Index Terms-self-healing, distributed energy resources, intelligent electronic devices, islanding, smart grid.

2018 Australasian Universities Power Engineering Conference (AUPEC), 2018

The effect of global warming is expected to increase the number of lightning strikes with the cap... more The effect of global warming is expected to increase the number of lightning strikes with the capacity to alter the operations of power lines and voltage regulating devices. This problem is exacerbated by the rapid proliferation of wind power generation in the distribution system, which increases the propagation of lightning strikes in the network. This paper presents the impact of lightning generated over-voltages on voltage regulating devices of the IEEE-34 feeder with utility-interactive centralized wind turbine generators (WTGs). Three deployment scenarios are considered: centralized WTG close to the feeder source, midpoint and end. Results show the occurrence of over-voltages and high fluctuations across the voltage regulators and fixed capacitors regardless of where the WTG is deployed. However, the WTG deployed closest to the feeder end resulted in higher over-voltages and fluctuations than the other two scenarios. This analysis is critical to network planners concerned about lightning protection and risk assessment.

2016 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), 2016

One of the value attributes of photovoltaic distributed generation (PV-DG) is the offset of feede... more One of the value attributes of photovoltaic distributed generation (PV-DG) is the offset of feeder currents which in turn reduces the overall feeder loading. In addition, for remote nodes at the end of the distribution network with high voltage unbalance tendency, PV-DG can be used to reduce this unbalance factor and its associated adverse impacts. This paper discusses the impact of distributed PVs on the equipment loading and voltage unbalance factor of the distribution network. Impact analysis has been carried out on the IEEE-13 distribution bus at different penetration levels using the Open-source Distribution System Simulator (OpenDSS). The results showed that for such highly loaded distribution network, PV-DG can be used to offset feeder current, active power demand, equipment loading and voltage unbalance. In addition, we use typical localized average temperature, solar irradiance and load demand profiles in this interconnection study.

Steel corrosion is a major and costly problem to industrialists and construction workers. The inh... more Steel corrosion is a major and costly problem to industrialists and construction workers. The inhibiting effect of dioctyl phthalate on the corrosion of mild steel was carried out in 1.0 M solution of HCl as the corrosion medium using the weight loss method. The adsorption of the dioctyl phthalate on the surface of the mild steel in 1.0 M HCl was found to follow the physisorption mechanism and also follow the first order rate law. The corrosion rate was found to be di-rectly proportional to the temperature of the medium, and inversely proportional to the concentration of the inhibitor in solution. The activation energy increases with increase in the concentration of the inhibitor. Values of standard free energy change, are consistently below ﹣20 kJmol﹣1. This solidly established that the adsorption mechanism of the dioctyl phthalate on mild steel surface is physisorption. Langmuir and Freundlich adsorption isotherms were used, with Freundlich isotherm as best fit for the modelling o...

As the solar PV technology continues to evolve as the most common distributed generation (DG) cou... more As the solar PV technology continues to evolve as the most common distributed generation (DG) coupled with increasing interconnection requests, accurate modelling of the potential operational impacts of this game-changer is pivotal in order to maintain the reliability of the electric grid. The overall goal of this research is to conduct an interconnection impact analysis of solar PV systems at increasing penetration levels subject to the feeder constraints within the distribution network. This is carried out with a time series power flow analysis method to capture the time-varying nature of solar PV and load with their interactions with the distribution network device operations. Also, this thesis analyses multiple PV systems scenarios and a wide range of possible impacts to enable distribution system planners and operators understand and characterize grid operations with the integration of PV systems. An evaluation of the operational and reliability performance of a grid-connected...

CrystEngComm, 2020

Flow-driven asymmetric growth of lithium phosphate in the presence of concentration gradients in ... more Flow-driven asymmetric growth of lithium phosphate in the presence of concentration gradients in a microchannel.

2019 IEEE Power & Energy Society General Meeting (PESGM), 2019

Main case Standard modeling assumptions Cost sensitivities Low cost wind High cost solar/storage ... more Main case Standard modeling assumptions Cost sensitivities Low cost wind High cost solar/storage High cost solar/storage + low cost natural gas Other sensitivities Eastern Interconnect has similar CO 2 targets (70% in 2030, net-zero in 2050) Duke able to secure firm capacity outside of the Carolinas All fossil fuel must retire as part of net-zero 2050 target NREL | 8

Solar Energy, 2020

Abstract This article reviews power system flexibility assessment, which is necessary to ensure b... more Abstract This article reviews power system flexibility assessment, which is necessary to ensure both instantaneous stability and long-term security of supply under high penetrations of variable, uncertain, and asynchronous renewable energy resources, such as solar photovoltaics. This article reviews the concept of flexibility and summarizes metrics for evaluating power system flexibility, which is not yet available in the literature. Power system planning and operational models applicable for flexibility assessment, including net load analysis, capacity expansion, production cost, and dynamic models, are reviewed in a comprehensive literature survey, with a focus on high solar and other variable renewable energy penetrations. Each of these models applies different methodological approaches and feasibility criteria appropriate at different timescales. Finally, this article presents a conceptual integrated framework to combine these models for a holistic assessment of power system flexibility requirements across all timescales, from multiyear to sub-cycle.

The United States Agency for International Development (USAID) has had a long and fruitful partne... more The United States Agency for International Development (USAID) has had a long and fruitful partnership with the Ministry of Power (MOP), Government of India (GOI) through several bilateral initiatives to modernize the energy sector. A key initiative under the U.S-India bilateral engagement is the Greening the Grid (GTG) program under the U.S. government's Asia EDGE (Enhancing Development and Growth through Energy) initiative. This 5-year program supports the GOI in its efforts to manage large-scale integration of renewable energy into the Indian power grid. A primary component of this initiative is the collaboration between the U.S. Department of Energy (DOE) national laboratories India's power system stakeholders, to explore solutions for successfully integrating renewable energy and enabling technologies. These collaborations build robust analytical capabilities within India's institutions through joint research efforts between the DOE laboratories and key actors in India's power sector. In addition to capacity building, the research outcomes will be used by Indian institutions and the global energy community to better prepare for a rapidly changing energy sector. One of the most essential institutions in India's power sector are the distribution utilities. Distribution utilities play a critical role in managing the electric grid, and their ability to evolve with the changing needs of their customers is important to catalyze modernization. Significant changes in the makeup of the demand, including the introduction of electric vehicles (EVs), is likely to take place as India seeks to achieve the ambitious goals set out by the GOI. Utilities will play a large role in enabling this growth by building charging infrastructure and learning to manage the additional demand. Additionally, energy storage has emerged as a new asset that utilities will use for various purposes; but high capital costs matched with limited experience from both utilities and regulators make the decision to invest in this technology challenging. To address these challenges, the National Renewable Energy Laboratory (NREL) partnered with BSES Rajdhani Power Ltd. (BRPL) to analyze the impact that EVs could have on its service territory and to understand the benefits that could be had from installing battery energy storage systems (BESS). NREL and BRPL developed an advanced power distribution system impact analysis framework of BRPL's distribution system to evaluate distributed photo voltaic (PV), BESS, and EVs. BESS are evaluated for their effectiveness on the grid to mitigate present and future feeder overloading scenarios and are analyzed for their costs compared to the costs of traditional upgradation measures. Scenarios include assessing the effects of EV density on grid infrastructure upgrades and interlinking EV management with BESS integration. The report "Preparing Distribution Utilities for Utility-Scale Storage and Electric Vehicles: A Novel Analytical Framework" provides both key insights for BRPL and a framework that will be useful to many of India's distribution utilities. The solution framework is built entirely on open-source platforms and programming languages, and therefore it could be replicated by other utilities and built upon as new questions arise in the planning of India's distribution grid. Ultimately, the outcomes from this report and the potential outcomes from the future use of this framework by utilities will provide policymakers and regulators with data-driven guidance on the impacts of their decisions. I would like to thank our bilateral partner, the MOP, for playing a key role in the effort to modernize India's electric grid and provide an enabling environment for renewable energy integration. I would also like to thank Mr. Amal Sinha, CEO and Abhishek Ranjan, AVP, System Operation, BRPL, for his leadership and support in bringing together NREL and BRPL engineers to produce a sound framework that could act as a template for distribution grid analysis in India. I would also like to congratulate team at NREL and BRPL for their excellent work in producing this framework and report. I hope that the findings of the report will be useful for a broad set of stakeholders across India. Thank you Michael Satin Director, Clean Energy & Environment Office USAID/India ACKNOWLEDGMENTS USAID's Greening the Grid (GTG) is a 5-year program implemented in partnership with India's Ministry of Power (MOP) under the USAID's ASIA EDGE (Enhancing Development and Growth through Energy) Initiative. The program aims to support the Government of India's (GOI) efforts to manage the large-scale integration of RE into the grid. This study was supported by the USAID/India, as part of the its Greening the Grid program. The study was undertaken in close collaboration with BSES Reliance Private Limited (BRPL), and the authors thank the Hon. CEO of BRPL Mr. Amal Sinha, and his team-including Abhishek Ranjan, Naveen Nagpal, and Sugandhita Wadhera-for their timely support and help regarding the data sets used in this report. The authors also thank USAID's GTG-RISE (implemented by Deloitte) team for their feedback and coordination. We also thank The Energy and Resources Institute for their support in reviewing and help making this report better. We are finally thankful to Ministry of Power for their support and review.

This report presents a net load analysis, geospatial analysis, and a web application for the Duke... more This report presents a net load analysis, geospatial analysis, and a web application for the Duke Energy Carbon-Free Resource Integration Study. In this collaborative engagement, the National Renewable Energy Laboratory (NREL) provides research support to Duke Energy to analyze the impacts of integrating significant amounts of new solar photovoltaic (PV) power into its service territory under a variety of scenarios. This analysis covers Duke Energy's territories in North Carolina and South Carolina, including two balancing authorities-Duke Energy Progress (DEP) and Duke Energy Carolinas (DEC)-with detailed assessments and discussions of the operations of the existing fleet, particularly nuclear generation, under high-penetration scenarios of solar PV. In addition to quantifying the solar potential, NREL is working with Duke Energy to identify possible opportunities for wind, storage, demand-side resources, and other technologies. Scenario Analysis This analysis looks at a variety of solar power penetration levels in Duke Energy's service territory in the Carolinas-compared to load and system-wide minimum generation levels-that best represent potential challenges and opportunities for renewable generation integration. An example of this includes an analysis of balancing solar and load for typical days during different seasons and extreme days, such as minimum and peak net load days. Net load is defined as the customer load less wind power and solar power generation. This analysis is performed by comparing estimated hourly solar, wind, net load, and system minimum generation time series for the different scenarios. The overall aim is to help Duke Energy understand initial estimates of possible curtailment, key periods of ramping, and load-following requirements. Further, this analysis captures net load impacts across different seasons and operational issues related to generation flexibility limit during periods of low load with high penetrations of solar energy.

IET Renewable Power Generation, 2020

The widespread deployment of autonomous inverter-based solutions for mitigating voltage and frequ... more The widespread deployment of autonomous inverter-based solutions for mitigating voltage and frequency excursions caused by high-penetration photovoltaic (PV) systems has drawn increased attention due to their potential impact on PV production. It is now important to quantify the amount of solar energy curtailed as a result of the activation of inverter-based grid support functions (GSFs). This study proposes a methodology for estimating the impact of volt-watt on customer PV energy curtailment using smart meter voltage data. This method estimates maximum possible curtailment for a given volt-watt curve based on the customer smart meter voltage during the time period of interest. This study compares the proposed methodology with field measurements using irradiance and customer inverter data from Hawaii as well as with results from a previous simulation-driven study on the impact of advanced inverter GSF activation on PV energy curtailment. Results show that the proposed method for estimating lost PV production caused by volt-watt control aligns reasonably well with field measurements and computer simulations for hundreds of customers. The proposed method could be used to estimate customer energy curtailment, which could inform future compensation mechanisms for utilities leveraging customer-sited resources to mitigate high voltage and defer infrastructure upgrades.

OALib, 2019

The research was aimed at the antibacterial studies and cytotoxicity of aqueous trona extract of ... more The research was aimed at the antibacterial studies and cytotoxicity of aqueous trona extract of Sclerocarya birrea (marula) stem bark. Extraction of the stem bark was carried out using decoction method from the dried stem bark of marula. The extract was subjected to phytochemical screening, antibacterial and cytotoxicity test. The extract indicated the presence of tannin, saponins and alkaloids with the absence of flavonoids, steroids and glycosides. An antimicrobial study of the extracts was carried out against Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae using agar-well diffusion method. The extracts with trona have higher zone of inhibition at 100 mg/ml, Escherichia coli, (zone of inhibition = 16), Staphylococcus aureus (zone of inhibition = 14) and Klebsiella pneumoniae (zone of inhibition = 9). The cytotoxicity tests were carried out on the extracts using brine shrimp lethality assay, the extract showed a mortality with 9 nauplii dead upon exposure at 1000 ppm, and had an LC 50 value of 63.1 ppm. The FTIR characterization carried out on the extract indicates the presence of functional groups such as: O-H, C=O, C-N and C-C(O)-C indicating peak of alcohols, carbonyl group amine and ester.