Enhancing microgrid resilience through integrated grid-forming and grid-following inverter strategies for solar PV battery control and fault ride-through – Nature

Report on Microgrid Resilience and Sustainable Development Goals

Executive Summary

This report analyzes the integration of a Grid-Forming (GFM) Battery Energy Storage System (BESS) to enhance the stability of microgrids with high renewable energy penetration. The findings demonstrate that GFM inverter technology, compared to traditional Grid-Following (GFL) inverters, significantly improves fault resiliency and operational stability. This technological advancement is critical for achieving several Sustainable Development Goals (SDGs), particularly SDG 7 (Affordable and Clean Energy), SDG 9 (Industry, Innovation, and Infrastructure), and SDG 11 (Sustainable Cities and Communities). The GFM-controlled system successfully maintained stability during severe grid disturbances, including a 50% drop in solar irradiance and a 46% increase in load demand, showcasing its potential to build resilient, sustainable, and reliable energy networks for the future.

1.0 Introduction: Aligning Microgrid Technology with Sustainable Development Goals

The global transition towards sustainable energy systems necessitates the integration of renewable sources like solar photovoltaics (PV). However, their intermittent nature poses significant challenges to grid stability. Microgrids, incorporating BESS and advanced inverters, offer a viable solution to these challenges. This report evaluates the role of GFM and GFL inverter strategies in enhancing microgrid resilience, framing the technological contributions within the context of the United Nations Sustainable Development Goals.

• SDG 7 (Affordable and Clean Energy): By enabling the stable integration of high levels of solar PV, this technology directly supports the goal of increasing the share of renewable energy in the global energy mix.
• SDG 9 (Industry, Innovation, and Infrastructure): The development of GFM inverters and resilient microgrid architectures represents a significant innovation, contributing to the creation of reliable and sustainable infrastructure capable of withstanding faults and disturbances.
• SDG 11 (Sustainable Cities and Communities): Resilient microgrids ensure a continuous and reliable power supply, which is fundamental for the functioning of sustainable cities, especially during grid outages or extreme weather events.
• SDG 13 (Climate Action): Facilitating the large-scale adoption of solar energy is a key strategy in mitigating climate change by reducing dependence on fossil fuels.

2.0 Technological Framework for Sustainable Energy Infrastructure

The study focuses on a microgrid model composed of a solar PV plant, a BESS, and an intelligent Energy Management System (EMS). The core innovation lies in the control strategies for the inverters that interface these components with the grid.

2.1 Grid-Forming (GFM) vs. Grid-Following (GFL) Inverters

A key distinction in microgrid control lies in the inverter technology used. This distinction is crucial for building the resilient infrastructure required by SDG 9.

1. Grid-Following (GFL) Inverters: These traditional inverters synchronize with an existing, stable grid, following its voltage and frequency. Their performance degrades significantly in weak grids or during disturbances.
2. Grid-Forming (GFM) Inverters: These advanced inverters can independently establish and regulate grid voltage and frequency, much like a conventional generator. This capability is essential for operating in islanded mode and providing stability during faults, thereby ensuring a reliable energy supply in line with SDG 7.

2.2 Role of Battery Energy Storage Systems (BESS)

The BESS is integral to mitigating the variability of solar power. When managed by a GFM inverter, the BESS becomes a proactive grid stabilizer, providing instantaneous power to balance supply and demand. This function is vital for maintaining the consistent energy access promoted by SDG 7.

2.3 Energy Management System (EMS)

The EMS optimizes the power flow between the PV system, BESS, and the grid. By using forecasting and optimization algorithms, the EMS ensures that energy is generated, stored, and consumed efficiently, which contributes to the overall sustainability and economic viability of the microgrid system.

3.0 Performance Analysis and Contribution to SDG 7 and SDG 9

Simulation results from MATLAB/Simulink confirm the superior performance of the GFM inverter strategy in creating a resilient and stable energy system, directly contributing to the targets of SDG 7 and SDG 9.

3.1 Enhancing Grid Stability and Fault Resilience

The GFM-controlled system demonstrated exceptional performance under various stress tests:

• Solar Irradiance Fluctuation: During a 50% drop in solar irradiance, the GFM-BESS system stabilized within 1 second by supplying reactive power and inertial support.
• Sudden Load Increase: In response to a 46% increase in load demand, the GFM-BESS immediately compensated for the power imbalance, maintaining stable voltage and frequency.
• Grid Fault Conditions: The GFM inverter enabled Fault Ride-Through (FRT), maintaining operational stability with voltage recovery within 300 ms and frequency deviations limited to ±0.5 Hz.

3.2 Comparative Analysis of GFM and GFL Inverters

The comparison highlights the innovative leap provided by GFM technology for building resilient infrastructure (SDG 9).

1. Weak Grid Performance: The GFL inverter struggled to stabilize under a low Short Circuit Ratio (SCR) of 0.423, leading to large voltage and frequency deviations. In contrast, the GFM inverter maintained robust stability even in weak grid conditions.
2. Fault Recovery: The GFM inverter restored microgrid stability more effectively and with faster fault recovery times compared to the GFL inverter.

4.0 Implications for Sustainable Cities and Climate Action (SDG 11 & SDG 13)

The successful implementation of GFM-controlled microgrids has profound implications for creating sustainable communities and combating climate change.

4.1 Building Resilient Communities

By ensuring an uninterrupted power supply during grid faults and outages, this technology enhances the resilience of critical infrastructure in cities and communities. This capability is a cornerstone of SDG 11, which aims to make human settlements inclusive, safe, resilient, and sustainable.

4.2 Accelerating Climate Action

The primary barrier to widespread solar energy adoption is its impact on grid stability. By solving this challenge, GFM inverter technology accelerates the transition away from fossil fuels. This directly supports SDG 13 by enabling a deeper penetration of clean energy, thereby reducing greenhouse gas emissions and strengthening resilience to climate-related hazards.

5.0 Conclusion and Future Outlook

This report concludes that the integration of GFM inverters with BESS is a highly effective strategy for enhancing the resilience and stability of microgrids with high solar PV penetration. The technology’s ability to ride through faults, manage sudden changes in generation and load, and operate in weak grid conditions marks a significant advancement over traditional GFL systems. These findings validate the practical viability of GFM inverters in future energy networks and underscore their critical role in achieving global sustainability targets.

Future research should focus on:

• Developing adaptive control strategies to further optimize performance under diverse grid conditions.
• Investigating cost-effective and scalable energy storage solutions.
• Integrating advanced solar and load forecasting to enhance the predictive capabilities of the Energy Management System.

By addressing these areas, the deployment of resilient, renewable-based microgrids can be accelerated, paving the way for a more sustainable and secure energy future in alignment with SDG 7, SDG 9, SDG 11, and SDG 13.

Analysis of Sustainable Development Goals (SDGs) in the Article

1. SDG 7: Affordable and Clean Energy

   • The article’s primary focus is on enhancing the stability and reliability of microgrids with high penetration of renewable energy, specifically solar photovoltaic (PV) systems. This directly supports the transition to cleaner energy sources. The study investigates technologies like Grid-Forming (GFM) inverters and Battery Energy Storage Systems (BESS) to overcome the intermittency challenges of solar power, thereby promoting “reliable, efficient, and sustainable microgrid operations.”

2. SDG 9: Industry, Innovation, and Infrastructure

   • The research contributes to developing resilient and sustainable infrastructure. Microgrids are presented as a modern, decentralized energy infrastructure. The paper’s core is an innovation in energy technology, specifically the “novel control strategy for Grid-Forming (GFM) and Grid-Following (GFL) inverters” and the design of a “Fault Ride-Through (FRT) mechanism.” These advancements aim to create more reliable and robust energy systems capable of withstanding disturbances, aligning with the goal of building resilient infrastructure.

3. SDG 11: Sustainable Cities and Communities

   • By improving the stability and reliability of local energy generation through microgrids, the article addresses the need for sustainable and resilient urban infrastructure. The ability of a microgrid to operate in “islanded mode” during a grid outage ensures an “uninterrupted delivery of power,” which is critical for the functioning of communities, especially during emergencies. This enhances the resilience of communities to disruptions.

4. SDG 13: Climate Action

   • The introduction explicitly frames the research in the context of “the pressures of climate change and the demands for cleaner energy.” By developing solutions that facilitate the large-scale integration of solar PV systems, the study directly contributes to climate change mitigation by reducing reliance on fossil fuels. Furthermore, enhancing the resilience of power systems through fault ride-through capabilities strengthens their adaptive capacity to climate-related hazards that can cause grid failures.

Specific SDG Targets Identified in the Article

1. Target 7.2: By 2030, increase substantially the share of renewable energy in the global energy mix.

   • The entire study is premised on addressing the challenges of “high renewable energy penetration.” It investigates solutions for integrating a “120 MW” solar PV plant, demonstrating a direct effort to increase the capacity and share of renewable energy in the power system. The development of GFM inverters and BESS is aimed at making this high share of renewables viable and stable.

2. Target 9.1: Develop quality, reliable, sustainable and resilient infrastructure… to support economic development and human well-being.

   • The article focuses on enhancing the “stability,” “fault resiliency,” and “reliability” of microgrids. The proposed GFM inverter technology is shown to “significantly improve fault resiliency and oscillation stability,” ensuring the microgrid can “continue to operate during grid faults.” This directly contributes to building more resilient energy infrastructure.

3. Target 9.4: By 2030, upgrade infrastructure… with increased resource-use efficiency and greater adoption of clean… technologies.

   • The research proposes upgrading energy infrastructure with advanced technologies like GFM inverters, BESS, and an Energy Management System (EMS). The article states that the “implementation of an Energy Management System (EMS) optimized power flow between the PV, BESS, and grid, enhancing system efficiency.” This represents a technological upgrade for greater efficiency and adoption of clean energy.

4. Target 11.b: By 2020, substantially increase the number of cities and human settlements adopting and implementing integrated policies and plans towards… resilience to disasters…

   • The article’s focus on “Fault Ride-Through (FRT)” capability is a direct measure to increase the resilience of energy systems to disasters or disturbances that cause grid failures. The ability of the microgrid to “remain operational during grid disturbances such as voltage sags, frequency dips, and faults” ensures a continuous power supply, which is a cornerstone of community resilience.

Indicators for Measuring Progress

1. Grid Stability and Resilience Metrics

   • The article provides specific, quantifiable metrics that serve as direct indicators of grid stability and resilience. These can be used to measure progress towards building reliable and resilient infrastructure (Targets 9.1, 11.b).
     • Voltage Recovery Time: The GFM inverter maintained “voltage recovery within 300 ms” during grid faults.
     • Frequency Deviation Limits: The system limited “frequency deviations… to ± 0.5 Hz.”
     • System Stabilization Time: The GFM-controlled system “stabilized within 1 s during a 50% solar irradiance drop.”
     • Fault Ride-Through (FRT) Performance: The ability to withstand temporary faults and recover “within 0.5 s after the fault is cleared” is a key performance indicator of resilience.
     • Short Circuit Ratio (SCR): The article uses SCR to measure grid strength. The GFM inverter’s ability to maintain stability even at a low SCR of 0.423, where the GFL inverter failed, is a clear indicator of its superior performance in weak grid conditions.

2. Energy System Efficiency

   • The article implies indicators related to the efficiency of the upgraded infrastructure (Target 9.4).
     • Optimized Power Flow: The use of an Energy Management System (EMS) to optimize power flow is an indicator of enhanced operational efficiency.
     • Power Extraction Efficiency: The use of Maximum Power Point Tracking (MPPT) to “extracts maximum power from the PV system” is a direct measure of the efficiency of renewable energy generation.

3. Renewable Energy Integration Capacity

   • The scale of the renewable energy project discussed serves as an indicator for increasing the share of renewables (Target 7.2).
     • Installed Capacity of Renewable Energy: The article models a large-scale “photovoltaic (PV) array that generates 120 MW,” indicating a substantial contribution to the energy mix.

Summary Table of SDGs, Targets, and Indicators

Source: nature.com