Surreal illustration of a degraded solar park impacting a stressed power grid.

Solar Power's Shifting Impact: How Plant Degradation Affects Distribution Networks

Jordan Keane in Climate & Environment June 2025 • 4 min read.

"A Deep Dive into the Quaid-e-Azam Solar Park Study and the Future of Sustainable Energy Grids"

Renewable energy is crucial for meeting future electricity demands, with solar power playing a significant role. Technologies like solar photovoltaic (PV) plants are becoming more prevalent, ranging from small-scale to large-scale installations. However, the intermittent nature of renewable sources, such as fluctuating solar irradiance, presents challenges that require careful planning and management.

Integrating Distributed Generations (DGs) from renewable sources into existing grids without proper planning can lead to power quality issues. Strategic placement and sizing of DGs are essential to maintain system performance and stability. A comprehensive understanding of real and reactive power sources is vital for effective integration.

This article examines the potential of the Quaid-e-Azam Solar Park (QASP) in Pakistan and its impact on distribution networks. By analyzing historical weather data and modeling PV plant yields, we uncover the long-term effects of solar power integration on grid efficiency and voltage stability. This study offers insights into the importance of detailed assessments for distributed generation planning, ensuring sustainable and reliable energy delivery.

Understanding the Quaid-e-Azam Solar Park (QASP) Study

Surreal illustration of a degraded solar park impacting a stressed power grid.

The Quaid-e-Azam Solar Park (QASP) is a 1000 MW solar PV plant located in Bahawalpur, Pakistan. It is one of Asia's largest solar farms. The park operates in phases, with the first 100 MW already installed and connected to the grid via a 132 kV substation. This plant aims to reduce Pakistan's electricity generation deficit by harnessing renewable energy.

A study was conducted to evaluate QASP's potential and its impact on distribution networks, utilizing 15 years of hourly weather data from the National Solar Radiation Database (NSRDB). The data was partitioned into four seasons and modeled using the Beta Probability Density Function (PDF) to generate 24-hour solar curves for each season. These outputs were then tested on an IEEE 33-bus distribution network to assess system losses and bus voltages.

Key aspects of the study include:

Data Analysis: Historical hourly weather data from 2000-2014 was analyzed to estimate PV plant yields.
Seasonal Modeling: Yearly data was divided into four seasons, each modeled using Beta Probability Density Function (PDF) to create 24-hour solar curves.
Network Testing: Solar farm power outputs were tested in an IEEE 33-bus distribution network with time-varying seasonal hourly loads.
Performance Metrics: System losses and bus voltages were calculated to evaluate the impact of solar PV power.

The results indicated that the impact of solar PV power on reducing system losses gradually decreases over time due to yearly degradation of PV module efficiency. System losses at the end of the PV farm's life were 10-12% higher compared to the first year. Additionally, low voltage buses faced increased risk as system voltages began to decrease.

Recommendations for Maintaining Network Quality

To maintain network quality and reliability, detailed assessments should be performed during the planning and sizing of distributed generation. These assessments should account for time-varying factors, such as seasonal load changes and PV module degradation. By considering these variables, operators can proactively address potential issues and ensure the sustainable integration of solar power into distribution networks. Long-term monitoring and adaptive strategies are essential for maximizing the benefits of solar energy while mitigating its challenges.

About this Article -

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Everything You Need To Know

What is the main focus of the Quaid-e-Azam Solar Park (QASP) study and why is it important?

The primary focus of the Quaid-e-Azam Solar Park (QASP) study is to evaluate the impact of solar power, specifically from the QASP, on distribution networks. This is crucial because solar power, while a vital renewable energy source, introduces complexities like fluctuating solar irradiance and the degradation of PV module efficiency over time. The study utilizes 15 years of hourly weather data, seasonal modeling with Beta Probability Density Functions, and network testing on an IEEE 33-bus distribution network. Understanding these impacts is essential for maintaining grid efficiency, voltage stability, and ensuring the reliable delivery of energy as more solar plants like QASP are integrated into existing infrastructure.

How does plant degradation affect the performance of the Quaid-e-Azam Solar Park (QASP) and the overall distribution network?

Plant degradation, specifically the yearly decline in PV module efficiency, significantly impacts the Quaid-e-Azam Solar Park (QASP) and connected distribution networks. The study found that the impact of solar PV power on reducing system losses diminishes over time due to this degradation. Specifically, system losses at the end of the PV farm's operational life (e.g. the lifetime of QASP) were found to be 10-12% higher than in the first year of operation. Moreover, the long-term decline in efficiency can lead to decreased bus voltages, increasing the risk for low voltage buses within the distribution network. This underscores the importance of accounting for degradation in planning and operational strategies.

What methodology was used to analyze the Quaid-e-Azam Solar Park (QASP) data, and how did it contribute to the study's findings?

The study employed a detailed methodology to analyze the Quaid-e-Azam Solar Park (QASP) data. This included analyzing 15 years of hourly weather data from the National Solar Radiation Database (NSRDB) to estimate PV plant yields. The data was then partitioned into four seasons and modeled using the Beta Probability Density Function (PDF) to generate 24-hour solar curves for each season. These outputs were tested on an IEEE 33-bus distribution network, allowing the researchers to assess system losses and bus voltages. The use of the Beta PDF was crucial for accurately simulating the time-varying nature of solar irradiance. The seasonal modeling and network testing provided insights into the impact of QASP's power output on grid performance, especially regarding the effects of seasonal variations and long-term degradation.

What are the key recommendations for maintaining network quality when integrating solar power, such as that from the Quaid-e-Azam Solar Park (QASP), into distribution networks?

To maintain network quality and reliability when integrating solar power, such as from the Quaid-e-Azam Solar Park (QASP), the study emphasizes the need for detailed assessments during the planning and sizing of distributed generation. These assessments should consider time-varying factors like seasonal load changes and the degradation of PV module efficiency. Proactive measures are essential for mitigating potential issues. This includes long-term monitoring and adaptive strategies that allow operators to respond effectively to changes in solar output and system performance. These strategies are crucial for maximizing the benefits of solar energy while minimizing its challenges, ensuring that distribution networks remain stable and efficient.

How does the Quaid-e-Azam Solar Park (QASP) contribute to Pakistan's energy landscape, and what are the broader implications of this project?

The Quaid-e-Azam Solar Park (QASP), located in Bahawalpur, Pakistan, is a 1000 MW solar PV plant designed to significantly reduce Pakistan's electricity generation deficit by harnessing renewable energy. The project, one of Asia's largest solar farms, operates in phases, with the first 100 MW already connected to the grid. The study on QASP highlights broader implications for the future of sustainable energy grids. The research offers insights into the importance of detailed assessments for distributed generation planning, emphasizing the need to consider factors like weather data, seasonal variations, and the long-term effects of plant degradation. This information can be used to optimize the use of solar power in other parts of the world, and promote more sustainable energy sources.