Seasonal grid instability challenges in Pakistan–I

Brownouts and blackouts are critical issues affecting the stability and reliability of power supply systems in Pakistan. A brownout is a partial, temporary reduction in power availability, often indicated by a voltage drop in the system.

This phenomenon usually occurs when the power system is under stress, possibly due to high demand or infrastructural limitations.

In contrast, a blackout is a more severe condition, characterized by a complete loss of power in a specific area, typically caused by overloads, system failures, or significant malfunctions in the power grid.

Both brownouts and blackouts can have a profound impact on the entire economy, including businesses and healthcare, thus emphasizing the need for a robust and reliable power infrastructure.

In this article, we investigate the challenges of Pakistan’s power sector, focusing particularly on the risk of blackout winters. We examine the effects of seasonal changes in power generation, such as the decline in hydroelectric power and gas supply limitations in winter.

We explore the phenomena of brownouts and blackouts, their causes, and their broader implications for power infrastructure. We delve into operational challenges, such as maintenance outages and the management of frequency reserves, as well as issues related to industrial demands and grid connections.

Our focus extends to the capacity trap in generation, complexities in power system management, investment deficits, policy dynamics, and technical constraints. Ultimately, the need for holistic solutions to enhance grid reliability and prevent blackout winters encompasses all aspects of power sector vulnerabilities.

Seasonal variations and generation capacity trap

Pakistan’s power generation, dominated by baseload capacities like nuclear, coal, and CCGTs, faces significant challenges in meeting the country’s fluctuating demand. Reliance on imported fuels (i.e., coal and LNG) coupled with financial constraints faced by the economy adds considerably to the power system’s vulnerability and leads to high capacity payments due to suboptimal utilization.

Hydroelectric power, a major component of Pakistan’s energy mix, is heavily influenced by seasonal variations that can be attributed to the country’s dependence on water flows for agriculture and the inherent nature of hydrological cycles that are vulnerable to weather extremes and shifting patterns.

As a result, hydroelectric generation drops significantly during winter months, causing a sizable reduction in overall power generation capacity. For instance, during FY22, Pakistan’s hydroelectric generation peaked at 7,561MW in August while the minimum output was recorded at 697 MW in January, compared to the total installed hydroelectric capacity of 9,477 MW.

Similarly, reduced gas supply during the winter also impacts generation from Gas Power Plants due to load profiling of Residential Piped Natural Gas Consumers, further limiting power production.

With an industrial base load of around 8 GW at present, large seasonal and intra-day variations in grid electricity make surplus capacity very expensive. On August 21st, 2023, for instance, the National Transmission and Dispatch Company (NTDC) supplied 25.5 GW of electricity at midnight, with approximately 17.5 GW catering to the seasonal demand for ventilation and air conditioning, i.e., cooling loads. Notably, the installed capacity of 22 GW in FY14 was sufficient to meet industrial demand of 7-8 GW.

The subsequent escalation in electricity demand and prices can therefore be attributed to higher consumption in non-productive sectors, particularly for cooling and ventilation.

It is important to note that hydropower plants are modeled based on their characteristic monthly minimum and maximum available capacities, along with their average monthly generation.

With more than a dozen new hydropower projects being installed, there is a clear indication that the future of energy in Pakistan hinges on adapting to seasonal patterns and integrating various forms of renewable energy to ensure a stable and reliable supply of electricity.

Moreover, operational constraints require nuclear and RLNG plants to run at a minimum capacity of 70%, and coal plants at 50%, leading to inefficiencies during low-demand period.

Consequently, the current generation mix, despite its diversity, struggles to match the variable demand and seasonal hydropower availability, resulting in underutilization of large fossil fuel plants due to financial and grid optimization limitations.

Operational challenges: frequency management and grid stability

Investment in transmission and distribution infrastructure, focused on short-term fixes rather than long-term solutions such as grid optimization and flexible generation, has not kept pace with the expansion of generation capacity, leading to overburdened systems and supply bottlenecks.

This, coupled with insufficient funding exacerbated by mounting circular debt, has caused serious transmission issues and network bottlenecks, with many sections operating above capacity. Additionally, managing frequency reserves, crucial for stability, especially during reduced generation, is challenging due to insufficient operating reserves, limiting backup power during demand spikes or generation drops.

The system has a reduced number of operational generating units, which leads to low inertia. Inertia is important for maintaining grid stability and the ability to recover from disturbances.

A lack of sufficient operating units makes the system more vulnerable to outages. Additionally, maintaining large spinning reserves to align with the biggest thermal generation units introduces additional operational and financial complexities.

Under severe outage events, all power plants must provide adequate frequency support. This support becomes crucial for the low-inertia system under very low load demands, such as during winter months.

Allegedly, power plants, especially IPPs, do not provide sufficient frequency support, leading to the system’s inability to restore its frequency and resulting in blackouts.

Furthermore, fog and smog can cause short circuits in transmission and distribution networks due to their moisture-laden conductive particles, leading to network tripping, brownouts, and operational disruptions that affect power supply stability and reliability.

The reduced visibility associated with these conditions further complicates network monitoring and maintenance.

The integration of High Voltage Direct Current (HVDC) systems into the network has improved south-to-center power flow, reduced bottlenecks, and enhanced transmission reliability. However, it has also introduced additional complexity, especially during HVDC line outages. The System Operator continually faces challenges in balancing AC and DC power flows under various operating conditions to ensure grid security.

Grid resilience through industrial solar integration

A significant portion of Large Scale Manufacturing (LSM) sectors, such as fertilizers, cement, sugar, and textiles, are not connected to the national grid, leading to an underutilization of available power generation capacity. Industries remain disconnected from the grid due to reliability and quality concerns, exacerbating the demand-supply mismatch.

In the last two years, Pakistan has witnessed the closure of numerous textile industries, looms, mills, and ice factories, with nearly half of its paper mills disappearing from the industrial landscape. This decline can largely be attributed to exorbitant electricity tariffs, which are two to three times higher than those in regional countries, placing a significant burden on these businesses.

Only those businesses with higher profit margins and efficient machinery are likely to endure.

Frequent electricity supply interruptions, equipment breakdowns, and voltage instability starkly contravene the regulatory standards set forth by power regulator NEPRA in the Distribution Code, compelling industries to seek self-generated power solutions to ensure operational continuity and stability. Industries in Pakistan are confronted with the necessity of maintaining Captive Power Plants (CPPs).

This necessity is driven not only by economic considerations but also by the unique energy challenges and infrastructure limitations faced by industries in Pakistan.

The power system often experiences electricity shortages, grid instability, and frequent power outages, which can significantly disrupt industrial operations.

To mitigate these challenges and ensure a continuous power supply, many industries in Pakistan have had to invest in Captive Power Plants (CPPs), which provide a reliable backup source of electricity, helping industries maintain production levels and avoid costly downtime. However, the financial burden of establishing and maintaining CPPs is a challenge not commonly encountered by industries in countries with more stable electrical grids.

(To be continued on Wednesday)

Copyright Business Recorder, 2024