ISLAMABAD: Pakistan’s national transmission system is grappling with a damaging combination of chronic overloading and underutilisation, resulting in higher electricity costs, operational inefficiencies and violations of the economic merit order (EMO), the National Electric Power Regulatory Authority (Nepra) has warned.
In a detailed review of the national grid, Nepra noted that the backbone of the transmission network — the 500kV and 220kV systems — remained “mostly overloaded” at the close of FY2024-25, particularly during peak summer demand. The regulator said the National Grid Company (NGC) faced critical constraints across several sections of its network, increasing the risk of equipment failure, voltage instability and outages.
According to Nepra, many grid stations and power transformers are operating beyond 80 per cent of their rated capacity. In FY25 alone, 116 out of 192 transformers across 68 grid stations were overloaded beyond this threshold. At the 500/220kV level, 30 of 47 transformers were overloaded, while at the 220/132kV level, 86 of 145 transformers exceeded safe operating limits.
Hyderabad, Islamabad, Lahore and Multan were among the most affected regions, with persistent constraints at key grid stations such as Gatti, New Multan, Sarfaraz Nagar, Muzaffargarh and Sheikhupura. Nepra noted that several grid stations — including Rawat, Sheikhupura, Gatti, Multan, Yousafwala, Jamshoro and Muzaffargarh — have remained overloaded since 2017-18.
“These limitations have led to reliance on expensive generation in violation of the economic merit order and have increased project costs due to persistent delays,” the regulator said.
The review highlighted that grid constraints have restricted full power evacuation from the 1,300MW Sahiwal coal-fired power plant, forced greater dependence on relatively expensive plants such as Attock, Halmore, Sapphire and Liberty, and aggravated bidirectional power flows due to limited transformation capacity in the south-central corridor.
Nepra called for fast-tracking critical transmission projects, upgrading substations with higher-capacity transformers and reactive power support, and strengthening real-time grid monitoring to address chronic overloading.
However, it noted that the exact financial burden of these constraints could not be quantified under current conditions, as this would require hourly digitised operational data to assess the severity and duration of overloading across transformers and transmission lines.
The regulator warned that transmission constraints significantly undermine the efficiency, reliability and affordability of electricity supply. “When adequate transmission capacity is unavailable, cheaper or renewable generation cannot be fully utilised, leading to congestion, higher transmission losses and increased overall electricity costs,” it said.
Nepra identified the persistent inability of the transmission system to evacuate low-cost and indigenous power from the southern region as one of the most critical challenges facing the power sector. As a result, the system is frequently forced to rely on more expensive generation in the north, pushing up tariffs for consumers.
Despite the long-standing nature of these issues, many bottlenecks have remained unresolved for years. Nepra observed that nearly every second project undertaken by the NGC suffers from delays and cost overruns, inflating capital costs and forcing inefficient plant dispatch in violation of the EMO, causing substantial financial losses.
The south-to-north transmission corridor continues to be a major bottleneck, limiting the transfer of cost-effective electricity from coal, nuclear and gas-based plants in the south to demand centres in Punjab and Khyber Pakhtunkhwa. Consequently, the system remains dependent on costly residual fuel oil (RFO) and re-gasified liquefied natural gas (RLNG) plants in the north.
Citing specific examples, Nepra said overloading at the 500kV Jamshoro and Matiari grid stations restricts power flow to around 1,800MW against an available system capacity of 4,500MW, resulting in curtailment of up to 1,750MW of cheaper electricity. Similarly, evacuation constraints limit the utilisation of more than 2,000MW from Karachi’s two nuclear power plants.
The regulator also pointed to the underutilisation of the 4,000MW high-voltage direct current (HVDC) Matiari-Lahore transmission line, commissioned in September 2021. Due to delays in completing the 500kV Lahore North substation and associated lines, the project continues to operate far below capacity. In FY2024-25, average loading of the line stood at 1,401.40MW, reflecting a utilisation factor of just 35.04 per cent.
“This inefficiency imposes a direct financial burden on consumers despite the line’s full operational readiness,” Nepra said, adding that several smaller-scale examples of similar inefficiencies also exist across the network.
The regulator further highlighted serious weaknesses in grid monitoring, noting that the Supervisory Control and Data Acquisition (SCADA) system and telecom backbone, operational since 1992, have become obsolete due to the lack of timely hardware and software upgrades, significantly impairing real-time grid visibility and control.
Story by Khaleeq Kiani
