Power transmission: challenges

The power sector in Pakistan is facing a crisis of public perception amid the litany of technical challenges prevailing within Pakistan’s sector.

While the popular media focuses on the capacity payments to power plants and use of expensive fossil fuels, deeper problems exist in the transmission sector, which acts as the nervous system transporting electrical energy from generating units to load centers under the ambit of the respective power distribution companies.

The National Transmission Dispatch Company (NTDC) and the National Power Control Center (NPCC) are the responsible entities that channel power across the country.

Today, an installed power generation capacity totaling 45,885 MW exists. This includes renewables as well as thermal based power generators.

Variations in the above number may occur due to intermittency factors inherent for renewables (hydel, solar and wind). Its share in the power generation mix is not constant. For example, hydel’s share peaks during the summer monsoon and dips during the winters.

NTDC’s transmission capacity however is not capable of transferring all that electrical energy. Power regulator Nepra notes that up to the year 2028, generation capability is expected to exceed NTDC’s projected demand during peak hours.

Essentially, this means, while Pakistan has a surplus in electrical energy, capacity constraints within the transmission network significantly restrict the generated power from being utilized completely. In fact, the excess (unutilized) energy is forecast to touch almost 10,000MW by 2026.

What are these constraints?

The regulator observes that the power dispatch company is not able to correctly utilize and prioritize its most valuable transmission assets. The number of under-utilized assets has increased. From 7 underutilized power transformers (500kV) in FY21-22 to 9 in FY22-23.

Similarly, on the 220kV network, the numbers have doubled. From 24 underutilized transformers to 48 for the same time-period. The story is the same for underutilised transmission lines on the 500kV circuits – increased to 53 from 43.

Since demand in a particular region usually stays the same, because of underutilization, the grid gets overloaded at other segments of its 220kV and 550kV networks causing critical consequences, including overheating, voltage and frequency fluctuations, and system failure that can lead to blackouts.

Power systems (transmission lines, transformers, and associated equipment) are sensitive equipment and are designed to operate at certain limits. When safe thresholds are crossed, the equipment can fail.

These constraints also cause deviations in the power dispatch according to the Economic Merit Order (EMO). Limitations in dispatching electricity from cheaper generating units force the network operator to buy electricity from expensive power plants to dispatch power, thereby burdening the consumers downstream.

In an assessment report by NPCC, (un)planning methodologies have resulted in two permanently vulnerable areas: the Southern Half of the 500kV (and 220kV) network and the Lahore ring.

The Jamshoro grid station – part of the Southern Half – is a major congestion point and a vulnerable node in the southern network due to insufficient incoming and outgoing transmission capacity, ageing infrastructure, and understaffing, notes the NPCC.

“Export constraints” on the AC/DC Corridors limit the transfer of cheap power from the nuclear power plants (K2 & K3), China Power Hub, Hubco and the sole evacuation point for wind power from Jhimpir and Gharo, resulting in “redispatch” and “curtailment” of generation.

Continuous investments

Grid companies’ world over are gearing up their systems for upgrades as the COP agreements begin to take shape to decarbonize the grid, meet climate goals and divert power as more power is to be diverted to urban agglomerations.

In its recently approved Investment Plan for KE’s distribution and transmission businesses, important augmentation projects have been highlighted. Privatization of KE has enabled its teams to plan innovatively for a frequently changing operational environment.

Likewise, Pakistan’s transmission sector requires a thorough assessment and support to increase its own capacities.

The NPCC report observes that new 500kV grid stations and transmission lines in the south with improved VRE forecasting and real-time data, deviation settlement mechanism for DISCOs and long duration energy storage systems for primary reserves are major infrastructure investments required to uplift vulnerable zones as discussed above.

This in addition to the “modernization” that is required to correctly make better decisions that come about through the induction of digital technologies.

SCADA systems, for example, are built to ensure real-time monitoring and control of the transmission network including deploying more Regional Control Centers (RCCs) for better coordination.

The regulator has also recommended that NTDC’s project management practices require a rigorous review to identify and rectify underlying causes for delays and cost overruns.

While the network operator has adopted “constraint removal schemes” projects to be actualized on a fast-track basis where some PKR 350 billion has been planned as future investments (up to FY 2024-25) by NTDC.

In its first hearing for the plan, the regulator raised several issues concerning the costs for these projects and is under Nepra’s approval process.

The flipside of this dilemma of Pakistan’s power sector is the haste to deploy power generation units without focusing on upgrading the transmission system.

At the same time as the Indicative Generation Capacity Expansion Plan (IGCEP) was published a Transmission System Enhancement Plan (TSEP) should have been authorized which would have given a clearer picture on future investments required well in advance.

Copyright Business Recorder, 2024