ISLAMABAD: The National Electric Power Regulatory Authority (Nepra) has expressed serious concerns over inability of the state-run transmission system to take full power generation from independent power producers (IPPs) of around 1,600-megawatt, causing colossal loss to economy and paying hefty capacity charges for no use.

In its report “State of Industry Report 2015”, the regulator has mentioned in particular a missing transmission link of a 400-MW power plant Prime Minister Nawaz Sharif had prematurely inaugurated 16 months ago despite public warnings. The line is still not in place and the plant unable to supply its full energy.

Nepra also highlighted a series of system shortcomings of the National Transmission and Despatch Company (NTDC) – the state-run network operator. It explained that as operator, NTDC was required to construct and operate Extra High Voltage (EHV) transmission lines and grid stations for transporting power from the existing and new generation facilities to the distribution system.

The regulator said the existing EHV capacity was “barely enough” to cater for the present generation capacity and certainly not capable of absorbing additional upcoming generation capacity. It has been noted that 80 per cent transformers at 500kV and 220kV grid stations in different regions were overloaded. With increasing demand and more generation expected in the system as a result of upcoming projects, the overloading of transformers would also increase in coming years.

It explained that there were 13 grid stations of 500kV with 33 transformers at 500/220kV level. “Out of these eight transformers are loaded above 80pc of their rated capacity. Similarly, out of total 129 number of 220/132kV transformers 90 transformers are overloaded representing around 70pc overloading in the system.

In addition to overloading of EHV transformers, constraints in power dispersal from certain major power plants and quality issues in NTDC’s system have also been reported. For example, the Nepra noted that 404MW Uch-II power plant was facing “evacuation problems due to transmission constraints”.

Located at Dera Murad Jamali in Balochistan, the low BTU (hence cheaper) gas-fired plant was required to be linked with the national grid by the NTDC. It was planned to construct a 125km long 220kV double circuit twin bundle transmission line from Uch-II power plant to Sibbi sub-station for evacuation of power after passing through Naseerabad, Kachi and Sibi districts.

In addition, a 500kV grid station at Shikarpur was also to be constructed. “Due to non-fulfilment of contractual obligations by NTDC, Uch-II power plant is facing power dispersal problems, transmission system constraints and frequent tripping on EHV networks, Nepra puts on record.

Likewise, 226MW Engro Powergen Qadirpur Ltd, a combined cycle power plant “is also facing the problem of low despatch/part load operation due to limitation and constraints of auto-transformer at 500kV Guddu Grid Station, which is reportedly resulting in a revenue loss of Rs80 million” per annum to the government.

Also, the 15MW Altern Energy complex was facing frequent tripping due to over/under voltage. During the year 2012-13 and 2013-14, this plant experienced 63 and 99 tripping respectively due to grid failure.

Similarly, power evacuation constraints confronted by 235MW Liberty Power were also due to the tripping of grid system and other technical reasons of transmission lines. 140MW Habibullah Coastal plant was not being used optimally due to low voltage on the power system and gas curtailments in winter.

In addition, 180MW Foundation Power at Daharki was to be connected with 220kV Rohri grid but due to delay in construction of 220kV grid and transmission lines, the plant was temporarily connected with 132kV grid station Sadiqabad. It has experienced many tripping since commissioning due to the problems in transmission lines between Guddu and Sadiqabad. Later on, 220kV New Rohri grid was commissioned and power dispersal was provided on both end, but still major part of power dispersal is through 132kV Sadiqabad which is not an efficient solution.

Also, 400MW Nishat Power Limited and Nishat Chunian Power Limited were facing power evacuation problems since commissioning due to constraints in the grid system of Lahore Electric Supply Company.

The main problem is the constraint in the capacity of three feeders which connect Bhai Pheru and Sarfraz Nagar Grids. In case one line is out, the remaining two get overloaded and trip; leading to a total shutdown of both plants of 400MW and supply failure. In just 12 months, Nishat Power has faced 14 such shutdowns while Nishat Chunian faced 45 shutdowns since its commissioning.

Published in Dawn, August 6th, 2016