ISLAMABAD: National Transmission and Despatch Company (NTDC) has supported conversion of M/s Lalpir (LP) and Pakgen (PG) into Thar coal, saying that operating LP and PG would certainly improve voltage stability and increase short-circuit power in the Mepco region.
In a letter to Managing Director, PPIB, Deputy Managing Director- System Operator (SO), Ali Zain Banatwala stated that the technical and commercial viability of the proposal / concept paper submitted by M/S Lalpir Power Limited depends on the future expected utilization / dispatch of Lalpir and Pakgen which, in turn, depends on the overall electricity supply demand balance of the country and transmission availability.
Banatwala said the expected number of dispatch hours based on the revised fuel price (using Thar Coal) can only be estimated when modelling the system-wide generation / demand balance. NTDC is currently preparing the IGCEP to be submitted to NEPRA as per the timeline defined in the Grid Code.
Two thermal plants hint at converting to Thar coal
Therefore, PPIB as the project sponsoring agency may submit the requisite data to model the converted projects as candidate projects in the upcoming (or any future) IGCEP.
However, it should be noted that IGCEP does not consider generator “re-dispatch” due to transmission constraints or system stability constraints. This would only be clear after finalization of the Transmission System Expansion Plan (TSEP).
With regards to transmission constraints that may be alleviated by LP/PG, he said the relevant constraints are the 500kV / kV220kV transformation capacities at Multan (3 x 450 MVA) and Muzaffargarh (2x 600MVA) grid stations.
At least 1600 MW can be provided from the 500kV network via voltage transformation at these two grid stations. In addition, NTDC is planning to build two new grid stations to serve the MEPCO region by 2027.
Once 500kV Vehari grid station and 220 kV Nag Shah are completed, transformation capacity for the Multan / Bahawalpur region will exceed 3000 MW with N-I contingency compliance.
This means that MEPCO would not have to shed any load due to NTDC Transformation constraints for the majority of the year. Hydropower generation capacity presently stands at 10 GW. This is sufficient to cover the present needs of the three northern Discos (PESCO, IESCO and GEPCO).
Once the existing hydro projects are completed (including Dasu, Mohmand, Suki Kinari and Tarbela Ext-5) hydro generation will exceed 15 GW. Assuming modest load growth of 1 GW, the additional 4 GW will have to be transported South via Fesco and Lesco.
After adding RLNG generation in Lahore and Faisalabad + HVDC imports hydropower imports, the demand for both Fesco and Lesco will be fully covered. Furthermore, 1200 MW Chashma 5 nuclear power station has been declared “committed” by the federal government.
As hydropower will exceed the demands of the northern Discos – Lesco & Fesco – the only possible interconnection for C5 to generate base-load power over the whole year is via a direct interconnection to the lone energy deficit region of Mepco, he added.
Assuming C- 5 as a 1200 MW base-load generator + 3000 MW transformation capacity 2000 MW potential solar projects in Mepco, the demand in the Mepco region would be covered without requiring any local thermal generation.
Sending power South, i.e., converting Mepco from an energy importing zone to yet another importing zone may not be possible due to the large volume of power
being transmitted North from HESCO/SEPCO via the 500kV AC corridors. Therefore, increasing base load power generation by 700 MW in Mepco would require curtailment of either hydropower/nuclear power in the North, or curtailment of wind/solar, Thar coal, nuclear (K2/K3) or indigenous natural gas in the South, Banatwal maintained. The system is long on base-load generation and short on fast-ramping / flexible generation.
Adding further base-load generation capacity which requires long start-up times and has high start-up costs is not recommended in general.
“Not operating any local thermal generation in Mepco is a serious concern for voltage stability during the summer months. Operating LP and PG would certainly improve voltage stability and would increase short-circuit power in the Mepco region,” he further added.
However, this may not be enough in itself to justify the investment, especially once C5 is connected to Mepco as that would also improve the short-circuit power in Mepco region, voltage stability concerns can also be mitigated if the 3 x 450 MVARSTATCOMs proposed in the SIFC can be realized or alternatively existing thermal generators at Muzaffargarh and Guddu are converted to synchronous condensers.
