A new interregional scheme that will strengthen the transfer between the southern and eastern grids has been proposed for implementation under the tariff-based competitive bidding route.
Estimated to cost around Rs.2,710 crore and with a tentative implementation timeframe of 30 months, this scheme will have PFC Consulting Ltd (PFCCL) as its bid process coordinator.
This scheme, which will fall under the ISTS-TBCB domain, has been termed as “Inter-regional strengthening between SR Grid and ER Grid.”
The National Committee on Transmission (NCT), in its latest meeting, approved the scheme and it now awaits final concurrence from the Union power ministry.
Rationale
The peak demand in SR (Southern Region Grid) was around 68 GW as of March 2024, and this is expected to grow to 97.5 MW, by FY30. Further, demand from upcoming green hydrogen/ammonia plants in SR is expected to be 23 GW by FY30, which will be over and above the projected peak demand of 97.5 MW. Hence, SR will experience a peak demand of over 120 GW, by FY30.
The peak demand of 97.5 MW has been projected by the 20th Electric Power Survey (EPS) while the green hydrogen-based demand projection has been done by Ministry of New & Renewable Energy (MNRE).
Serving SR demand
At present, the total transfer capacity (TTC) for import of power by SR Grid from the NEW Grid is about 24,500 MW and this is expected to reach 25,000 MW once the under-construction 765kV Narendra-Pune double-circuit is commissioned. [NEW Grid refers to the combined grids of the northern (NR), eastern (ER) and western (WR) regional grids.]
The limiting constraint
Currently, the limiting constraint for transferring power from ER to SR is the 765kV double-circuit Angul-Srikakulam line and that for WR-SR transfer is the 765kV, 1500 MVA interconnecting transformer (ICT) at the Nizamabad substation.
The solution
Under the new interregional scheme under discussion, a second 765kV double-circuit line will be built on the Angul-Srikakulam alignment, traversing Odisha and Andhra Pradesh. This line, with a running length of around 275 km, will be supported by line bays and bus reactors at the two substations. Power Grid Corporation of India Ltd (PGCIL) currently owns the existing Angul-Srikakulam line and the terminal substations.
It may be noted that an independent interregional scheme has been proposed for strengthening the transfer between WR and SR. The scheme, discussed in this story, is limited to ER and SR.
ER-SR transfer
According to official statistics, in FY25, a total of 16,627 MU was transferred from ER to SR. Over 52 per cent of this was from the 765kV double-circuit Angul-Srikakulam line. Another important channel for ER-SR transfer is the ±500kV Talcher-Kolar HVDC line that has a transfer capacity of 2,500 MW. Incidentally, this line, commissioned in 2003 and also known as the East-South HVDC Interconnector, is nearing the end of its useful lifespan of 25 years. With frequent failures currently being witnessed in real-time operations, it is proposed that this line be refurbished on priority or an alternate EHV or HVDC line be planned.
Also read: Interregional electricity transfer up 4.2 per cent in FY25
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