The 220kV Pedhambe-Apta transmission line of state transco Maharashtra State Electricity Transmission Company Ltd (MSETCL) is coming up for a major upgrade – a proposal that was approved in a recent meeting of Maharashtra Transmission Committee (MTC).
Commissioned in 1967, the Pedambe-Apta line, traversing the adjacent coastal districts of Ratnagiri and Raigad, has completed nearly five decades of operations and has surpassed its intended useful life.
The existing transmission assets have become aged, resulting in increased maintenance requirements and reduced operational reliability. Although the network performs satisfactorily under normal operating conditions, it experiences stress and voltage deviations during peak loading conditions, it was informed at the MTC meeting.
The project has been forwarded to the Grid Coordination Committee (GCC) of Maharashtra for final approval. The project cost is currently estimated at Rs.2,997.74 crore.
Rationale
The Raigad and Ratnagiri districts have emerged as strategically important load centres in Maharashtra owing to rapid industrialization, expansion of MIDC areas, port-led economic development influenced by the JNPT corridor and Dighi Port, establishment of data centres, major infrastructure projects, and increasing urbanization in the Panvel–Uran–Alibag–Mahad–Karjat–Khopoli–Apta–Tambati–Kharghar region.
It was also informed by MSETCL that nearly 30 pumped storage projects (PSPs) with an aggregate capacity of about 9.5 GW have been planned in the region, with likely grid connectivity at Karad, Apta and Kandalgaon.
The existing transmission network is therefore required to be substantially strengthened to facilitate future power evacuation and cater to the projected load growth.
Incidentally, Maharashtra is planning to develop a series of 400kV and 765kV substations through the TBCB route, which will act as interchange points between the intrastate and ISTS grids. In particular, Apta and Kandalgaon cited above, are locations for such proposed substations.
Multi-circuit configuration
As per the proposed upgrade, the new Pedhambe-Apta transmission system will involve construction of a 400kV multi-circuit line with top two circuits strung by 0.5 Moose Twin conductor at 400kV level and the bottom two circuits strung by 0.4 ACSR Zebra conductor at 220kV. The total route length of the system would be 182.12 km.
The existing 220kV double-circuit line (of 182.12 km) between the Pedhambe and Apta substations will be dismantled.
Modality
Though the project cost is above Rs.200 crore, MTC has recommended that the project be implemented by MSETCL under the regulated tariff mechanism. The committee observed that practical delineation and segregation of ownership, operation, maintenance responsibilities and interface arrangements under a separate TBCB/SPV framework may not be feasible in the present case.
It may be mentioned that as per guidelines issued by Maharashtra State Transmission Utility (STU), greenfield intrastate transmission projects costing over Rs.200 crore would be developed under the TBCB framework, under normal circumstances. These guidelines became effective from April 1, 2025.
Anticipated benefits
MTC observed that the Pedhambe-Apta upgrade scheme would facilitate enhancement of power transfer capability, reduction in operational constraints, improvement in voltage profile and strengthening of the intrastate transmission network across Mumbai MMR, Thane. Raigad and Satara districts.
The committee also noted that the proposed modernization would enable optimum utilization of the existing transmission corridor and RoW, while also creating provision for future interconnections, network sectionalisation, load growth, and integration of additional substations and emerging loads such as industrial development, data centre load growth, urbanization, and future network expansion requirements of NAINA project.
Spearheaded by nodal agency CIDCO (City & Industrial Development Corporation of Maharashtra Ltd), the NAINA (Navi Mumbai Airport Influence Notified Area) project envisages development of a massive smart city spread over 370 sqkm of area, across the Thane and Raigad districts in Maharashtra.
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