Two new transmission lines between Kharghar and Vikhroli, and Kudus and Aarey Colony that are projected to go on stream from December 2023 and 2026, respectively, will help Mumbai have additional transmission corridors. This will lessen the burden of the Kalwa substation and prevent power outages from recurring, according to industrial officials.
The additional corridors will also help Mumbai source cheaper and cleaner power. Domestic customers in Mumbai currently pay tariff at an average of 4.5-6 per unit, which is much higher than the spot power available on the exchanges which is ruling at around3/unit at present.
Of course, in the interim, in order to avoid outages like the one witnessed in Mumbai on February 21, the companies supplying power to the city – Tata Power and Adani Electricity – are ramping up their battery storage facilities that could withstand outages for short periods.
In 2011, Tata Power was awarded a 400kv high voltage AC(HVAC) transmission line from Kharghar to Vikhroli and Adani Electricity (then Reliance Power) was awarded a 1000 MW Kudus-Aarey line. The intention was to improve the overall transmission capacity to the city, after Mumbai faced one of its most severe power outages in 2010. However, in 2019, the Vikhroli project was taken away from Tata Power and a competitive bidding was done, following which it was awarded to Adani Electricity. At present, both the projects are with Adani Electricity.
Sources in Tata Power said the project required several approvals and clearances at the forest, mangrove and airport authority levels which delayed the project. The commercial capital’s peak pre-covid demand for power was around 3.8 GW, out of this Tata Power provided around 1.4GW from its Trombay and Hydro power plants, while Adani Electricity provided 500 MW from its Dhanu power plant. The remainder 2 GW electricity was brought from outside Mumbai to meet the city’s requirement.
At present, the transmission capacity to secure external power is around 2.3 GW which will increase to 4.3GW after the two projects are operational. An industry official said, the Kalwa substation bears the onslaught of the Trombay line if two more corridors are available it will increase the reliability margin of the transmission lines. “If one or two transmission lines are down then others can share the burden of line tripping,” the official said.
Also, the two generators in Mumbai can focus on addition of transmission capacity and phasing out old coal-based power plants, which are fossil fuel guzzlers and reason for high pollution in the city, the official added. There are also stated position among few experts that embedded generation is no longer required when we have surplus power generation capacity and it can be sourced from anywhere within the country.