1. What Does power grid corp do ?

As per their website

POWERGRID, a Navratna Public Sector Enterprise, is one of the largest
transmission utilities in the world.POWERGRID wheels about 45% of the total power generated in the country on its transmission network.POWERGRID has a pan India presence with  around 71,500 Circuit Kms of Transmission network and 120 nos. of

EHVAC & HVDC sub-stations with a total transformation capacity of 79,500 MVA .POWERGRID has also diversified into Telecom business and established a telecom network of more than 20,000 Kms across the country.POWERGRID has consistently maintained the transmission system availability over 99% which is at par with the International Utilities.

Power grid corp is in business of electricity transmission. Any electricity company like Adani, Reliance will have to use power grid's transmission network to flow electricity from stations to consumers.

That's exactly the reason power grid has consistent cash flow. Not a too high return on equity but CONSISTENT.

It has huge capex plan to increase capacity for upcoming power capacities around the country.

Since it's almost a monopoly does not mean PGC can charge anything to its customers . CERC is a body that make sure that power grid gets fair share of profit. Recently CERC increaded cap on ROE from 14% to 15.5% for tariff determination purpose . That means direct addition to PGC bottomline.