In Feb 2022, Tata Power was looking for a valuation of 6-7B dollars i.e. 45000-50000cr for its renewable business (via CPPIB and General Atlantic) and today’s valuation according to 4000cr raise is at 34000cr so I don’t understand how they are selling it at premium 
The other business is valued at 53000cr(at cmp) which is mostly thermal and not growing so this business should not trade for more than it’s book value. The book value for the whole company including the renewable segment is 66.6(according to screener.com) so if I give it 1x book value the share price should be 66.6 + 106.25 (for renewable division) so roughly the fair value should be around 170rs. I’m not even considering debt else the fair value will be far far less.