Solar power VS coal power
There are many issues/ hurdles like coal availability, environmental clearance ( including FC) , water availability and land availability etc, I am still positive on Coal based power inverter plants' contribution towards capacity building (government push and impartial :-) support required).
Assuming in next 20 yrs it (coal) contributes around i.e. around 400 GW ( plus coal right now has 160 GW installed capacity), India need around 2.8 Billion Tonnes annual coal production capacity for total 560 GW ( assumption: Plant specific heat- 2300 kcal/kwh, Calorific value of coal (Indian)- 3500 Kcal/kg, PLF-90%). India has more than 50 billion tonnes of coal reserves ( correct me if I am wrong) which could last for plant life i.e 25 yrs if above things go as stated. Note: I haven't taken coal import into consideration.
Gas resources are depleting (ref: KG basin), I don't know about Shale gas potential in India and don not support the gas import economics.
As far as Solar inverter is concerned, India already has a target of having 22 GW by 2022 ( 2 GW is already commissioned, so rest 20 GW will be solar contribution towards capacity building in next 10 yr). India has solar inverter potential of 5000 trillion kWh/ yr and it gonna achieve grid parity in near future. I really hope to see ministry to revisit the target or big solar capacity after 2022.