Today the problem isn’t really the cost of the solar panels – or the land to put them on.
It’s been calculated, that with modern solar panel designs, and reasonable considerations about whether to tilt them to follow the sun or not – you’d need about 10,000 square miles of solar panels to power entire USA.
That sounds like a lot – but there are places out in the Arizona desert that rarely see much cloud and are very sunny – and where a 100 mile x 100 mile solar panel array could be located without significant ecological damage.
The problem is that the sun only shines with enough power for about 8 to 10 hours per day – so we’d have to store power during the day so we could provide power during the night.
That means that we’d need enough batteries (or other storage systems) to store enough power to power the entire USA for the remaining 14 to 16 hours.
Doing THAT is a nightmare!
So it makes more sense to provide a mix of solutions…some solar, for sure…but also some wind power (which works as well at night as during the day – but can be useless on calm days) – some tidal and wave power (which is super-reliable, but costly) – some geothermal (which has lifespan problems) and even some advanced, modern nuclear power to fill in the gaps when all of the other things aren’t working so well.
A mixed strategy will minimizes the risk of everything going dark at the same time. This is true for India too.
Reference- Steve Baker, Blogger at Let’s Run With It!