[simiones]

Solar is also dead dead for more than half of the day most of the year, and working at much lower capacity during the monsoon season. At the very least, you would need somewhat more than 2x storage.

And, 2x storage is NOT dead easy or dead simple, especially with only 3x capacity, since storing the electricity will not happen with 100% efficiency, or anything close to that.

[credit_guy]

That's not really the problem with solar. Storing energy in batteries from day to night is a solved problem, it doesn't even double the price of electricity. The round trip efficiency is about 80%. The big problem is storing electricity from summer to winter at higher latitudes; it's difficult because the day is much longer during the summer than the winter, the incidence angle higher, so you may end up producing as much as 10 times less energy in the winter, while the energy demand is actually higher; storage losses over 6 months are very high, but that's not the really big problem. The big problem is that you are not getting the bang for the buck. For batteries used from day to night, you get MWh of energy into and out of them every day, and you can charge for that, so you can get a decent ROI. For batteries used from summer to winter, you'll charge for the energy once a year; you need to charge much, much more, and this becomes uneconomical by a huge distance.

There's an alternative to storing energy from summer to winter: you simply overbuild solar capacity so that even in the winter you can produce enough during the day to last you through the night. At high latitudes, you need to overbuild by a factor of 10, and solar may be cheap, but not 10 times cheaper than other sources of electricity. However, if you find something to do with the excess summer energy, you may end up being profitable.

India, being at a lower latitude, has a much easier problem. First, it's very likely the demand during "winter" months is not much higher than during "summer" months if at all. Then the day length during winter is not that short. So the overcapacity that you need may be only a factor of 3x. This guy wants to manufacture green hydrogen. Even if he sells it at a loss, the overall venture may still be profitable.

[simiones]

> That's not really the problem with solar. Storing energy in batteries from day to night is a solved problem, it doesn't even double the price of electricity.

I very much doubt this is "solved" at the scale of an entire country's energy needs for half a day, never mind the entire world's. Lithium and other materials for batteries are not that abundant, and definitely not that abundantly extracted.

[credit_guy]

You are moving the goalposts. It's a solved problem at the scales that are relevant for today's needs. As the needs will expand, there's no reason to think the solution will suddenly fail.

Tesla sells Megapacks with a capacity as high as 3 GWh (but I'm sure if you're the richest person in India, they'll be more than happy to customize bigger solutions for you) [1].

You can head to their website and order right now over the internet a 15 MHh pack for $6.4 MM; the annual maintenance is listed as $21k. These things are supposed to last for 10 years, have a 90% round trip efficiency, and have a capacity of 70% left at year 10. So you can charge and then discharge (and sell) about 50 GWh over these 10 years, for a total investment of less than $7 MM. That is $0.14 per kWh. If you buy 1000 such packs, you get a 30% discount [1], so you end up with a breakeven cost of $0.10 per kWh.

As I said, Tesla offers now up to 3 GWh Megapacks. Would they be able to manufacture 100 such Megapacks over a 5y period? It does not sound that crazy.

[1] https://www.thestreet.com/tesla/news/new-tesla-megapack-deta...

[2] https://www.tesla.com/megapack/design