A few weeks ago there was a link paper by an green energy investment advisor firm posted on HN. It displayed the economics pretty clear. Depending on location, a battery with capacity up to 6 hours can be economical viable as long they get a full discharge (ie they sell all the energy) each day at peak price and can charge when the price is at the bottom. It depend in location, how big the difference is between bottom and peak price, and how long that the price sits at each price point.

For wind all those assumptions are wrong and thus won't work. You do not get a daily discharge where you can sell all the energy, you don't get a significant price change each day where you can utilize the price difference, and the capacity needed is a few orders of magnitude greater. Green hydrogen is one of the bigger bets people are hoping on, and right now it only cost several times more than nuclear. Except rather than using nuclear countries are burning fossil fuels because that is cheaper, and thus coal.

(Wind + batteries) wasn’t something I saw in what I linked to, so in this sub-thread I’m focussed on (PV + batteries) even though the link said the LCOE of onshore wind (by itself) was lower than that of coal.

Afaik thats one of the challenges: there is no such thing as utility scale batteries. Nothing that stores a summers worth of PV and releases it in winter.

That’s kinda why Tesla is doing what it’s doing. I’m not sure the exact production, but it looks like nearly 4 GWh in fixed storage last year, and at least 50 GWh (0.93 megacars * 54 kWh smallest battery) in their cars required the ability to rapidly make factories that can make batteries that could also be used in grid storage (I’m assuming making the batteries is the hard part of both electric cars and grid storage, if I’m wrong about that it breaks my argument).

(And inter-season storage is too high a threshold: not many people are living in the artic/antarctic circles away from grids connecting them to places that still get some sun even in winter).

Its a decent effort, but to put 4GWh in perspective: my small house requires about 10MWh in heating over the winter. I can reduce that with a heat pump by a factor 4, but that till means the storage is only enough for about 1800 homes.

We need a PWh+ of storage, and we need it in the next decade, and we are nowhere near on schedule.

Very few people need seasonal storage, most people are on a grid connected to somewhere closer to the equator: https://en.wikipedia.org/wiki/Wide_area_synchronous_grid

All of Europese, far starters.