My model shows 150% solar + 16 hours storage can cover 95.2% of electricity. One way to model this effect of large electrolyzers that can be curtailed on demand is that you effectively have additional solar power at the same price point. So instead of 150% solar power maybe you get 300% solar power at same cost. My model shows 300% solar + 16 hours storage covers 98.8% of electricity. For this case you would still want long duration storage to cover the remaining amount if your goal is 100% renewable electricity.
Not clear to me how much demand there is for industrial hydrogen. In theory if the demand is high enough it might offset the need for long duration storage. However you aren't simply doing seasonal balancing. You are also covering short periods (days) of extremely low solar production.
I haven't explicitly modeled the relationship but my view on solar, for most of the world, is the same - over build the solar, add some storage, and you can get close to full replacement of fossil fuels in the electric grid.
The challenge I see, and it is purely anecdotal, though I also believe directionally accurate, is that solar isn't well distributed over the seasons. Closer to the equator - good. In the US, CA and AZ for instance - I don't live there but I expect winter solar is still pretty good.
As a point of comparison, I have a 10kw solar system on my house in the Portland, OR area. Our winter days are both short and cloudy. As a result, I routinely see 60 kWh production on summer days and even a few days of just over 70 kWh. Anything under 50 kWh is outstandingly bad for the summer, but it does happen.
The winter days though are routinely closer to 5 kWh. Days at sub 1 kWh aren't common, but they also aren't as rare as those 70 kWh days (not by a long short). Running Oregon, or at least the Portland, OR area off of solar, will require that the energy be imported. I don't know if Easter Oregon could act as Portland's generator - I don't know that area well enough. I expect significantly less clouds over the winter, but it's still as close to the pole, so days are short.
This same dynamic, but even more extreme will affect places that are farther north.
I do think we'll still get there; this isn't intended as an argument against. A purely solar grid though needs to be built around these more extreme circumstances. Using my particular situation as an example, it looks like a minimum of 1000% (10x) is needed, and it might be closer to 60x (I don't really believe it's that high).
On the plus side, all that over built solar (and as mentioned elsewhere - wind) will provide for a lot of excess power most of the time. That is going to create new economic activity that we can't fully imagine or design today. The world has never had that over abundance of energy at any point in history, any more than the world has had anything like the level of communication the internet provides today. We're still learning what to do with this abundance, and soon we'll be trying to figure out what to do with all of that abundance of energy (I can't wait to see what we do!)
