[osmala]

For society you need reliability, you just don't stop freezers just because sun goes down, or there is period of storms or night. You would need atleast 14 times the hour capacity just to smooth the daily curve. [In winter there is less sunlight hours and maximum sun light is mid-day.] The cost is more than 0.1$ per watt hour of capacity, just for battery, and not for any power electronics going with it.

https://en.wikipedia.org/wiki/Rechargeable_battery

So this alone would increase your cost estimates by 150$

And for society you probably want a weeks worth of electricity stored in some form or other to deal with weather differences, and not summer winter difference. So minimal goal would be 24*7. Or just more than 150 hours.

Or that another 1500$ of cost not included in your estimations. Now a big thing to realize, in electricity markets where networks are required to take in solar and wind from other players, its not the producer of electricity that bears the cost of that large storage its the utility that buys the electricity from market.

Right now it works somewhere along the lines. Lets make 40% efficient fossil fuel plants instead of 60% efficient slowly starting fossil fuel plants, so that we can turn them on and off for covering the difference between intermitted sources and consumption. So in reality renewable plants end up just becoming fuel saving devices for fossil fuel plants while reducing fuel efficiency of said plants when they actually are turned on . In long run I believe nuclear is way to go if we want to stop global warming. The intermittency problem goes away with it and you can run a grid with 100% nuclear with very little storage because production isn't intermittent, and with modern plants you can vary electricity production between 50 and 100%

Global warming is accumulating effect, the emissions are just rate of change, and not the temperature difference, and we need to aim pretty close to zero emissions to stop it. [Yes nature takes some of it off from circulation but a lot less than people think because naysayers compare our emissions to winter, summer cycle of plants that cancels itself in yearly basis.]

[trhway]

it isn't a car, so the range of technological options is much wider, ie. there is no need for high capacity small batteries. One can hydrolyze the water during low loads and store the resulting hydrogen (hydrolysis equipment and stationary storage is relatively simple and cheap). A generator with gas turbine to burn the hydrogen would cost on the scale like $400/kw - a small addition to the $2K/kw capital cost for solar panels install. The week of reserve storage - 200kwh to be generated - with even low 40% efficiency of turbine generation - would require storing 250m3 of hydrogen to provide a week reserve per 1kw of basic capacity. Lets say that storage is generous $1/m3.

As result, under $3K/kw we'd have a week of reserve and the ability to short-term double power during peaks using the gas turbines. And using the same loan calculations it is $0.075/kwh.