This idea they can only hold for minutes or hours is simply not true not to mention the entire premise is false. Only the cloudiest of days the solar panels produce 20% what they do on the sunniest days that means you only need to build out 5 times the expected output to always be able to produce what you need during sunny hourse. That means you only need to have battery backup for 16 hours. Something that's completely feasible. The idea batteries can't hold power for months isn't true it's that it's not currently economical. How long do you think your electronics take to get from the plant to the store till you buy it and turn it on. If we're talking about cost then let's look at this plant. 1.1GW nuclear reactor costs 35 billion and 15 years. A solar farm built out to 5 times capacity would cost roughly 6 billion. Now triple that for battery costs if you want 24/7 electricity were on the order of 18 billion. That's nearly half the cost and this is being very conservative assuming you want this to be a baseload supplier but will output way more most of the time. Now you will have nearly free electricity during most of the year that other industries could take advantage of like aluminum processing or something like that.