Thank you for the graph.
It would appear that the daily variation is about 9 GW, so that is the maximum nominal solar power that it makes sense to build.
Apparently some kind of daylight saving time is used, since the consumption is high after sunset, apparently due to air conditioning load.
A similar curve for Finland (at Alaska latitudes) is available at
The base electric consumption is more than 12 GW during the winter night and about 14 GW during the winter day.
Someone might think that putting up 2 GW of solar power would solve the problem. Unfortunately, at such high latitudes, the sun does not shine much in the winter. A solar panel would only produce a few watts. So in reality, the solar power array would be usable only during a few summer months.