I'm kind of hoping that wind power covers most nighttime demand eventually. Right now we have so little renewable generation in most grids that just adding the cheapest option without caring about storage at all seems best.
Wind is useful, but not really as base load. There are long lulls sometimes, more than a week. You could run gas peakers but then you haven't fixed anything...
Fixing wind lulls requires continent-wide network of wind farms with corresponding grid. Computations suggest best case even 100 GW across Europe. That is nothing compared to demand.
(Un)fortunately we have nuclear as a base load option. And fusion as research program.
Potentially space solar including space mirrors too.
You can use power-to-gas technology together with the existing infrastructure for strategic gas reserves to store enough renewable energy to run your gas plants during windstill winters. Maybe that's cheaper than nuclear power. It's probably easier to do politically.
So you're saying we should concentrate on (cheap) photovoltaics before moving onto expensive storage? Agreed although we do need to be thinking about storage, so we have technologies ready to go when the photovoltaics are built out.
Speaking from a UK perspective, renewables now account for about a third of electricity production, so that's well on the way in certain scenarios to be thinking about storage. The UK is lucky in that most of this is wind which tends to coincide with peak demand, if it were solar generation, night time and evening could start being a problem.
That seems the most reasonable scenario?