Wind blows around the clock and solar runs most of the time we are awake. If renewables are super cheap but storage is not viable, can't we simply overbuild?
Then you have to add transfer issues, and you have situations where North Germany is exporting, while south Germany is importing, and there's a lot of fossil fuels burned just so you have capacity to keep the grid in shape.
There are of course alternatives, like controlling demand via methods such as informing people they have to reduce power usage ASAP or get cut off (hope you didn't just start washing machine or put food into electric cooker)
Improved distance transmission would definitely be a big help.