Paying for the plant but not having to pay for it to run most of the time is probably cheaper than having it running most of the time.
Maybe there's opportunities for net metering for customers with backup generators. At the right price per kWH, I would run my generator and feed into the grid... personally, my fuel cost is likely too high for that to make sense very often, but I think there's likely some hidden capacity there with the right incentives.
Germany will require 100-150 GW capacity which cost about 1000 EUR/kW and would require an investment of 100+B EUR.
Electricity prices already skyrocketed in Germany and no end in sight.
Listen: I invested in PV, in low energy houses, in heat pumps - but the PV/wind strategy doesn’t work the way people would like them to in their ideology and Germany has proven that.
Now that you've built those plants, would you rather pay to operate them year round, or only when needed?
PV/wind won't help you reduce capex for winter, but it should reduce opex on gas. And that's something.
Spending capex on interconnections may reduce the total dispatchable capacity needed; if it's done carefully. Having more time zones in one grid helps because peaks correspond with time of day; having more latitude helps because day lengths and cloud cover varies. Having more of both helps because still air tends to be geographically bounded. But long distance transmission is expensive.