Not sure whether you're just using the term incorrectly, but I see this claim repeated a lot so forgive me for explaining: you do not need baseline power.
Baseline power is the observation that if we have less than ideal power plants that need to run 24/7 to be economical (usually because of high capital costs, e.g. nuclear plants), we can still deploy them if we then also invest in other plants for filling in the peaks.
See, the important part here is that you always need to meet demand (maybe you can shift demand around a bit, but after shifting it the observation still holds).
If you have baseline plants, your supply curve is a flat line so the peaks in the demand are the holes you need to fill in somehow.
With a renewable source like wind or solar, you may actually be able to meet the peak demand, but then have a hole in the supply at some other point (say at night, or when there's no wind). So you need to fill in these somehow (as you say).
