> Nuclear, hydro, and geothermal are great for baseline load, but adjust very slowly to changing load requirements.

Hydro adjusts very fast, it's literally just letting more water through. Nuclear is slower, but since its fuel costs are so low, you can typically just run it at full power all the time. Of course, with this approach you'll be overproducing, but with efficient spot market for electricity, you'll have businesses taking advantage of this cheap energy during overproduction to generate the necessary load.