Just households. The inverse of what Germany did.
Say a system had X capacity and 100% utilization. Now someone wants to build a data center that consumes 0.1X power. Demand is now 1.1X and to prevent the system from going over capacity 0.1X of pre-existing demand has to be destroyed.
Subsidizing other users makes the problem worse because they will increase their energy usage in response to the lower prices.
Every household gets X gallons of water a month at a regulated rate. After that, everyone competes equally.
Regulation and increased taxes/fees just make everything more obtuse and expensive, not better or simpler.
But you're right, we could also solve this problem very simply, without gradiated utility rates, by taxing the crap out of corporate profits and redistributing them to everyone else. This would punish corps who aren't building data centers, but if you don't mind turning the whole country into an AI server farm, I guess that would work too.
Money does, in fact, create generating capacity, as expensive, idling energy sources are turned up.