It all seems like a backdoor to let tech companies build power generation on site without all the red tape and sell the excess power to consumers. This indirectly allows them to offload some of the fixed operational costs onto consumers.

We just approved the first nuclear plant in 20 years to a company owned by Bill Gates and in a state that has basically nothing but farmland and a Microsoft datacenter.

This absolutely cannot backfire. /s

What’s wrong with this?

Price of power goes up and the local people are not connected to the benefits. You might think they will receive a lot of money in taxes but you would be wrong because they have tax breaks.

Why would adding a new supplier to the market cause the price of power to go up?

Because on-site powerplants owned by datacenter operators are not "just another supplier".

The threat is: This "datacenter power" disincentives buildout of "free" powerplants (by eating up significant demand at very low margins thanks to basically vertical integration); this slows down buildout of "normal" infrastructure (possibly both grid connectivity and power), and the electrical energy market becomes worse for consumers than it is now.

I personally think all of this is very speculative for now, but allowing industry to rely on the grid (which they still would!) while almost exclusively "buying" their own power is a risky proposition from a consumer perspective.

Not to mention the danger of energy production, even nuclear, becoming resource-constrained to the point where datacenter power plants leave no room for municipal plants. We're seeing it happen with consumer hardware; make no mistake on who will get preference.