[xvedejas]

The capital costs mean the plants cost more to run than they would otherwise, but this wouldn't necessarily factor into the price. There's no reason to pay more for extra energy that costs more, so adding a plant that charges even more than the market price would not be able to sell any energy: the market already provides for demand at a lower price. What might actually raise the price is plants going offline, or existing plants raising their price. These things will probably happen, but they could happen anyway regardless of whether new plants come online.

To attempt an analogy, if I put up a sign that I'm selling iPhones at $6000 each, that won't actually raise the prices of iPhones. That's because customers can already get enough iPhones from Apple, even though they complain that Apple sells them for too high a price too. My offer is just never an alternative, not until Apple raises their prices much much higher (or goes out of business).