Something didn't mesh with numbers on all this with me so I did some crunching, just out of plain curiosity. So the initial, call it 20 billion expense (I'm using round numbers for ease, but bear with me) is against a customer base of approximately 20 million customers. Even if debt service and profit were figured for 10%, this would equate to roughly a $100 per customer increase annually, or $8.33 per month per customer. This is a bit misleading though, because this customer base includes commercial customers, who obviously consume more power. So I think it's fair to say, that the impact to most residential customers would be considerably less than even that. Even with the the cost over run, lets say you doubled it to the tune of $40 billion, and applied the same basic numbers, the math would say $16.66 per customer per month, which again includes commercial customers, which wildly skew the numbers.
What I'm getting at, is that this report seems to be very misleading, I'm going to guess that the average residential customer is only going to see a monthly increase of $8 per month, which given inflation is barely noticeable to most people (not to minimize the importance of it). This would also explain why no one is up in arms about it. I'd also point out, that the anti-nuclear group is the pushing narrative on the doomsday customer costs (hint they want coal).
As to the argument on the utility itself profiting off the over run, this to me is a separate issue, but at the end of the day, once you have a certain set sunk cost, in this case $15 billion, you have two options, either stop or keep going. If you stop, you spent $15 billion for essentially nothing, if you see the matter thru you paid more but it works. This really isn't much of a choice. No one is going to dead weight loss $15 billion, that'll assuredly get you tarred and feathered. In order to finish the job, there will be change orders and add on costs, so while I get the framing of the argument "Georgia Power shouldn't profit off it's mistakes!", anyone that has ever been around any sort of development knows that there will be over runs and change orders, this is normal. Interestingly enough, this exact circumstance occurred when Vogtle 1 and 2 started. Both were in mid construction right when 3 mile island happened and overnight the design had to be refined for additionally safety, which of course ballooned the project.
One other aspect about the budget over run, the plan first came to fruition in about 2006 with that budget. It was based on costs for the first 2 reactors that were completed 20 years early. For the next few years, the project had to thru regulatory review, and redesigned to meet the new regulatory demands. All this added tremendous cost, but was far from unexpected. I'd be willing to be that well over half the over run came before the project actually kicked off, and that very little of the overrun was due to actual construction change orders done post kick off.