Why are nuclear plants so expensive? Mainly it's the cost of building one, with a recently cancelled Florida nuke plant exceeding $20 billion. Yet, once a nuke plant stops operating and must be decommissioned, another huge bill comes due. How big?
In the case of Three Mile Island, current estimates are $950 million for just decommissioning the plant.
That $950 million decommissioning bill is enough money to build a 1,000 megawatt natural gas plant or a 500 megawatt wind farm. It is a huge amount of money all by itself.
Yet, it is just a small part of the total costs of building, running, and decommissioning a nuclear plant.