https://en.wikipedia.org/wiki/Shoreham_Nuclear_Power_Plant
Built and powered up, but never used..
"...the state taking over the plant and then attaching a 3 percent surcharge to Long Island electric bills for 30 years to pay off the $6 billion price tag"
"Had the Shoreham Nuclear Power Station gone into operation as planned, it would have prevented the emission of an estimated three million tons of carbon dioxide per year"