Why Was 20% of Vogtle's Nuclear Cost Overrun Just Interest?

Scott Nolan says interest during a long construction job, not the famous accidents, is a large part of why American nuclear plants got so expensive. Vogtle ran far over budget and behind schedule. About 20 percent of that cost overrun was interest, and that was in a period of historically low rates. When a plant takes about 10 years to build, the overnight construction cost matters less than the interest paid while it sits unfinished. His fix for the big reactors is to build them faster and to build more of them, so the work finally gets economies of scale.

John Collison points to the 1970s slowdown, when mortgage rates reached about 18 percent in 1981 and the cost of capital was well north of 10 percent. Nolan treats Three Mile Island and Chernobyl as a slight pause that gets blamed for the whole stall. The deeper problem is that the electricity was not cheaper. Nuclear is the cleanest and safest baseload, and it still has to win on price.