A decision last week by Duke Energy Corp. to scuttle a proposed nuclear reactor project in Central Florida leaves utility customers in the state with a tab of more than $1 billion, most of it already paid to Duke, for unbuilt plants that may never produce a single kilowatt of energy,Bloomberg Businessweek reported. In June, MidAmerican Energy Co. ended its bid to build a nuclear plant in Iowa, but promised customers they would be refunded $8.8 million they paid for a feasibility study. The costs of the failed Florida project exposes the "insanity" of allowing utilities to recoup engineering and planning costs years before plants are built, critics said.