Unlike solar and windpower, which have had orders-of-magnitude reduction in cost as experience and manufacturing have scaled, the cost of building a nuclear reactor has increased over time—in both the U.S. and abroad. No country, including France with its uniquely ambitious nuclear program, has yet demonstrated a nuclear cost learning curve. A reactor ordered today in the U.S. is 5–8 times more expensive per watt of capacity (after adjusting for monetary inflation) than a reactor built in the 1970s.
The overnight capital cost is what a plant would cost to build if it could be completed overnight. Actual project cost is typically almost twice as large because it also includes financing and real escalation during construction.
The history of nuclear power plant construction in the U.S. is filled with cost overruns and missed deadlines. Until the Three Mile Island accident, the U.S. pursued an aggressive nuclear program, ordering 253 reactors. But three-fifths of these were abandoned before completion or prematurely closed amid cost overruns totaling hundreds of billions of dollars. No nuclear power plants have been built in the U.S. in the past 10 years, and recent projections for capital costs of new nuclear plants have all been above historic actual costs and are climbing. All of this had created an increasingly unfavorable financing climate even before the Fukushima accident.
Koomey, J., and N.E. Hultman. 2007. “A Reactor-Level Analysis of Busbar Costs for US Nuclear Plants, 1970–2005.” Energy Policy 35 (11): 5630–42.