CAPACITY FACTOR RISK AT NUCLEAR POWER PLANTS Yangbo Du* and John E. Parsons** first draft November 2010 this revision January 2012 We develop a model of the dynamic structure of capacity factor risk. It incorporates the risk that the capacity factor may vary widely from year-to-year, and also the risk that the reactor may be permanently shutdown prior to the end of its anticipated useful life. We then fit the parameters of the model to the IAEA’s PRIS dataset of historical capacity factors on reactors across the globe from 1969 to 2010 (i.e., before the Fukushima disaster). The estimated capacity factor risk is greatest in the first year of operation and quickly declines until it is approximately constant through the life of the reactor. We also obtain a relatively low estimate for the mean capacity factor, approximately 73%. We discuss variations on these estimates and emphasize the importance of judgment in making these estimates. * Center for Energy and Environmental Policy Research, MIT, E19-411, 77 Massachusetts Ave., Cambridge, MA 02139 USA, E-mail:
[email protected] ** Corresponding author: MIT Sloan School of Management, MIT Center for Energy and Environmental Policy Research, and the MIT Joint Program on the Science and Policy of Global Change, MIT, E19-411, 77 Massachusetts Ave., Cambridge, MA 02139 USA, E-mail:
[email protected] 1. INTRODUCTION One of the critical risks facing an investor in a nuclear power plant is uncertainty about the plant’s realized capacity factor. Realized capacity factors show great variation. Although the typical investor’s cash flow model of a proposed plant shows a projected capacity factor of 85% or more, many reactors have problems achieving this target.