LAG TIME IN CARBON EMISSIONS AND CO2 CONCENTRATIONS PRODUCED BY COMMERCIAL NUCLEAR POWER

There is now a resurgence of interest in new nuclear power plants in the U.S. and abroad. On the eve of this possible expansion, we evaluate the reduction in carbon emissions from 43+ years of global nuclear power generation. If nuclear power had not been commercially developed, what carbon emissions and atmospheric CO₂ levels would now be observed? To evaluate this scenario we replace the power actually supplied by commercial nuclear units with power from additional fossil fuel plants, which would result in added carbon emissions (energy life-cycle differences are included). Our study is based on three main data sources: (1) estimates of global carbon emissions provided by the Carbon Dioxide Information Analysis Center at ORNL [Boden et al., 2009], (2) estimates of annual world primary energy consumption [BP, 2009], and (3) atmospheric CO₂ data from Mauna Loa (NOAA’s ESRL) [Tans, 2009]. The uncertainties in these data sources translate directly to our results and conclusions.

More than 43 years of global nuclear power have produced a lag time of at least 1.2 years in carbon emissions and the buildup of CO₂ through the end of 2008. As of 2008, nuclear power had reduced cumulative anthropogenic carbon emissions by ~12.3 gigatonnes, and the mean annual CO₂ concentration at Mauna Loa would have been ~2.6 ppm greater in the absence of nuclear power. The calculated lag time represents conditions at the end of 2008, and will change with time. Although a lag time of at least 1.2 years may seem relatively small for a global industry, it is noteworthy considering the commercial nuclear industry did not have significant power production until the mid-1960’s and has experienced reduced growth since 1995. By comparison, fossil fuels have been burned at increasing rates for several centuries and global consumption has nearly tripled since 1965, contributing to a rapid rise in atmospheric CO₂. [The views expressed are the authors.' They do not reflect any judgment or determination by the NRC]