This article screens 103 lifecycle studies of greenhouse gas-equivalent emissions for nuclear power plants to identify a Subset of the most current, original, and transparent studies. It begins by briefly detailing the separate components of the nuclear fuel cycle before explaining the methodology of the survey and exploring the variance of lifecycle estimates. It calculates that while the range of emissions for nuclear energy over the lifetime of a plant, reported from qualified studies examined, is from 1.4 g of carbon dioxide equivalent per kWh (g CO(2)e/kWh) to 288 9 CO(2)e/kWh, the mean value is 66 g CO(2)e/kWh. The article then explains some of the factors responsible for the disparity in lifecycle estimates, in particular identifying errors in both the lowest estimates (not comprehensive) and the highest estimates (failure to consider co-products). It should be noted that nuclear power is not directly emitting greenhouse gas emissions, but rather that lifecycle emissions occur through plant construction. operation, uranium mining and milling, and plant decommissioning. (C) 2008 Elsevier Ltd. All rights reserved.