Baker, Daniel N., et al. (2008). Severe Space Weather Events – Understanding Societal and Economic Impacts: A Workshop Report. National Academies Press. str. 77. ISBN978-0-309-12769-1. »These assessments indicate that severe geomagnetic storms pose a risk for long-term outages to major portions of the North American grid. John Kappenman remarked that the analysis shows “not only the potential for large-scale blackouts but, more troubling, ... the potential for permanent damage that could lead to extraordinarily long restoration times.”«