Space Weather and the Vulnerability of Electric Power Grids

A number of trends are causing overall increases in geomagnetically-induced currents (GIC’s) and associated threats from geomagnetic storms for electric power grids. GIC threats have been a concern for power grids at high-latitude locations due to disturbances driven by electrojet intensifications. However, other geomagnetic storm processes such as SSC and ring current intensifications are also proving to cause GIC concerns for the power industry at low-latitude locations as well. In addition to threats arising from various regions of the space environment, the response of local ground and power system design have important roles that can significantly increase risk from geomagnetic storms. In particular a number of long-term trends in power system design and operation have been continually acting to increase geomagnetic storm risks. These design implications have acted to greatly escalate GIC risks for power grids at all latitude locations. As a result, GIC impacts may now be of concern even to power grids that have never considered the risk of GIC previously because they were not at high latitude locations. The paper will provide a comprehensive overview of these risk issues as they apply to many world power systems and particularly review the potential impacts to power system operations due to extreme geomagnetic disturbance events.