Solar Shield -- Protecting the North American Power Grid

[link to science.nasa.gov]

Oct. 26, 2010: Every hundred years or so, a solar storm comes along so potent it fills the skies of Earth with blood-red auroras, makes compass needles point in the wrong direction, and sends electric currents coursing through the planet's topsoil. The most famous such storm, the Carrington Event of 1859, actually shocked telegraph operators and set some of their offices on fire. A 2008 report by the National Academy of Sciences warns that if such a storm occurred today, we could experience widespread power blackouts with permanent damage to many key transformers.

What's a utility operator to do?
A new NASA project called "Solar Shield" could help keep the lights on.

"Solar Shield is a new and experimental forecasting system for the North American power grid," explains project leader Antti Pulkkinen, a Catholic University of America research associate working at NASA's Goddard Space Flight Center. "We believe we can zero in on specific transformers and predict which of them are going to be hit hardest by a space weather event."

The troublemaker for power grids is the "GIC" – short for geomagnetically induced current. When a coronal mass ejection (a billion-ton solar storm cloud) hits Earth's magnetic field, the impact causes the field to shake and quiver. These magnetic vibrations induce currents almost everywhere, from Earth's upper atmosphere to the ground beneath our feet. Powerful GICs can overload circuits, trip breakers, and in extreme cases melt the windings of heavy-duty transformers.

This actually happened in Quebec on March 13, 1989, when a geomagnetic storm much less severe than the Carrington Event knocked out power across the entire province for more than nine hours. The storm damaged transformers in Quebec, New Jersey, and Great Britain, and caused more than 200 power anomalies across the USA from the eastern seaboard to the Pacific Northwest. A similar series of "Halloween storms" in October 2003 triggered a regional blackout in southern Sweden and may have damaged transformers in South Africa.

While many utilities have taken steps to fortify their grids, the overall situation has only gotten worse. A 2009 report by the North American Electric Reliability Corporation (NERC) and the US Department of Energy concluded that modern power systems have a "significantly enhance[d] vulnerability and exposure to effects of a severe geomagnetic storm." The underlying reason may be seen at a glance in this plot: