Coronal mass ejections--enormous magnetized clouds of electrified gas emitted from the sun--have been known to disrupt the electric grid as they hit the Earth's protective magnetic field, and because mitigation strategies have not been widely applied to the U.S. electric grid, severe damage is a possibility, according to a November report (.pdf).

The research was conducted by JASON, the self-selecting scientific advisory panel directed by the Defense Department to study a wide range of topics. The Federation of American Scientists obtained a copy, making it public Dec. 20.

The 107-page document suggests a rigorous risk assessment is needed to determine how severe electric grid damage could be; previous research (.pdf) suggests the electric grid damage could be catastrophic, leaving millions without power for months to years--a scenario researchers say is unconvincing.

The report notes the need for advanced warning through continued improvements in space-weather monitoring, but more than that, it emphasizes the need for electric grid risk management. Authors note that Finland's electric grid has shown resilience against strong solar forcing and large geomagnetically induced currents, because of its specialized transformer design. Canada also serves as an example. After an electric grid collapse in 1989, Hydro Quebec tweaked control relays and transformers to minimize chances of further problems, say report authors.

The report recommends the United States protect vital grid components by:

• Using relays set to trip before grid equipment is seriously damaged while avoiding being tripped inappropriately by GIC harmonics;
• Mandating component design standards;
• Blocking GIC with capacitors in transformer neutrals together with short protection against ground faults; and
• Using small series-blocking capacitors in transmission lines where neutral-current blocking is not feasible.

JASON also recommends a simulation of a space weather incident against the U.S. grid to perform a risk analysis that can be repeated to uncover vulnerabilities.

The report warns that budget constraints could put CME modeling and warning programs at risk. Its recommendations include developing a replacement for NASA's Solar Terrestrial Relations Observatory (STEREO) for insertion at other suitable orbits.

Communication and collaboration across space weather programs also needs improvement, according to the report, says JASON. Severe space weather monitoring by NASA and the National Oceanic and Atmospheric Administration "should be treated as one coordinated effort" recommends the report. Air Force and NOAA could also be doing more to coordinate the shared use of satellites and sensors, authors add.

For more:
- see the JASON report (.pdf)

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