Continuing with our emergency preparedness theme I’ve decided to take a closer look at solar flares, something regarded by many scientists, including those at NASA, as a significant potential threat to satellites and our power grid.
On a sunny September morning in 1859 two English astronomers named Richard Carrington and Richard Hodgson independently witnessed an unusually bright discharge from spots on our sun’s surface. The next morning people around the world awoke to strange colors and auras flashing across the sky. Telegraph machines went haywire, sparking at their operators and starting fires. The magnetized atmosphere allowed the conduction of signals on the worldwide messaging system even after the machines were disconnected from their batteries.
Scientists believe that the 1859 white-light solar flare responsible for these strange events, now popularly known as the “Carrington Event”, was a particularly powerful solar eruption. Not only was it visible to the naked eye (as projected on a screen from lenses) but radioactive isotopes and nitrates measurable in Greenland in 2005 also suggest its magnitude. Similar studies of other geomagnetic storms from arctic ice tell us the solar flare associated with the Carrington Event produced the largest geomagnetic storm in the past 500 years.
Solar flares can create a Coronal Mass Ejection comprised of energized particles and radiation that travels outward into the solar system sometimes striking Earth’s magnetosphere where a geomagnetic storm is produced. Electrical discharges produced in these storms often jump to the electrical grid where they induce DC currents that can destroy electrical lines, transformers, capacitors and generators. The earth’s magnetic shielding is strongest at the equator but decreases the further you get into the northern and southern hemispheres making these areas most vulnerable to damaging induction currents.
Some documented disruptions from high intensity solar flares follow below. The list does not include radio-disruption-only events which are too frequent to list:
- 1859 – Carrington Event.
- 1880 – Northeast United States. Telegraph lines disrupted.
- 1882 – United States, Europe. Telegraphs disrupted, stock exchange halted.
- 1898- United States. Telegraph lines disrupted.
- 1903- United States and Europe. Telegraphs and transatlantic lines disrupted. Electric streetcars halted in Great Britain and Switzerland.
- 1909 – United States. Telegraphs down.
- 1918 – United States and Europe. Telegraphs disrupted.
- 1920 – United States. Telephone and telegraph disrupted.
- 1921 – United States and Europe. Telegraphs disrupted. Switching stations at Train hubs catch fire in US and Europe.
- 1937 – United States. Telegraphs disrupted.
- 1940 – United States. Severe damage to telegraph and telephone lines across the country.
- 1972 – North America. Telecommunication systems disrupted nationwide.
- 1989 – Quebec, Canada. Hydroplant tranformers burn. 6 million people without power for a short period. Momentary blackouts in the New England.
- 1989 – Salem, MA. Nuclear power plant transformer melts.
- 2003 – Satellites malfunction / destroyed. Astronauts exposed to radiation. $450 million in damages. Communications systems in Africa and elsewhere disrupted.
- 2005 – Globally. GPS systems down for 10 minutes as satellite communications disrupted.
It is clear that solar flares large enough to impact the earth are frequent. With some exceptions the disruptions that result merely amount to inconveniences. But what are the chances of another Carrington Event sized solar flare and CME occurring?
Solar storm activity varies in 11 year cycles and the peak activity level for our current solar cycle is approaching over the next year or two. An article in Space Weather: The International Journal of Research and Applications puts the chances of a massive solar storm that affects earth significantly at 1 in 8 over the next decade. The results of such an event could be significant.
Scientists are concerned that the army of satellites responsible for GPS systems, financial transactions and communications could be destroyed or put of commission for an extended period.
Astronauts would be exposed to high levels of radiation.
Here on the planet’s surface our power system is vulnerable. We have a much more robust electrical system than we did 150 years ago. High voltage power lines are particularly effective at drawing damaging inductions currents from geomagnetic storms and the United States relies heavily on these structures. Due to the need to provide cheap power at peak demand from a distance our power grid is highly integrated, meaning a surge in one area can “contaminate” a wide area of the grid. In addition we have 350 super-sized, high voltage transformers in the US, none of which can be quickly or readily replaced as there is no manufacturing capacity in the US to make them at this time. The cost of each is unit about $10 million and each has a manufacturing time of 6 months to a year.
An Oak Ridge National Laboratory report believes the effects of a Carrington-sized geomagnetic storm on the US would be immense. Initially leaving 130 million people without power that would take months to years to recover, economic damages would be in the $2 trillion range.
What can be done? As our ability to forecast CMEs increases some suggest that transformers can be taken “off-line” prior to the discharge’s arrival to earth effectively protecting them (but causing a temporary blackout). It has also been suggested that surge blockers be installed at key locations across the country at a cost of $1 billion. Another proposal under consideration is the development of a fleet of mobile, high-voltage replacement transformers that can temporarily be moved into place and utilized if a catastrophe occurs (RecX Project). Unfortunately, it appears these mobile systems are only 345 kv while super transformers they may need to replace are 500 kv or more.
Steve – Green Beetle