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Solar storms can cause power grids to fail at lower latitudes

A solar storm caused a power failure in Quebec in 1989. Another solar flare apparently caused a power failure in New Zealand in 2001.

The American Geophysical Union in Washington D.C released a story in August, 2012 suggesting the sun does have the capability of disrupting electrical systems on Earth – not just at high latitudes (near Earth’s poles) as happened in Québec in 1989 – but also at lower latitudes. How does the sun do this? The source of the potential disruption is solar flares, which are powerful releases of energy from the sun – and their subsequent coronal mass ejections (CMEs), which are massive burst of solar wind and magnetic fields released into space, sometimes headed Earth’s way.

The video below, from NASA, illustrates the awesome power of a solar flare and its subsequent CME.

We humans on Earth are at no danger from solar flares and CMEs. Earth’s atmosphere protects us, and, in fact, earthly life has evolved under the influence of these events for billions of years. But there’s been an increasing awareness that perhaps science should evaluate the potential impact of a flare event on earthly technologies, especially electric power grids.

The NASA video above is from June, 2011. But the study – which was published in the journal Space Weather in August 2012 – focuses on an event that took place 11 years ago, on November 6, 2001. At 1:20 UTC that day, a high-density pocket of solar wind sped past SOHO (the Solar and Heliospheric Observatory satellite), orbits around the L-1 point in the Earth-sun system, nearly 200 Earth-radii above our world in the direction toward the sun.

Half an hour after SOHO recorded this unusual 2001 high-density packet of solar wind, this high-pressure wave travelled more than a million kilometers (620,000 miles) to the Earth’s magnetopause, which is the boundary between Earth’s magnetic field and the solar wind.

On March 13, 1989, a CME caused a power failure in Quebec and the northeastern U.S. That night, the aurora, or northern lights, was visible much farther south than usual.

According to these scientists, the high-pressure pulse induced currents both in the magnetopause and in power lines across New Zealand. At the power grid, alarms were tripped and a transformer failed catastrophically.

New Zealand is not at a high latitude. Instead, it extends from a latitude of 35 degrees South to 46 degrees South. A Northern Hemisphere equivalent would be a zone extending from Maine to North Carolina. Prior to this study, New Zealand would have been considered outside the region susceptible to the effects of solar flares. But, if this study is correct, lower latitudes on Earth are not immune.

What are we saying here? Do we need to add solar flares and CMEs to our list of things to worry about? These storms are rare. People talking about power failures from solar storms always point back to March 13, 1989 – 23 years ago. A CME caused a power failure in Québec, as well as across parts of the northeastern U.S. In this event, the electrical supply was cut off to over 6 million people for 9 hours.

Could a solar storm cause a major, longer-lasting power outage in the United States, if a stronger flare occurred on the sun (as some suspect is inevitable)? This study suggests the answer is yes. Scientists are asking more questions about this, especially as power grids around the world undergo renovation and upgrading.

Bottom line: The AGU announced a study in August, 2012 that suggests the sun does have the capability of disrupting electrical systems on Earth – not just at high latitudes as was observed in Québec and parts of the northeastern U.S. in 1989 – but also at lower latitudes.

Are solar storm dangerous to us?

Deborah Byrd


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