Monday, February 6, 2012

Complexity and Geomagnetic Storms

A Perfect Storm of Planetary Proportions is a fascinating article linking two of my pet fascinations: complexity and catastrophe.The immediate prompt for the article is the expected 2012-13 peaking in solar activity and the potential it has for a geomagnetic superstorm that could disrupt power grids all over the world. The article provides lots of fascinating detail about the storms themselves. Here I focus on the connection to the disruption of power grids
From where we sit, the sun seems quiet enough. And yet it is constantly bombarding Earth with electrons, protons, and radio through X-ray waves. ... Under normal circumstances, this solar wind produces only negligible effects on Earth. Occasionally, though, the sun erupts violently, emitting solar flares or throwing out coronal mass ejections consisting of billions of tons of charged particles. ...

But how does all this space weather cause damage down on the ground? It's a multistep process. First, the intense magnetic field variations in the magnetosphere induce electric fields and currents over large areas of Earth's surface. In turn, this geoelectric field creates what are known as geomagnetically induced currents, or GICs, which flow in any available conductor, including high-voltage transmission lines, oil and gas pipelines, railways, and undersea communications cables. These interconnecting networks essentially act as giant antennas that channel the induced currents from the ground. Hit with a 300-ampere GIC, a high-voltage transformer's paper tape insulation will burn, its copper winding will melt, and the transformer will fail, either right then and there or in the future. High-voltage power grids are designed to withstand the loss of any single important element, such as a substation transformer, and then recover within a half hour or so. For a terrestrial storm like a hurricane or a tornado, this approach works well. But a severe geomagnetic storm covering an entire continent would cause multiple failures all at once.

The video below discusses the most recent major geomagnetic storm from 1989, a storm of roughly 1/10 the magnitude of those known to have occurred in the past. The last time we had a truly powerful storm was in 1921—decades before developed economies became utterly dependent on electrical infrastructure. So here we have a wonderful example of how complexity begets more complexity -- how the development of a complex technological infrastructure has led to the emergence of a new type of problem; a problem that requires yet more complexity (in the software and other aspects that manage the grid) in order to minimize the potential for widespread blackouts.

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