Recent studies from the USA and Sweden make the same conclusions: once in 100 years solar storm is possible in the near future and it can cause extreme damage to our power grids and modern societies leaving large areas out of electric power for years, even for one decade.
The Swedish study (2012) suggest the probability of a perfect 100% geoeffective solar storm to occur during years 2012-2014 to be 4,7%. Would you buy a flight with such adds of the plane crashing?
The US study (2010) told 70 % of the USA to be blackout area after such a solar storm. Each single giant transformer damaged and to be replaced takes at least a year in normal conditions to be back in duty - after such a disaster the demand for such large special units would be peaking and the delivery times could be several years. In some studies 4-10 years blackouts in some parts of the USA can be expected.
The most vulnerable units are coal and nuclear power plants with their large GSU-transformers. The worst would be NPP:s: 92% of them (in the NE Quad) could be out of business for a longer period of time.
NPP:s are also having trouble with their GSU-transformers during minor or medium class solar storms. It is quite probable that year 1994 M-class solar storm caused GIC that injured 12 nuclear power plants GSU-transformers - one died in two days , the other 11 during next two years.
A Medium -geomagnetic storm caused also one NPP fire that was threatening the whole plant when it spread from the transformer to hydrogen-cooled parts of the generator and the vital electrical systems at Zion nuclear plant.
It's kind of a rule that the power companies in question deny the correlation between solar storms and transformer incidents. They don't measure GIC-currents either.
Link - METATECH/FAS: http://www.fas.org/irp/eprint/geomag.pdf
(I have analyzed these studies more on my Finnish SOLARWINDPRONET-SUOMI -blog, use Google or other translaters, please: http://solarwindpronet-suomi.blogspot.fi/2012/08/ruotsalaistutkimus-2012-aurinkomyrskyt.html )
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