http://science.nasa.gov/science-news/science-at-nasa/2012/22mar_saber/

March 22, 2012: A recent flurry of eruptions on the sun did more than spark pretty auroras around the poles. NASA-funded researchers say the solar storms of March 8th through 10th dumped enough energy in Earth’s upper atmosphere to power every residence in New York City for two years.

“This was the biggest dose of heat we’ve received from a solar storm since 2005,” says Martin Mlynczak of NASA Langley Research Center. “It was a big event, and shows how solar activity can directly affect our planet.”