What happens to all the power being generated by all the wind farms, solar cells, and nuclear and coal plants (and hydroelectric?)? My understanding is that those can't go on- and off-line rapidly (one of the big advantages of natural gas plants). Is there a way to "ground" the excess, or does that end up causing problems with over-supply in the parts of the grid still online?

Also, won't the flux from the solar storm cause current to flow through power lines, regardless of what is actually connected? I suppose the transformers would still be protected, but there may still be damage to grid.