by Joseph Somsel, American Thinker:
Big sections of the European electric grid had a blackout recently. First reports blamed a frequency dip due to a lack of “spinning reserve.” When frequency gets too low, automatic electrical breakers open, isolating sections of loads and the transmission grid. The power plants can only safely operate within a narrow frequency range (pumps spin too slowly, etc), and they too will isolate and trip to protect themselves from damage.