A commenter wondered whether grid frequency anomalies -- running higher than 60 hertz -- could have made BGE meters run faster and BGE bills go higher than they should have:

What if the power generating stations were erroneously making electricity at 65, 70, or 75 Hertz? Just as the frequency of the alternating current will affect the speed of a motor, it will affect the speed of electric meters.

Whereupon reader Bryan put the question to Mike Holt's electrical training forum, which elicited the following replies from the community, which is skeptical:

The US electrical grid is so interconnected that is is all but impossible for the grid frequency to fluctuate by more than tenths of a frequency. If you ever saw 70Hz, the reading would immediately be followed by 0Hz as the grid shuts down causing a multi-state power outage.

And:

NERC Regulates the grid to 60Hz +/- 5%, so the highest you could see is 63Hz. But local regulations are more restrictive and the most you typically see is 60.1 Hz for sustained periods. Over/Under frequesncy relays would prevent any large distortion as Jim said.

And:

Just think of all the electric clocks that would run fast! Most devices that use large amounts of electricity for heating or lighting are rather frequency insensitive.