Huge Electricity Bill - Plot Thickens

I agree with Byrogie. And my experience is that the power company has no issue with adjusting the bill if they find a new reading doesn't jive with what they had initially.

While anything is possible, meters are very robust and will seldom fail. Furthermore, failures are almost always limited to failure to read usage, not run up some ridiculous bill. Do you know if the meter is read remotely or if there is a meter reader that visits the address. If someone physically reads the meter, it is possible for them to misread it or to transpose some numbers or for the data entry person to misread their writing. That can cause a temporary long or short reading that gets straightened out at the next reading.
Many older systems not on electronic reading estimate usage and only actually read the meters quarterly or less. This can result in a very large, unexpected bill if they have estimated low in the period in question. Then there is the issue in California of seasonal rates. Where my winter home is, the winter rate is around $.14 per kilowatt hour. In the summer that rate jumps to $.37 which is insane, but you pay what you have to pay. No wonder solar companies are thriving in the California Desert. Power companies generally give little leeway when it comes to adjusting bills, so hopefully it is an error. If it is actual usage, the best you can hope for is a payment plan if The $800 bucks isn't doable in one lump sum.

First task when receiving any abnormal bill is a call to the utility for meter verification......

It was just simply misread. Happens fairly often. Just ask them to adjust your bill.

Good luck with this - let us know the outcome.