My "electric company" sells me energy, billed in units of "kilowatt-hours"
Yes, but my heating oil company sells me "energy" too, and so would a gas
company.
We have no word for the "energy" sold by electric companies. Somewhere
along the line, somebody decided to name it "electricity." Unfortunately
the word "electricity" was already in use: it meant "charge." Read
Faraday and Maxwell (and Franklin), and you'll see how physicists
discussed "quantity of electricity." At least this is how they used the
word until it became corrupted by alternate definition as "quantity of
electromagnetic energy."
I guess I cannot complain, since we also have no word for the mechanical
energy which flows along a drive shaft. If the energy companies
distributed energy via spinning shafts and long leather belts, we could
say that they're sending us quantities of "mechanicity!" (And I'd be
right there insisting that "mechanicity" is a kind of low-frequency sound,
in the same way that 60Hz "electricity" is really an electromagnetic wave
rather than a quantity of electrons.)