power company vs electric company

power company and electric company both are nouns.

Word	Noun	Adjective	Verb	Adverb
power company	Yes	No	No	No
electric company	Yes	No	No	No

As nouns, power company and electric company are synonyms defined as:

power company and electric company: a public utility that provides electricity

Other synonyms of power company include light company, power service.

power company (noun)	electric company (noun)
a public utility that provides electricity	a public utility that provides electricity