power service vs light company

power service and light company both are nouns.

Word	Noun	Adjective	Verb	Adverb
power service	Yes	No	No	No
light company	Yes	No	No	No

As nouns, power service and light company are synonyms defined as:

power service and light company: a public utility that provides electricity

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

power service (noun)	light company (noun)
a public utility that provides electricity	a public utility that provides electricity