When “name” (ὄνομα) refers to “power or authority”, it always refers to the power or authority of a person. This is relevant because the Jehovah's Witnesses's rendering of Mattthew 28:9 would have ὄνομα refer to the power or authority of the Father, then the Son, and then an impersonal “active force”. This is, of course, an interpretation which is immediately awkward, desperate, and unintelligible.1
“Name” (ὄνομα) can refer to “power or authority”.1
By way of response, however, when “name” (ὄνομα) refers to authority, it more specifically always refers to a person's authority. See above.
“...the word ‘name’ does not always mean a personal name… Robertson’s Word Pictures in the New Testament says: ‘The use of name (onoma) here is a common one in the Septuagint and the papyri for power or authority.’” [Should You Believe in the Trinity? 21-22.]
So for example:
Deuteronomy 8:5-- For the Lord your God has chosen him and his sons from all your tribes, to stand and serve in the name of the Lord forever. By way of response, however: (a) These are very few examples, and it is telling that no Greek examples for this use of 'name' could be marshalled (it always refers to a person).
Robert Bowman: “…the Greek word for ‘name’ (onoma) is used some 228 times in the New Testament, and except for four place-names (Mark 14:32; Luke 1:26; 24:13; Acts 28:7; see also Rev. 3:12) always refers to persons.” [Why You Should Believe in the Trinity, 114-115.]1 (b) As clarified by one apologist: Steve Rudd: “Authority of law has its source in persons, not electricity! So Mt 28:19 is an example of metonymy. (a device whereby one thing is used as a substitute for another with which it is closely identified. ‘Word today came from the White House…’ it actually came from someone in the White House)” [Online at bible.ca]