From nothing, a power unit raised capital (6)

I believe the answer is:

ottawa

'capital' is the definition.
(Ottawa is an example)

I don't understand the remainder of the clue.

(Other definitions for ottawa that I've seen before include "Canadian capital" , "somewhere in Canada" , "N. American city" , "The capital of Canada (6)" , "Canada's capital" .)

I've seen this clue in The Guardian.

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