Fruit drink from the electricity company (5)

I believe the answer is:

juice

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'fruit drink' is the definition.
(I've seen this before)

I don't understand how the remainder of the clue works.

(Other definitions for juice that I've seen before include "fuel" , "Sap; petrol" , "Fruit drink" , "Energy" , "It can be expressed" .)

I've seen this clue in the Evening Standard.

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