As a driving force, it's electrifying! (7)
I believe the answer is:
voltage
'as a driving' is the definition.
I can't judge whether this definition defines the answer.
'force it's electrifying' is the wordplay.
'force' becomes 'volt' (I have seen 'little force' mean 'volt' so perhaps 'force' could also mean 'volt').
'it's electrifying' becomes 'age' (I can't explain this - if you can you should believe this answer much more).
'volt'+'age'='VOLTAGE'
Can you help me to learn more?
(Other definitions for voltage that I've seen before include "current potential" , "Power supply rating" , "Measure of electrical potential" .)