It's like that great system we all live in (5)
I believe the answer is:
solar
'it's like that great system we' is the definition.
I can't tell whether this definition defines the answer.
'all live in' is the wordplay.
'all' becomes 'soar' (I can't justify this - if you can you should believe this answer much more).
'live' becomes 'l' (electrical abbreviation).
'in' is an insertion indicator.
'soar' going around 'l' is 'SOLAR'.
Can you help me to learn more?
(Other definitions for solar that I've seen before include "Pertaining to the sun" , "Using the sun's energy" , "Sort of power" , "revolutionary system" , "Relating to our star" .)