One of blue design going round as a source of energy (7)
I believe the answer is:
biofuel
'a source of energy' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'one of blue design going round' is the wordplay.
'one' becomes 'i' (Roman numeral).
'design' is an anagram indicator.
'going round' means one lot of letters goes inside another (some letters go around others).
'blue' is an anagram of 'buel'.
'i'+'of'='iof'
'iof' placed inside 'buel' is 'BIOFUEL'.
'as' acts as a link.
Can you help me to learn more?
(Another definition for biofuel that I've seen is " that avoids putting fossils into power".)