Clue: Lover of metal car was made to conserve energy at first (10)
Answer: HEADBANGER
Explanation: Definition: Lover of metal
in definition, "metal" the genre of music 
BANGER=[an old] "car", with HAD around E (energy) going in front/"first'
 
I think this is HAD="was made" as in 'I had to attend'/'I was made to attend'