More than ever, it needs this gas (6)
I believe the answer is:
ethane
'this gas' is the definition.
(ethane is a gas)
'more than ever it needs' is the wordplay.
'needs' indicates the answer is hidden within the clue.
'ETHANE' can be found hidden inside 'more than ever it'.
(Other definitions for ethane that I've seen before include "Athene (anag.); a colourless gas" , "Flammable gas; eat hen (anagram)" , "Ate hen (anag) - hydrocarbon gas" , "Compound" , "Flammable hydrocarbon" .)