Inexperienced volunteers full of energy may find drink (5,3)
I believe the answer is:
green tea
'drink' is the definition.
(type of tea)
'inexperienced volunteers full of energy' is the wordplay.
'inexperienced' becomes 'green' (similar in meaning).
'volunteers' becomes 'TA' (abbreviation for Territorial Army).
'full of' is an insertion indicator.
'energy' becomes 'e' (physics symbol as in E=mc2).
'ta' placed around 'e' is 'tea'.
'green'+'tea'='GREEN TEA'
'may find' is the link.
(Other definitions for green tea that I've seen before include "Brewed" , "Drink - generate (anag)" , "Infusion" , "Infused drink" , "Beverage" .)