Development of green factory’s latest power supply (6)
I believe the answer is:
energy
'power supply' is the definition.
'development of green factory's latest' is the wordplay.
'development of' indicates an anagram (I've seen 'development' mean this).
'latest' says to take the final letters.
The last letter of 'factory' is 'y'.
'green' with letters rearranged gives 'energ'.
'energ'+'y'='ENERGY'
(Other definitions for energy that I've seen before include "Dynamism" , "Fuel" , "Exertion of force" , "Healthy capacity for vigorous activity" , "Power or vigorous activity" .)