Plain accommodation in order for current provider (3,4)
I believe the answer is:
dry cell
'current provider' is the definition.
(provider of electrical current)
'plain accommodation in order' is the wordplay.
'plain' becomes 'dry'.
'accommodation in order' becomes 'cell' (room for a monk, who might be a member of an order).
'dry'+'cell'='DRY-CELL'
'for' acts as a link.
(Other definitions for dry cell that I've seen before include "Source of power" , "a prisoner's more comfortable with" , "Healthy accommodation for a prisoner" , "Source of energy" , "Type of battery" .)