5 litre of fuel at lets say 1.50per litre even if run for 18hrs every 2 days is 54.00 . I know that seems alot but it is actually less during flowering. I am running 4x 600w lights plus 2x400w for mother tent. I live in a regional center bout 3 hrs from brisbane. I have a new house and underground power. Can run everything of house if i wanted to but i use both Mains and the genie and find its very economical not that im paranoid it just keeps things lower on the elec bill. We have MAGGOT POLICE POWERS UP HERE