I was looking at the Canning Machine and Fuel Cans on the wiki, and it didn't really document much on how much you get from the two kinds of Fuel Cans. So I made a test world and checked how much various types of fuels give you.
Fuel Cans filled with BioFuel cells give you 26040 EU when used in a Generator(this information is on the wiki, although it doesn't say it's specific to BioFuel Fuel Cans)
Fuel Cans filled with CoalFuel Cells give you 76440 EU when used in a Generator(NOT on the wiki)
1 Coal/Charcoal give you 4000 EU in a generator(common knowledge)
64 Sugar Cane will give you 7680 EU when used in a Generator(much less efficient than taking 48 of them and making one BioFuel Fuel Can)
64 Cactus will give you the same amount as 64 Sugar Cane
1 Wooden Plank gives you 750 EU
1 Wood(tree block) gives you 750 EU
For Equivalent Exchange users:
Mobius Fuel gives you 64000 EU in a Generator
Alchemical Coal gives you 16000 EU in a Generator
Thanks for your time, and I hope that it helps.