I've been looking at a similar concept myself, except using cacti, which have the added benefit of not needing pistons or redstone circuitry to be automatically harvested.
Remember, too, that to fill a can with bio-fuel requires not only the 1.5 tin, but also twelve compression operations at 625 EU each and six extractions at 313 EU each.
16200 - (625x12 + 313x6) = 6822 EU. You're better off just burning them raw.