(Back on topic)
I honestly don't see where people pull the idea that biofuel with less cost would be OP. Currently, most people completely overlook fuel. With regular fuel, you're burning diamonds (1 64th of one per cell). While Superfuel may exist, that's a lot closer to endgame than where biofuel is useful (or, in my mind, intended for use). Biofuel covers, to some extent, that gap between coal-fueled generators and their more advanced, passive counterparts like solar cells and wind turbines. It's massively prohibitive, at this point. It uses almost half a tin bar per can of fuel. That's one tin bar to replace 13 charcoal, which, by the way, is completely renewable (that's two to three trees). Compared against lavacells (bad example since you can just use buckets) that's 4340 energy per cell at biofuel to 20000 per cell at lava (or 2000 per cell for water, both of which are completely avoidable with the use of a single bucket which is also renewable). Biofuel in and of itself is a major pain to create in the first place, involving a lot more work than simply burning wood and throwing it into the same generator.
On top of all this, it's four tin ingots to make a solar generator. AFK EU generation that requires absolutely 0 maintenance. Same numbers for any other AFK EU generator. 16 empty cells is the tin component for a generator. Those 16 cells are going to get you just over two cans of biofuel.
Energy generation is a very big point towards progression through technology in IC. It sits right next to getting machines built in the first place. As it is right now, you go from regular generator with charcoal next to a batbox straight to your final preferred method for producing energy piped straight into the top (when there's a mind for efficiency which is a big facet of IC). There's no ground level/slightly more effective ground level/final level. It's just ground level generator with renewable charcoal then BAM, final level with some passive energy generation which transcends renewable.
Honestly, it feels like biofuel is just there for refueling without using up precious , rather than as a viable fuelsource.
Logically, it makes no sense that is USES the cells when you can the fuel. Where does that cell go? If anything, when the cell gets canned, it should turn into a depleted cell of its type, which could be 're-enriched' into a bio-cell. Personally, if I knew how to make a plugin to modify the recipies, I would either 1/6th the tin cost for biocells or make a packaged unstackable biofuel cell recipie that costs 6 biofuel cells that isn't consumed by the canning machine (returns a 6x empty cell item which can be crafted into 6 empty cells to restart the whole process).