Coke Pellet Production is currently very lossy. It requires 5 coal, that turn into 5 coke, that turn into 1 coke pellet. 5 coal is 20mj of fuel, 5 coke is 15mj, and 1 coke pellet is 18mj. There is no point in using coke pellets unless you're obsessed with compression for fuel and are willing to take a loss just to transport fewer stacks of something.

Edit: somehow I missed the coke processing further down the tech tree which has better yields. Maybe move coke pellets down to that technology to avoid intermediate players wasting resources.