Hello, yes, this mod was done quickly and will not be optimized due to lack of time. The reason is that it scan all surfaces every 2 seconds to find all "fuel-depot" and takes longer with a lot of surface discovered. It will be marked as deprecated with version 1.0 of Factorio. I authorize the use of the current code to anyone with time to improve it.
For a quick fix you can delete the "control.lua" file from the mod folder and this will stop the scan and automatic fuel filling. This mod can help you for use another fuel type: https://mods.factorio.com/mod/Transport_Drones_Fuel
Sorry for the inconvenience.
Have a nice game.
