Burner inserter

A burner inserter is a mechanically powered inserter that uses burnable fuel instead of electricity to perform item transfers. It does not draw from the electrical grid; instead it carries an internal fuel buffer that supplies the energy required for motion. All other mechanical and logistic characteristics of the burner inserter match those of other inserter types in the game, with the primary difference being how it obtains and stores energy.

A burner inserter spawns with an internal energy buffer of 500 kJ. That buffer is represented in-game as 25% of the energy value of a piece of wood, with wood valued at 2 MJ. While idle a burner inserter consumes no power and therefore places no passive load on an electrical network. When active it does not continuously draw the theoretical maximum power; its effective energy use is tied to discrete item-transfer actions. The amount of energy required per transfer is approximately 66.9 kJ. That figure implies runtime and endurance values relative to different fuels: a single piece of wood (2 MJ) provides just under 30 transfers, a piece of coal provides roughly 60 transfers, and a piece of solid fuel yields about 179 transfers. Given the burner inserter’s maximum operating speed of about 0.79 transfers per second (around 1.27 seconds per transfer), a single piece of solid fuel will let it operate at full speed for roughly 141 seconds before needing refueling.

Burner inserters exhibit a behavior commonly called leeching, where they will take fuel items from their input inventory and use those items to replenish their internal buffer. Leeching is triggered when the internal fuel inventory reaches zero, and the act of retrieving fuel consumes energy because movement itself uses fuel. This behavior can result in burner inserters consuming the very items they are meant to transfer if those items are burnable and are present on the input belt or chest.

Practical notes and operational tips:

• Use burner inserters where electrical infrastructure is not yet available or where you intentionally avoid power connections early in a base’s development.
• Avoid feeding burnable resources as production outputs into a system served by burner inserters unless you want those resources to be consumed; separate fuel inputs or dedicated fuel chests prevent accidental leeching.
• Solid fuel is the most energy-dense common fuel option and extends uninterrupted runtime substantially compared to wood or coal.
• A burner inserter’s initial 500 kJ buffer gives it limited initial activity without fuel; plan refueling intervals accordingly for continuous operation.
• Burner inserters pair well with devices that produce intermittent solid fuel (for example recyclers), since recyclers can output solid fuel frequently enough to sustain a burner inserter at or near full speed in some setups.
• Treat burner inserters as temporary or situational solutions in mid-to-late game designs where electrical inserters provide greater convenience and do not consume the items they handle.