Storage tank
Overview
The storage tank is a fluid container used to buffer large amounts of liquids and gases in Factorio. It is most commonly used to hold raw materials and excess output from oil processing, letting refineries continue operating smoothly even when the rest of the line is temporarily backed up. Because it can be connected to the circuit network, it also serves as a convenient way to read fluid contents as a signal.
A storage tank is part of the fluid segment it is connected to, so every tank and pipe in that segment shares the same fill percentage. There is no actual flow distance inside a segment, which means a tank will always match the average fill level of the connected pipes regardless of where fluid enters. If several storage tanks are attached to the same segment, they all remain at exactly the same fill state.
Storage tanks are useful as short-term buffers for high-throughput processes such as acid neutralisation and steam condensation, where temporary imbalance can otherwise cause machines to become full or run dry. They can also be used as a form of energy storage by holding steam for later use, effectively replacing accumulators in systems where steam production and consumption vary over the course of a day, such as solar-backed grids or defenses with laser turrets.
- A storage tank filled with 500°C steam from heat exchangers stores about 2.4 GJ of energy.
- A storage tank filled with 165°C steam from boilers stores 750 MJ.
- One tank holds 25,000 units of 500°C steam, enough to run a steam turbine at full output for about 416.7 seconds.
- One tank holds 25,000 units of 165°C steam, enough to run a steam engine at full output for about 833.3 seconds.
The contents of a storage tank can be removed without destroying them by draining the tank with a pump. They can also be deleted by flushing the tank or the entire fluid system through the GUI, or lost by mining and rebuilding the tank. When a storage tank is mined, its contents are transferred to the nearest compatible storage tanks if possible, provided the fluids match.