Huge chambers for storage of collected gas. Each new level of infrastructure development increases the capacity by 1%. If the chamber is full, it will stop gas collection. All gas that is improperly stored on the planet will be corrupted and lost at 10% per day.
Vespene Gas Concentrator capacity can be increased by hiring Officer Storekeeper. Facility capacity can be increased by the capacity of the fleet at the facility (if hired Storekeeper), and by the capacity of the Sower (regardless of the presence of Storekeeper).