(suggestion) Ion engines require gas to function

Ion engines in their current se1 (and arguably se2) state are pretty much direct energy to propulsion converters.

what i suggest is implementing a ion engine fuel system where non explosive nitrogen gas tanks (or any gas commonly used in modern ion propulsion) are required for operating ion engines.

ion engines wouldn't need to be connected to these gas tanks via conveyers but would still require a gas tank with nitrogen inside be on the same grid, these gas tanks however would still have a conveyer connection to allow refilling from other grids storage or production facilities.

nitrogen (or otherwise) gas would be produced by refineries as a optional byproduct that if a nitrogen gas storage tank is present on the same (or a connected) grid would fill it slowly with time. alternatively nitrogen could be harvested from a planets atmosphere via an air vent which would fill any empty nitrogen tanks on its conveyer network.

Ion engines would very slowly use nitrogen gas as "fuel" at a rate much lower than that of a hydrogen engine while still consuming electricity.

my thoughts with this are to make ion engines less "cheaty" feeling and to introduce a small but still present sense of needing to monitor your "fuel" levels that are present with hydrogen engines. on top of this the need to have nitrogen gas tanks (whether small volume or large volume) would incentivize ship design to shield nitrogen gas storage or in combat to target an opponents nitrogen gas tanks to disable a ships movement capabilities without having to take out every battery or other power generator. this would both work to make hydrogen engines even more viable as a pure in space propulsion method as well as to introduce new design constrains without the same level of complexity seen with hydrogen engine conveyer networks.