Butanium

Butanium, a natural gas which is used throughout Yavaun to power machinery, is gathered in a number of ways. The Workbot, Butanium Refinery, and Butanium Synthesiser, when built over a source of Butanium (easily seen as a jet of greenish steam), yield a constant supply, one Butanium every time segment. The S.U.N. Ground Harvest spell, however, extracts a large amount of Butanium from the designated source at one time. Vehicles or mechanised units require Butanium fuel in different amounts, but all are refueled every seven time segments (approximately twenty seconds of game play).

Fuel Shortage
If you are not producing enough Butanium to sustain structures and equipment that require fuel, then the surplus slowly diminishes. If the Butanium supply is empty, then all units that require fuel suffer a penalty, which is detailed below. Units with an alternate power upgrade are not affected by fuel penalties.
 * All low fuel unit speeds are reduced to a crawl move rate.
 * All low fuel units get a -30% to hit.
 * No spell casting by low fuel units.
 * Influence is reduced to one half (does not increase over one half until fuel shortage is lifted).
 * Low fuel units flee combat if reduced to 50% Life (not applicable to vehicles).