A hydrocarbon point is a position on the map where a hydrocarbon power generator can be built. It is very important during the early parts of a battle because it provides access to significant power at a lower cost than building an equivalent number of tech 1 power generators. A hydrocarbon power generator also has a very good adjacency bonus, and air factories are particularly power-hungry, so battles on maps that have hydrocarbon points are more likely to involve air units earlier in the battle.