Much like in base Zero-K, there are two elementary resource types: Metal and Energy.
Metal is required to build any structures. Each faction's base Metal income is 100 per turn. This metal is awarded to the players involved in the invasion which occurred that turn. In addition to this 5% of a faction's unused energy income is converted to metal. Scrapping a structure refunds 50% of its metal cost.
Energy is produced every turn by energy structures, whose output is shared across the faction. If a faction does not have enough power to run a structure, it shuts down.
All buildings require 40% of their metal cost in energy to run. The exceptions are the power generators and the basic wormhole, which require no energy to run, and the Planet Buster and Galaxy Compressor, which both require different amounts of energy.
Energy is the only resource that cannot be stored.
Dropships, bombers and warp cores are derived resources used for offensive actions. They are explained on the attacking page of the manual.
Resources are physically the property of the faction. Spending resources draws from the faction pool. You can learn more about the way they are spent by the faction's managers on the PlanetWars faction roles page.