Power

Power is the system that quietly scales with everything else. Every building you add to solve oxygen, food, or cooling draws watts, so the colony’s power demand climbs the whole game, and the generators you start with cannot keep up. The arc of power in ONI is a transition: from dupes running in a wheel, through coal, and on to cleaner or stronger fuels that free your crew for real work. Running alongside that is a second problem most beginners meet the hard way, which is that wires and circuits have limits, and overloading them does damage. This page covers both the generator ladder and the wiring rules that keep it safe.

The generator ladder

Generators trade fuel, output, and side effects. The early ones are cheap but dirty or dupe-hungry, and the late ones are strong but need a supply chain.

Generator	Output	Notes
Manual Generator	400 W	Dupe-run. Fine to bootstrap, a waste of labor long-term
Wood Burner	300 W	Renewable with tree farming
Coal Generator	600 W	The early workhorse. Adds CO2 and heat
Hydrogen Generator	800 W	Burns SPOM hydrogen, clean
Natural Gas Generator	800 W	From geysers or the petroleum chain
Petroleum Generator	2000 W	The strongest, 3 kW after a tune-up. Adds CO2 and heat
Steam Turbine	up to about 850 W	Recovers heat as power in a cooling loop

Carbon burners (coal and petroleum) add CO2 and heat, which is the hidden cost that ties power straight into the heat wall. Cleaner generators exist partly to keep that heat out of your base.

The transition off coal

Coal is where nearly every colony starts its real power, because a Coal Generator is cheap and coal is easy to find. The trap is that natural coal is finite. The first half of the transition is making coal renewable: a Hatch ranch produces coal from tame Hatches eating rock, at about half the eaten mass, which turns a finite deposit into a standing supply. The ranching guide covers that setup.

The second half is moving off coal entirely to reduce the CO2 and heat it dumps. The SPOM is the natural first step, because it produces surplus hydrogen that a Hydrogen Generator burns cleanly, so your oxygen machine also carries some of your power. From there, Natural Gas Geysers and eventually Petroleum Generators take over the heavy load. A single Petroleum Generator gives 2 kW, or 3 kW tuned, which is enough to carry a large base, so a small petroleum setup replaces a wall of coal burners and the heat that came with them.

Wires, the limit that burns

Wires are rated on the load they carry, not on the generators feeding them, and going over the rating does damage. This is the single most common power mistake.

Wire	Limit
Wire	1000 W
Conductive Wire	2000 W
Heavi-Watt	20 kW
Heavi-Watt Conductive	50 kW

The rating counts the draw of the buildings on that section, so a run of high-draw machines needs a heavier wire or a split circuit. Overloading is not a soft warning. The wire takes damage and can break your power, so plan circuits around the limit rather than discovering it.

Charging batteries do not count toward wire limits. Only the draw of running buildings does. This lets you use batteries as a buffer between a generator and a heavy circuit, but it also means the limit is about instantaneous load, so a spike from several machines starting at once can overload a wire that looked fine.

Batteries and transformers

Batteries store surplus and smooth demand. Standard, Jumbo, and Smart Batteries all hold charge, and the Smart Battery adds automation: it can trigger generators on and off by charge level, so your generators only run when the battery is low. That is how you stop burning fuel to charge a full battery.

Transformers separate circuits and step power down. A Small Transformer feeds a circuit up to 1000 W and a Large Transformer up to 4000 W, which lets you run a heavy main line and branch protected, lower-limit circuits off it. Between Smart Batteries triggering generators and transformers isolating circuits, you build a power grid that runs itself and does not overload.

Next: burn SPOM hydrogen with the SPOM oxygen build, make coal renewable with food and ranching, and manage the heat every generator makes in heat management.