Advanced Power

Lore & Background

In the world of Oxygen Not Included, colonists are stranded on a remote asteroid, tasked with building a self-sustaining habitat from raw ore and ingenuity. Early on, a few solar panels and a coal generator keep the lights on and the air recyclers spinning. But as the colony expands—more colonists breathing, more crops growing, more machines humming—the power deficit becomes a crisis. The Advanced Power tier of the research tree represents the moment the colonists stop scraping by and start engineering a future.

Nuclear fission, in the ONI universe, is treated as a mature but dangerous technology. The Nuclear Reactor produces enormous electricity but radiates intense heat into its surrounding tiles, forcing players to design elaborate cooling loops, heat sinks, and ventilation shafts. This turns power generation from a simple 'plug it in' task into an architectural puzzle, and it is a design choice that many fans cite as the game's most satisfying engineering challenge.

The broader narrative implication is one of escalating responsibility: each tier of technology the colonists unlock trades one set of problems for a more complex set. Advanced Power is the tier where the colony stops being a survival camp and starts being a true industrial habitat, with all the infrastructure, waste management, and thermal engineering that implies.

In Their Own Story

The reactor room smelled of hot metal and ozone. Kessa wiped sweat from her brow and checked the output gauge for the third time in two minutes. Sixteen kilowatts. Steady. The colony's oxygen recyclers, the grow-lights over the wheat field, the water purifiers—all of it drawing from that single glowing core behind the reinforced glass.

She could feel the heat even through the double wall of tiles she'd packed with cool metal. The vent shafts she'd routed through the ceiling groaned softly, pushing the excess warmth up into the empty space above. If she'd miscalculated by even a few tiles, the reactor would have cooked the control room alive.

"You're holding," she muttered to the machine, almost talking to it the way you'd talk to a horse. Then she pulled up the research log, found the next node in the queue, and started sketching the coolant loop for the second reactor. The colony was growing. It always was.

Reader's Guide

Tier / Branch: Power Generation – Advanced Tier

Nuclear Reactor – Tier: Advanced (late-game). Unlocks the Nuclear Reactor machine. Burns uranium fuel rods to produce a large, continuous output of electricity while radiating substantial heat into adjacent tiles. Requires careful placement near heat sinks or vent shafts to prevent overheating surrounding rooms.

Uranium / Fuel handling – Tier: Advanced. Unlocks the ability to mine, refine, and store uranium ore as fuel rods. Adds a new resource pipeline (ore → refined fuel → loaded reactor) that must be integrated with your existing mining and transport infrastructure.

Battery storage upgrades – Tier: Advanced. Unlocks higher-capacity battery banks or improved charging rates, allowing you to buffer the reactor's constant output against fluctuating colony demand. Reduces the risk of brownouts during peak load (e.g., running multiple o2 recyclers and grow-lights simultaneously).

Planning note: Because the Nuclear Reactor emits heat into every adjacent tile, most experienced players dedicate an entire room or sub-level to the reactor and its cooling infrastructure. Route heat up through dedicated vent shafts, line the walls with cool metal or stone, and keep colonist workstations at least two tiles away. Treat the reactor room as a hazmat zone: no sleeping, no food prep, no extended work shifts nearby.

Resource loop: Uranium ore (mined) → Refinery (refined into fuel rods) → Nuclear Reactor (consumes rods, outputs electricity + heat). Monitor fuel rod stockpile; a dead reactor in a late-game colony with no backup solar or coal can cascade into a total power failure within minutes.

Did You Know?

• The Nuclear Reactor's heat output is so intense that placing it next to a colonist's sleeping quarters will rapidly raise ambient temperature to lethal levels, making thermal management a core part of late-game design.
• In Oxygen Not Included, the power branch is one of several parallel research tracks; you do not need to fully complete Advanced Power before pursuing advanced agriculture or life-support tiers, though most players interl
• The game's heat simulation is tile-based and real-time, meaning a single misplaced reactor can cook an entire side of the base if vent shafts are not routed correctly—a design choice that makes power planning feel like g
• Klei Entertainment's Oxygen Not Included was released in 2019 and has since received multiple DLC expansions that add new biomes, colonist traits, and research options, keeping the tech tree a living system.