Solar panels carry most early bases in Subnautica 2, but their output collapses after sunset an, any base relying solely on them will start losing oxygen and crafting power overnight. The fix is to either store excess daytime energy, supplement solar with a generator that ignores sunlight, or replace solar entirely with a night-stable source like a hydroelectric turbine, thermal plant, or bioreactor.
Why solar fails at night
A solar panel produces up to 8 energy per second in direct daylight and drops to around 4 per second at night, with output falling further the deeper the panel sits below the surface. That means a base running a fabricator, lights, and a water purifier will often outpace generation once the sun goes down.
The HUD power readout on the top left of the screen shows incoming power in blue and outgoing draw in red. If the red number stays higher than the blue at night, you will eventually drain the base completely, lose oxygen, and lock yourself out of every machine until the sun returns.
Add Power Storage first
Power Storage is the single most important wall module for a solar-only base. It banks any surplus generated during the day and feeds it back into the base when generation drops below consumption.
The blueprint unlocks after scanning two Power Storage units found inside derelict structures near the starting lifepod, one near a Rebreather workbench, and another inside an investigation site flagged by the story. Once unlocked, each unit costs 1 Germanium Ingot and 2 Titanium and snaps onto the interior wall of any room.
Step 1: Scan both Power Storage units in the early-game wrecks to register the blueprint. The HUD will show "POWER STORAGE UNLOCKED" once the second scan completes.
Step 2: Process Silver into a Germanium Ingot at a processor, then open the Habitat Builder and select Power Storage under the Interior Facilities tab.
Step 3: Place the unit on an interior wall. Build one per solar panel as a rough starting ratio, so daytime overflow has somewhere to go.
Generators that ignore the day-night cycle
Solar plus storage only stretches you so far. To genuinely stop caring about night, you need at least one generator that produces power independent of sunlight. There are three options, each suited to a different base location.
| Generator | Output | Placement | Notes |
|---|---|---|---|
| Hydroelectric Turbine | 12 energy/sec, steady | Inside a visible water current | Needs Power Transmitters to reach the base |
| Bioreactor | 1–20 energy/sec | Inside a base room | Burns plant matter or fish; can be overcharged |
| Thermal Plant | 1–16 energy/sec | On the seabed near heat vents | Needs Power Transmitters; full output only in hot zones |
Hydroelectric Turbine
Currents appear as wavy, translucent tunnels of moving water that push you along when you swim into them. Place a turbine inside one, and it puts out a flat 12 energy per second with no fluctuation, day or night. A single current can hold multiple turbines.
The blueprint is scannable at two early locations, including a turbine sitting on a rock formation about 358 meters from the lifepod and another near wreckage roughly 186 meters south at around 90 meters deep. Crafting one costs 3 Silver, 3 Bronze, and 3 Titanium.
Bioreactor
The Bioreactor is the only night-stable generator that goes inside the base, which makes it the simplest option if your build is nowhere near a current or heat vent. Load it with plants or fish, and it averages around 10 energy per second, peaking at 20 when overcharged. Overcharging doubles fuel burn, so use it as a temporary boost rather than a permanent setting.
Thermal Plant
Thermal Plants unlock deeper into the campaign, after crossing the vast empty into the later biome. They sit on the seabed and only hit their 16 energy per second ceiling when planted directly in a hot zone, typically near lava geysers or vents flagged by translucent donut-shaped jellyfish. Like turbines, they need a chain of Power Transmitters back to the base.
Connecting external generators with Power Transmitters
Turbines and Thermal Plants do not transmit power on their own. You build Power Transmitters as relays, with each transmitter covering up to about 100 meters, and the chain ends at one transmitter attached directly to the exterior of your base.
The most common reason power "doesn't work" after building a turbine farm is that the final transmitter is hovering in mid-water instead of snapping to the base hull. Move it closer, rotate the placement, and wait for the connection mode to change from the floating mid-chain version to the wall-mounted version before confirming the build. If the chain still reads zero after that, deconstruct the base-side transmitter and rebuild it; the connection can occasionally bug out and refuse to register until replaced.
A practical nighttime setup
For a shallow surface base, the cheapest stable configuration is three to four solar panels feeding two Power Storage units, plus a Bioreactor inside one room kept topped up with kelp or fish. The panels recharge storage during the day, storage carries the base through dusk, and the Bioreactor covers any deficit overnight or during heavy crafting.
For a base built near a current, skip storage almost entirely and run two Hydroelectric Turbines through a transmitter chain. The flat 24 energy per second handles a fabricator, scanner room, and water purifier without ever dipping. Deeper bases in warmer biomes can do the same with a pair of Thermal Plants on nearby vents.
Sleeping through the night is not an option in Subnautica 2 the way it was in the first game, so there is no shortcut around generation. Build for the night first, and daytime takes care of itself.