Solar Panel

Solar Panels are power-generating buildings that convert sunlight into electricity with no direct resource consumption and no byproducts. They are one of the cleanest power sources in Oxygen Not Included, but they require open access to light and careful protection from space hazards. In the base game, that usually means a significant investment in rooftop infrastructure; in Spaced Out!, many planetoids make them much easier to use because meteor activity is absent on most of them.

A Solar Panel produces power in proportion to the total illuminance falling on all of its tiles, up to a maximum output of 380 W. The building reaches full output when the combined light striking it is high enough; in unobstructed direct sunlight, a single panel produces about 264 W on average across a cycle because daylight rises and falls over time. At night it produces no power at all, and its output ramps up and down with the day-night cycle rather than staying constant.

Because output depends on light, any obstruction reduces performance. A panel can still reach full output even when partially blocked, provided enough of its surface remains illuminated and the ambient light is strong enough. However, anything that blocks sunlight lowers generation, and meteor fallout can shut production down for long stretches. In the base game, panels are especially vulnerable to Meteor strikes and also to overheating from hot regolith or other falling debris. There is no special material that makes them immune, so protection must come from layout and shielding rather than construction material.

Common ways to support Solar Panels include:

• Using transparent tiles such as Window, Airflow, or Mesh to separate panels from hot regolith while still allowing some light through.
• Placing Bunker Doors above the array as a dependable meteor shield, usually controlled by automation through Space Scanners.
• Using Robo-Miners to break up accumulated regolith, though they also need their own cooling and protection.
• Supplying battery storage to bridge the night cycle and any meteor-related downtime.

The downside of transparent shielding is that it can still complicate maintenance and may reduce performance. Window Tiles partially block light, lowering Solar Panel efficiency by about 10%, and they also absorb heat from regolith, which can then spread to nearby machinery. Robo-Miners help with clearing debris, but they do not remove the need for thermal management or defensive layering.

If a colony relies on solar power as its main source, storage becomes important. For a single panel with uninterrupted access to space, about 39.3 kJ of storage is enough to cover the average day-night gap, which is close to two Smart Batteries or one Jumbo Battery. In the base game, where a meteor shower can block access for an entire cycle or longer, a worst-case buffer of about 158 kJ per Solar Panel is needed, roughly equal to 9 Smart Batteries or 5 Jumbo Batteries. When Solar Panels are combined with fuel generators, Smart Batteries can automate the handoff between sources and reduce the amount of storage needed.

Solar Panels can also convert Shine Bug light into power, though the output is very small and only works when the bugs are extremely close, making this mainly useful for Shine Bug Reactors. They cannot receive tune-ups from the Power Control Station.