Solar 20

Lore & Background

In the Factorio world, the alien continent is a place of brutal industry and relentless expansion. The player arrives with a handful of blueprints and a desperate need to build a rocket. Every resource is finite, every machine hums with purpose, and the landscape is slowly consumed by conveyor belts and storage tanks. Into this mechanical sprawl, solar panels introduce a quiet, almost alien calm: vast fields of dark blue panels tilting toward the sky, producing kilowatts without a single puff of smoke or groan of a piston. The progression from Solar 10 to Solar 20 to Solar 30 mirrors the player's own journey from fumbling survival to commanding a continent-spanning empire. Early on, a few panels near the starting area are enough to trickle-charge a battery. By the time Solar 20 is researched, the player has the infrastructure to lay down hundreds of panels in neat rows, and the energy surplus becomes real. The panels themselves are simple, silent, and utterly reliable—no fuel logistics, no boiler explosions, no cooling loops. Just the sun, the sky, and the steady hum of electricity flowing into the grid. Fans often describe the moment a fully solar-powered factory first lights up at scale as one of the game's most satisfying achievements. There is something deeply gratifying about watching a sprawling base of assemblers, furnaces, and labs run entirely on photons, with no coal trains and no oil refineries in sight. It is Factorio at its most elegant: complex, beautiful, and quietly sustainable.

In Their Own Story

The wind had died down again, and the only sound was the faint tick of cooling metal. Mara stood at the edge of the solar field, her boots crunching on the gravel path that bisected the rows. Three hundred and twelve panels stretched in every direction, their dark faces catching the low afternoon light. Somewhere behind her, the chemical plant was running—sulfuric acid, plastic, green circuits—all fed by nothing more than the sun and a battery bank the size of a warehouse. She pulled up the blueprint on her tablet. Solar 20. Checked. The next field was already mapped, another two hundred panels to the north, where the terrain was flat and the shade from the old trees had been cleared. She tapped the share button and sent it to the comms channel. Within minutes, the first few workers were already driving out with the panel frames on their backs. The rocket still wasn't ready. The alien artifacts still glowed on their pedestals, patient and indifferent. But the energy problem—the one that had nearly choked the whole operation to death back when the coal ran thin—was solved. And for the first time in months, the factory hummed without a single black plume rising into the sky.

Reader's Guide

It requires 50 energy units to research and has a single prerequisite: Solar 10. In the broader tech tree, Solar 10 itself typically requires Electric Engines, placing the solar line in the mid-game window after basic electricity is established but before late-game nuclear or advanced renewable options. In practice, Solar 20 is the technology that makes solar power genuinely viable as a primary energy source rather than a supplementary trickle. Players usually research it after they have established their first battery banks and are looking to reduce coal consumption. Together, the three-tier solar line lets players scale from a handful of panels near the starting area to continent-spanning arrays that can power entire factory complexes without a single drop of fuel. Because solar panels produce zero pollution and require no fuel logistics, they are especially popular in late-game bases where the player has the land area and the energy demand to justify the footprint. The main trade-off is spatial: solar fields need open, unobstructed ground, which can compete with other factory layout needs.

Did You Know?

• In vanilla Factorio, solar panels produce power continuously unless the player enables the optional day/night cycle in the settings, in which case they only generate during daylight hours.
• Solar panels are one of the few energy sources in the game that generate absolutely no pollution, making them a key tool for players trying to minimize their environmental footprint.
• The three-tier solar line (Solar 10, Solar 20, Solar 30) is one of the few technology chains in Factorio that follows a simple, linear upgrade path with no branching choices.