Solar 10

Lore & Background

On the unnamed alien world, the sky is a pale, featureless dome that never truly darkens. There is no day-night cycle, no weather front that will roll in and smother the light. The sun simply is—constant, patient, and inexhaustible. For a stranded industrialist trying to rebuild a civilization from scrap, that constancy is the single most valuable resource on the planet, and Solar 10 is the moment the player learns to harvest it. The technology itself is modest in scope: a thin sheet of photovoltaic material mounted on a small iron-and-copper frame. Yet in the broader narrative of Factorio, it is a quiet revolution. Every other power source the player will eventually master—coal generators, oil refineries, nuclear reactors, fusion plants—demands fuel, supply chains, and the slow grinding of the planet's finite resources into energy. The solar panel demands nothing but the light that is already falling. It is the first technology that whispers that the alien world does not need to be consumed to be used. Fans often describe the moment of unlocking Solar 10 as a small emotional beat in an otherwise relentless optimization game. The factory hums, the belts keep moving, and for the first time the player can look up at that pale sky and feel less like an invader and more like a tenant.

In Their Own Story

The last coal generator sputtered and died at 03:47 by the factory clock. No more coal. The belts stuttered, the furnaces groaned, and the whole sprawling assembly line shuddered to a halt like a held breath. She stood at the edge of the solar array—two hundred panels, each one a small blue-black mirror angled toward the unblinking sun. They had been built in a single afternoon, slot by slot, while the coal stockpile dwindled. Now they were the only thing between the factory and a dead stop. The first panel flickered. Then the second. A low, steady hum rolled through the concrete floor, and the lights in the control room snapped back on. The belts shuddered, caught, and began to turn. She exhaled. Above her, the pale sun poured its endless, indifferent light across the field of panels, and the factory breathed again.

Reader's Guide

Solar 10 is a single, focused technology in the Electricity section of the tech tree. It costs 10 to research and requires that you have already unlocked Batteries. In practice this places it firmly in the early-to-mid game: you will have your first electric poles, basic circuits, and battery packs, and you are ready to add a clean power source to the mix. What it unlocks is the Solar Panel, a 15 W power generator that requires no fuel, produces no pollution, and simply converts ambient light into electricity. Because the alien world has no day-night cycle, panels produce at full output continuously, making them the most reliable per-tile power source in the game. They are cheap to build (a small amount of iron, copper, and glass) and can be laid out in vast flat arrays. In progression terms, Solar 10 is the gateway to renewable energy. It does not replace coal or nuclear at scale—later technologies like Solar 20 and Solar 30 push the output per panel higher—but it establishes the design language of the solar endgame. Many players build their first satellite base or their final "green" factory around a sea of panels, and that vision starts with this single ten-point unlock. Blueprints interact with Solar 10 straightforwardly: once researched, you can place panels with a blueprint, share the array layout, and paste it anywhere. The community has produced enormous solar-field blueprints, and because panels have no fuel logistics, a shared blueprint is essentially a plug-and-play power plant.

Did You Know?

• The alien world in Factorio has no day-night cycle, so solar panels produce at full rated output around the clock—there is no 'night penalty' to plan around.
• The '10' in the technology name is the research cost itself; Factorio uses this naming convention across many of its early-game techs.
• Because solar panels require no fuel input, they are the only power source in the base game that can run an entire factory with zero ongoing resource consumption beyond the initial build.
• Later technologies (Solar 20, Solar 30) increase the output per panel but do not change the fundamental mechanic—each tier simply multiplies the wattage of the same item.