Solar 24

Lore & Background

In the Factorio world, the player arrives on a desolate planet and must bootstrap an industrial civilization from scratch. Early on, steam engines and burning coal or oil are the only options. But as the technology tree opens, the player discovers that the planet's sun is a reliable, inexhaustible resource. Solar panels let the factory breathe without belching smoke, and the visual contrast between a soot-stained coal plant and a gleaming solar array becomes a quiet narrative beat: the player is no longer just surviving, they are building something sustainable. The second-tier solar technology—often informally called 'Solar 24' in community shorthand for its configuration efficiency—marks a meaningful step. The panels are larger, more efficient, and require fewer of them to meet the same power demand. This frees up floor space for production lines, and the base begins to look less like a hodgepodge of generators and more like a deliberate, engineered landscape. For many players, the moment they replace their last coal generator with a solar farm is the emotional turning point of the game. Of course, the sun is not always cooperative. Clouds drift across the sky on a timer, and during overcast periods solar output drops sharply. This introduces a design tension: the player must either oversize their solar array, pair it with storage, or accept brief power dips. It is a small, elegant reminder that even renewable energy has its rhythms, and a factory must be designed to flex with them.

In Their Own Story

The sky turned the pale grey of a bruise by the time the clouds rolled in. Mara watched the output meter on her solar array dip, then dip again, the long rows of dark panels going quiet one by one like a choir losing its voice. She'd built the farm on the southern plateau, where the sun hung longest, and for three in-game days it had been perfect—endless, silent, clean. Now the wind was picking up, stirring the dust around her boots, and the factory's lights flickered at the edges. She didn't panic. She'd planned for this. Beneath the array, buried in the concrete foundation, sat a bank of accumulators that would carry the line through the worst of the overcast. The assemblers would slow, the furnaces would idle, but nothing would stop. Nothing would break. That was the whole point of building it this way—not to fight the weather, but to let it pass through without consequence. She pulled up her blueprint, checked the grid, and walked back toward the control tower, where the rest of the factory hummed on, patient and steady, waiting for the clouds to peel away.

Reader's Guide

In Factorio's technology tree, solar power sits in the 'Electric Energy' research category. The progression is straightforward: first, the player researches 'Electric Energy' (which unlocks basic power infrastructure), then 'Solar Panels' (which unlocks the first-tier Solar Panel), and finally 'Solar Panels 2' (which unlocks the higher-output Solar Panel 2). Each tier requires the previous one as a prerequisite, and the research costs scale accordingly, with the second tier demanding more science packs and a longer research time. The first Solar Panel produces a modest amount of electricity and is useful for early renewable needs or small off-grid setups. The second-tier panel roughly doubles the output per tile, making it the go-to choice for mid-to-late-game solar farms. Because solar panels produce no output under clouds, players typically oversize their arrays or pair them with energy storage (accumulators) to smooth out production dips. In the blueprint system, solar farms are among the most shared community designs. Players routinely post large-scale solar array blueprints—sometimes covering hundreds of tiles—along with matching accumulator banks and distribution wiring. These blueprints interact with the tech tree simply: you can only place a panel if you have researched its tier, and the blueprint will grey out any items you haven't unlocked yet. For a 'Solar 24' style layout, the key design principle is maximizing panel density while leaving room for the cloud-timing buffer, ensuring the factory never starves during overcast periods.

Did You Know?

• Solar panels in Factorio produce zero energy when a cloud passes over them, making cloud-timing a genuine design consideration for large farms.
• The second-tier Solar Panel roughly doubles the power output per tile compared to the first tier, allowing players to halve their required panel count for the same load.
• Solar panels are the only power source in the base game that requires absolutely no input items, fuel, or fluid—making them the most 'set and forget' energy option available.
• Because solar output is weather-dependent, experienced players often design their solar arrays to produce 20-30% more than their peak demand, ensuring the factory stays powered even during extended cloudy periods.