Coal

Coal is a basic combustible element resource used primarily as a fuel and as an industrial input. It appears in the world as a mineable resource and as producible material through animal ranching; it is also present on Carbon-class asteroids where deposits replenish themselves, making Coal renewable when obtained from those sources or when produced by Hatches fed with renewable inputs. Coal interacts with power generation, refining, crafting and high-temperature mechanics across the game.

Coal serves as the fuel for the Coal Generator, producing electricity and exhaust when consumed. 1 kg/s of Coal in a Coal Generator yields 600 W of power and 20 g/s of Carbon Dioxide. Coal can be refined and transformed: a Kiln can refine Coal into Refined Carbon at the conversion rate 125 kg Coal → 100 kg Refined Carbon, and Coal is involved in ceramic production inside a Kiln at 100 kg Clay + 25 kg Coal → 100 kg Ceramic. Coal undergoes a high-temperature phase change: at 279.85 °C (melting point + 3 °C) Coal converts into Refined Carbon. If a Coal Tempshift Plate is built in the tile of a high-temperature intermittent vent (such as volcanoes or metal volcanoes) and the vent erupts above that temperature, the Coal will change into a single 800 kg Refined Carbon block, which can reseal the vent.

Coal is also a raw material in drug and consumable crafting. A duplicant with the appropriate Apothecary/drugcrafting ability can convert Coal into medical items: 1 kg Coal → 1 Vitamin Chew, and 1 kg Coal + 1 kg Water → 1 Healing Tablet.

Practical notes and usage tips:

• Coal is renewable when produced via Hatch ranching (Hatches accepting renewable feed) or when harvested on Carbon Asteroids, which replenish their Coal deposits.
• Use Coal early- to mid-game as a reliable generator fuel; plan for Carbon Dioxide handling near generators since they emit 20 g/s CO2 per 1 kg/s of burn rate.
• Refining Coal into Refined Carbon is material- and mass-efficient for producing steel-grade inputs; staging Kiln batches to match required throughput avoids overflow.
• The high-temperature phase change can be exploited defensively: placing Coal on Tempshift Plates over eruptive vents will convert it into a large Refined Carbon block during eruptions, which can be used intentionally to block or reseal vents.
• Coal’s role in Kiln recipes (Ceramic) and in medical production provides multiple sinks for surplus Coal beyond simple burning; balance consumption between power needs and industrial recipes to avoid shortages.