Coal is a resource unlocked by researching the Steel technology. It is a component of the steel resource, and is required to run Steamworks.
- Coal's primary use is to be converted into steel. At the workshop you can craft 1 steel from 100 iron and 100 coal.
- Coal implicitly powers the Steamworks, which can be built after researching Machinery. When active, the steamworks (initially) reduces coal production by 80% but perform a variety of operations. This is a flat cost and does not scale with the number of steamworks built. Coal production from smelters is unaffected.
- After you upgrade High Pressure Engines, the coal production penalty is reduced from 80% to 60%.
- After you upgrade Fuel Injectors, the coal production penalty is reduced by an additional 20 percentage points.
- Initial storage capacity is 60.
- After you research Agriculture, you can build Barns, which increase storage by 60.
- After you research Construction, you can build Warehouses, which increase storage by 20.
- After you research Navigation, you can build Harbours, which increase capacity by 100.
- Certain workshop upgrades can increase the coal capacity of Barns, Warehouses, and Harbours.
- After you research Rocketry and complete Moon Mission, Piscine Mission, and T-minus Mission you can build Cryostations, which each increase storage by 25K.