Steam Cores are a very rare and valuable resources in Frostpunk, which can be found in Frostland and Tesla City. It can be used to constructs advanced buildings, Steam Hubs and even Automatons.
As the foundation of advanced technology in Frostpunk, a Steam Core is an essential item to build more advanced buildings, such as steam production buildings and Infirmaries. Its sophistication exceeds the factory's manufacturing capacity, so it can only be obtained outside of Frostland. They can also be consumed to divert the Generator overdrive stress level in the event that the Generator is close to exploding.
Tesla City is the only place in the game with the capability to produce Steam Cores.