Adds steam engines and turbines with primary and tertiary priority. Useful whenever you want to prioritize using certain power plants, especially when using different steam sources with different resource costs and pollution factors.

In vanilla-like games you might want to burn away wood and overflowing solid fuel before tapping into coal, while in modded games you can use priorities to mainly use (primary) Thermal Solar Power, backed up by a (secondary/default) nuclear reactor, which can be supported by your old (tertiary) burner infrastructure during peak demands.