Age of Empires Series Wiki

Factory Coin production increased.
—In-game description

Steam Power is a technology in Age of Empires III that can be researched at the Factory. Once researched, it increases the rate at which Factories automatically produce coin by 30%, from 5.5 coin to 7.15 coin.

Steam Power is useful if the player configures their Factories to produce coin.

Factory technologies
Cannery · Water Power · Steam Power · Mass Production