The British Empire lacked one thing that was abundant in the Roman Empire - lumber - and Britain needed lumber, the heat source, more, both because Britain is c

The British Empire lacked one thing that was abundant in the Roman Empire - lumber - and Britain needed lumber, the heat source, more, both because Britain is colder (residential heating) but also because of high demand for charcoal needed to fire blast furnaces to smelt iron. It was for this reason that Britain began mining coal at scale (as well as harvesting peat), and found herself in need of an efficient way to de-water her mines. And when the prerequisites (metallurgy, abundant fuel, and economic necessity) converged, the steam engine emerged.