Math & science · 1824
Carnot's heat engine theory
Carnot shows that an engine's efficiency is limited by its hot and cold temperatures.
Reflections on the Motive Power of Fire founded the theory of heat engines. Its limit still sets the ceiling for every power plant and car engine.
What it built on 2
What it led to 3
Related measurements
The dashed line marks when it first worked.
UK coal production since 1700 Latest: 2.17M tonnes (2019) Source: Our World in Data
Energy used per dollar of GDP Latest: 1.21 kWh per $ (2022) Source: Our World in Data
Fossil fuel consumption Latest: 144k TWh (2025) Source: Our World in Data