Stationary energy refers to burning fuel for energy in settings other than transport - hence the word 'stationary'. Settings include power plants and buildings. The fuels include gas and coal. What is Mt CO₂-e? Emissions are a combination of gases. Most are Carbon Dioxide (CO₂). The other gases are measured as a Carbon Dioxide equivalent (CO₂-e) based on the amount of heat they trap in the atmosphere. They’re measured in Million Tonnes (Mt).