Energy consumption, Calories
The calculation of energy consumption is a guideline based on the Metabolic Equations of the American College of Sports Medicine. In these calculations resting energy is included. In addition, the elevation profile of your activity is taken into account. An example for cycling can be found at Wikipedia. Due to the large number of parameters involved in these calculations you can expect significant differences in the results calculated in different apps. Also the resting energy is not always included within other apps or portals.