Where energy comes from

Energy explanations become confusing when every part is called a source. A simple model separates four roles. First, a source provides energy that a system can use. Second, equipment converts or generates a useful form such as electricity. Third, a grid or other carrier delivers that energy. Fourth, a battery may store electricity until a vehicle needs it. The vehicle is the user. This model is simplified, but it prevents one common mistake: a socket or charging point is a delivery point, not an electricity tree. Comparisons also need limits. A transport choice may use less energy per passenger when it carries many people, but the result depends on distance, passenger numbers and the system being studied. State which part you are comparing and where the information came from. Careful labels are more useful than a large claim with no boundary.