Elevation can have an impact on your vehicle's range, using more energy driving up steep terrain. Taking changes in elevation along your route into account will help to plan out expected range.
Go to the Trip Planner, plan your route and click on the "Elevation" button:
This will populate an elevation map and the distances between marked stations you have routed on your trip. We suggest making adjustments if an elevation has a sudden rise to ensure you will make it to your destination.