What does the blue bar mean on the dashboard?

The power bar on the right side of the screen is an indication of how much power is available to the user and how efficient the ride has been.

The bar being in the blue zone is an indication that the ride has been efficient so far and is on track to hit TrueRange.

When the bar lowers and reaches the red zone, it means that the ride’s efficiency has lowered and the amount of power available to the user is low.