I propose a way to generate power from your shoes
The shoe is lined with thin strips of piezo electric material, that when flexed produces a current.
This is then fet into a small rectifier and conditioner circuit, and then used to charge a small battery in the heel. Batteries are interchangeable for each charging, and are super lightweight.
Once the battery is removed, it clips into a general purpose power unit.
The power unit is a small block that houses the battery, and provides many different size outputs for common devices.