Electric bikes are generally quite heavy to lift. While you are riding with assistance, this becomes almost unnoticable. Most models have a walk assist function, meaning if you need to manouevre your bike it will provides a small amount of support power to help you manoeuvre the bike which is especially useful if you need to pass obstacles on trails or push your bike to a particular point.
The bikes below are highlighed as being particularly lightweight, while still providing enough power and range to tackle the most demanding Cornish hills. An average electric bike weighs 24-26kg, these bikes are all under 20kg.