In 2017, it was estimated that there are two billion computers were in use in the world. These systems require energy. While one individual system may not need much energy to Run, two billion systems require a lot of electricity.
In general, the larger the computer system the more energy it will consume. For this reason, desktop systems often consume more energy than laptops, laptops more than tablets and tablets more than smartphones.
As a user, it is important to consider the steps that can be taken to reduce unnecessary energy use.