As of 2017, it is estimated that two billion computer systems are in use in the world. These systems require energy. While one individual system may not need much energy to operate, two billion systems require vast amounts of electricity. The list shown below is not exhaustive but details some of the components and peripherals that require power when the system is in use:
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.