You could monitor your devices power consumption with a power meter to add on a plug, so choose the appropriate device based on the softwares and performance you need.
For example, to only browse the internet for social media or news, your smartphone only consumes ~10W. But if you need a bigger screen, use a Raspberry Pi and an energy saving monitor (or reduce brightness to your), which is ~3W for the RPi and range 7-20W for monitor.
Or use a tablet instead of laptop or desktop (which without screen could consume 70W!)!
Or reduce the traffic you generate sending... (More)