You have a weird idea of how a telephone line or a network works 
When you receive or transmit data your network card absorbs from the network approximately the same energy it emits. All this energy doesn't go somewhere: simply becomes heat.
But when I watch a picture on my screen, some of the electricity (data bits) that are being transferred to the monitor will become light energy when the monitor displays it. When you receive or transmit data your network card absorbs from the network approximately the same energy it emits. All this energy doesn't go somewhere: simply becomes heat.i say this with all respect, but are you an idiot? your sceen is connected to a power source that provides all the power = light. the data from your computer is carried in a fraction of a watt, and simply tells the screen where to point the power to make light on a pixel
