Question: How does texting, calls or internet work? How much energy does it take?

Sam Geen answered on 20 Jun 2013:

Phones and internet are information being transmitted from one place to another.

In the early days, the sound waves in people’s voices were captured as waves in electricity, and either passed along a wire or sent by radio waves (which are in fact waves in the electromagnetic field, like all frequencies of light). This is called “analogue” signals. When you tried to call someone, a person with a big board full of wires moved the wire from your phone to the wire on the phone of the person you were trying to call. Then a machine was designed to do it (the story is that a funeral director in a town invented it because he was losing business as the wife of the other funeral director was the telephone operator, and kept connecting people to her husband, his competitor).

Then when computers came along, digital communications started. This is where sound waves are turned into ones and zeroes by a computer, transmitted according to 2 voltages in the wire, and then turned back into sound. The advantage of this is that if you lose some of the signal on the way, you’re less likely to lose information because there are only 2 values to choose from – there’s less crackle and static in digital communications. Nowadays, most phone lines are optical fibres – these are strands of glass that lasers are fired down, and the lasers reflect off the glass down the line until they hit the other end and are turned back into electrical signal, then sound.

Mobile phones work by sending microwave signals through the air to big masts on hills or tall buildings. These can often pass through walls, unless they’re thick stone walls (sometimes in old buildings like castles you can’t get good reception, and this is why). They send information digitally, like I described before, and the masts turn these microwave signals into electrical signals.

The internet uses the same networks – sending 0s and 1s around – and then turns the 0s and 1s into information (for example, each letter has a code made of 0s and 1s – A is 1000001, B is 1000002, etc).

In terms of energy, I can’t find good numbers, but I’ve found somewhere that 300 million tonnes of carbon dioxide are produced each year by telephones and computers sending information to each other, although this number could be made lower with better technology. Another cost is the computers that run Google, Facebook, etc. There are various ways to save on energy for this – Facebook has recently opened a computer centre in the Arctic in Sweden, where the cold temperatures help cool down the computers and green hydroelectric power saves on carbon dioxide emissions.