At first glance, the most logical thing may be Netflix, since we are doing streaming of content directly without having to download it. However, we must take into account the entire intermediate process through which the information has to pass until it reaches our home, where that of a torrent is much faster and easier than it seems thanks to the protocol P2P.
The torrent is very efficient thanks to P2P
In the case of a torrent, the figure can vary greatly depending on the size of the file, its location, its popularity, its seeds, the average Internet speed of each user, etc. The marginal cost of a torrent is negligible if we consider that many others follow the same path and take advantage of economies of scale. In addition, computers are usually downloading and uploading several torrent at the same time, being even more efficient, and it depends on the energy mix of the country where the torrent is being downloaded or uploaded.
Let’s assume a consumption of 80 watts of a PC at rest downloading torrent, and a torrent with 100 seeds of a 4K movie of about 20 gigs that takes an hour to download. 10 of those computers are only torrenting, while 60 are using half for torrenting and half for other tasks. The remaining 30 are multitasking and the torrent only represents 10%.
Thus, the first 10 consume 800 watts (10 * 80), the next 60 2,400 watts (60 * 80 * 0.5), and the multitaskers are consuming something more with 120 watts on average, where the torrent is only 12 watts , staying at an additional 360 watts. Therefore, all the computers involved are consuming 3.56 kWh. Monitors or routers may have to be added to this consumption, but it is difficult to quantify it because they can be used for other tasks at the same time. Also, here we are assuming that only one torrent is being shared or downloaded, where it is normal that there are several on a computer. If we assume 10 torrents on each computer, consumption plummets to 356 Wh.
Netflix: the great efficiency of streaming at home
However, streaming platforms like Netflix need servers to store content and a wide content distribution network to reach homes. In this process, a study by the Shift Project estimates that one hour of Netflix consumption is equivalent to 6.1 kWh of electricity. According to this study, Netflix consumes about 370 TWh (Terawatt hours) per year, more than the 270 more or less that Spain consumes in a year.
However, figures from Netflix itself place this figure at 0.45 TWh, and even that of the study exceeds the estimated consumption of all data centers in the world with 198 TWh in 2018. The failure of the study was to overestimate many data , like assigning 24 Mbps to Netflix’s bitrate, where not everyone sees it in 4K, and even in that resolution that figure is not reached in a stable way. It also estimates the consumption of mobile phones, computers and TV too much. Thus, if we make a more realistic calculation of watching Netflix on a Smart TV, the consumption figure is more in 500 Wh, moving away from 6.1 kWh, as calculated by Carbonbrief. This would be equivalent to about 100 grams of CO2 in Spain for every hour according to the current mix.
In short, the efficiency of the torrent it depends on how many files you are sharing and downloading, where the more files you have at the same time, the more efficient it will be. Fiber optic connections also help reduce the ecological footprint by allowing more information to be transferred in less time, so we can turn off the computer after downloading the file in just a few minutes instead of having it turned on for the duration of the viewing.
It must also be taken into account that, over time, companies will have a lower ecological footprint, while the energy mix of the countries is using more and more renewable energy. Fortunately, currently consuming streaming multimedia content legally is very efficient; much more than going to a physical establishment by car to buy it as had to be done before the massive arrival of streaming platforms such as Netflix.