Entering a phrase into the world's most popular search engine and waiting for the results uses about 0.0003 kWh, according to data from Google itself. Two hundred searches therefore adds up to roughly the same amount of energy needed to iron a shirt. And the total monthly search queries of an average user is enough to supply a 60-watt light bulb with electricity for at least three hours.
Doesn't sound like a lot? Not at an individual level. But according to the most commonly quoted statistics, Google alone receives around 3.8 million search queries a minute. All of those add up to an energy consumption that Google itself put at 5.7 terawatt hours - for 2019 alone. The annual energy consumption of the city of San Francisco is around the same.

But online searches are by no means the core of the problem: the new power guzzler is in fact music and video streaming. 80 percent of all data flows through the net in the form of moving images. Online videos - available on different platforms and viewed without being downloaded - account for almost 60 percent of global data transfer. Transmitting these moving images requires huge amounts of data. And the higher the resolution, the more data is sent and received.
The average CO2 consumption of streamed online video is more than 300 million tons per year (based on measurements taken in 2018). This is the same as what Spain emits in a year. Another comparison out of interest: streaming ten hours of film in HD requires more bits and bytes than all of the articles in the English Internet encyclopedia Wikipedia put together.

Music streaming also comes off quite badly: a new study by the universities of Glasgow and Oslo shows that music streaming services emitted around 200 to 350 million kilograms of greenhouse gas in 2015 and 2016. That means that using streaming services such as Spotify or Apple Music is in many cases more harmful to the climate than the production (and subsequent disposal) of CDs or records.

Cloud computing is another major power guzzler. This is where data is no longer stored locally on a computer or smartphone, but on servers that can be located anywhere in the world, meaning it can be accessed anytime and anywhere. Checking your email via gmail and backing up your photos to the cloud are just two examples of these kind of services.

Most cryptocurrencies also consume large amounts of energy. One example of this is Bitcoin, probably the best-known digital currency. According to calculations by the Bitcoin Energy Consumption Index, a single Bitcoin transaction consumes around 819 kWh. The same amount of energy could operate a 150-watt refrigerator for about eight months. And in a 2018 study, the Technical University of Munich determined that the entire Bitcoin system produces around 22 megatons of carbon dioxide per year, the same as the CO2 footprint of cities such as Hamburg, Vienna or Las Vegas.
Our digital energy consumption isn't only determined by what we do, but also how we do it; the software we use also has a big impact. For example, a less efficient word processor needs four times as much energy to process the same document as an efficient one. While at the same time, software updates often cause computers or smartphones to slow down or stop working, forcing consumers to buy new hardware.


And in the future, digitalisation's growing demand for electricity will certainly also be driven by an increase in smart technologies, such as those we are increasingly using at home, in the IoT sector, in industry and in our increasingly digitalized cities.

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