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Energy explained

Making sense of the carbon impact of digital activities

This pandemic means many of us are using our devices and the internet more. You've probably seen people talking on social media about how sending emails, having your camera on for video calls and watching telly has a carbon impact. This is true. Changing our digital habits can help make small carbon savings. And it can make a difference when we all do it. But we also think it's important to understand how that compares to the impact of other daily activities.

Watching Bridgerton in standard definition rather than HD might save CO2, but it's a small saving compared to other daily things, like driving. So we’ve worked out the carbon footprint of some activities we’re probably doing more of at home. We hope this helps give you a relative sense of the impact your daily routine has on the planet. 

Using your video camera for an hour produces the same CO2 as eating a cheese sandwich

People have been debating the impact of video calls - especially the difference between having the camera on and off. With many of us working from home, and catching up with loved ones via screens instead of in person, we wanted to unpick the impact.

Doing one hour of video call produces about 1kg of CO2e (or ‘carbon dioxide equivalent’). That’s about the same carbon impact as eating a cheese sandwich. To help put that into context, you’d need to do 290 hours (or 12 days) of video calls to have the same impact as buying the laptop you’re calling on in the first place. 

Streaming in high resolution produces 8 times more CO2 (than an already small number)

The carbon impact of streaming is relatively small. You’d need to stream about 16 hours of telly to have the same carbon impact as driving one mile in a petrol car. Of course, we can reduce that impact by using smaller devices and watching in standard resolution. 

Watching in high resolution creates up to 8 times more carbon emissions. But it’s 8 times bigger than an already small number. You’d save about 0.252 kg of CO2e by watching a two-hour movie in standard, rather than high, definition. That’s about the same carbon saving as forgoing your egg for breakfast. (Note, that’s a singular egg).

skating egg loop
Watching a two-hour movie in standard, rather than high, definition saves the same amount of CO2 as forgoing your egg for breakfast

Sending emails isn’t as bad as the headlines suggest

You might have seen some pretty alarming headlines suggesting emails damage the environment. And that cutting back on e-mails could lead to carbon savings of 16,000 tonnes a year. These headlines are based on analysis that’s 10 years old, which estimates that sending one email produces 1g of CO2e. 

The reality is a lot of that CO2 will still be produced whether or not the email is sent. For example, your laptop and Wi-Fi will still be on. So the real figure is much lower. We recently calculated the carbon impact of sending emails to our members. We estimate the figure is around 10 times lower than the headlines suggest. To give you a sense of scale, you’d need to send more than 3,200 emails to have the same carbon impact as driving a petrol car for one mile.

Making a cuppa has a relatively small impact (if you only fill up the amount you need)

If you’re anything like us, you’re probably making a lot more tea at home. Boiling the kettle produces around 0.02 kg CO2e. This is a small number, and it varies slightly how much you fill the kettle up. (Here’s your friendly reminder to only fill up the amount you need to help save on bills and CO2).

You’d need to make 4,500 cups of tea to have the same carbon impact as buying a new phone.

Graph of digitaland lockdown activities CO2
Data: Bulb’s own calculations, based on various sources.

Putting these numbers into perspective can help you understand what really makes a difference

Changing your digital habits can help you make small carbon savings. And when we all do it, it can make a difference. But it's important to put that into perspective, and focus on the things that have the most impact. 

The internet contributes about 2% to global emissions. Some predict this could rise to 23% by 2030. Technology will get more efficient over time, which will help reduce carbon impact. But it’s likely these efficiency gains might not be able to keep up with growing demand for the internet. That’s where renewables come in. Switching power to renewable sources is the best way to reduce the carbon impact of our digital (and other) habits.

It might be helpful to remember that total UK emissions are around 400 million tonnes a year. And each person in the UK produces around 13 tonnes of CO2 a year from just living. So, next time you see something online that says you can save 0.00004 grams of CO2 by not eating marmite toast every morning*, you can compare that to those numbers to try to make sense of how big a difference it might make.

And don’t forget you can work out how your daily lifestyle affects your carbon footprint with our Carbon calculator.

*Not real maths - we wouldn’t dream of telling you to stop eating marmite.