How much CO2 does Sustainable Digital Design emit?

3 mins read

As you know, we then set out to build a website that transferred less data and therefore emitted less CO2. According to calculations from the Lowww Directory, Sustainable Digital Design emits 0.357 grams of CO2e per visit on average — 43% less carbon than an average website. This month, we set out to track our progress and see exactly how much CO2 the Sustainable Digital Design platform has emitted since we launched in January 2022.

But first - why does a website emit carbon?

The internet is stored in data centres: huge warehouses full of servers, routers, and firewalls that require an enormous amount of energy to stay online. Every time we access something online, we are relying on these energy-hungry, carbon-spewing data centres to find and deliver the content. However, not all data centres are created equal, as they can be powered by a range of renewable and nonrenewable energy sources, such as wind, solar, and hydro.

The moving pieces

The amount of carbon emitted when you visit the SDD website depends on two factors:

1. What energy source is powering the data centre? The source of energy for your local data centre can be roughly estimated by the energy usage of the country you are accessing the content from. Electricity Map allows us to see historical and real-time carbon intensity data for each country.

2. How much data is required to load each of the web pages you access during your visit? Not every visit to the SDD website is the same, as each page has different data storage and download requirements, based on the size and number of pages you’re loading.

The calculation

First, we looked at the number of page visits per page and per country. For example, the homepage has been accessed 1,598 times in the Netherlands, while the quiz has been accessed 164 times from the United Kingdom. Then, we retrieve the average carbon intensity for each country since the SDD launch.

Carbon Intensity: How many grams of carbon dioxide have been emitted for each kilowatt per hour of energy, specified as gCO2e/kWh.

From here, by using the method of Sustainable Web Design by Tom Greenwood, we can apply a formula to calculate the amount of carbon emitted for each page of the website, based on where that page was accessed.

The findings
Total kgCO2e for the whole website between now — November 2022 — and our launch in January 2022: 4.43kgCO2e — or 4432.11gCO2e. Below, we’ve also broken down the emissions on our website by country and by page on the website.

What matters?

Carbon intensity matters when it comes to Sustainable Digital Design - a factor which is unfortunately out of our control. For example, if we look at the average visit to SDD, which requires 2.6MB of data, through the lens of a visitor from Sweden, the total cost would be 0.127gCO2e, where the carbon intensity is 27gCO2/kwh. However, if the exact same visit took place from the United States, it would cost 1.87gCo2e, based on their 398gCO2/kwh carbon intensity — an increase of 1,362% over Swedish visitor.

Lightening the load of our web pages is also important. As an example, if we are in the United States and load the Sustainable Digital Design homepage (0.81MB of data transfer) versus the a heavier homepage like the Unreal Engine landing page (10MB of data transfer), this would equate to 0.58gCO2e and 7.60gCO2e respectively — a 1210% increase in emissions to load the heavier webpage. Reducing the carbon load of interesting and interactive webpages is something that we are conscious of at Wonderland and SDD. We are actively searching for new techniques of lightening the load of interactive webpages and ethical methods of offsetting remaining emissions.

And what can we do about it?

1. Sharing resources and implementing coding strategies for building data-light websites.

2. Keeping an eye on developments in sustainable data centres — like Project Natick or JRC Best Practices.

In addition to this is the carbon impact of the physical hardware (laptops, phones, tablets, etc.) that are being used to load the SDD website. Our current method of calculation only considers the digital cost, i.e. the software and data transfer required for a website, and not the hardware which facilitates its access. The carbon impact from the creation of hardware was brought to our attention recently and is a topic that we are actively investigating at SDD. We will share our findings on the matter in an upcoming blog post here on SDD- so stay tuned!