The future of digital government is green: on the web sustainability guidelines

A presentation at User Needs First Conference 2025 in April 2025 in Amsterdam, Netherlands by Hidde de Vries

Hello, my name is Hidde, and I want to welcome you to this session called “The Future of Digital Governments Is Green.” Bold statement, I know, but we’ll get into it, and I hope to give you some practical advice on making your services more green and understanding what that’s all about.

To briefly introduce myself, I’m a web developer turned accessibility specialist, and I blog as well. I have a website called hidde.blog, feel free to like and subscribe.
Note that I am here today in a personal capacity, so I don’t represent any of my clients or employers.

I’m also not alone in worrying about the climate crisis.
The climate crisis is a huge thing that kind of lingers above us. I try to do a few things.

I eat vegetables instead of meat; I line-dry my clothes; I try to hang on to devices as long as I can to get as much longevity out of them as I can. I even own some solar panels.

I’ve got a little forest online through a service called Ecologi that allows you to pay monthly or yearly. They’ll plant trees for you on your behalf and occasionally do other stuff too, because they realise that planting trees alone isn’t actually going to work, so we need to do more things.

I do these things, but if you talk to me and find out more about how my life is structured, you’ll find out that I am somewhat hypocritical.
In fact, I think we’re all somewhat hypocritical, all in different ways, and that’s okay, it shouldn’t stop us or mean we simply do nothing. We can embrace our inner hypocricy and still…
(Pictured: cover of Ariana Grande’s single “Yes, And?”)

make the world greener faster at work.
If we work on digital government services, that is likely to be aligned with some higher-level goals. Actually, some of the highest level ones.

Specifically the 2015 Paris Agreement if you are in one of the 195 countries that signed that agreement or if you’re in the European Union. The European Commission’s Digital Strategy 2030 has sustainability as one of its focuses.

Now, I’ve been interested in sustainability for a while, but I recently got more active when I got the chance to join the Web Sustainability Interest group at the W3C, the World Wide Web Consortium.
This group makes a new set of guidelines that I’ll talk about in a minute, the Web Sustainability Guidelines.
And since I got involved with that about four months ago, that’s why I’m showing you this social media post, I excitedly joined and I realised now that in those last four months I’ve learned a bunch of things about sustainability and how to do things. So I wanted to come and share those with you.
So, to be clear, this is not a field that I’ve been in for decades, but I hope to have some valuable advice for anyone who may be as new to this as I am.

I always thought that the major thing that affected the climate was us flying in airplanes. And I feel bad about the airplanes that I use.

But that was until I found out that IT emissions are actually higher, on a global scale, than aviation emissions.
And when I found out, I was like, oh no, that’s the industry I’m in. I’m in IT. And now I’m also contributing through that.

If the internet was a country, research has shown, then it would be the 13th largest emitter between Mexico and Brazil.
(Source: Sustainable Web Manifesto, based on CO2 emissions in Our World in Data vs IT emissions data from Green Web Foundation)
What can we do about this?

Unfortunately, there’s no magic button that we can press as Hannah Smith of the Green Web Foundation explained in her 2022 talk at Pixel Pioneers about sustainable web design.
It’s a great talk. I recommend you watch it.
But there are some buttons now that we can press and some of those now, also thanks to Hannah, are encompassed in the web sustainability guidelines.

There are a set of guidelines that are somewhat inspired by WCAG, the Web Content Accessibility Guidelines, that many here are probably familiar with. It is the set of guidelines that underlies a lot of accessibility legislation worldwide.
The Web Sustainability Guidelines provide guidance on how to make web stuff more sustainable.

It’s got six principles, it’s got 92 guidelines, it’s got 253 success criteria and then those are all made by over 100 contributors.

They’re divided over user experience design, web development, hosting infrastructure and systems and business strategy and product management.
So those four areas are kind of divided among those and there’s something in there for all of us.

They are tagged with inmpact: low impact, for quick wins, medium impact, meaning noticeable sustainable impact, and high impact, significant long-term benefits.
In terms of effrot, some thing sare low effort, minimal implementation, some medium effort, some changes are needed, and some high effort, heavy refactoring will be needed.

For all of those goes that progress is more important than perfection. We want to make progress and a lot of this progress is meaningful.
It is going to make a change.

What are the things that make up the climate impact of IT? It’s three things.
data centers. So emissions of server hardware, of making the hardware, but also of running it, it costs electricity to power data centers.
networks. So basically downloading stuff and uploading stuff. If you’re live streaming on YouTube or that’s upload. If you go to a website, you’re going to receive the website on your device.
consumer devices, like the impact of manufacturing laptops, phones, tablets, and anything that accesses the web.

Quiz time!
When does a phone cause most of its carbon emission? There’s three answers.
a. Before it’s in your hand, during production. b. during usage. c. after you own it, so when you recycle it.
The answer was A. It’s before it is in your hands.

You can find that in environmental reports that companies like Apple publish. Like this one is about the iPhone 14 Pro.

And in this life cycle carbon emission statement, they say that 81% of the carbon emissions within the life cycle of an iPhone 14 Pro are during production.

And then 15% are during usage.
It makes a lot of difference when we buy a phone or decide to wait another year for the next phone.
That is a way we can personally reduce carbon emissions.

When we’re talking about carbon emissions, sometimes we’re talking about eliminating them. And sometimes we’re talking about offsetting them.
It’s important to know the difference because we need to know what works best.
Elimination means that you don’t have the emission in the first place.
Offsetting means that you have the emission, but you compensate with something, like by planting trees or things like that.

Some things we cannot eliminate and we’ll need to offset them. But elimination is our main focus here.
We’ve got to reduce a lot of what we do.
Now, that sounds maybe like a really difficult job that we have ahead of us. But there’s a lot that maybe isn’t so hard to do.

I have five things for you.
Some are a bit bigger than others, but we’re just going to walk through them. If they’re not things you can do in your role, feel free to tell your colleagues you can.
We’ll start with 1: Make smaller web pages.

Make websites smaller, because the median website size is growing and growing.
From the HTTP archive, we know that in 2011, 467 KB was the median website size, while today, in 2025, it is 2678 kilobytes.
That is more than five times the size.
We need to make them smaller, and it can even make a lot of difference to shave mere kilobytes off, especially on code that is used in a lot of places.

Danny van Kooten makes plugins for WordPress that are used on millions of websites.
He calculated that if he would reduce one kilobyte of a plugin that he distributes, and that code gets used on two million websites, that’s actually going to reduce CO2 emissions by 2950 kilograms per month.

That’s like five flights or 118 kilograms of beef, as he explains in his blog post.
Now, I should note that some of these numbers have since been disputed; the post is 5 years old and it’s now generally agreed the relationship between kilobytes transferred and emissions is more complex.
But it’s interesting to think about our work like that.
If we write code that is going to be used in many different places or going to be loaded by many of the citizens that use our services, we can really make a difference.
There’s really two sides to this coin.
On the one hand, we can feel really sad about the huge carbon impact that we have.
On the other hand, it feels like an opportunity. There are opportunities to make a huge difference by shaving off kilobytes.

If you want to know how you’re doing, and you might want to know by now, right? I’ve been talking to you for 10 minutes.
I suggest we all go to a website called websitecarbon.com.
Feel free to use your laptop or your phone and type in the URL of whatever thing you are working on or your team is responsible for.
And you’ll get information about where you fall on a scale.
It’s a scale from A+ all the way to F.
And the scale basically tells you how green your website is based on the grams of CO2 emissions equivalent per page view.

It will give you nice stats as well, like how many trees are needed to absorb the carbon that your webpage emits. How far could you have driven an electric car instead?

A quick note on the numbers, though.
The numbers are always to be taken with a pinch of salt.
Because some stuff is easier to measure, like transferred data, number of HTTP requests and DOM size.
And some other stuff is harder to measure and sometimes missed, like calculations in JavaScript, the usage of the CPU and GPUs, memory, real user journeys, all these kinds of things.
So you should always realize that some of your data is going to be measured and other data is going to be estimated.

As Fershad Irani explained in his talk “The nuance of quantifying digital carbon emissions” at Green I/O in Singapore… you need to know what you’re doing. Are you estimating or are you measuring?
And you can do both.
They’re both valuable things to do in themselves.

Something that can help you measure is the Sustainable Web Design Model, SWDM.
It’s got a formula to calculate the average emissions per page view.
I’m not going to explain the formula. I’m not a mathematician, so I probably wouldn’t do a very good job of explaining it.
But basically, into the formula go two data points.
One is how much data is being transferred. And the other is what was the carbon intensity.
Carbon intensity is basically about how much CO2 is emitted per kilowatt hour. How much energy you’re using might not change. But how green that energy is, is likely to change because of how much green energy is available.
Some green energy is only available when it’s sunny, or when there’s a lot of wind. At times where there’s no sun and no wind, the carbon intensity is a lot higher.
Because, you’d probably need to burn coal. Or wherever the energy comes from where your data center is located.

There’s also something called CO2.js, made by Chris Adams at the Green Web Foundation.
He made this JavaScript library, that allows developers to estimate carbon emissions that are produced by transferring data.
It also lets them to get different forms of grid intensity data, like annual average and marginal data by country as well. And you can check if a website uses a known green web host.

So this can help you with 3.1 of the web sustainability guidelines. Which reads, “set goals based on potential impact considerations”.
You want to be setting goals. As the UK government did.

They just published a report on that, the Green and Government Commitments ICT annual report, for the last two years.
It shows they had a reduction of 9% of CO2 equivalent emissions.
link
Be like them, and keep metrics so you know what’s going well!

A practical tip: minimize images and videos.
I’ll show you a Dutch government website of a Dutch city. I won’t say which one it is, I don’t want to pick on anyone specifically.

This specific website is 1.2 megabytes.

It has a hero image image that is 367 kilobytes. That’s almost a third of the weight of this whole page.
If you would want to reduce this page’s emissions by like 30%, you would simply need to take away the photo and replace it by a color.
That’s amazing to me. It’s like the one kilobyte reduction. It can make so much of a difference to have that image or not have the image.
And we currently look at it with a lens of maybe marketing or visual design. It looks nice if there is an image. But if we look at it through a sustainability lens, maybe we should not have the image.
Through a user lens… I’m not sure if they’d mind.
We can also reduce the size of the image quite well This doesn’t have to be that many kilobytes. It could be a third of that quite easily.
There’s a great talk by Emily Trotter from Nomensa on the design side of web sustainability.

She explains “detail is data” when it comes to images.
So she recommends to have less detail in your images.

She goes on to explain a couple of things. Like you can blur stuff, the whole thing or parts of it. You can remove some of the background. You can simplify the image. And you can also use image compression.
If you put a lot of compression on your image, it’s going to make the image look ugly. But there is a bit of compression that you can do and that almost impossible to notice.
If you do want to have images to really optimize them well.

What you can also do is make sure they don’t load.
If there’s web images in your footer for instance, even if you can’t see them, the browser is going to load them. Unless you add lazyload=lazy:
<img src="" alt="" lazyload="lazy" />

What you should also do is reduce JavaScript and CSS. It can make a lot of difference.

If you’re interested in seeing a nice little donut chart of your JavaScript and CSS, specially if you’re not a web developer with dev tools, check out ecograder.com.

As I got for two Dutch cities. I’m not going to name which one’s which, but they are both similar size cities.
That have the exact same goals that they’ve been given from the central government. They need to have the same stuff on their website.
One of them is 1.32 megabytes. The other is 2.72 megabytes. That’s more than double.

The CSS of Dutch city 2 is 1.3 times more than the CSS of city 1. And the script is 1.8 times more.
One of them could be optimising more! And to be fair, both could. I’m maybe showing my age here… but when I started wbe development, websites were way under a megabyte, much much smaller.

Related WSG guidelines: 4.3 says “Compress files where it is beneficial”.

3.4 recommends “treeshaking” to remove unnecessary code.

3.16 says to use the right dependencies, and to maintain them. Many, many codebases have vast amounts of packages that they don’t actually need or.

3.21 recommends to take advantage of native features and functionality.

Because I couldn’t help myself, I looked up what Dutch city 2’s website looked like 20 years ago. It was a slightly less beautiful site, but it only weighed 248 kB. It’s grown 10 times.

And that’s not because of the spacer.gif that I found. A 1x1px image that we used to use for layouts… oh, the good times.

It seems like the assignment had been to make the logo bigger. And sorry I will need to disclose the city now, to show you. Again, this is not to pick on this particular team… I used to work there, great people.
But in 2005, their logo was a gif file of 4.31 kB. Today, it’s a 173.53 kB jpg file. This is an opportunity for more optimisation.

A case study I liked reading was from the UK government team that worked on the GOV.UK One Login service..

And one thing I want to end this section with, recommended in WSG 5.2, is to assign a sustainability representative. And then to give them power, resources, budget and time, all the good things.
Because a lot of what I mentioned in this section isn’t rocket science, necessarily, but it is easy to miss file sizes, if no one is responsible for monitoring.
I can’t remember working as a web developer and being told you know what we want a homepage to be under 200 kilobytes or something. It’s often not a consideration.
I hope by know you all realise the the bigger the pages are, the more data is being transferred, the more energy that costs, the more climate impact.
So: reduce, make everything smaller.

Tip two: Support older devices.

A fun fact from Gary McGovern’s Worldwide Waste. He said that reading an e-book instead of physical books is only going to be more sustainable once you’ve read 100 books on the device.
You need to read a lot for it to be worthwhile and use the devices really long. This is important because e-waste is a large part of the sustainability impact of our services.

And the way that we impact it most often is that we could be the reason that users upgrade.
And we want to avoid that. Don’t be the reason that users upgrade.

During covid lockdowns, there was this Dutch government app that you could use to show a QR code to prove you had been vaccinated.
That used the “Exposure Notification API” developed by Apple and Google and that was available from specific versions of Android and iOS.
Potentially a factor that could leave people behind. And it did, newspapers talked about a million Dutch people left behind, and after pressure, Apple updated it such that it would work for iOS version 12 instead of version 13. That meant devices over 10 years old could still use it.
What was great, too, is that a paper fallback existed. So even people with no smartphone whatsoever could get their QR codes.

This is an example of what web developers call ‘progressive enhancement’. You make functionality available in simpler ways before adding more complex ways.

The starting point for all becomes simpler version (eg content).

Then when JavaScript is loaded, a potentially fancier version is loaded, but the initial version works without all the fanciness, so that older devices are served.

You can apply the same to different kinds of functionality.
Some devices have GPS functionality, in your application, you can use a user’s location to do stuff in your UI, and if you do that, users will be prompted by their browser first, to ask if they want to allow location info to be shared with the website.

Your application won’t “know” if the location is available, so you want to make a basic version first, that works without knowing precise location. Maybe the user denied the request, or they are on a phone that doesn’t have a GPS.
In that simpler version, you can ask the user to type in their departure station. This simple version is a good starting point for all.

If you do have the location data to use in your application, hyou can make it fancier.
For instance, you can say “It looks like you departing from London, UK.” and present a button just to find London times. Silly example, but you could do anything you can imagine with location data, the point is, that location-aware version is built on top of a simpler version, that works for more people, including the ones with location turned off.

Tip 3: choose green hosting.

That’s 4.1 in WSG, “Choose a sustainable hosting provider”.

The cloud may be a fantastic metaphor, but what many forget is that in fact…

…the cloud is real.

It’s real and it’s basically lots of big machines in a warm room. And they use a lot of energy.

To minimise emissions, you can switch to a green or greener provider.

Find out what the current state of your application is on thegreenwebfoundation.org.

GWF lists 329 verified green hosting providers in 34 countries. Ask sales reps how theirs compares. Especially if you’re in procurement of have friends who are. It makes a difference.

The major cloud providers all tout big ambitions around sustainability on their marketing pages.
And many do have a lot of things they do to make their footprint smaller, a lot of efficiecny gains are added, it makes their systems greener and also cheaper to operate.

Factors that affect the sustainability of a host include: renewable energy, equipment longevity and waste recycling (From: WSG, 4.1).

Another thing you can do is to consider timing.

We’ll return to what we talked about earlier: carbon intensity. It is basically how clean energy is at a given time, in a given place. This varies, for instance the intensity is lower if the sun is shining and it is windy. Data centres next to the solar or wind parks can offer leverage greener at that time.
How can we use that? For timing?

Well, let’s say your team page has a 4K high definition video of your team. It’s like a documentary style thing, 30 minutes long. You can imagine that visitors watching all this would lead to relatively large carbon emissions, for a team page.

If you know carbon intensity is high, you could serve a lighter version. Just photos of the team. members.

If you know carbon intensity is extremely high, you could serve a very light version, just their names. Maybe phone numbers. Text is very cheap in terms of emissions.
Adapting your service to carbon intensity is also called “carbon aware software”.

A shop called organicbasics have lots of photography in their online stores. Lots of kilobytes.

But they developed a low carbon version that has vectors instead of photographs. Pretty handy! This is a screenshot of it, I wasn’t able to access this version myself as the site had a server error when I checked, but they described it in a blog post.

Tip 4: only add necessary features. Avoid unnecessary features.

And especially: avoid technology that has a relatively large energy use. I think we probably know examples.

It’s the elephant in the room…

Artificial Intelligence.

The International Energy Agency concluded in their recent Electricity 2024 analysis that energy use may quadruple in the next few years, largely due to data centres, which they specifically correlate with data needs of AI and crypto.

The Guardian reported on their messaging and wrote “Al has the potential to reverse all the gains made in recent years in advanced economies to reduce their energy use, mainly through efficiencies.”.

A paper on efficiency gains and “rebound effects” shows some of the good and bad of AI and sustainability: on the one hand there is the enormous impact of servers right now, on the other there are some promising results of AI actually helping to reduce energy use.
They conclude, wisely, that we “simply cannot hope for the best outcome”. That’s not good enough.

It’s clear that adding AI to a feature means adding magnitudes more emissions, period. Not just a little bit, but actual magnitudes more.
We need to consider impact, when we consider adding AI to our services. Especially for those cases where old school, perhaps more boring technologies, will do the job just fine. There are many of those.
In many, many cases, we don’t actually need to add AI. It’s being pushed upon people who didn’t ask for it, and often without very good reason.

Wim Vanderbauwhede estimated that replacing all search engines with chatbots would lead to 60x more emissions if it was a GPT-3 style model and 200x times more if it was a GPT-4 style model (one diference being that the latter model is larger).
blog post

Another sustainability aspect of AI is that training LLMs can involve unhumman strain on websites.
Just the last couple of weeks, a number of system adminsistrators went to their blogs to write about how crawlers for AI affected the load on their server.

Xe Iaso from Canada wrote that Amazon’s AI crawler makes their git server unstable.

Dennis Schubert from Germany said, I quote, “it looks like my server is doing 70% of all its work for these fucking LLM training bots that don’t to anything except for crawling the fucking internet over and over again. quests.”

“Please stop externalizing your costs directly into my face”, said Drew DeVault who works for SourceHut.

And then Wikimedia, the people behind my favourite website, Wikipedia, just posted to say that traffic for images grew by 50%, likely due to AI crawlers.

One thing to more mindfully implement energy heavy features, is to hide them behind a click. Or to communicate what the impact is to users.

That’s WSG 5.4: communicate the ecological impact of user choices.

For instance, if a user uses a search engine that has a chatbot, you could let them choose between chatting or manually browsing and indicate which choice is greener.

Ultimately, we want to spend more time on removing features than on adding them, and I realise that is a difficult conversation for product managers, a hard sell to the client if you’re going to “give” them less. But you know, it’s more, you give them a more sustainable service.

Tip 5: weed out all the things.

Reduce requests.

For instance by, instead of requesting new data from the server, serving old data, from browser cache or a Service Worker. Leverage CDNs.

You could hide a feature that needs more data behind a click.

Many contact pages have a map, while users might just want to copy paste your addresss. Would you be able to hide the map behind a click?

You also want to duplicate code less…

3.5 of the WSG says redundancy and duplication in code should be avoid.

Over 45% of requests on the web are third party requests. Check if they are green too.

You can do that with this tool by Fershad Irani: https://aremythirdpartiesgreen.com

So, in summary:
Make smaller web pages
Support older devices
Choose green hosting
Design services that last
Weed all the things

Thank you!

Tools:
Ecograder, https://ecograder.com/.
Are My Third Parties Green, https://aremythirdpartiesgreen.com/.
Website Carbon, https://www.websitecarbon.com/.

Books:
Gerry McGovern, World Wide Waste (2020).
Anne Currie, Sarah Hsu, Sara Bergman, Building Green Software (2024).
Tom Greenwood, Sustainable Web Design (2021).
Tim Frick, Designing for Sustainability (2016).

Technical specifications:
Software Carbon Intensity (SCI) Specification. https:// sci.greensoftware.foundation/.
Digital Services Ecodesign ISO standard. https://www.iso.org/standard/ 86105.html Web Sustainability Guidelines. https://w3c.github.io/sustainableweb-wsg/

Hidde de Vries
@hdv

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Digital transformation has an elephant in the room: the energy use of digital services can be enormous. In 2024, the World Bank estimated the internet to account for 1-4% of global greenhouse emissions, similar to aviation. The good news is: there are opportunities to improve. From user centered design to web development and infrastructure: they all impact how government digital services use energy. In this talk, we’ll look at best practices from the W3C’s new Web Sustainability Guidelines.

Resources

The following resources were mentioned during the presentation or are useful additional information.

European Commission: Europe’s Digital Decade: digital targets for 2030
Sustainable Web Manifesto
Hannah Smith at Pixel Pioneers 2022
Web Sustainability Guidelines (Draft)
iPhone 14 Product Environmental Report
Danny van Kooten’s blog post “CO2 emissions on the web”

From which I quoted: “Shaving off a single kilobyte in a file that is being loaded on 2 million websites reduces CO2 emissions by an estimated 2950 kg per month.”
Info on Website Carbon’s rating system
The Sustainable Web Design Model

Info on how emissions are calculated.
Fershad Irani’s talk “The Nuance of Quantifying Digital Carbon Emissions”
CO2.js, by Fershad Irani
Corporate report: Greening government ICT: annual report 2023 to 2024

Annual report of the progress made in 2023 to 2024 towards making digital services and technologies in government more sustainable.
ecograder.com: get a donut chart of how your site performs
Blog post: The web is fast by default: let’s keep it fast
Squoosh.app: simple no ads tool to make any images much smaller
js;dr = JavaScript required; Didn’t Read.

From which I got the quote: “In 10 years nothing you built today that depends on JS for the content will be available, visible, or archived anywhere on the web.””
The Green Web Foundation: check if your host is green

They have metrics for what “green” means, provide data and a tool to look up your domain right now.
Electricity 2024, from the International Energy Agency

from which I got the chart that showed energy usage could double.
The Guardian: “Energy demands from AI datacentres to quadruple by 2030, says report”

From which I got the quote that AI has the potential to reserve all the gains made in recent years.
Paper: “From Efficiency Gains to Rebound Effects: The Problem of Jevons’ Paradox in AI’s Polarized Environmental Debat”

By Alexandra Sasha Luccioni, Emma Strubell and Kate Crawford.

Compares the “AI to destroy all” camp with the “AI will save all” camp, and concludes, among other things, that we ‘cannot simply hope for the best outcome’.
Emissions from ChatGPT are much higher than from conventional search
AI crawlers vs sysadmins: “Amazon’s AI crawler is making my git server unstable”
AI crawlers vs sysadmins: “Looks my server is doing 70% of all its work for LLM training bots”

full quote: “it looks like my server is doing 70% of all its work for these fucking LLM training bots that don’t to anything except for crawling the fucking internet over and over again.“
AI crawlers vs sysadmins: “Please stop externalizing your costs directly into my face”
AI crawlers vs sysadmins: 50% growth on Wikimedia

Full quote: “bandwidth used for downloading multimedia content [grew] by 50%. This increase is not coming from human readers, but largely from automated programs that scrape [Wikimedia] to feed images to AI models.”
Are my third parties green?
Green Software Practitioner Learning Guide
The Linux Foundation’s free Green Software for Practitioners guide

comes with an exam you can do at the end
World Bank: Measuring the Emissions & Energy Footprint of the ICT Sector (PDF)