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Council website emissions

You may not think of websites as sources of carbon emissions but they are. Data centres, transmission networks, and the devices we use to access them all use electricity which, in turn, produces carbon emissions. When your website has lots of visitors that can easily add up.

The internet consumes a lot of electricity. 416.2 TWh per year.

According to Wholegrain Digital, the average web page creates 1.76g of CO2 per page view. If that average page gets 10,000 views a month, that works out as 211kg of CO2 per year. That's equivalent to boiling water for over 10,000 cups of tea! And that's the average website. Websites can produce many times more than this and the web has been getting worse year-on-year.

We work with several local authorities. Many of them have also declared a climate emergency and committed to reducing their carbon emissions. An overlooked part of their emissions will be their websites where people go to pay their council tax, check their bin collection days, and a use a range of other services local councils provide.

As well as the environmental impact of large websites, there is also the impact on visitors with limited data plans. A single visit to a 30MB homepage (12g of CO2) would use an entire day's worth of data for someone on a 1GB monthly plan. Accessing local government shouldn't put that much of a burden on the poorest in a community.

How well are UK local authorities doing? Over recent months we've used the fantastic Website Carbon Calculator (created by Wholegrain Digital) to assess how much CO2 UK council homepages generate for every visit. The news is good. On average, local councils generate 1.15g of CO2 per visit - that makes them better than the rest of the web. But there is also a huge amount of variation with some producing many times more than that. Here are the 10 councils with the lowest and highest emissions but you can also check out the full list.

Top 10 lowest emissions

CouncilCO2 / grams
Scottish Borders Council0.11
Kent County Council0.13
Bury Metropolitan Borough Council0.15
Eden District Council0.15
Buckinghamshire County Council0.16
East Sussex County Council0.16
Rossendale Borough Council0.16
Carmarthenshire County Council0.17
Luton Borough Council0.17
Torbay Council0.17

Top 10 highest emissions

CouncilCO2 / grams
Nottingham City Council11.38
Sheffield City Region8.54
Redcar and Cleveland Council7.51
Warwickshire County Council7.43
Watford Borough Council6.70
West of England6.51
Fareham Borough Council5.87
Cardiff Council5.33
London Borough of Newham5.30
Southend-on-Sea Borough Council5.26

Doing better

If you are a local authority producing lots of emissions, don't despair! The worst offenders usually have some very easy things they can do to dramatically reduce their CO2 emissions that most likely don't need the IT department to get involved.

The first thing to do is check the file sizes of images you use. Often a homepage will have a large header image, images in a carousel, or images associated with news items. These are most likely added through a content management system which doesn't optimise the image. You can use your web browsers' Developer Tools to check the file sizes of images used on webpages and look for the biggest. Make sure that the pixel-size of the images is appropriate for your webpage and reduce them where they are far too big. The next step would be to use useful tools such as and to optimise the images further.

One UK local authority website had two 11MB images on their front page. By both shrinking the image a bit and using tinyjpg it was possible to reduce this by a factor of nearly 30. So next time, before you add a nice photo straight from a digital camera, stop and spend a minute optimising the image first. A great example is Hambleton Council. Back in March, they were able to reduce their front page from 20MB (11g of CO2 emissions) to 2.6MB (1g of CO2 emissions) just by doing some quick image optimisation. They said they'd make sure to optimise images in the future. If they get 10,000 visits a month that is about 1.2 tonnes of CO2 per year or the same as boiling water for 57,000 cups of tea. Can we get more councils to follow their lead?

Optimising images is often the biggest win for a website and usually doesn't need the IT department to get involved. If your site is still large, you may want to ask the web team to look at the amount of CSS and Javascript included on your pages. Do large Javascript frameworks need to be included on every page if it could be done in a few lines of vanilla Javascript? Last year Danny van Kooten wrote about saving 59kg of CO2 per month by removing a single 20kB Javascript dependency from his WordPress plugin. Whilst most council websites will be getting less traffic than he does, I regularly see megabytes of Javascript and CSS dumped on pages that could be reduced with a little thought.

Other things that factor into your website emissions are how and where your servers are powered. Are you web servers close to the majority of your visitors or are they on the other side of the planet? The further they are away the more internet infrastructure is likely needed each time someone visits. Is your server powered by green energy? That can be hard to know as it isn't often mentioned by hosting companies. If you host your own pages that is something you'll have more control over and may already be on top of. If you use an external host, you could try asking them what their plans are for using renewable energy sources.

You can find the full list of council website emissions on our microsite. You'll also find individual council breakdowns that list specific things each council can do to improve.

As well as the pointers above, checkout these 17 tips from Wholegrain Digital, our tips from #PlanetData2, and our advice on some practical steps for local authorities. Let's make the web greener and faster.