Interactive: How the UK transformed its electricity supply in just a decade

Category: Best visualization (small and large newsrooms)

Country/area: United Kingdom

Organisation: Carbon Brief

Organisation size: Small

Publication date: 6 Dec 2019

Credit: Simon Evans, Rosamund Pearce

Project description:

In June 2019, just as the UK became the first nation in the world to legally commit itself to a “net-zero” carbon emissions target by 2050, Carbon Brief published an interactive feature and accompanying map showing exactly how the UK had radically transformed its electricity supply in just a decade. The “scrolling narrative” article took more than a year to research, write, design and code, and brought together six datasets and 800,000 data points. It was the first time this dramatic transformation to the UK grid had ever been visualised in such detail before.

Impact reached:

The feature was a huge hit with Carbon Brief’s readers straight away and has since become one of the website’s most-read and most-shared articles since first launching in 2011. Civil servants even told Carbon Brief that the UK’s climate minister, Claire Perry, had shown the article in her own presentations and had “pinned a copy on her wall”.

Rachel Kye, the special representative of the UN Secretary-General for sustainable energy, tweeted a link to her followers, adding: “We talk about energy transitions and it is wonderful to be able to see one. Dr Simon Evans et al at Carbon Brief produced this. Fascinating. Superb. Important.”


Techniques/technologies used:

It took several months to identify the various databases holding the information required and then establish whether the data could be scraped, verified and “wrangled” into a single dataset. The 800,000 data points were carefully melded together using Python and then visualised into the scrolling narrative and map using D3 and Mapbox GL JS. These tools allow the map within the article to be interactive and, for example, let the user “journey through time” from the handful of coal-fired giants that dominated UK generation a decade ago up to the reality today which sees a much more decentralised grid with hundreds of windfarms and thousands of solar rooftops.

This data had never been amalgamated and presented in this way before. Therefore, great care was taken to check the underlying geo-tagged data by doing random samples of generating sources and comparing their location on Google Maps. During this long process, Carbon Brief found several errors in the primary datasets and notified their owners. The article contains a lengthy “Methodology” section to ensure full transparency and allow the reader to see exactly how the data was handled and then visualised.

What was the hardest part of this project?

In 2015, Carbon Brief had tried to “map” the UK’s power generation using Carto. While that provided a fascinating snapshot of the UK’s grid for that year, it could not show the rapid changes the grid had seen since the end of the previous decade. So it was important for the 2019 iteration to provide the reader with an interactive narrative – part in-depth feature, part data visualisation.

A lot of time was spent by the writer Simon Evans and multimedia journalist Rosamund Pearce working out how to make key moments and insights in the article “spark” a corresponding visualisation in the map as the reader scrolled down.

They also found that, due to the article’s length – almost 7,000 words – it was important for the reader to always know which year they were looking at as the map changed visually before their eyes. So a legend was introduced on the right-hand side of the page to highlight the year-by-year transition as the reader descended down through the article. Similarly, a stacked bar chart showing the year-on-year change in generation sources was also introduced on the left-hand side.

The article then concludes with a full-width interactive map of all the data to allow the reader the chance to explore it themselves in detail using the dashboard. This was added at quite a late stage when testers said they wanted to “play with the data” by themselves as well as be guided through it by Carbon Brief.

A sense of the thought process that Carbon Brief went through when designing this feature can be seen in this early rough sketch of how it might work…


What can others learn from this project?

Consulting and testing are two key lessons that Carbon Brief took away from this project. The two journalists who researched, wrote, designed and coded this feature consulted at each stage with the whole team (8 staff) to get as much feedback as possible, particularly to ensure “usability” and a “sense of journey”. Carbon Brief also asked a small handful of trusted contacts to “road-test” the interactive ahead of publication to further refine it.

It took a lot of time and resource to complete the project – Simon Evans had to teach himself Python along the way! – but it was a perfect example of how such an investment can pay off. An ambitious (yet daunting) vision was combined with the creativity and skills of the two journalists to produce one of Carbon Brief’s most influential showcase articles.

Project links: