We are about to break the 1.5°C limit, but could we get energy from this untapped source?

18 May 2023

Energy-hungry data centres already match the aviation industry in terms of their contribution to global warming. Could they be adapted to heat other buildings as standard, wonders Kunle Barker

An article in the Economist last year entitled, ‘Say goodbye to 1.5°C’ made for depressing reading. It claimed we had already lost one of the critical battles in the climate war. The article suggested that we stood little chance of restricting the world’s post-industrial temperature rise to 1.5°C. The only way I could process this news was to ignore it. I convinced myself we were still on target and that the messaging was helpful as it would chivvy us all into focusing on hitting the 1.5°C target.

Sadly, the UN Climate Report released in March confirmed the Economist s conclusion. And this week, scientists have said the 1.5°C threshold is likely to be broken over the next few years.

Even for an eternal optimist like myself, this is worrying and disappointing. After COP26, as I drove back to London in my EV, I felt hopeful and sure that the world would do what was needed to save the planet. Little did I know, as I triumphantly plugged my EV into a supercharger at Rugby services, it was already too late to save the 1.5-degree target.

I’ve written many columns about the critical role the built environment sector could play in averting a climate disaster. To a large extent, as an industry, our intent is clear: we question, campaign, and push each other to do better. However, something sinister may lurk underneath the surface of our hubris.

A recent BBC story about a swimming pool in Exeter that used a data centre as its heat source grabbed my attention. The story reminded me of a train journey I shared with fellow Manser Medal judge, Joe Jack Williams, in which he described using data centres as heat sources in heritage assets. The use of waste heat fascinated me, but the wider application struck me only while reading this BBC article. Could data centres be used as heat sources for homes, schools even entire developments?

Using excess heat is by no means a new idea. The Churchill Gardens estate, which started construction in 1946, used excess heat from Battersea Power Station. However, my research into the topic revealed a surprising fact about the impact on our environment of data centres: They are ‘sleeping giants’ when it comes to CO2 emissions.

Today, data centres account for 2 per cent of the world’s carbon footprint, similar to the aeronautical industry and only 1.6% less than the petrochemical industry. This is worrying enough, but there are predictions that by 2030 data centres will be responsible for more carbon emissions than both those industries combined.

When this sleeping giant awakens, our industry will shoulder the blame because we will have designed and built the structures these carbon goliaths inhabit.

An obvious solution would be to argue for restricting the growth of the data centre industry, but I believe it’s too late for this. In many ways, it has already happened. Our reliance on online payments, AI, cloud storage and so on is already integrated into our society’s fabric, and it is too late to go back.

But there could be a solution. Around 70 per cent of data centres’ energy is used for cooling, and this is set to climb to 80 per cent as machines used for AI and Blockchain operate more efficiently at lower temperatures. Data centres are usually designed on a large scale but perhaps they could be used to heat individual buildings if they were made smaller and supply and demand of this heat were efficiently balanced.

Designing smaller data centres would allow their integration into large-scale developments. Imagine a mini data centre located in each plot of a development, using the excess energy to heat space and water. This would represent a significant carbon saving for all involved.

This concept is not without its challenges. Although data centres produce heat constantly, it’s not very high quality, and even with the best form of heat exchange, you will struggle to get 30 degrees out of the system. But we as an industry must try, must ask ‘what if?’ and must push for rapid innovation. Unlike the adage, ‘the diet begins tomorrow’, it seems we may have already run out of tomorrows.

Kunle Barker is a property expert, journalist and broadcaster