Data centres are the foundation on which the Internet operates. Every time we perform an action online, data is generated and these hubs are responsible for processing it.

But the ever-increasing volume of data and the speed at which it’s handled means data centres are a significant contributor to the global carbon footprint. They account for up to 1-1.5% of global electricity consumption – which could rise to 8% if action isn’t taken – and contribute 1% of energy-related greenhouse gas emissions, according to the International Energy Agency.

Much of the energy waste data centres contribute comes from the cooling systems used to maintain optimal temperatures for IT equipment.

In 2010, data centres were handling 2 zettabytes of data, but that estimate has increased exponentially to 120 zettabytes per year. And it’s only going to keep increasing as the use of data-heavy technologies like AI becomes more widespread.

It’s not just the number and capacity but also the scale of data centres that continues to grow, with “hyperscale” locations that exceed 5,000 servers and 10,000 square feet.

Big tech has an important role to play, as leaders of the sector, in reducing global emissions. Thankfully, where data centres are concerned, there are actionable solutions, like redirecting the energy they produce so it can be reused rather than released into the atmosphere as carbon dioxide. With data centres producing such vast amounts of energy, it makes sense to harness this output as part of a circular energy model.

Here are four innovative projects using heat exchanger and other clean technologies to harvest and reuse waste data centre energy, or even power them.

In Rjukan, Norway a trout farm is being powered by renewable energy from data centres. This is the result of a partnership between Hima Seafood and Green Mountain Technology, which uses 100% renewable hydropower to fuel its data centres. The sustainable food company has been building what it says will become the world’s largest land-based trout farm, 800 metres from one of Green Mountain’s data centres. A pipe system will connect the two, delivering water heated via the data centre to the farm, reducing the carbon footprint of both operations.

On a smaller scale this leisure centre in Exmouth, United Kingdom, heats its swimming pool with energy produced by a small data centre. Startup Deep Green provides data centres to businesses using AI and machine learning technology, and channels the heat produced to the leisure centre. Seven more British leisure centres have signed up to use Deep Green’s renewable energy. The computers inside the household appliance-sized data centre heat oil, which is then pumped to a heat exchanger used by the leisure centre, significantly reducing its energy bills.

Technology company WindCORES has placed data centres inside wind turbines in Paderborn, Germany. As they use so much energy, powering data centres directly from the turbines instead of going through the national grid, made sense to WestfalenWIND, the parent company of WindCORES. The business estimates that wind power could be used to operate one-third of all data centres in Germany.

In Stockholm, Sweden, 10,000 apartments are receiving heat channelled from a data centre, thanks to a partnership between data centre operator DigiPlex and heating and cooling provider Stockholm Exergi. The Stockholm Data Parks initiative is aiming for 10% of the city’s heat to come from data centres, and for the Swedish capital to be fossil fuel-free by 2040. Sweden leads the Forum’s ETI rankings, followed by Denmark and Norway.

As part of its commitment to helping countries and organizations around the world transition to renewable energy, the World Economic Forum aims to accelerate the transition to a “fit for 2050” energy system, at its Annual Meeting in Davos, 15-19 January 2024. The programme will explore the newly emerging geography of critical minerals, the geopolitics of energy and the scaling of new energy technologies.