Cement is the key component of the concrete structures we see and use every day, from our cities and roads, to every bridge and every home. Cement manufacture is both expensive and energy intensive: energy consumption accounts for more than 50% of total manufacturing costs, with electrical energy accounting for a significant proportion of this – historically estimated to be 1% of the world’s electrical energy (circa 1966). However, electricity usage for cement manufacture has steadily been overtaken by that used to power the world’s data centres, which store the vast amounts of data generated over the internet. Whether you’re ‘liking’ something on Facebook, streaming the latest Tarantino movie, or posting an Instagram picture from the pub, every internet activity involves huge amounts of data that needs to be stored somewhere. And as the ‘internet of everything’ brings innovations, such as driverless cars and high-definition video watches, ever closer, the vast network of data centres that have sprung up in the past decade will spread. Already, data centres have mushroomed from virtually nothing 10 years ago to consume about 3% of the global electricity supply, accounting for about 2% of total greenhouse gas emissions.