Photos: Unearthing the zero-carbon data centre

The underground data centre also has a stable temperature. Smith told silicon.com: "With us it's like being winter all the time and we are not at all affected by the sun."

While over-ground data centre power bills can go up in the summer months, Smith said the Smartbunker only has to cool the heat kicked out by its servers.

But the subterranean nature of the Smartbunker did make it tricky to connect the data centre to the outside world.

Smith said putting in the infrastructure was one of the key challenges which timed the launch and Smartbunker had to invest a lot with BT to bring in the connections.

One of the underground entrances to the Smartbunker server rooms is pictured above.

Photo credit: Gemma Simpson