The Swedish datacentre with a bunker mentality

The plants, water and lighting effects are intended to keep the staff happy. "If you are underground, you don't feel the time go and you get depressed. You need some variation in your surroundings", France-Lanord said.

The metal halide lighting is programmed to give the plants and the 15 full-time staff a natural daily cycle.

Other technologies are emerging in Sweden which could do this, according to France-Lanord. "You can use optical fibre for solar-capture outdoors, and pipe real sunlight indoors," he said. 

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