Found this video on underground Helsinki. It's nice to see that my old hometown has found some innovative solutions for a green datacenter. The datacenter uses cold seawater to cool the computers down and the excess heat created by the computers will be distributed to the heating system that warms up peoples homes. A win-win for everybody.
Google is also using the Baltic seawater to cool down their computers in the datacenter in Hamina, Finland.
It seems like the new facebook data center to be built in Luleå, Sweden, will mostly count on the cold weather to cool the computers down and not seawater but they have additionally announced that they will use renewable energy, however, there is not very much details on how much energy used will be renewable.
Seems like it is popular to build datacenters in the nordics.