Marks and Spencer’s sustainability challenge

Forget furnaces and fireplaces. In Stockholm, Sweden, residents are staying warm with the help of excess heat from more than 6,000 computer servers.  It’s one of the many creative ways that green data centers around the world are trying to become more energy-efficient and more environmentally friendly.  The idea belongs to Swedish internet service provider Bahnhof, which has turned an old rock cavity below a public park into a cutting-edge data center. Known as Pionen, the futuristic space is filled with densely packed IT hardware and infrastructure that produces a massive amount of energy and heat.  When it established Pionen in 2007, Bahnhof wasted that heat by venting it away. Then, it decided to partner with local energy company Stockholm Exergi, whose Open District Heating program allows entities that produce excess heat to generate revenue by recovering surplus heat and selling it as energy with which to heat homes and businesses.