Data centers are and will continue to be one of the biggest industrial power consumers. Until recently, the optimisation of power usage (PUE) has been a top priority. In the future this will not be enough as data centers are growing enormously. Recycling of energy, reusing heat is mandatory and offers great business opportunities too. The Yandex data center in Mäntsälä, Finland will capture and recycle (sell) heat rejected from data center.