Mijnwater is a supplier of sustainable energy, supplies heat and coolness to offices, commercial buildings and homes. It does this via a circular energy network, a so-called fifth generation ‘Smart Grid’ for district heating and cooling. In addition, the company stores the (recovered) heat, at times when there is little to no demand. This innovative circular energy network in Heerlen is seen as a well thought-out infrastructure for the distribution of hot and cold energy and can also be used in other urban areas.