heating demands this allows waste heat from cooling to be used in heat pumps at those buildings which need heating. The overall temperature within the ambient circuit is preferably controlled by heat exchange with an aquifer or another low temperature water source to remain within a temperature range from 10 °C to 25 °C. While network piping for ambient ground temperature networks is less expensive to install per pipe diameter than in earlier generations, as it does not need the same degree of insulation for the piping circuits, it has to be kept in mind that the lower temperature difference of the pipe network leads to significantly larger pipe diameters than in prior generations. Due to the requirement of each connected building in the fifth generation district heating and cooling systems to have their own heat pump the system can be used both as a heat source or a heat sink for the heat pump, depending on if it is operated in a heating and cooling mode. As with prior generations the pipe network is an infrastructure that in principle provides an open access for various low temperature heat sources, such as ambient heat, ambient water from rivers, lakes, sea, or lagoons, and waste heat from industrial or commercial sources. Based on the above description it is clear that there is a fundamental difference between the 5GDHC and the prior generations of district heating, particularly in the individualization of the heat generation. This critical system has a significant impact when comparing the efficiencies between the different generations, as the individualization of the heat generation moves the comparison from being a simple distribution system efficiency comparison to a supply system efficiency comparison, where both the heat generation efficiency as well as the distribution system efficiency needs to be included. A modern building with a low-temperature internal heat distribution system can install an efficient heat pump delivering heat output at 45 °C. An older building with a higher-temperature internal distribution system e.g. using radiators will require a high-temperature heat pump to deliver heat output. A larger example of a fifth generation heating and cooling grid is Mijnwater in Heerlen, the Netherlands. In this case the distinguishing feature is a unique access to an abandoned water-filled coal mine within the city boundary that provides a stable heat source for the system. A fifth generation network ("Balanced Energy Network", BEN) was installed in 2016