District heating in Denmark is a closed system. The heated water leaves the Combined Heat & Power plant (CHP) or an industry’s heat pump and runs towards the consumers. In radiators it flows through and you pay for the difference in heat in/out and for tap water/shower etc. you have a heat exchanger that heats up the normal cold water line. The now colder heated water then runs back to the CHPs where it gets reheated.
Denmark may be big on windmills but CHPs are actually another energy technology that’s widespread here.
GenEcon@lemm.ee 11 months ago
Germany has this concept implemented in a lot of places, too.
Ironically this results in some problems now. For example the city Salzgitter (100k inhabitants) is heated by the local steel plant – which currently transitions towards green steel. Their transition also leads to a shut down of their blast furnaces, leaving the inhabitants of Salzgitter out of heating.
No idea what their plan is to replace it, though.