The context is the current use and typical applications of thermal energy storages within contemporary district heating and cooling systems. Storage examples and experiences are mostly provided from the Nordic countries in Europe. No focus is directed toward new storage methods or technical development of the current storage technologies used. Issues discussed are cash flows from storages, a variation assessment method, central versus distributed heat storages, hourly heat storage in networks, daily storages in both district heating and cooling systems, weekly heat storages, and seasonal heat storages. Recent investment costs are also summarized.