Thermal storages for thermal grids can help to smooth out peak loads and to avoid or reduce the use of fossil back-up systems. Heat surpluses can be stored temporarily. Decentral storage systems in partic-ular also make it possible to relieve the load on individual grid sections, or to enable grid densification and expansion. They are also ideal for the efficient integration of decentral heat sources. In this project, the possible cost and emission savings through the use of decentral thermal storage units in different district heating grids are quantified. In addition to recommendations for the dimensioning and operation of such storage units, an Excel user tool will be published, which will allow planners to determine the influence of storage units on the thermal load distribution and the costs of a thermal grid. In the first project year, three typical thermal networks are chosen and defined by their heat demand, specific costs, and environmental impacts of components and operation. The approach for generating data on the effects of using (de-)central storages in the networks was adapted. The development of the tools used for generating data and for presenting the results for planners is ongoing.