This presentation highlights how simulation-driven development accelerates the uptake of large-scale heat storage in district heating networks. LTES systems enable cost-efficient and scalable energy storage, with benefits increasing at larger volumes. It outlines key technologies (ATES, BTES, CTES, PTES, TTES) and shows how simulations support all stages—from feasibility to operation—reducing risks, costs, and implementation time, as demonstrated by the TREASURE project.