The management of Municipal Solid Waste (MSW) is a very important issue that must be dealt by the perspective of the 3 Rs (Reuse, reduce, recycle. MSW incineration bottom ash (BA) accounts for 85-95% of the total solids that remained after incineration. Finding suitable alternatives for its revalorization is very attractive, especially in terms of environmental sustainability. Thermal energy storage (TES) is a complementary technology of renewable energy. The aim of this study is to evaluate the thermophysical properties of weathered BA (WBA) in order to find suitable alternatives for its valorisation. Several samples of WBA were collected from a waste-to-energy facility located in Tarragona (Spain). This facility sieved to different size fractions. Each size fraction was characterized with respect its physicochemical properties and the energy density (ren) was calculated. The results obtained showed that this residue is a suitable alternative candidate material for TES as it presents an energy density of 1461.2 kJ m 3 K 1 for the 1-2 mm fraction. In addition, the low cost of this type of residue (0.6V per t) and its high production rate per year makes it an attractive and sustainable alternative for TES.