The project aims at developing “Nanoparticle Embedded in Alloy Thermoelectric (NEAT)” materials to harvest energy in the KW range. Thermoelectric Generators will help to recover some of the huge amount of wasted high-grade thermal power leading to significant savings in fuel and Green House Gas emissions. These innovative materials will be designed to perform efficient waste heat recovery in high thermal differentials provided by high temperature industrial processes and automotive engines.Conventional thermoelectric materials are toping ZT values of 1 since several decades. Recently, ZT values as high as 3 at 550K have been reported for thin film nanostructured materials. However, bulk materials are far from reaching a similar performance.NEAT is an innovative nanocomposite alloy capable of attaining ZT>3 at high and medium temperatures. The material concept is based on the joint optimization of nanoinclusions and grain boundaries in order to maximize phonon scattering at multiple length scales, without increasing electron scattering significantly.NEAT will focus on:- Mg2Si nanoparticles in n-Mg2SiSn alloy matrix, for medium temperature range (500-800K)- Ge and Silicide nanoparticles in SiGe alloy matrix, for high temperature range (900-1200K)- A graded nanocomposite of both medium and high temperature materials, for high thermal gradients accommodation.The concept achievement will require manufacturing process innovations enabling the inclusion of well controlled nanoparticles in a host polycrystalline alloy and the preservation of the initial architecture during the sintering. It will benefit from advanced theoretical simulation providing fundamental physical understanding, and materials development guidance. The demonstration of the nanocomposites thermoelectric performances in proof of concept thermoelectric generators and the assessment of its energy pay-back will unambiguously state the potential industrial impact of the project outcomes.