Nano-particle (NP) production processes may involve the use of significant amounts of complex chemicals. A more advanced approach for producing metallic NP materials may be the use of high voltage arc- or spark-driven systems. In addition to a reduction in chemicals use, the energy use of arcs/sparks exclusively in the form of electricity may be significantly less than the energy needs of waste stream processing from chemical usage, handling and post-treatment in nano-tech industry. Using exergy as a fundamental tool we assess the energy efficiency of NP material production, a subject obscured by lack of data and literature. One goal of this paper is to introduce a description of the exergy of NP materials and their processing. Silver, gold, copper, nickel, zinc and aluminium were taken as case studies. The results show that especially for NP material