Continuity — Nessus said "... our civilization was dying in its own waste heat. Total conversion of energy had rid us of all waste products of civilization, save that one" (Ringworld ch. 5, p. 70). However, Puppeteers are described elsewhere as using efficient fusion. In particular, the account published as Fleet of Worlds describes extensive use of fusion power, and has no mention of total-conversion power. Therefore, it seems best to presume Nessus was just trying to, so to speak, "impress the natives". ↵
