What is the PMS number for the cyan blue of the ENERGY STAR logo?

The cyan blue color for the ENERGY STAR logo is called "process cyan." There isn't a Pantone or "PMS" number. The PMS (Pantone Matching System) refers to a system for mixing colors and since this is pure cyan, there's no mixing to do. You need to specify "process cyan" because "process blue" is a different color.