ISO/NP TS 27164

Hydrogen generators using water electrolysis — Calculation methods for system-level hydrogen production energy consumption and hydrogen production energy efficiency

Scope

This document defines methods for calculating hydrogen production energy consumption and
hydrogen production energy efficiency for system-level hydrogen generators using electrochemical
V01/2025
reactions to electrolyze water to produce hydrogen. The calculation of hydrogen production energy
consumption and hydrogen production energy efficiency at the single-cell and stack levels is not
covered by this document due to current technical uncertainties. This document is applicable to
hydrogen generators that use the following types of ion transport media:
— aqueous alkaline (basic) electrolytes, such as potassium hydroxide or sodium hydroxide solutions;
— solid polymeric materials with acidic functional groups, such as proton exchange membranes
(PEM);
— solid polymeric materials with basic functional groups, such as anion exchange membranes (AEM).