Standards Development

Scope

This document describes methodologies that can be applied to estimate the greenhouse gas (GHG) emissions associated with the conditioning, storage and transport of gaseous and liquid hydrogen up to the consumption gate. GHG emissions from cradle to gate (well-to-consumption gate) in the hydrogen supply chain can be assessed by combining ISO/DIS 19870-1, which defines methodologies for determining the GHG emissions associated with various pathways of hydrogen production, with this document.

ISO 14044 requires the goal and scope of a life cycle assessment (LCA) be clearly defined and be consistent with the intended application. Due to the iterative nature of LCA, it is possible that the LCA scope needs to be refined during the study. According to ISO 14040, Annex A2, the goals and scope of LCAs correspond to one of the following two approaches:

a)       an approach that assigns elementary flows and potential environmental impacts to a specific product system, typically as an account of the history of the product (see 4.1.2);

b)       an approach that studies the environmental consequences of possible (future) changes between alternative product systems (see 4.1.3).

In this document, approach a) is referred to as an attributional approach, while approach b) is referred to as consequential approach. Complementary information is accessible in the ILCD handbook[5].

A carbon footprint of a product or partial CFP as defined by ISO 14067 can be estimated using either the attributional or the consequential approach, the latter corresponding to the use of “system expansion via substitution” to avoid allocation when a unit process yields multiple co-products.