cen:proj:80559

Gas infrastructure — Methodology for methane emissions quantification for gas transmission, and distribution systems, underground gas storage and LNG terminals

Scope

This document describes a methodology to take account for different types of methane emissions from gas infrastructure and it explains, step by step, how to quantify each type of emission in a gas transmission, distribution and/or storage system and in an LNG terminal.
Note 1: Natural emission by the soil or seepage of methane due to gas field, above or next to the storage reservoir, are not taken into account.
Methane emission from utilisation, CNG/LNG fuelling stations, biomethane production and upgrading plants and LNG liquefaction and transport are not covered in this document.
Note 2: These principles can be applied to other parts of the gas value chain.
In this standard gas is considered any product with a high methane content that is in gaseous or liquid form inside the respective gas infrastructure (e.g. natural gas, biomethane or mixtures thereof with each other or with hydrogen).
The standard specifies source-level methods to quantify the identified methane sources. The methods for and site level measurements and reconciliation are specified in an informative Annex.
Source-level method - Emissions from each identified source are individually quantified. Total emissions on a given asset are calculated by adding each type of emission source data. Methods by modelling from samples are possible.
This quantification method consists in splitting the gas systems into groups of assets, devices and components and indicating categories of emission sources that can be expected from these groups.
Quantification is performed by (direct) measurement, calculation or using emission factors based on measurement and activity factors . Detailed descriptions of measuring methods, measurement equipment and calibration procedures are not covered in this standard.
Note 3: Some references can be found in CEN/TC 264 and API standards.
This standard provides guidelines for sampling strategy and materiality.
Methods to calculate the uncertainties associated with the quantified amounts of emitted methane are covered in this standard.