Glossary

To support the industry and stakeholders in the use of consistent terminology, Ipieca, IOGP, GIE and MARCOGAZ prepared this methane emissions glossary covering the whole natural gas value chain.

Intended for policymakers and regulators working on methane regulation in Europe, this glossary will be updated to reflect new legislation and technologies.

Download the Methane Emissions Glossary

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There are currently 4 names in this directory beginning with the letter U.
U
Uncertainty (of measurement)
A parameter, associated with the result of a measurement, that characterizes the dispersion or range of the values that could reasonably be attributed to the quantity measured. [10]
(Note 1 - The parameter may be, for example, a standard deviation (or a given multiple of it), or the half-width of an interval having a stated level of confidence.
Note 2 - Uncertainty of measurement comprises, in general, many components. Some of these components may be evaluated from the statistical distribution of the results of series of measurements and can be characterized by experimental standard deviations. The other components, which also can be characterized by standard deviations, are evaluated from assumed probability distributions based on experience or other information.
Note 3: It is understood that the result of the measurement is the best estimate of the value of the measurand, and that all components of uncertainty, including those arising from systematic effects, such as components associated with corrections and reference standards, contribute to the dispersion.
Note 4: The definition of uncertainty can also apply to characterize the dispersion for estimated values and calculated values.)
Underground Gas Storage (UGS)
The part of the gas supply chain that stores natural gas underground under pressure, to be used when there is a high demand. (Note - Underground gas storage facilities are created in depleted gas or oil reservoirs, salt cavern formations and aquifers.)
Upstream pipeline network
Any pipeline or network of pipelines operated and/or constructed as part of an oil or gas production project, or used to convey natural gas from one or more such projects to a processing plant or terminal or final coastal landing terminal. [1]
US EPA Method 21
A specific emission detection methodology specified by the US EPA Technical Guidance on ‘Determination of Volatile Organic Compound Leaks’. This method is applicable for the determination of VOC leaks from process equipment. These sources include, but are not limited to, valves, flanges and other connections, pumps and compressors, pressure relief devices, process drains, open-ended valves, pump and compressor seal system degassing vents, accumulator vessel vents, agitator seals and access door seals. [8]

References

[1] Directive 2009/73/EC of the European Parliament and of the Council of 13 July 2009

[2] EN-12186 – Gas infrastructure – Gas pressure regulating stations for transmission and distribution – Functional requirements

[3] EN-12327 – Gas infrastructure – Pressure testing, commissioning and decommissioning procedures – Functional requirements

[4] EN-12583 – Gas Infrastructure – Compressor stations – Functional requirements

[5] EN-15446 – Fugitive and diffuse emissions of common concern to industry sectors – Measurement of fugitive emission of vapours generating equipment and piping leaks

[6] GIE & MARCOGAZ Report “Potential ways the gas industry can contribute to the reduction of methane emissions” https://www.gie.eu/index.php/gie-publications/methane-emissions/methaneemission-report-2019/27786-gie-marcogaz-report-for-the-madrid-forum-potentialway-gas-industry-can-contribute-to-the-reduction-of-methane-emissions/file

[7] IPIECA/API/IOGP (2020). Oil and gas industry guidance on voluntary sustainability reporting https://www.ipieca.org/media/5105/ipieca_sustainability-guide_2020_glossary.pdf

[8] IPIECA Methane Glossary http://www.ipieca.org/resources/awareness-briefing/methane-glossary/

[9] ISO 14532 – Natural gas — Vocabulary

[10] JCGM-100 – Evaluation of measurement data – Guide to the expression of uncertainty in measurement. s.l.: Committee for Guides in Metrology (JCGM/WG 1), 2008

[11] MARCOGAZ – Assessment of methane emissions for gas Transmission and Distribution system operators, 2019 https://www.marcogaz.org/app/download/8161672063/WG_ME-485- Assessment+of+methane+emissions+for+gas+Transmission+and+Distribution+system+ operator.pdf?t=1602849054

[12] MARCOGAZ – Guidance for using the MARCOGAZ methane emissions reporting template – DSO, TSO, LNG receiving terminals and UGS https://www.marcogaz.org/app/download/8271109963/WG_ME710.pdf?t=1606988780

[13] MGP Reducing methane emissions: Equipment leaks https://methaneguidingprinciples.org/best-practice-guides/equipment-leaks/

[14] MGP Reducing methane emissions: Identification, detection, measurement and quantification https://methaneguidingprinciples.org/wp-content/uploads/2020/09/ReducingMethane-Emissions_Identification-Detection-Measurement-andQuantification_Guide.pdf

[15] MGP Reducing methane emissions: Transmission, storage, LNG terminals and distribution https://methaneguidingprinciples.org/wp-content/uploads/2020/09/ReducingMethane-Emissions-transmission-storage-LNG-terminals-and-distribution-Guide.pdf

[16] Oil and Gas Methane Partnership Technical Guidance Documents https://ccacoalition.org/en/content/oil-and-gas-methane-partnership-technicalguidance-documents

[17] Regulation (EC) No 715/2009 of the European Parliament and of the Council of 13 July 2009

[18] US EPA – ‘Method 21: Determination of volatile organic compound leaks’