We offer a high value-added service for the measurement of the energy content of natural gas to companies in the industrial sector, customers and end users.

In the measurement process, the quantity and quality of gas are determined at all points in the system where this is required under the relevant regulations. This covers the receipt of natural gas or LNG through to its use by transmission companies, distributors or end customers.

Spanish legislation establishes the kWh as the unit of energy for natural gas. The energy calculation is based on the gas volume measured under normal conditions (T=0ºC P=1.01325 bar) and the Gross Calorific Value (GCV), which is obtained by analysing the natural gas with gas chromatography equipment.

Natural gas is measured using equipment that has been certified and metrologically approved by independent and reputable organisations. Current international standards are used for its calculation.


Enagás’ measurement processes are certified according to the ISO 9001 standard

ISO 9001 seal


Natural gas and/or gas from non-conventional sources, such as biogas, fed into the Spanish Gas System must meet the quality specifications laid down in the Technical Management of the Gas System Regulations and Detail Protocol PD-01.

Our services

All our measurement processes are certified in accordance with ISO 9001, providing assurance that they are oriented towards continuous improvement, standardisation, process traceability and communication mechanisms. Similarly, the laboratories of our Metrology and Innovation Centre [SMN1] are accredited by the Spanish National Accreditation Body (ENAC), in accordance with the ISO/IEC 17025 Standard for the performance of all calibration activities.



Gas meter calibration

Turbines, rotary pistons, MUS, membrane, etc. Calibration with air at atmospheric pressure and with natural gas at operating pressure (16-50 bar). Flow range 0.032-10,000 m3/h.


Calibration of equipment for custody transfer

Pressure (digital pressure gauges and transmitters. Up to 100 bar absolute pressure), temperature (digital thermometers, transmitters, characterisation of isothermal media). Range (from -10ºC to 50ºC) and electricity (I/V meters and generators, resistance measurement. Ranges up to 1 A, 1000 V and 10 MΩ).


Analysis of natural gas and renewable gas quality

Analysis of natural gas and biomethane compounds. Analysis of sulphur compounds. Dew point analysis.


Metrological verification of equipment in situ and in laboratory

Verification of measuring equipment and field analysis of customers connected to our pipelines by direct lines. Approval of measuring equipment for use in Enagás. Calibration and verification of customer measuring equipment.


Advisory and consultancy services on gas measurement and quality

At Enagás, we have qualified professionals with different technical and scientific backgrounds, and a high level of specialisation, knowledge and experience in gas measurement and quality to provide these advisory and consulting services to our customers.

Publication of hourly gas quality data

Check the GCV and the Wobbe Index for hourly updates.




Six-monthly gas quality parameters

Check the six-monthly gas quality parameters published by the GTS.



Note: Section 5.4 of Annex PD-01 “Measurement, quality and odourisation of gas” of the Resolution of September 22, 2011 of the Directorate General for Energy Policy and Mining provides that the change of gas quality in the PTZ converters will be every six months, and that the Technical Manager of the System is responsible for issuing a list of networks where the gas quality must change and the new composition to be introduced.

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