In this period of profound changes and new dynamics in trying to find more sustainable and interoperable solutions also in the Utilities sector, we think about the measurement of gas delivery at the distribution level, i.e. at the final points to the distribution system, focusing on what is happening in Europe.
This reflection is needed just at this time when the renewable energy revolution is also beginning to take place in the gas distribution network, with the injection into it of blends of different sources, qualities and quantities (natural gas, hydrogen, biomethane, etc.). In addition to this matter, we know that thanks to all the IoT (Internet of Things) services, in managing the daily life of the end consumer (both companies and home users) it becomes essential to be able to interconnect and compare one’ own data (especially energy data) in order to make sustainable choices.
To this purpose, it would be very useful if it were possible to have energy consumption data available with the same unit of measurement, knowing its quality and potential. If for electrical energy the matter is of easy solution, it is not so for gas delivery, which can be measured in quantity – volume (cubic metres) or in quality – energy (kWh, MJ).
Let us briefly look at how the topic of the delivered gas measurement at distribution level in Europe is approached, which is the trend in European legislation and, finally, the impact on measuring instruments and their certification.
As the tables show, currently in Europe, 74% of the states express the measurement of gas delivery at distribution level in energy (kWh, MJ), 19% in volume/mass (cubic metres or standard cubic metres) and for the other 7% this classification is not applicable, as these are countries (Cyprus and Malta) that use gas cylinders (LPG).
The trend of European regulation on delivered gas measurement at distribution level is clear, although not completely explicit. In other words, if on the one hand it is urged to adopt national regulatory solutions favouring an optimised management of energy consumption, thus allowing end-users to be able to monitor their energy consumption through smart meters and advanced tariff formulas, on the other hand it is not clearly established that the unit of measurement of delivered gas at distribution level is energy, leaving de facto its determination in quantity or quality free to each Member State*.
Here are some articles highlighting the trend of European legislation.
Article 3, paragraph 8, of Directive 2009/73/EU (the Gas Directive) mentions: “In order to promote energy efficiency, Member States or, where a Member State has so provided, the regulatory authority shall strongly recommend that natural gas undertakings optimise the use of gas, for example by providing energy management services, developing innovative pricing formulas or introducing intelligent metering systems or smart grids where appropriate”.
Article 9, paragraph 1 and paragraph 2 letters a) and e), and Article 12, paragraph 1, of Directive 2012/27/EU (the Energy Efficiency Directive) state: “Member States shall ensure that, in so far as it is technically possible, financially reasonable and proportionate in relation to the potential energy savings, final customers for electricity, natural gas, district heating, district cooling and domestic hot water are provided with competitively priced individual meters that accurately reflect the final customer’s actual energy consumption and that provide information on actual time of use. … Member States shall ensure that the metering systems provide to final customers information on actual time of use and that the objectives of energy efficiency and benefits for final customers are fully taken into account when establishing the minimum functionalities of the meters and the obligations imposed on market participants. … Member States shall require that appropriate advice and information be given to customers at the time of installation of smart meters, in particular about their full potential with regard to meter reading management and the monitoring of energy consumption. … Member States shall take appropriate measures to promote and facilitate an efficient use of energy by small energy customers, including domestic customers. These measures may be part of a national strategy”.
Assuming that a measurement of gas delivery at the distribution level would be very convenient if expressed in energy unit, thus knowing its quality and potential; considering that in Europe the legislation is oriented in this direction and the majority of Member States already adopt this solution, it remains to be clarified whether from the point of view of the legal metrology the gas meters are ready to display the measurement of gas in energy, thus highlighting its quality, and they can be properly certified.
Here the matter becomes a little more complex because different factors come into play that are needed to convert the quantity of gas delivered into energy: volume, temperature, pressure, the composition of the blend, as well as the structure of the distribution network. The basic instruments to be used are: gas meters, volume conversion devices, gas chromatographs and calorific value determining devices.
Currently, the gas meters, certified according to the MID Directive 2014/32/EU (mandatory in Europe), Annex MI-002 Part I, and the OIML R137 Recommendation (voluntary certification), display the measurement in quantity, i.e. in volume or mass. In order to achieve the measurement in energy unit, these ancillary instruments are used: volume conversion devices, which are certified according to MID Directive 2014/32/EU (mandatory in Europe), Annex MI-002 Part II; gas chromatographs and calorific value determining devices, that are regulated by OIML R140 Recommendation (for which a Certificate of Conformity actually cannot be issued). The latter two associated instruments can usually have an Evaluation or Parts Certificate to be linked to the gas meter certificate, and/or a national type approval certificate, depending on the requirements of the individual European state. In practice, in order to obtain the measurement of gas delivery at distribution level in energy/quality, today, a “measurement system” is required, not a single instrument, with all the consequences that then fall on the concrete management of the distribution network.
To conclude, there are still steps to be taken to ensure that delivered gas measurement at distribution level is expressed in energy and quality in a smooth way, giving a strong push to the sustainability revolution. The path, however, is already well marked. The sector is in turmoil both on the side of the Member States where the measurement is still expressed in volume/quantity, on the side of legal metrology (OIML Recommendation R140 is currently under revision, and it is open the discussion to amend Annex MI-002 of the MID Directive 2014/32/EU), and last but not least, on the side of technology, which will allow only one instrument, and not one system, to be used to measure in energy the gas delivery at distribution level.
* See article 2, point 3), of Regulation (EC) 715/2009 where “capacity” is defined as “the maximum flow, expressed in normal cubic meters per time unit or in energy unit per time unit, to which the network user is entitled in accordance with the provisions of the transport contract”.
Resources
- Policy Guidelines by the Energy Community Secretariat on measurement in the natural gas distribution network, PG 01/2020 / 8 June 2020.
- Acta of CIG Forum dated 22/09/2022.
- ACER, European Union Agency for the Cooperation of Energy Regulators.
- European national regulatory authorities.
- Eurogas and Marcogaz associations.
- Directive 2009/73/EC concerning common rules for the internal market in natural gas (the Gas Directive).
- Directive 2014/32/EU MID.
- Directive 2012/27/EU on energy efficiency (the Energy Efficiency Directive).
- Regulation (EC) 715/2009 on conditions for access to the natural gas transmission networks.
