In the near future, European policy to increase energy consumption from renewable sources will have a significant impact on the European gas infrastructure:
- Power generation from wind and solar energy sources will lead to the development of so-called “power to gas (P2G)” solutions to compensate for the fluctuating electricity supply produced by these energy sources by converting electricity into hydrogen and injecting it in large quantities into the gas network.
- Biogas produced by the anaerobic digestion of organic waste from different sources (conventional farms, landfills, sewage sludge) will need to be directly measured and burned in cogeneration facilities or injected into the gas network after purification to biomethane and with subsequent upgrading.
The modification of the characteristics of energy gases throughout Europe is needed, but this process will depend on local renewable energy policies which are not precisely defined at the moment (objective 1).
Many operators are involved in the gas network (i.e. gas producers, gas utilities, transport, the gas industry, private individuals) and all require accurate measurements in order to bill transactions according to commercial contracts. Therefore, gas meters are certified according to the Measuring Instruments Directive (2014/32/EU), using EN or OIML standards which have been written for natural gas applications. Despite this, experts are expecting a significant impact, from the introduction of energy gases from renewable sources, on the design of normative documents and calibration test benches. The impact of this needs to be fully evaluated (objective 2). This has resulted in the absence of accredited laboratories which are needed to provide reliable calibrations of the meters that are used with renewable gases to ensure the reliability of transactions (objective 3).
This project aims to address the need for a common European approach to evaluating the conformity of commercially available meters to EN standards and the MID directive and/or to provide recommendations to adapt their designs and the associated standards (objective 4).
The overall objective of the project is to increase knowledge about the accuracy and durability of commercially available gas meters after exposure to renewable gases. This should lead to the improvement of existing meter designs and flow calibration standards.
The specific objectives of the project are:
- To assess the typical uses of renewable gas for which the effects on accuracy, costs and life time are not sufficiently known. Furthermore, to define an acceptable range of gas compositions, which will be suitable to support the new “renewable” framework and to list the missingtests which need to be performed during calibration to cover the use of renewable gases with existing gas meters.
- To develop traceable methods for the type testing and verification of flow meters that are used to measure renewable gas flows in compliance with the requirements of the 2014/32/EU Measuring Instruments Directive and to determine the uncertainty budget. Uncertainties of 1/5 Maximum Permissible Error (MPE) have to be achieved for type testing and 1/3 MPE for field verification. In addition, this project will study and evaluate the integrity of the meters’ internal components, the durability of the materials, the insulation of electronic components and other possible technical issues (dependent on the composition of the evaluated gas).
- To validate the calibration methods and uncertainty budgets developed for two flow calibration standards via an appropriate inter-laboratory comparison and to carry out type testing procedures for domestic and commercial gas meters with hydrogen.
- To contribute to the standards revision work in technical committees CEN/TC 237 and OIML TC8/SC7 to ensure that outputs from the project are aligned with their needs, communicated quickly to those developing the standards and to those who will use them, and in a form that can be incorporated into standards at the earliest opportunity.
Progress beyond the state of the art and results
To assess the typical uses of renewable gas for which the effects on accuracy, costs and life time are not sufficiently known. Furthermore, to define an acceptable range of gas compositions, which will be suitable to support the new “renewable” framework and to list the missing tests which need to be performed during calibration to cover the use of renewable gases with existing gas meters.
Harmonised CEN/TC 237 standards and the OIML R137:2012 recommendation are used for the certification of the legal metrology meters that are intended for use with conventional natural gas as defined in the EN 437 standard. The use of renewable gases is not taken into account and no international studies about their impact are known by the industrial and laboratory community. This conclusion was made based on a publication from a consortium composed of FARECOGAZ (European gas meters manufacturers association) including WELMEC WG11 “Utility Meters”, MARCOGAZ (Technical Association of the European Natural Gas Industry, which includes Transmission System Operators (TSO) and Distribution System Operators (DSO)) and CEN/TC 237 experts. In the same way, EMPIR stated in a 2016 report from the 2009 Energy call that “incorporation of renewable and non-conventional fuels into the energy mix creates a range of measurement challenges. (…) While traditional natural gas has very well-known properties, fuels from renewable sources are more varied in terms of chemical composition and behaviour. In order to assess the amount of fuel and its energy content at the point of trade, its properties in terms of volume, density and chemical composition need to be known.” The goal of this project is to improve knowledge and understanding about the impact of renewable gases on gas meters in the gas network and to provide reliable data to ensure confidence in the measurements that are used for billing.
A literature study will be carried out to gather available knowledge on the performance of existing gas meters to enable their use with renewable gases. The study will focus on accuracy and durability, and all available technologies. This will also provide insight on the gas compositions of different renewable gases that can be produced, transported and metered in Europe. This study will highlight the global knowledge gaps faced by the scientific community and industry and it will define the most important areas which have to be studied to address objectives 2 and 3.
To develop traceable methods for the type testing and verification of flow meters that are used to measure renewable gas flows in compliance with the requirements of the 2014/32/EU Measuring Instruments Directive and to determine the uncertainty budget. Uncertainties of 1/5 MPE have to be achieved for type testing and 1/3 MPE for field verification. In addition, this project will study and evaluate the integrity of the meters’ internal components, the durability of the materials, the insulation of electronic components and other possible technical issues (dependent on the composition of the evaluated gas).
The documentary standards used to demonstrate conformity to the MID will be challenged against the wider scope of metering renewable gases. Tests will be performed to systematically assess the extent to which current gas meter standards need modification, especially for accuracy and durability. Recommendation reports will be provided as input to technical committees CEN/TC 237 and OIML TC8/SC7 for potential revision of the standards (see below).
To validate the calibration methods and uncertainty budgets developed for two flow calibration standards via an appropriate inter-laboratory comparison and to carry out type testing procedures for domestic and commercial gas meters with hydrogen.
A literature study will be carried out to gather available knowledge on the principles that can be used for accuracy testing gas meters with renewable gases (in the scope of MID). The study will deliver solutions which provide sufficiently low uncertainties (1/5 MPE for type testing).
Based on the operating ranges of currently available test facilities for hydrogen and methane, an inter-comparison test campaign will be held on domestic gas meters to demonstrate the equivalence of the existing flow calibration standards, as well as checking the applicability of new test procedures.
These results will increase stakeholders’ knowledge and give them confidence in the updated gas meter normative documents.
Impact on industrial and other user communities
This project will provide input to several standardisation organisations (CEN/TC 237, ISO/TC 30 and OIML TC8/SC7) and to NMI/DIs on the measurement of renewable gases. It will also establish guidelines and uncertainty calculations and produce results from testing the accuracy and durability of gas meters. This project will create impact by improving the accuracy and uncertainty of gas meter measurements and calibrations when they are used for renewable gases.
This project will also create impact as the NMI/DIs will be able to provide new calibration and consultancy services for flow standards, to the private and public sectors. It will benefit gas meter manufacturers by providing them with the proper knowledge required to develop products compliant with non-renewable gas. The availability of gas meters with assessed and demonstrated performance will enable non-renewable gases to be more widely used within gas networks. In addition, it will especially benefit the manufacturers who joined the consortium as their meters will be tested during the test campaign.
This project will benefit the end users and authorities that are responsible for ensuring that gas transactions are fair. At the moment it is unknown whether the gas network can be used ‘as is’ to transport gas from P2G plants to end users in good condition and with a guarantee that measures are reliable (meaning that the gas meters comply with the requirements of the MID directive especially related to accuracy and to the use of test benches with reliable uncertainties). Therefore, this project will create impact as the consumption of renewable gas will be able to be fairly measured and as a consequence it will reduce conventional energy consumption and it will contribute to European policies for reducing greenhouse gas production.
In order to transfer the knowledge developed in this project to stakeholders and end users, there will be considerable engagement with industrial stakeholders including standardisation bodies, manufactures of gas meters, their organisations, notified bodies, European technical associations, DSOs, TSOs and gas suppliers, as well as with end users and their representation bodies, and calibration laboratories. The participation of industrial partners in the project and the establishment of a Stakeholder Committee will also ensure that the project is aligned with industrial needs. The project will provide new technical specifications to the existing working groups to issue modified standards which take into account the specificity of renewable gases.
Impact on the metrology and scientific communities
The most important technical objectives of this project are to develop traceable calibration methods and to validate them with an inter-comparison campaign. Based on these outputs, NMIs/DIs will be able to establish new capabilities and new knowledge at their institutions for the calibration of gas meters when using renewable gases. This will improve their understanding of the behaviour of the gas meter when measuring renewable gases which in turn will allow them to reduce the calibration uncertainty (uncertainty target: 1/5 MPE for type testing). The new test benches will be listed in the calibration and measurement capabilities and will be used in future key comparisons if required.
Notified bodies will benefit from revised standards when making assessments and initial approvals of new gas meters which will be designed to measure renewable gases.
Impact on relevant standards
This project will create impact by providing input to several standardisation organisations that deal with the metrology of gas meters such as CEN/TC 237 “Gas meters” and OIML TC8/SC7 “Gaseous fuel”. Relevant input will be delivered into all international bodies dealing with gas meters, and the following standards used for certification and/or calibration could benefit:
- EN 12480:2015 Rotary displacement gas meters
- EN 12261:2018 Turbine gas meters
- EN 1359:2017 Diaphragm gas meters
- EN 14236:2007 Ultrasonic domestic meters
- NMIP 00237040 Thermal-mass flow-meter based gas meters
These standards have recently been updated (or will soon be updated) according to European mandate M/541 in order to comply with MID directive 2014/32/UE. Nevertheless, these revisions did not take renewable gases into account. In the same way OIML recommendation R137:2012, whose revision will start in 2019, could be supplied with this project’s results.
Certification standards need to be improved, therefore this project will create impact by improving calibration processes in order to adapt them to a wider range of gas compositions. This project will also providemeasurement data that could be used to revise the following calibration standards that are managed by ISO/TC 30 “Measurement of fluid flow in closed conduits”:
- ISO 17089-1:2010 Ultrasonic gas meters, Meters for custody transfer (…)
- EN ISO 5167 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full: Parts 1 to 5
- ISO 10790:2015 Coriolis gas meters
Longer-term economic, social and environmental impacts
The EU strategy plan aims to reduce greenhouse gas emissions by 40 % by 2030 compared to the 1990 level, and to increase the renewable share of total energy consumption to at least 27 %. This major change aims to decarbonise energy production and to avoid energy imports from countries outside Europe. These renewable energies are produced using natural processes that are constantly replenished such as electricity produced by solar, wind or biomass resources. There is currently no large-scale industrial solution to store this electricity and to provide it throughout Europe. A new process called P2G aims to transport this potential power to end-users using the existing European gas network by converting electricity into hydrogen, or with syngas when combined with carbon monoxide. Another way to develop energy bio-sources is to install biogas/biomethane facilities that are supplied by agricultural by-products or by bio-waste which can be burned or injected in to the gas network.
By investigating the effect on gas meters and delivering solutions to industry and to standards bodies, this project will improve the confidence of consumers and suppliers in the billing of renewable gases. This will help to develop renewable resources in Europe in order to reduce fossil fuel consumption according to the European Union Directive for Renewable Energy.