Hydrogen meters are under development and testing in the prospect of hydrogen blending into the gas distribution networks for supply to consumers.

The introduction of hydrogen – ideally and eventually 100% green hydrogen – as a replacement for natural gas, which is gathering momentum in many parts of the world, is set to require large-scale modification and probable eventual replacement of the gas distribution infrastructure and gas-powered appliances and other equipment.

While there are arguments and supporters for going direct to 100% hydrogen, in practice in most cases its introduction is most likely to be blended with natural gas starting with a low percentage and gradually increasing as the infrastructure is adapted and as the production and supply of green hydrogen is ramped up.

The reason for modifications, simply, is the different energy characteristics of hydrogen compared to natural gas.

Its energy content is about only one-third that of natural gas. Thus not only is more hydrogen-blended natural gas needed to deliver the same amount of energy to users compared to pure natural gas but also a higher volumetric flow rate is required.

Options for this latter include increasing the operating pressure in the distribution system or replacing the existing pipelines with larger ones.

In use for appliances, for example, the main concerns are potentially higher combustion temperatures with hydrogen-natural gas blends, which could lead to local overheating of components, and the increase in the burning velocity, which poses a risk of potential flashbacks.

Coupled with the changes on both the utility and consumer sides, there also will need to be changes to the primary interface, the meter, with an eventual full gas meter/smart meter replacement with hydrogen meters in hydrogen-fed jurisdictions.

In prospect, hydrogen meters are being developed by several manufacturers and demonstrated and tested in what amounts to real world conditions.

Hy4Heat

A key driver for hydrogen meter development has been the British government-funded Hy4Heat project with development firm Arup leading a 40-strong industry consortium.

The goal of the project, which launched in 2018 and ran through early 2022, was to establish the feasibility of replacing natural gas with hydrogen in residential and commercial buildings and gas appliances, including establishing standards and safety requirements and prototyping appliances.

A key component – and one of the ten work packages – was the development of smart hydrogen meters, with the two Italian gas meter manufacturers, MeteRSit and Pietro Fiorentini, selected for this task.

The outcome was the development of three smart meters – one for domestic use from Pietro Fiorentini and one each for domestic and commercial uses from MeteRSit.

The meters are hydrogen ready with the ability to measure both natural gas and hydrogen, but a key difference between them is the underlying technology, with Pietro Fiorentini’s based on ultrasonic measurement and MeteRSit’s on thermal flow sensing.

In addition, a difference from standard gas meters is that the flow valves that are built in to stop the supply of gas to a dwelling have extended functionality to detect excess flow and shut off the supply.

Camillo Fontana, Marketing Director at the SIT metering division, says that with the company’s hydrogen meters based on its proven technology in approaching 7 million meters over the past decade, the essential difference is in newly developed internal intelligence.

“The meter is the same size as a traditional meter, despite the lower calorific value of hydrogen,” he explains.

“This is important as there is often limited space for the meter – in effect the hydrogen meter and a standard meter look the same.”

The meters, under the Domusnext name, have since obtained the EU’s Measuring Instrument Directive (MID) certification on accuracy and reliability with validity in Europe and the UK but also recognised in other non-EU countries and the Commercial Product Assurance (CPA) digital security certification for the UK from the country’s National Cyber Security Centre.

With this, the company is able to proceed with full production.

Hydrogen homes

As part of the Hy4Heat project, the utility partner Northern Gas Networks has built two demonstration hydrogen homes at its innovation site in Gateshead on England’s northeast coast, close to the border with Scotland.

The intent of the homes fitted with the new hydrogen meters and appliances and fully fuelled by hydrogen is to test and demonstrate these for the public and enable them to experience a home of the future.

“From the user point of view the meters and prototype appliances have the same look and feel as their natural gas equivalents and if they weren’t branded as hydrogen then one wouldn’t know,” says David Tomkin, Project Engineer and Hydrogen Home project lead at Northern Gas Networks.

“So the experience for visitors has been underwhelming but that is the whole point of it! If we know people who come to visit the homes leave feeling underwhelmed, then we have done our job as they will know there are no major disruptions or changes coming with a transition to hydrogen.”

In terms of installation, Tomkin says that standards are being developed for the formal installation of hydrogen meters, but in practice, their installation is identical to that of a gas meter.

“Ultimately it’s about changing a gas meter, which we do on a daily basis across Britain,” he says of a transition to metering for hydrogen.

He adds that in principle hydrogen ready meters could be installed at any time to be in place for the future, although the form of any rollout programme is obviously in the hands of policymakers.

Next steps

Fontana says that MeteRSit expects the market to evolve with testing and small trials over the next two years, with larger installations starting from 2025 when hydrogen villages and towns emerge – such as that proposed in Britain – to lay the further groundwork for an eventual transition.

As part of its roadmap, MeteRSit is continuing to develop its hydrogen-ready meter, which also should be usable for all gases that could be injected in the future, such as syngases and biomethane.

He adds that as well as Northern Gas Networks, the MeteRSit hydrogen meters are being trialled with a Dutch utility and interest also has been expressed by parties in Germany and Italy.

The latter in particular is expected to be a large market and Italgas has indicated its intent to develop a hydrogen-ready meter to start installation in 2026.

Another company known to be developing hydrogen meters is Switzerland-based Sensirion.

Tomkin says that Northern Gas Networks has spoken to several other meter manufacturers and several have visited the hydrogen homes, but he himself isn’t aware of any other developments.

“But I’m sure once hydrogen starts coming through, other companies are going to want to be on board.”