Central heating boilers in homes are generally designed for a specific gas composition. This makes switching to other types of sustainable gases, such as green gas or hydrogen, a complex process. A Dutch consortium has developed a proof-of-concept for a central heating boiler that can automatically operate on different types of gas. This is the Multifuel boiler, which is suitable for natural gas, green gas, hydrogen and mixtures thereof.
The prototype has been developed by a consortium comprising Stedin, Intergas, GasTerra, Bekaert and DNV. With the multifuel boiler, the parties aim to work towards a future in which different types of gas are used alongside one another. The initiators argue that natural gas, green gas, hydrogen and other sustainable gases will all form part of the Dutch energy supply simultaneously in the coming decades. Furthermore, the Dutch housing stock is still largely dependent on individual central heating boilers; it is estimated that there are around seven million central heating boilers in use.
Suitable for varying gas compositions
According to the parties involved, in many homes a heat pump will be combined with a central heating boiler in the future. The heat pump will cover the majority of the heating demand, whilst the central heating boiler will provide additional heating during cold spells or when there is a high demand for hot tap water.
With the Multifuel boiler, they aim to develop a heating system capable of handling varying gas compositions without the need for technical modifications each time. At present, such a switch requires adjustments not only to (parts of) the gas network, but also to the individual central heating boilers connected in homes. In practice, this means that network operators must wait until entire neighbourhoods have been adapted before they can introduce a different type of gas.
‘Slow, expensive and complex’
“At present, whenever there is a switch to a different gas grade, not only does the network need to be adapted, but the equipment in every single home must be adjusted as well. This makes the transition to sustainability slow, expensive and complex. With this new boiler, that’s no longer an issue – it can handle all types of gas. The new boiler is also suitable for hydrogen,” explains Albert van der Molen of Stedin.
With the Multifuel boiler, they aim to simplify this process by ensuring the boiler automatically switches to the type of gas available. Existing heating equipment, such as radiators and pipework, can be retained when the Multifuel boiler is installed.
Also of interest to other countries
The current prototype runs on Dutch low-calorific natural gas, hydrogen and all mixtures in between. The developers aim to expand the technology so that high-calorific natural gas and so-called off-spec biogas can also be used. This would also make the technology relevant for other countries where different types of gas will be available alongside one another in the future.
“Countries all over the world are looking for ways to future-proof their existing energy infrastructure,” says Johan Knijp, Director of DNV’s Technology Centre Groningen. “The Netherlands is demonstrating that you don’t have to choose a single ‘winning’ molecule. You can also develop appliances that are smart enough to handle different gases. Technically, everything works; this unique Dutch innovation is now ready to be scaled up.”
Dutch gas supply is changing
This development is in line with the changes currently taking place in the Dutch gas supply. For example, since the closure of the Groningen field, more gas has been imported. This gas often has a different composition to the low-calorific natural gas for which many Dutch installations were originally designed. The imported high-calorific natural gas is processed at a nitrogen plant in Zuidbroek to make it suitable for existing domestic systems in the Netherlands. This plant produces what is known as ‘pseudo-Groningen gas’ by adding nitrogen to the imported gas.
According to the consortium, the Multifuel boiler takes a different approach. Rather than adapting the gas to the characteristics of the heating system, the system automatically adapts to the composition of the gas. In this way, the parties involved aim to reduce dependence on a single, fixed gas quality.
