Hydrogen and biogas are getting huge backing right now as our clean green gas alternatives to non-renewable natural gas and LPG. Here we shine a light on what that means for homes and appliances, and what we can learn from current pilots.


What is happening with gas in homes?

In a nutshell, our current gas in homes in New Zealand is non-renewable - either natural gas (piped) or LPG (bottles). We know that the road to carbon zero 2050 means replacing these gases over time with low and zero carbon renewable future gases such as hydrogen and biogas.

Hydrogen and biogas are green because they do not require digging into our earth and they don’t release CO2 when they are burned. Green hydrogen is made by splitting water (hydrogen and oxygen), and then when burned the only by-product is water vapour (hydrogen meeting oxygen). Hydrogen gas can also be non-renewable, with non-renewable versions known by other ‘colours’ such as grey, brown and blue hydrogen

The goal is to have 100% green gas coming into our homes and businesses by 2050. To get there will be a transition.


What will transitioning to green gas for homes look like?

It won’t be overnight. There won’t suddenly be a flick of a switch and we’ll be 100% green gas. Existing natural gas and LPG will continue to be delivered to consumers over a number of years as we transition.

The first step in this transition is blending. Our current gas piping infrastructure and appliances allow us to blend up to 20% of hydrogen or biogas with natural gas, with no changes expected to our current appliances based on overseas trials. A positive step on the journey towards decarbonising our gas supply.

The next step, which will happen somewhat simultaneously and beyond, will be to get our network and appliances ‘hydrogen ready’ or ‘green gas ready’. ‘Ready’ means that we’re sure they can safely handle 100% green gas.

And the final step is using only 100% green gas.


How will our network and appliances get green gas ready?

Luckily around 90% of New Zealand’s gas infrastructure is plastic piping, which is already green gas ready. It’s only a small amount that will need to be replaced. In contrast, places like the UK have much older steel systems and need a much larger investment to work with green gases.

Major gas appliance manufacturers are already designing green gas ready (or hydrogen ready) appliances, aiming to be on the market from around 2025. That means that when the life of your current gas appliances run out over the next 15 or so years, you’ll naturally replace them with green-gas-ready appliances.

The entire country’s gas pipes will not be switched to green gas in one go. Areas will be ready to be transferred across to 100% green gas at different times and this will be well communicated so that everyone will have plenty of time for preparation. It’s anticipated that the conversion process for hydrogen-ready appliances (currently running on non-renewable gas) will be minimal for a gas tradesperson to perform when the time comes.


So why choose green gas ready appliances instead of going electric?

It's a completely personal choice. Green gas appliances will have the same existing benefits as current gas appliances; instant heat for hot water (it only heats what you need), direct heat for cooking (it’s a dense energy), efficient and powerful heat for warming (it responds quickly).

However, there’s also a lot of benefit in keeping gas in the greater scheme of things. If we keep a mix of energy solutions, it means we’re more climate resilient and we’ll have more options to meet ever increasing energy demand. There are some industries where switching away from gas in the foreseeable future would be extremely challenging. 


What will a hydrogen home, or green gas home, look like?

Exactly the same. It’s funny but the designers of the UK Hydrogen Home say they’re winning if people see them as unremarkable. That’s because the idea is that a hydrogen home should feel and function exactly the same.

The UK Hydrogen Home is two pilot townhouses in Gateshead that are trialing out what it’s like to be 100% hydrogen. It’s set up by two networks (Northern Gas Networks and Cadent) who have partnered with the government. The idea is people can walk around and test the different brands’ appliances, so far there have been boilers from Baxi, Valliant, Ideal and Worcester Bosch, stoves and hobs from Belling, and prototypes of fires. Viessman is another such hydrogen-leading brand.

One subtle difference is the colour of the hydrogen flame which is sunny yellow orange, rather than the blue of natural gas. Hydrogen rises quicker so there’s less heat lost when cooking. And just like natural gas, hydrogen is naturally odourless, so an odour must be added for supplying to homes to signal it being on, along with LED indicators and safety features.


What will a hydrogen or green gas neighbourhood look like?

There are a few hydrogen street and suburb pilots happening over the UK, and other countries too.

HyDeploy, for example, is a project in Winlaton, Gateshead, that supplied a 20% hydrogen blend into the natural gas network to 100 homes and 30 businesses, over 18 months. This ended in 2021 and was followed by increasing the number to 668 houses, a school and several small businesses over 10 months.

HyStreet is a pilot in UK’s Cumbria hills where a block of houses is run on a blend of hydrogen, testing how they can carry it in the network, how it travels under streets, how it behaves in a potential leak, and interacts with steel. Also known as the H21 project, it focuses on how we’ll get green gas to the hard-to-decarbonise sectors, like factories, industrial clusters and power plants. 

H100 is a project happening in Buckhaven and Methil, Scotland, powering 300 homes with a hydrogen blend gas. Their 200m wind turbine generates green electricity to power the electrolyser that separates hydrogen from water, to use for the network. Stored in tanks, it will soon supply 1,000 homes from the one turbine


So, when will we see hydrogen in homes and neighbourhoods here?

We’re looking to have a small blending project in Taranaki complete in 2024.

The bigger plan is for us Kiwis is to build hydrogen separating and storing capabilities in the 2020s, introduce blended current and green gasses in pipelines in the 2030s, and gradually become 100% hydrogen by 2050. Read about the already-live green gas projects that will help to get us there, in another spotlight article.