Hydrogen: brown, grey blue and green

Following on the heels of electric vehicles (EVs) and supporting EV infrastructure, another future energy source, green hydrogen, has been earmarked as a contributing factor to decarbonise New Zealand Inc.

The Government has identified green hydrogen as having the potential to play a significant role in our energy system and decarbonising parts of our economy. The Ministry of Business, Innovation and Employment (MBIE) plays a central role in shaping how green hydrogen can support our energy profile, economy, and environmental footprint. Green hydrogen has the potential to help reduce emissions by replacing fossil fuels in some harderto-decarbonise sectors, such as long-distance and heavy transport; iron, steel, and chemicals production; and the marine and aviation sectors. So what is green hydrogen – and other types of hydrogen fuel?

It takes energy to produce hydrogen. The source of energy and the production method used to make hydrogen determines whether it’s classified as brown, grey, blue or green hydrogen.

Brown hydrogen is produced by gasification, where carbonous materials, fossil fuels ,are heated into a gas. This extraction process involves turning coal into gas and produces large quantities of carbon emissions that are released into the atmosphere.

Grey hydrogen is hydrogen produced through steam reformation of natural gas. Grey hydrogen accounts for roughly 95 percent of the hydrogen produced in the world today. In 2022, 94 million tonnes of grey hydrogen were produced globally using natural gas and are therefore a significant source of greenhouse gas emissions.

Blue hydrogen is similar to grey hydrogen. Blue hydrogen is produced through steam reformation, a process that uses steam to separate hydrogen molecules from natural gas except that most of the CO2 emissions are sequestered (stored in the ground) using carbon capture and storage (CCS).

Green hydrogen is hydrogen produced using

Mat.alderdice@mta.org.nz electricity from clean energy sources. Green hydrogen is considered low or zero-emission hydrogen because it uses energy sources such as wind and sola,r which don’t release greenhouse gases when generating electricity.

Source: MBIE - Hydrogen in New Zealand

New Zealand has considerable renewable energy resources that could be used to produce green hydrogen. MBIE has signalled that growing the country’s hydrogen industry can help us achieve commitments to reduce net emissions of all greenhouse gases (except biogenic methane) to zero by 2050 and has the potential to support the Government’s goal of reaching 100 percent renewable electricity by 2030.

Similar to the EV space, where a national EV charging network is being constructed by ChargeNet, NZ business such as Hiringa, based in New Plymouth, are constructing a nationwide refuelling network to produce and distribute green hydrogen. They already have four sites operational (Auckland, Hamilton, Tauranga and Palmerston North) that provide coverage for key heavy freight routes in the North Island, and another 24 sites under construction for completion by 2026, with a target of 100 green hydrogen stations operational throughout New Zealand by 2030.

A challenge for New Zealand businesses working in the green hydrogen space is the regulatory settings. Although hydrogen is already well regulated for its traditional uses, the existing regulatory systems are not well set up to support new hydrogen technologies and applications. It is important to evaluate how fit-for-purpose the current regulatory settings are for new hydrogen technologies and novel applications of hydrogen, such as a low-emissions fuel, and ensure they are consistent with international best practice standards.

MTA is participating in discussions regarding future energy states for New Zealand and informing our members of developments and initiatives in clean energy.

Some helpful links for more information green hydrogen and the supporting infrastructure in New Zealand: New Zealand Hydrogen Council: https://www.nzhydrogen.org/

MBIE: Hydrogen in New Zealand https://www.mbie.govt.nz/building-andenergy/energy-and-natural-resources/ energy-strategies-for-new-zealand/ hydrogen-in-new-zealand/

Hiringa: https://www.hiringa.co.nz/projects

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ƒ brian.anderton@mta.org.nz michael.wells@mta.org.nz