Green hydrogen mobility: The road to hydrogen fuel stations
Modular electrolysers can help unlock the hydrogen refuelling stations needed
14. juin 2022
Today, with constant reminders of soaring gas prices and the need to establish energy security, it’s clear to see that green hydrogen can deliver a much-needed alternative molecule for mobility.
Given the climate crisis, green hydrogen mobility was growing even before the latest energy crisis.
The drivers of green hydrogen mobility are fuel cell electric vehicles – FCEVs for short. Like battery electric vehicles (BEVs), they are powered by electricity but derive this from fuel cells that reconvert hydrogen instead of drawing it from batteries. While the debate over FCEV and BEV superiority continues, the faster refuelling and higher range of FCEVs gives them advantages in some use cases.
These include vehicles for long-distance and heavy-load transport, aviation and even high-utilisation fleets of hydrogen cars, such as taxis or police cars which benefit from quick refills and long ranges.
When you combine this with the potential for green hydrogen to couple energy storage and peak balancing with zero-emission transport, it’s easy to see why we’re starting to see announcements of hydrogen hubs at airports and ship ports that focus on H2 production, utilisation and export.
As obvious as it may seem, refuelling is a vital enabling aspect of hydrogen mobility but there is much more to the process than meets the eye. Where can we find hydrogen fuel?
Meet the station
For a start, let’s take a quick look at the different stages of green hydrogen refuelling taking place at what’s known as a Hydrogen Refuelling Station (HRS). An HRS gathers the infrastructure for refilling fuel-cell vehicles with hydrogen that the fuel cell vehicle converts into electricity and water vapour.
First, we have to acquire the H2. Ignoring grey H2 made from fossil fuels like natural gas, the options are using green ammonia gas – an emerging approach which “cracks” ammonia to release hydrogen – the delivery of green H2 by trailers or pipes, and on-site production of hydrogen via electrolysis.
Since we’re convinced in the power of decentralised hydrogen production, let’s assume on-site production using modular electrolysers powered by renewable energy. As the hydrogen leaves the electrolysers, a dryer removes any excess water to reach the purity level needed for fuel cells.
Then comes the more challenging part.
Getting the gas
Once you produce the hydrogen, it has to be stored – likely in low-pressure source storage tanks on site. The green hydrogen stays here until it’s needed for refuelling, at which point it usually goes through a compressor to start bringing it up to the pressure needed for the particular FCEV.
It then goes into cascade storage or high pressure buffer storage that brings the green hydrogen to the optimum pressure for refuelling. With the hydrogen either at 350 bar or 700 bar, it is then run through a refrigeration unit to cool to sub-minus temperatures and then routed to the dispenser.
This is the bit we all know well from gas stations – a flexible hose that connects to the vehicle, except in this case it has extra safety monitoring equipment and connects seamlessly while refuelling.
In simple terms that’s it. Some HRS do refuel with liquid hydrogen or cryo-compressed hydrogen and refuelling times differ, but many FCEVs can be refuelled in a five-minute coffee break.
Hitting the road
Fleets are where a lot of the action in FCEVs and demand for hydrogen fuel stations can be seen now – particularly for fleets of vehicles such as hydrogen buses where investment into green hydrogen refuelling systems pays off quicker thanks to guaranteed and regular usage in transport hubs.
Such HRS for fleets can also be seen as an enabler of other FCEV mobility, with these in some cases opening up to refuelling of private vehicles which may otherwise not have options to tank up.
And as HRS begin to serve an expanding range of use cases, the need for multi-purpose refuelling solutions is growing, with some integration specialists rising to the challenge.
For example, the German company JA-Gastechnology (JAG) has developed a multi-function hydrogen refuelling system that draws on stacked AEM Electrolysers to deliver hydrogen for diverse FCEVs. Solutions like this mean the same HRS can refuel vehicles with 350bar requirements, such as forklifts and buses, or directly fuel standard hydrogen cars with 700bar needs.
HRS like this that employ modular electrolysers are seen as advantageous as they enable customers to pilot green hydrogen refuelling in smaller volumes and scale up by just adding more electrolysers.
Hubs, sea and sky
But hydrogen hubs and associated hydrogen fuel stations won’t just be limited to land.
Many hydrogen hubs are now being established at ports thanks to the confluence of green hydrogen potential for land-based mobility, export, industry use, energy needs, and even H2 bunkering that will enable early marine FCEV use in zero-emission ships.
While they are now mainly small-scale, larger port-based hydrogen hubs are emerging from Belgium to Australia, some with ambitious cross-sector uses like that of the Port of Newcastle Hydrogen Hub.
Looking beyond land and sea, airports offer another opportunity for refuelling ecosystems and hydrogen hubs. This is due to upcoming demand for green hydrogen to power FCEV aircraft, existing transport infrastructure, nearby industry and potential to install on-site solar and electrolyser capacity.
An early example of how this works is seen in the HyFlyer project led by ZeroAvia, an aviation company replacing conventional aircraft engines with hydrogen-electric powertrains.
Their partners Fuel Cell Systems Ltd and the European Marine Energy Centre delivered an aircraft-compatible mobile hydrogen refuelling unit including Enapter’s AEM Electrolysers for on-site green hydrogen. Based on this Hydrogen Airport Refueling Infrastructure (HARE), ZeroAvia is now looking at further developing and scaling up green hydrogen refueling infrastructure at airports globally.
What’s coming up
By the end of 2021, there were at least 685 hydrogen refuelling stations worldwide. While that number may be small when spread out globally, it’s set to grow rather quickly.
Asia is one growth market: Japan is leading the charge, aiming to be the world’s first “hydrogen society”. Fittingly, it had 159 operational HRS by the end of 2021. South Korea is also up there, with the intention to create 100,000 hydrogen fuel cell cars by 2025, while China has set a goal of using over one million FCEVs for commercial purposes by 2030.
Europe is catching up, with 228 hydrogen stations in operation by the end of 2021. One estimate foresees at least 60,000 fuel-cell electric trucks in operation in Europe by 2030, which would need a huge number of heavy-vehicle HRS for this purpose – likely 300 in Germany alone.
It’s a big number, but to name just one partnership facing the challenge, Philips 66 and H2 Energy laid recently agreed to build up to 250 refuelling stations in Germany, Austria and Denmark by 2026.
This only goes to show that while the infrastructure to fuel the growth of green hydrogen mobility is still emerging, the solutions are already there. And as the growing number of HRS and hydrogen hubs helps solve the green hydrogen conundrum of demand and supply, this growth, alongside the rising costs and volatility of fossil fuels, unlocks FCEVS for many more decarbonisation solutions.
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