How clean is a hydrogen bus? routeone examines Ryze’s ambitions for green hydrogen, which promises unambiguously clean energy ‘from well to wheel’
Jointly owned Ryze Hydrogen is supporting Wrightbus with the rollout of is hydrogen-fuelled buses, with the vehicles seen as a key early demand for the Ryze business.
Its first major project will shortly be underway to generate hydrogen produced from renewable wind power.
The environmental impact of alternative drivetrains further upstream is a concern often raised when discussing zero emission technology.
This means that, while clean at point of use, the well-to-wheel impact of zero-emission vehicles such as battery-electric and hydrogen fuel cell-electric vehicles (FCEVs) has not escaped scrutiny. Zemo Partnership pointed this out in a recent conversation with routeone, when Project Manager Dan Hayes warned that certain technologies can risk an increase in greenhouse gas (GHG) emissions overall if that well-to-wheel impact is not considered.
The question then is how to ensure that new technology remains green throughout the whole supply chain. One manufacturer looking unambiguously at the well-to-wheel impact of the roll-out of its alternative drivetrain vehicles is Wrightbus. Its push to put hydrogen fuel cell-electric buses on the road has been accompanied by a conscious effort to build a carbon footprint where GHG savings are built into the production process of both the vehicle and of the fuel that powers it – in this case dubbed green hydrogen.
routeone learns just how clean the process is compared to alternatives, and if that clean energy will be sufficient to meet the demands of the hydrogen fuel cell-electric bus industry.
Ryze: Cleaning up hydrogen
While the benefits of hydrogen have been well established at point of use for zero-emission vehicles, further down the supply chain, the picture is not so clean-cut for the majority of hydrogen produced.
The most common methods for making hydrogen today are natural gas reforming and electrolysis. In the former, steam reacts with a hydrocarbon fuel (in most cases natural gas) to produce hydrogen.
In electrolysis, electricity is used to split water into hydrogen and oxygen in an electrolyser. Depending on where the electricity for this process is sourced, it can be a very clean process. For that reason, it is a promising method for Ryze Hydrogen and Chief Engineer Joe Hobbs.
While the optimal hydrogen solution is yet to be determined for every customer demand and environmental requirement, Joe says Ryze is relatively close to finding it compared to some competitors. The company’s pilot project in Herne Bay, Kent, which was given the go-ahead in 2020, will be directly connected to an offshore wind farm. That renewable power will then be coupled to an electrolysis plant to produce renewable hydrogen in an unambiguous supply chain. With construction due to start this year, it is hoped the project will be live by 2022.
A pipeline of similar projects is due afterwards to meet government targets of 5GW of low-carbon hydrogen by 2030 (published under the government’s ten-point plan in November 2020). Herne Bay will be the “trailblazer” plant according to Joe, with a total production capacity of some 18MW when complete: “It will be the first large scale renewable hydrogen production facility of its kind in Great Britain, of an order of magnitude larger than anything else, when it goes live.”
The aforementioned optimal solution for hydrogen often differs depending on whether it is approached from an economic perspective or indeed from an operational perspective. “One of the key things that we are expecting is to see if the government is going to meet its hydrogen ambitions is the introduction of schemes to make sure that those perspectives align. At the moment, they don’t necessarily,” Joe says.
Balancing the grid
According to Joe, the benefits of all kinds of hydrogen, not just green hydrogen, are well understood, but change takes a long time. Much like electricity, carbon emissions associated with hydrogen production depend on how it is generated. While the embodied carbon associated with fossil fuels such as oil are not present with hydrogen – itself fundamentally a zero-emission fuel – carbon emissions per unit of energy produced from, for example, a coal-fired power station used to generate hydrogen become high. When the energy comes from wind turbines, it is negligible. But the UK electricity grid is not fully decarbonised, and it has thus far been difficult to judge hydrogen’s GHG emissions on the basis of that supply chain.
That is what makes the Herne Bay project significant. Ryze’s hydrogen production will not be judged on the basis of the national grid – the supply chain will be simple and “almost auditable” as the hydrogen is produced directly from zero-carbon energy. It should also be noted that Ryze is from the outset a renewable hydrogen business.
“If you speak to different people, you hear a lot of different viewpoints on hydrogen,” Joe says. “There are a lot of people pushing for blue hydrogen, which is hydrogen generated from fossil fuels but with carbon capture, and I think the long and short of it is that hydrogen cannot be lumped together in its environmental impact. You have to look at the supply chain.”
Is it an efficient use of energy? Taking electricity generated by wind and turning it into hydrogen, storing it, transporting it, dispensing it into a vehicle, and turning it back to electricity in order to drive the wheels on that vehicle is obviously an energy intensive process and the round trip efficiency of hydrogen is lower than it is for batteries.
“But while that is a valid technical argument, it misses the wider point about the benefits of hydrogen,” Joe points out. “No process is 100% efficient. The benefit of hydrogen is it helps balance the electricity grid. Hydrogen can be produced at times of excess electricity production, where for example the wind is blowing stronger, but when immediate use is not needed. You can then de-couple that from when you need to refuel vehicles.
“So the idea that it’s a lower efficiency – yes, it’s one part of that whole set of different inputs and compromises that people have to make in these types of large scale engineering projects. But that’s not to say that it’s a barrier to widespread adoption.”
The ability to de-couple hydrogen production from immediate use also gives FCEVs a green edge over battery-electric vehicles, where operators tapping into the grid when energy is needed have no control over how that power is being sourced at time of use.
What is the carbon cost of the process? A compressor is electrically driven at the same source of the electrolyser and would be powered in a similar manner. Delivery depends on distance, and Ryze plans to meet this with an ambition of multiple production sites across the UK. GHG emissions would then stem from diesel-driven deliveries, which could be switched over to zero emission with the use of hydrogen-powered vehicles. Ryze has no firm answer on the embodied energy of producing fuel cells.
But while there is currently an associated carbon cost with hydrogen fuel of all types, delivering more hydrogen fuel-cell electric vehicles on the road is what creates the potential to drive more demand for clean, renewable solutions. Will wind power be sufficient in the medium term? For Wrightbus and Ryze owner Jo Bamford, it will be only one piece of the puzzle to the rollout of hydrogen – other solutions may include the previously mentioned carbon capture, and even nuclear power.
“[Wind] will be one of the energy inputs,” Jo says. “One of the areas we’re looking to connect to is a nuclear power station because it gives consistent power. But as you scale up, you’re going to need to have other forms of hydrogen coming from multiple different sources. It can’t just be from wind. For example, you can turn waste plastic into hydrogen – that’s going to be a solution that comes forward in the next two or three years. It will be wind, it will be solar, it will be nuclear, it will be blue hydrogen, it will involve all forms of energy.”
Jo makes his position clear that the benefits of hydrogen are not confined just to its generation through renewable energy – and urges those looking at hydrogen to “compare apples with apples,” pointing out that the electricity grid is still only 30% decarbonised.
“You’ve still got massive gas-fired power stations providing the electricity for battery. So they are not green. The energy input is not green.
“I like green hydrogen because it is the best solution out there for going green, and you can make it end to end and connect to renewables.
“But I still believe that blue hydrogen has a place to play, and I think you can potentially even use grey hydrogen as a starting point too. It’s really no worse than releasing the carbon from gas-fired power stations.”
Costs and learnings
The major challenge the hydrogen industry still needs to overcome is cost. But Wrightbus has already made big strides on the cost curve.
Ryze is still at the beginning of that journey, according to Joe. Another challenge faced by the UK is a skills shortage as the industry scales.
“We need to consider that everyone working in hydrogen almost needs to be training two replacements for them every year for the next couple of years as the industry scales,” he says. “And where you’ve got skills shortages, you have high costs with any projects you run.”
In order to drive that cost down, more projects need to be undertaken and more support for those early projects is needed to understand all the possibilities. “The discussions we’re having are very theoretical at the moment,” Joe says. “We need the project to be done to trial these things and fully understand which techniques work and which ones don’t.”
Of course, Rome wasn’t built in a day, and 10-15 years ago, battery-electric vehicles looked very different – hydrogen may not be far off a similar pace of change. “Ryze is from the beginning a renewable hydrogen producer,” concludes Joe. “Our investment and our infrastructure will be set up around it. That leaves us in a much better place going forwards. The pragmatic view is that it’s probably never going to be perfect from day one – but the push has always got to be where you want to end up, not where we’re starting today.”
