Martin Johannes Schneider, business development manager, Siemens New Energy Business looks at the role that hydrogen can play in decarbonising the rail sector.
According to the IEA’s report ‘ The Future of Rail ‘, rail is already amongst the most efficient and lowest emitting modes of transport, which was published two years ago. Urban and high-speed rail hold “major promise to unlock substantial benefits”, the report said. This is something that is sure to be discussed at COP26 this month.
There is a strong case for two energy solutions, the hydrogen, and the battery solution for trains particularly on some of the UK regional lines. Hydrogen is already starting to play a significant role in the decarbonisation of mobility with trains offering huge potential. However, using hydrogen as a fuel is not as simply as charging a battery and for that reason the issue of a hydrogen infrastructure needs to be considered.
Looking to sector coupling for answers
If green hydrogen is to play its part in the decarbonisation of rail networks, then it must be readily available within the broader rail infrastructure. Electrolysers that generate green hydrogen can be positioned strategically within a rail network providing a reliable hydrogen supply to trains such as the Mireo Plus H train, which is already in service in Germany.
That hydrogen infrastructure needs to be developed now because over the next 20 years, large numbers of diesel-electric multiple-unit trains will need to be replaced by environmentally friendly alternatives. In the UK diesel-powered trainsets are still in service today on non-electrified rail routes. So how can a sustainable and climate-friendly mobility approach be achieved in the years to come? And how could a hydrogen infrastructure be developed to achieve carbon free mobility in the UK?
Siemens Energy markets the systems and solutions needed for the generation and provision of green hydrogen. At the same time, Siemens Mobility focuses on rail transport solutions, including the required train maintenance and depot equipment. Working together, Siemens Energy and Siemens Mobility can provide a solution to these challenges. In turn this helps support the industry’s acceptance of hydrogen power in the transport market and promotes a sustainable hydrogen economy. Collaboration is the key to success. Besides Siemens Energy and Siemens Mobility as OEMs for electrolysis the key stakeholders in the hydrogen gas market and the train market play a decisive role in rolling out the necessary hydrogen infrastructure in the upcoming years.
On-site or off-site hydrogen production and the challenges for refuelling infrastructure
Siemens Energy has already developed the proton exchange membrane (PEM) electrolyser technology to produce hydrogen at very high efficiency and high-quality purity. For train operations the SILYZER 300 half array can produce enough hydrogen to refuel 20 to 25 trains a day while a SILYZER 300 full array can supply a fleet of up to 50 trains.
The question is, where do you place these large-scale electrolysers to produce hydrogen? And what does the value chain look like to refuel a train? There are two distinct paths to secure green hydrogen supply to a train depot. You can either place the electrolyser on site at the train depot where you will refuel the train or put it off site, typically in close proximity of cheap renewable energy, such as close to a wind or solar farm.
Depots that are traditionally located in highly populated urban areas will require a connection to renewable energy sources. Logistics become rather complex as soon as hydrogen demand grows beyond a requirement of two to three tonnes of hydrogen per day. The refuelling infrastructure footprint that will be required for hydrogen is of course different from the current diesel requirements of a tank and nozzle.
Besides hydrogen production hydrogen storage and transport come into play as well. High-pressure hydrogen transport by pipeline or trailer as well as cryogenic hydrogen via the liquefaction route will play an important role in the further roll-out of hydrogen mobility. Each of these production and delivery routes has a different price point and different technical boundary conditions. Which is the optimal solution depends on the daily demand, supply routes, the available space at the depot, the grid fees and electricity price, the refuelling window, and the fleet size.
Where there is a will, there is a way
With large hydrogen projects on the horizon and the scale-up of the hydrogen supply chain in the UK there seems little doubt that green hydrogen volumes will be increasing. Today hydrogen is at the point where renewable energies were 10 to 20 years ago. With the price of green hydrogen falling rapidly more and more use cases will become economically viable.
Hydrogen train mobility is at the forefront of the hydrogen-powered energy turnaround. The UK Hydrogen Strategy is setting the course for hydrogen to become cost competitive with the still predominant fossil-based solutions. It is only by broad collaboration between the key stakeholders of industry and the public sector and with sufficient support and political will that this promise can be kept in the years to come.