From the platform it looked like any other British commuter train. But as several hundred passengers climbed on board the steel-bodied carriages at Long Marston, they were met with an unusual sight. In one of its cars, passengers were encouraged to perch around four hydrogen fuel tanks, a fuel cell and two lithium batteries.<\/p>\n
The train\u2019s hydrogen power system produces sufficient power to take the train 50 to 75 miles. The train, called Hydroflex, is the UK\u2019s first to be powered by hydrogen. It was being shown off to the public in June 2019 for the first time on the tracks at the Quinton Rail Technology Centre, a test facility at Long Marston, near Stratford-upon-Avon, in England.<\/p>\n
Engineers who developed the new train, from the University of Birmingham and British rail company Porterbrook<\/a>, wanted passengers to sit alongside the train\u2019s hydrogen fuel cells. The sooner they would become familiar with the technology, the sooner they would feel safe, they reasoned.<\/p>\n Some apprehension around hydrogen as a fuel source is perhaps understandable considering the unfortunate history of hydrogen-filled dirigibles, namely airships such as the ill-fated British R101 and the German Hindenburg<\/a>. But hydrogen-powered trains have been emerging as a viable \u2013 and much safer \u2013 means of transport. How close are we to fleets of trains that release only water as a waste product?<\/p>\n You might also like: <\/em><\/p>\n The way hydrogen powers a train like the Hydroflex is quite simple. The fuel cell is made up of an anode<\/a>, a cathode and an electrolyte membrane. The stored hydrogen passes through the anode, where it is split into electrons and protons. The electrons are then forced through a circuit that generates an electric charge that can be stored in lithium batteries or sent directly to the train\u2019s electric motor. The leftover part of the hydrogen molecule reacts with oxygen at the cathode and becomes the waste product \u2013 water.<\/p>\n The Hydroflex\u2019s hydrogen tanks, fuel cell and batteries currently sit inside a passenger car, but the ultimate plan is to store them underneath the train in order to fit in more passengers. Hydrogen is of course extremely flammable, but on the Hydroflex it is stored in four secured high-pressure tanks, one of a range of measures to ensure passengers\u2019 safety.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n In the midst of the climate crisis, the demand for decarbonisation<\/a> across transport industries has grown and the Hydroflex is just one product of that. In 2016, Germany unveiled the Coradia iLint<\/a>, the world\u2019s first hydrogen-powered train, which can run for 600 miles<\/a> on a single tank of fuel \u2013 on par with the distances that traditional trains achieve<\/a> on a tank of diesel. Engineers in the US are also working on bringing a version<\/a> of a \u201chydrail\u201d to the states. However, since rail is already among the lowest greenhouse gas emitters<\/a> in transportation, it remains to be seen whether the value of a massive overhaul of rail systems will be worth it.<\/p>\n The UK already has 42% of its route miles electrified<\/a>, according to the Institution of Mechanical Engineers, meaning those trains are ready to become zero-carbon, if they use a renewable source of power. A single line running to London from Hampshire is currently the only one in the world to run<\/a> solely on solar power. However, the remaining 58% of UK track is not yet electrified, so diesel trains are still needed to keep those areas connected by rail.<\/p>\n Engineers working on the Hydroflex say that hydrogen-powered trains could be the answer to decarbonising the UK\u2019s rail system without incurring the high cost of electrifying its track. According to an assessment of 20 lines<\/a> in Britain and mainland Europe, electrifying a single kilometer of track can cost \u00a3750,000 to \u00a31m ($965,000 to $1.3m). Hydrogen-powered trains are less expensive, because they don\u2019t require massive track overhauls and they can be created by retrofitting existing diesel trains. This is especially beneficial in rural areas where there are more miles to cover, but fewer passengers to justify the expense.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n But hydrogen trains come with their own challenges.<\/p>\n \u201cWe store about 20kg of hydrogen<\/a>, and that is enough to run the fuel cell for three hours,\u201d says Stuart Hillmansen, professor at Birmingham University and leader of the Hydroflex project. As such, longer-distance journeys wouldn\u2019t yet be feasible. Engineers at the University of Birmingham\u2019s Centre for Railway Research and Education, Porterbrook\u2019s partner on the Hydroflex, are working on ways to extend these limits.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n And while hydrogen fuel cells can be as energy-efficient as diesel fuel, storing the gas can be a problem. \u201cWhile hydrogen has a lot of energy per mass, because it is super light, it also takes up a lot of volume,\u201d says Raphael Isaac, a researcher on fuel alternatives in rail at Michigan State University’s Center for Railway Research and Education. \u201cWith our current hydrogen storage technologies, hydrogen takes up significantly more space than [equivalent] fossil fuels do.\u201d Even though hydrogen is typically compressed, it\u2019s still not as efficient per unit volume as fossil fuels.<\/p>\n It\u2019s also a space issue on trains. The fuel tanks on the Hydroflex, for example, have to be small enough to fit in an ordinary car that can pass through Victorian-era railway tunnels. These space constraints are one reason that Porterbrook chose to retrofit older train models with the hydrogen fuel power system, rather than construct entirely new vehicles like the Alstom did in Germany \u2013 the existing trains were already made to measure for the tunnels they had to pass through.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n Even though the only direct waste product of hydrogen fuel is water, obtaining this form of power is not necessarily squeaky clean. \u201cThe challenge is, at the moment hydrogen is made as a byproduct of chemical processes,\u201d says Helen Simpson, innovation and projects director at Porterbrook. The cheapest and most common method at present uses natural gas and high-temperature steam<\/a> to produce hydrogen. Hydroflex runs on hydrogen produced from a combination of hydrogen produced using natural gas but its supplier, BOC, says it is looking into renewable options.<\/p>\n In order for hydrogen power to be truly sustainable, other methods of producing it that don\u2019t rely on fossil fuels would need to become mainstream. \u201cHydrogen can be produced using other methods and from renewable energy sources, e.g. electricity from solar photovoltaics and electrolysis of water,\u201d says Margaret S. Wooldridge, an aerospace engineer at the University of Michigan.<\/p>\n Electrolysis creates hydrogen by separating oxygen from water using an electric current. That current can be created using energy from renewable energy sources, but it has yet to be done outside of small test demonstrations. In order to be a truly green form of travel, the hydrogen would need to be created and stored using renewable energy sources, like off-shore wind farms and solar grids, rather than fossil fuels.<\/p>\n Another lingering environmental issue with hydrogen-powered trains is their use of lithium batteries. Currently, lithium processing takes a major toll on the surrounding environment. Mining one tonne of lithium requires 500,000 gallons of water<\/a>, for example, and lithium mining has been linked to several measures of environmental degradation<\/a>. Researchers hope that in the future it may be feasible to extract lithium from seawater instead using solar power<\/a>, but the idea remains experimental.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n On the flipside, one major benefit of trains like the Hydroflex is their potential as a bi-mode<\/a> train, meaning they can run on the electrified or conventional lines alike. So even though there is certainly an expense to building new hydrogen-powered trains (one of the Alstrom hydrogen trains costs approximately \u00a35.19m<\/a>), or retrofitting older ones, they are a flexible alternative while the majority of lines \u2013 especially rural ones \u2013 are yet to be converted to carry electric-trains.<\/p>\n \u201cThis is really the space where hydrogen fuel comes in as a real cost-effective and valuable alternative and delivers a low-carbon railway,\u201d says Simpson. \u201cWhere we\u2019ve got all these long routes that don\u2019t have as much passenger demand, the cost-benefit of electrifying the lines isn\u2019t there.\u201d<\/p>\n There are benefits to passengers too. Hydrogen-powered trains, like electric trains, are also incredibly quiet compared to their diesel counterparts. And unlike electric trains, they are more resilient to network-wide disruption. \u201cThe shared electric infrastructure means that if there is damage to the infrastructure, the operations of many trains on a line will be impacted,\u201d says Isaac. A hydrogen powered train could switch over to its fuel cells if the electricity lines went down, for example.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n
![](\"https:\/\/ichef.bbci.co.uk\/wwfeatures\/live\/976_549\/images\/live\/p0\/84\/zv\/p084zv5y.jpg\")
<\/div>\n![](\"https:\/\/ichef.bbci.co.uk\/wwfeatures\/live\/976_549\/images\/live\/p0\/84\/zv\/p084zvnv.jpg\")
\u00a0The German Coradia iLint was the world’s first hydrogen-powered locomotive (Credit: Getty Images)<\/div>\n\n
With our current hydrogen storage technologies, hydrogen takes up significantly more space than equivalent fossil fuels do \u2013 Raphael Isaac<\/h2>\n<\/div>\n<\/blockquote>\n
\n
Hydrogen can be produced using other methods and from renewable energy sources, e.g. electricity from solar photovoltaics and electrolysis of water \u2013 Margaret S. Wooldridge<\/h2>\n<\/div>\n<\/blockquote>\n
![](\"https:\/\/ichef.bbci.co.uk\/wwfeatures\/live\/976_549\/images\/live\/p0\/84\/zw\/p084zw6y.jpg\")
<\/div>\n\n
There is a huge challenge in terms of developing the infrastructure to supply the hydrogen to the railway \u2013 Stuart Hillmansen<\/h2>\n<\/div>\n<\/blockquote>\n