Concentration of CO2 in the Atmosphere

Sustainable Trains and Planes

Hydrogen-powered passenger train Image: Alstom.

Jessie Haas

Transportation is one of the most persistent sources of greenhouse gases (GHG) and one of the most difficult problems to solve. But recently some countries have been making strides, with both electric and hydrogen fuel-cell-powered mass transit.

In Europe, where most countries take their obligations under the Paris Accords seriously, hydrogen fuel cell-powered trains are beginning to make inroads. Since September 2018, two Alstom iLint trains have been used in northern Germany, each carrying 150 passengers per trip. More hydrogen trains are scheduled to come on line in 2021-22 in Lower Saxony, which projects having 27 hydrogen trains by the end of that period.

The trains use hydrogen fuel cells instead of overhead electrical wiring. The power modules are located on top of the train. They extract oxygen from the ambient air, while storage tanks supply the hydrogen. The only emission is water vapor. The iLint trains have a range of 1000 kilometers per hydrogen tank fueling, which matches the miles-per-fueling performance of conventional regional trains. They reach a top speed of 140 kilometers per hour and are much quieter than diesel trains.

Similar trains are being tested in the Netherlands and the United Kingdom (UK). A train called the Hydroflex, developed by engineers from the University of Birmingham and the British rail company, Porterbrook, currently houses its hydrogen tanks, fuel cells, and batteries inside the passenger cars, though the future plan is to site them underneath the train in high-pressure tanks. The UK has 42% of its route miles electrified; adding hydrogen trains to the mix offers a conversion to green transit at a lower cost, as they don’t require massive track overhauls and can be created by retrofitting existing diesel trains. Cost is an especially important factor for rural areas, with more miles and fewer passengers. Hydrogen trains are only as green as the fuel used to create the hydrogen. Currently the cheapest way to do that is with natural gas, but photovoltaics are a possibility, and areas with an excess of offshore wind are already planning to go into hydrogen production.

India plans to electrify its entire rail system by 2030, reducing carbon emissions to zero. They plan to use land alongside the tracks to install solar arrays. The Indian rail system is the third largest in the world, behind the U.S. and China, carrying eight billion riders and 1.2 billlion tonnes of freight a year.

In the U.S., the biggest bang for the buck would be converting freight trains to hydrogen fuel. However, freight is typically heavier than passengers, so more space is required to store hydrogen.

Are hydrogen-powered trains even a good idea? “I think it is too early to tell,” said Christopher Parker, executive director of the Vermont Rail Action Network. He believes that further research is needed, and the European experiments may provide useful information. What’s important is “getting the technology right and creating a product that is reliable and not too expensive. Getting ahead of ourselves means the technology would not get a fair trial and risks being abandoned prematurely.”

He pointed out that rail is already three times more efficient than driving and favors better land use. “Reliability is more important than fuel source because that is critical to wooing people from their car. The biggest improvement in sustainability could come from using self-propelled railcars instead of locomotives. I favor electricity (as a fuel-source) but realize that overhead wires double the sunk cost of infrastructure (a big challenge in a rural state with infrequent service) which causes me to wonder if there is a case to be made for routing highvoltage power lines down rail corridors to share the cost of poles, etc.

In 2016, Solar Impulse 2 was the first solar-powered aircraft to complete circumnavigation of the world.

Meanwhile, strides have been made recently in electric commuter planes. A retrofitted Cessna Grand Caraven nine-passenger plane had a successful test in May 2020 in Washington state. The Grand Caravan is a popular mid-range commuter airplane. The plane is nearly silent in flight, is expected to be up to 80% less expensive to operate and will need far less maintenance.

Really, though, in a world which, as of this writing, is bracing for a second wave of the coronavirus, sustainable travel may seem a trifle academic. None of us should be going anywhere, period. And this, in fact, is the greenest form of travel. Just as the greenest watt is the one you don’t use, the greenest trip may be the one you avoid. As businesses locked down worldwide this year, telepresence expanded massively. It isn’t seamless or perfect, not everyone loves it, and it’s not without energy costs; those devices all use electricity. But it’s always been easier and more cost-effective to green a stationary grid than a moving vehicle. In fact, telepresence was identified by Project Drawdown ( as #63 in its hierarchy of global warming solutions, with an estimated reduction of 1.99 gigatons CO2 by 2050. This comes at a $127.7 billion cost, and a $1.31 trillion in net savings. This also results in 82 billion fewer unproductive travel hours.

Many of our fellow global citizens are experiencing this change already. Adoption was considered the biggest barrier to telepresence; Covid-19 forced adoption overnight. Drawdown ( noted, “More and more, we will be able to go to work without going anywhere at all, and potential carbon emissions will stay put, too.” According to an article in Bloomberg Green, working at home and online shopping will reduce driving in the U.S. by up to 270 billion miles a year.

Jessie Haas has written 40 books, mainly for children, and has lived in an off-grid cabin in Vermont.



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