Battery Powered Trains will be 35% Cheaper Than Hydrogen, Study Concludes

The price of batteries keeps dropping, so why do people keep talking about hydrogen?

Alstom electric train
Not your childhood Lionel electric train.

 Alstom press release

Just about everyone agrees that the best way to power a train is with electricity from overhead wires; the only problem is that it is really expensive to install. Even in Europe, which is pretty dense and has a great rail system, as much as 40% of the 25,000 miles (40,000 kilometers) of track is not electrified, and on many of these lines, the demand isn't high enough to ever justify the cost, which can be huge. There isn't only the wiring, but often all the bridges have to be rebuilt higher to handle the height of the catenary wires and pantographs on the roofs of the trains.

European governments want to get rid of diesel-powered trains as part of the fight against global heating, so they have been buying hydrogen-electric multiple units (HEMU), which are electric trains powered by fuel cells running on hydrogen.

But there is another player in the game: battery electric multiple units (BEMU) – trains powered directly from giant batteries, which are getting better and cheaper by the day. They are now pushing 75 miles (120 kilometers) in range; Rail Journal quotes Brahim Soua of Alstom, who says “This was not the case several years ago where the level of autonomy was close to 40km. This is thanks to an improvement in the battery’s capability to store more energy for the same mass of battery.” This is good enough range to skip through many non-electrified sections of Europe. The Alstom press release explains how it works in these sections:

The Coradia Continental BEMU has a range of up to 120 kilometres and can be operated under catenary as well as on non-electrified sections. The three-car-trains will be 56 metres long and equipped with 150 seats. They will have a top speed of 160 km/h in battery mode. The capacity of the batteries (high-power lithium-ion) is calculated to ensure catenary-free operation of the line Chemnitz-Leipzig without any sacrifice in performance or comfort.

Now Oliver Cuenca of International Railway Journal reports that the battery-powered trains cost 35% less to buy and operate than hydrogen trains. The batteries don't have to be replaced as often as fuel cells, either, so maintenance costs will be lower. Cuenca notes some caveats:

However, the study assumes that only ‘green’ hydrogen made by electrolysis using electricity from renewable sources will be used. In reality, the cheaper so-called ‘grey hydrogen,’ made as a by-product of the chemical and oil industry, will be used in some cases.

(See more about the different colors of hydrogen here.)

This is likely true. The problem is, there is no point in replacing the diesel trains if they run on gray hydrogen, which is made from natural gas and emits 9.3 kg of CO2 for every kg of H2 in the process. The hydrogen-hype people say this is just an intermediate step, that "The plan is that hydrogen will be produced on site via electrolysis and wind energy at a later stage of the project." But as we noted before, "while Germany's renewable electricity supply has grown dramatically, they still get half their power from coal and are closing their nuclear reactors. It will be a very long time before they are making hydrogen from electrolysis."

Unless it was made at night...

The study also assumes that hydrogen will be more expensive than electricity because electricity is needed to produce the hydrogen in the first place. This may not be true, as electricity used to produce hydrogen generated at night will likely be significantly cheaper due to much lower demand compared with the daytime electricity used when most electric regional trains operate.

Except that if the trains operate during the daytime, they can be charged at night with the same cheap electricity, just like people do with their electric cars. And it will store a lot more of that electricity. Hydrogen is a lousy battery; the efficiency of splitting it from the oxygen is now up to about 80%. Then there are losses compressing and cooling it, and then the fuel cell is only about 50% efficient, giving an overall efficiency at the wheels of about 35%. This all might get better with improved technology, but batteries are running at 80% efficiency now and they are getting better too. As energy expert Paul Martin notes,

A technology which uses 3x as much energy as its competitor, at bare minimum, will have a hard time competing- if they share the same energy source. So if H2 is going to be competitive, beware- it won't be "green" hydrogen they reach for. It'll be the only kind you can currently buy- BLACK hydrogen made from fossils without carbon capture. And that's a highly questionable way to "green" a diesel.

Here at Treehugger we have done quite a few posts about hydrogen trains and this is the first discussing electric trains; hydrogen is a lot sexier. But even the people who buy the trains are voting with their wallets:

The report also found that the adoption of BEMUs for regular operation is increasing rapidly, with 31.2 million km of German railway now exclusively contracted or tendered for BEMU operation. By contrast, hydrogen trains represent only 5.2 million km, limited to two contracts in Lower Saxony and Hessen which both use Alstom iLINT trains.

The hydrogen hype will continue; the fossil fuel giants and gas distribution companies have so much invested in pipes and infrastructure and have vast quantities of cheap natural gas that they can strip the hydrogen out of. They will keep promising that it will someday be green or blue so that they can keep control of the system. But really, electric systems, whether in houses, cars or trains, just keep getting better and better. So let's just electrify everything and be done with the hydrogen hype.