Running on fuel-cell technology
Two Coradia iLint trains are now running passenger services in the German state of Lower Saxony
The launch of hydrogen-powered train services in Germany marks a breakthrough in the commercialisation of fuel-cell technology. Fuel cells are potentially the cleanest of technologies. The waste product is plain water. However, although the basic idea has been around for many years, this is a very important commercial application.
The Coradia iLint is one of the Coradia range of trains produced by the French MNC, Alsthom. It’s powered by fuel-cells. Two of these trains are now running passenger services in the German state of Lower Saxony. There are plans to induct at least 14 more such “hydrail” trains in Germany.
A fuel cell works by fusing two easily available gases, hydrogen and oxygen to produce water. The chemical reaction is exothermic, releasing excess energy as heat. That heat can be converted to mechanical energy to drive a motor, which can, in turn, produce electricity. Hence, fuel-cell technology is zero-emission.
Hydrogen is the most common element, making up over 50 per cent of the mass of the universe. Not coincidentally, the most common isotope of hydrogen, is also the simplest element, with just one proton and one electron. Oxygen is also easily available. So the “fuel” in a fuel cell is inexhaustible. The two elements combine to produce that most common compound, water. The chemical formula H2O indicates that each molecule contains two atoms of hydrogen and one of oxygen.
Hydrogen and oxygen can be collected by just running an electrical current through water. Electrolysis separates the elements. The two gases can be recombined in a fuel cell releasing energy. These reactions have been known for well over a century.
But carrying out these processes efficiently presents a sequence of engineering problems. It takes energy to separate the two gases. It costs a little more to produce hydrogen and oxygen than it does to mine and refine crude to produce diesel. It’s roughly about as efficient as the process of mining and storing natural gas and costs about the same.
In energy terms, the entire separation-recombination process is now roughly 30 per cent efficient. That is, a fuel cell releases about 30 per cent of the energy required to separate the elements via electrolysis. That is actually a pretty good ratio and it has improved considerably over the years. The equipment and storage cells have gotten smaller and lighter.
A key game changer is the usage of renewable energy. Renewables are cleaner than thermal power sources and crucially, renewables tend to produce excess energy at specific times. For example, California has surplus solar power during the day, to the point where solar units are sometimes wheeled onto the grid, for free. Germany has excess wind power at night. If that cheap surplus power is used to collect hydrogen, a fuel cell can be recharged cheaper. The Coradia iLints collect their hydrogen from a dedicated wind farm.
The Coradia iLint trains have a range of about 1,000 km on a single hydrogen tank and that’s about the same as a diesel train. The energy from the reaction is stored in lithium ion batteries, which are used to run an electric motor. The motor is embedded in the chassis, along with the battery that maintains a flow of power. The hydrogen storage tanks are above, and the fuel cell is in the roof in the middle of the train. The technology uses ambient air (which contains about 21 per cent oxygen).
A second problem — the fact that the chemical reaction is explosive and loud — has apparently been dealt with. The hydrogen tank has to be fail-safe to prevent explosions and the fuel cell conversion is dampened with smart sound insulation. The trains are said to be quieter than conventional diesel-electrics. Alsthom has designed for easy swapping out of engines and is said to be looking at selling about 60-odd units in the near future.
Any rail network that's not electrified could consider using these as alternatives to the very expensive process of electrification of the network. Alsthom is also said to be looking at refurbishing existing trains, by adding on a fuel cell unit that integrates with an electric motor.
There are quite a few hybrid fuel cell cars around. A couple of drones have also been tested successfully. The German navy’s Type 214 submarine uses fuel cells underwater and quite a few surface vessels also use fuel cells. Scaling up the technology could go hand-in-hand with more renewable power and it promises to be a much cleaner alternative to fossil fuels.