Can you decarbonize 'Thomas & Friends?'
Decarbonization refers to the process of reducing man-made carbon dioxide emissions from the environment. CO2 is a greenhouse gas and when released into the atmosphere in large quantities leads to global warming which then triggers a lot of environmental hazards. What does this mean to the steam locomotive (Thomas& Friends)? Well, rail transport accounts for about 4.2% of the global CO2 emissions from the transport sector. These emissions are a result of the operational diesel and steam engines in the railway industry. Hence, several efforts are currently being made all over the world to decarbonize railways.
Decarbonizing diesel-only trains is easy compared to steam engines because these trains can either use bio-diesel or can be made electric using hydrogen fuel cells. It’s not the case with steam engines because these engines represent the social and cultural history and hence are harder to replace providing the same heritage feel. The main point of attraction for these locomotives is the burning of coal and the steam that comes out of it. It’s only hard but completely possible. There are two ways to do it. Let’s have a look.
Bio-Coal
Bio coal can be produced by drying biomass using a process called torrefaction, thereby reducing its weight and increasing its energy density. Torrefaction is the process of anaerobic degradation of biomass at temperatures between 250 °C to 350 °C. It is also called partial pyrolysis. The major difference between torrefaction and pyrolysis is the temperature as pyrolysis is conducted at temperatures above 500 °C. The torrefied biomass has a similar heating property compared to conventional coal and can be used as a fuel to power steam locomotives without any major modification in the engines. The major advantage of bio-coal over coal is that its free from sulfur, nitrogen oxides, and mercury, are hydrophobic and ignites faster than coal, and can be cheaper than coal with a well-established torrefying system. A non-profit scientific and educational organization, known as Coalition for Sustainable Rail (CSR) is already working on developing modern steam locomotives with bio-coal. This solution though seems promising, is not perfect because it's regarded as being carbon neutral and not carbon-free. The only solution that is carbon-free is using hydrogen.
Hydrogen
This solution will however need a complete reconstruction of any present steam engine as the locomotive itself will be bigger in size due to the huge volume of space needed for hydrogen storage. This hydrogen can then be burned inside a hydrogen boiler, which is also huge in size, to create the required steam output. This method seems to be a perfect solution as it preserves the heritage feel of traveling on a steam engine. Companies like Bosch and Viessmann have already developed hydrogen firing boilers with could then be modified for use in a steam engine making this idea the best possible solution. A possible layout of such a hydrogen-powered steam engine is shown below.
Conclusion
There is always a solution to a problem. The properties of hydrogen, make it so flexible that it can either be physically burned like any fossil fuel, inside a boiler or chemically burned inside a fuel cell to generate energy. Hydrogen fuel cells are the best solution for future diesel engine trains and hydrogen-fired boilers are the perfect solution for future steam locomotives. This makes hydrogen the best alternate clean fuel to decarbonize not only the steam locomotive industry but also the entire railway industry of planet Earth.
-Afrin Hewitt Alban.