Battery-powered electric trains could clean up the rail industry and save money


Between trains, planes and cars, this last means of transport is well on its way to reducing its carbon footprint by running on batteries. But electrifying planes and trains will be much more difficult.

Or will he do it? For freight trains at least, electrification is within reach and could make economic sense, according to a new analysis published in Natural energy. Improvements in battery technology and easy access to cheap renewable electricity make the battery-powered electric rail possible, say the authors of the article.

This switch to electric freight trains could bring additional benefits. Considering the health damage from air pollution and climate damage from carbon dioxide emissions, battery-powered locomotives could save the US freight rail industry US $ 94 billion over 20 years, according to researchers from Lawrence Berkeley National Laboratory.

US freight trains carry more freight than any other rail system in the world. Each year, they produce about 35 million metric tonnes of carbon dioxide. And although they are more fuel efficient than trucks, they are not required to have strict pollution control measures, resulting in about 1,000 premature deaths in the United States per year.

The capacity of the US rail freight sector is expected to double by 2050, and if it continues to run on diesel, by then it will consume half of the diesel used by freight trains worldwide.

One way to electrify trains is to install overhead power lines on existing rail infrastructure. But it is difficult in large countries like the United States and Canada.

The good news is that today’s American locomotives could be easily adapted to run on battery power. This is because they use diesel-electric transmissions: a diesel engine drives a generator to produce electricity, which then powers an electric motor that turns the wheels. Converting these trains to fully electric trains would require a large battery and wiring to supply electricity to the transmission.

Amol Phadke and his colleagues propose that each train have a boxcar carrying a 14 megawatt-hour battery. Their analysis shows that a single boxcar would haul a typical large freight train – with four locomotives, 100 freight cars and about 6,800 metric tonnes of payload – a distance of about 240 kilometers on a single load. This is the average distance traveled by typical trains before stopping for a shift change. The batteries could be recharged during these stops. On busy roads, unloaded boxcars could be exchanged for loaded cars.

The researchers also calculated the economics of owning, maintaining, and operating battery-powered freight trains compared to diesel-electric freight trains. Over 20 years, battery-powered electric tender cars cost between $ 6.47 million and $ 8 million and diesel locomotives between $ 5.85 and $ 11.83 million, they found, depending on whether the environmental damage was. included or not. And at battery prices of $ 100 per kilowatt hour expected in the near future, battery-powered electric trains would be comparable to the costs of diesel-electric trains taking into account environmental costs, or if rail companies could obtain wholesale prices of electricity and use 40% of their charging infrastructure.

Finally, researchers show that switching to batteries alone would cost $ 15 billion. However, when pollution damage is taken into account, the electric battery scenario saves $ 44 billion, and when climate damage is also considered, these savings more than double to $ 94 billion. dollars.

Source: Natalie D. Popovich et al. Economic, environmental and network resilience benefits of converting diesel trains to electric batteries. Nat Energy, 2021.

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