Zero emission rail and network security with large batteries on wheels


The virtual elimination of air pollution from diesel-electric freight trains by 2025 is now possible by modernizing them with battery-powered cars.

Berkeley Lab study shows how battery-powered electric trains can bring environmental justice, savings and resilience to the United States

Trains have long been on the sidelines of electrification efforts in the United States because they account for only 2% of transportation sector emissions, but diesel freight trains emit 35 million tonnes of carbon dioxide per year and produce a air pollution which leads to $ 6.5 billion. health costs, resulting in approximately 1,000 premature deaths each year. In addition, these deaths and adverse health effects disproportionately affect disadvantaged and low-income communities, which are more likely to be located near rail yards and railroads.

The recent dramatic drop in battery prices has created a new possibility of electrification of freight trains. Researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), working with researchers at UCLA and UC Berkeley, argue that the United States can modernize diesel-electric trains with batteries in a way that is competitive with diesel. It would prevent these unnecessary deaths and health impacts, and save the US freight rail industry $ 94 billion over 20 years through reduced air pollution and carbon dioxide emissions. Their study was recently published in the journal Natural energy.

“A rapid conversion of the rail freight sector is not only technically feasible and cost effective, it would bring immediate and lasting health and economic benefits to low-income communities,” said Natalie Popovich, scientist at the Berkeley Lab and lead author of the ‘study. “And that would give a boost to our nation’s efforts to fight climate change, especially since US freight rail capacity is expected to double by 2050.”

Trains play an important role in transporting goods across the United States, especially heavy goods such as coal, lumber, and ore. According to the Federal Railroad Administration, 28% of American freight is transported across the country by rail, and that percentage is expected to increase dramatically over the next two decades. At the recent United Nations Climate Change Conference in 2021, the United States joined a dozen other countries in signing new agreements to reduce emissions from shipping, and zero-emission solutions for the rail freight transport will be part of this commitment.

Diesel-electric, but not battery-electric

Unlike many other parts of the world, all freight trains in the United States are still diesel-electric, largely because the typical electrification strategy of building electrified lines on tracks is more difficult to implement. in the United States with its vast distances. In diesel-electric trains, a diesel engine is connected to an alternator which then supplies electricity to electric motors connected to the axles of the locomotive. It is therefore possible to modernize trains so that they are powered by batteries because diesel-electric trains are already equipped with an electric motor.

“Dramatic improvements in battery technology, coupled with existing electric transmission in predominantly diesel-electric freight trains in the United States, pave the way for a rapid conversion to battery-electric freight rail and cost savings. substantial costs, ”said Amol Phadke, Berkeley Lab scientist. , corresponding author of the study. “In addition, the weight of the batteries is less restrictive than it would be for electric vehicles or trucks. We can add a car to a freight train built with batteries, and the weight of that battery car is not a problem with trains.

Diesel-electric trains have been around since the 1920s and they began to replace steam trains in the 1930s because they were more efficient and less polluting. At that time, using diesel engines to generate power for train engines was cheaper than trying to develop fully electric trains due to the high costs of electricity. Today, a century later, we are at a point where the price of electricity is competitive with diesel, and the environmental and health costs of continuing to depend on diesel to power freight trains are too devastating to be ignored.

“Our analysis shows that a switch to battery-electric freight will cut the industry’s annual carbon dioxide emissions by more than half, eliminating more than 400 million metric tonnes of carbon dioxide in 20 years,” said Popovich.

Freight train car

The tank cars are modular and can be deployed in different configurations in locations experiencing power outages as well as in other sectors, such as the electrification of ships.

The study points out that there are other ways to electrify US freight trains, such as electrifying trains via overhead power lines or using hydrogen fuel cells in conjunction with battery-powered trains. However, based on the fact that freight trains are already diesel-electric and given recent advances in battery technology, the researchers show that the battery-electric route offers the most cost-effective long-term solution with multiple additional benefits.

Their analysis shows that existing battery technology could power a freight train for 150 miles (the average daily distance traveled). A battery-powered freight train would use half the energy required by a diesel-electric train, and with falling battery prices and the environmental costs of diesel, battery-powered electric trains are on the way. more competitive than diesel-electric trains. Since rail freight planning is centralized, the study suggests that railways could achieve a high volume of use of fast-charging infrastructure, further reducing costs.

One of the main advantages of modernizing existing diesel-electric freight trains with battery-powered cars – also known as battery-powered cars – is that battery-electric trains can still use the diesel engine as a backup fuel source. This dual fuel capability, allowing the use of batteries or diesel, is a unique advantage over the full electrification of the freight rail system or the use of hydrogen fuel cells.

Modular batteries provide resiliency benefits

Another major advantage is that battery-powered electric trains can be deployed as their own back-up power supply, thus enhancing the resilience of the power grid. Historically, diesel-electric trains have been used as generators of electricity in emergencies. In early 1998, a series of ice storms left more than a million people without power in the northeastern United States and parts of Canada. In a suburb of Montreal, the mayor moved an entire diesel-electric locomotive near City Hall to power their emergency response operations.

With the increase in extreme weather events and power outages, battery-powered electric trains have the potential to be deployed across the country to prevent blackouts. These battery-powered modular cars can be transported to where needed and loaded to locations with low electricity prices, providing significant advantages over grid-scale storage. In addition, battery-powered tank cars could function as modular shipping containers, capable of exchanging between rail freight and maritime transport vessels, with positive benefits for the decarbonization of both sectors and the expansion of the scope of resilience.

“Converting the US rail freight industry to battery electric would generate approximately 220 gigawatt hours of mobile storage,” said Phadke. “Plus, these battery-powered cars could be deployed during extreme events, such as the recent catastrophic wildfires in California or the 2021 winter storm in Texas that left millions of people without access to electricity. This mobile energy storage capacity would also create a potential new source of revenue for freight rail operators. “

From a technical point of view, the researchers demonstrated that there should be no constraints to switching to fully electric freight trains, but more research and large-scale demonstration projects are needed to optimize the infrastructure. charging. “Berkeley Lab’s systems and market analyzes have shed light on this neglected area and demonstrated that we can decarbonize certain sectors with existing technology, which will help us meet our climate goals much faster while advancing justice. environmental impact and network resilience. It’s a win-win, ”said Berkeley Lab energy storage facility manager Noel Bakhtian. “The technical-economic analysis of battery-powered electric freight trains shows that we have viable solutions to enable the transition to a clean, affordable and resilient energy future. “

Reference: “Economic, Environmental and Grid-resilience Benefits of Converting Diesel Trains to Battery-electric” by Natalie D. Popovich, Deepak Rajagopal, Elif Tasar and Amol Phadke, November 11, 2021, Natural energy.
DOI: 10.1038 / s41560-021-00915-5

The research was supported by the William and Flora Hewlett Foundation, through the Berkeley Lab Foundation.


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