A Berkeley Lab study shows how battery-powered electric vehicles can provide the United States with environmental justice, cost savings, and resilience.
Trains have long been on the sidelines of electrification in the United States as they account for only 2% of the transport sector’s emissions, but diesel freight trains emit 35 million metric tons of carbon dioxide annually, leading to $ 6.5 billion in air. Increasing medical costs cause pollution, resulting in an estimated 1,000 premature deaths each year. In addition, these mortality and adverse health effects disproportionately affect the disadvantaged low-income communities that are likely to be located near freight railroads and railroads.
The recent dramatic drop in battery prices has created new possibilities for the electrification of freight trains. Researchers at the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Institute) can work with UCLA and UC Berkeley researchers to modify diesel electric trains with batteries in a cost-competitive manner with diesel. Claims. Doing so avoids these unnecessary deaths and health implications and saves the US freight rail sector $ 94 billion from reducing air pollution and carbon emissions in 20 years.Their study was recently published in a journal Nature Energy..
Natalie Popovich, a scientist at the Berkeley Institute and the lead author of the study, said: “And that will support our efforts to curb climate change, especially given that the capacity of US freight railroads is expected to double by 2050.”
Trains play an important role in the movement of goods throughout the United States, especially heavy cargo such as coal, lumber and ore. According to the Federal Railroad Administration, 28% of US freight travels nationwide by rail, and that percentage is expected to increase significantly in the coming decades. At the recent 2021 United Nations Climate Change Conference, the United States joined 12 other countries and signed a new agreement to reduce transport emissions. A zero-emission solution for freight rail transport will be part of that effort.
Diesel electricity, but not battery electricity
Unlike some other parts of the world, all freight trains in the United States are still diesel electric. This is mainly because the typical electrification strategy of building an electrified track on a track is difficult to implement in the long distance United States. In diesel electric trains, a diesel engine is connected to an alternator, which powers an electric motor connected to the locomotive’s axle. Therefore, since diesel electric trains are already equipped with electric motors, it is possible to modify the train to be battery-powered.
“Dramatic improvements in battery technology, primarily coupled with the existing electric drive trains of US diesel electric freight trains, pave the way for rapid conversion to battery electric freight railroads and significant cost savings,” Berkeley said. Institute scientist Amor Padke said. , The corresponding author of the study. “Also, the weight of the battery is less constrained than electric cars and trucks. You can add a car to a freight train made of battery, and the weight of that battery car is not an issue on the train. . “
Diesel electric trains have existed since the 1920s and began to replace steam locomotives in the 1930s. This is due to improved performance and less contamination. At that time, it was cheaper to use a diesel engine to generate electricity for a train motor than to develop a complete train because of the higher electricity costs. A century later, we are at a stage where electricity prices are competitive with diesel, and the environmental and health costs of continuing to rely on diesel to power freight trains are non-negligible and devastating. is.
“According to our analysis, switching to battery-powered electric vehicles will reduce the industry’s annual carbon dioxide emissions by more than half and reduce more than 400 million tonnes of carbon dioxide in 20 years,” Popovich said. I am.
This study emphasizes that there are additional routes for electrifying US freight trains, such as electrifying trains over fictitious power lines and using hydrogen fuel cells in combination with battery-powered trains. .. However, based on the fact that freight trains are already diesel electric, and given recent advances in battery technology, researchers have found that battery electric paths are the most cost-effective, long-term with multiple additional benefits. Indicates that a specific solution will be provided.
According to their analysis, existing battery technology can power freight trains with 150 miles (average daily travel distance). Battery-powered freight trains use half of the energy required for diesel-electric trains, and battery-electric trains tend to be more cost-competitive than diesel-electric trains, given falling battery prices and the environmental costs of diesel. I’m going to. .. As the freight railroad plans are centralized, this study suggests that railroads can achieve high-volume use of fast-charging infrastructure and further reduce costs.
One of the main advantages of modifying an existing diesel electric freight train with a battery car (also known as a battery tender car) is that the battery electric train can always fall back to the diesel engine as a backup fuel source. This dual fuel feature, which can use either batteries or diesel, is a unique advantage over fully electrifying freight rail systems or using hydrogen fuel cells.
Modular batteries offer the advantage of elasticity
Another major advantage is that battery-powered trains can be introduced as a clean backup power source, increasing the resilience of the power grid. Historically, diesel electric trains have been used as generators in emergencies. In early 1998, a series of ice storms lost more than a million electricity in the northeastern United States and parts of Canada. In the suburbs of Montreal, the mayor moved the entire diesel electric locomotive closer to the city hall to power emergency response operations.
Due to extreme weather and increasing power outages, battery-powered electric vehicles may be deployed nationwide to avoid power outages. These modular, battery-powered bidders have significant advantages over grid-scale storage because they can be transported to where they are needed and charged where electricity costs are low. In addition, the battery tender car acts as a modular shipping container that can be exchanged between freight railroads and sea shipping vessels, providing positive benefits for decarbonization and greater resilience in both sectors.
“Converting the US freight rail sector to battery electricity produces about 220 gigawatt hours of mobile storage,” Phadke said. “In addition, these battery tender cars could be deployed during extreme events such as the recent catastrophic wildfires in California and the 2021 winter storm in Texas. This mobile energy storage. Functions are also a potential new source of revenue for freight rail operators. “
From a technical point of view, researchers have shown that there should be no constraints on the transition to a fully battery-powered freight train, but further research and is needed to optimize the charging infrastructure. Demonstration project is needed. “Berkeley Labs’ systems and market analysis shed light on this overlooked area and demonstrated that existing technologies can decarbonize some sectors, thereby enhancing environmental justice and grid resilience. While improving, we will be able to reach our climate goals much faster, which is a win-win, “said Noel Bactian, director of the Berkeley Lab Energy Storage Center. “Technical economic analysis of battery-powered freight trains shows that there are viable solutions that enable the transition of clean, affordable and resilient energy to the future.”
Reference: November 11, 2021, “Economic, Environmental and Grid Resilience Benefits of Converting Diesel Trains to Battery Electricity” by Natalie D. Popovich, Deepak Rajagopal, Elif Tasar and Amol Phadke. Nature Energy..
DOI: 10.1038 / s41560-021-00915-5
This study was supported by the William and Flora Hewlett Foundation via the Berkeley Lab Foundation.
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